Develop Reference

Android - Child view touch positions incorrect

I have a RelativeLayout which has a ViewDragHelper which I use to move the view around. I have to use layout(boolean changed, int left, int top, int right, int bottom) to update view size on drag because the views inside need to resize. This all works fine. Now the child views inside have their touch positions all wrong. Buttons work as if they were on top of the screen as opposed to where they are.
private void changeDragViewPosition(int top, float verticalMovementFactor) {
int right = calculateViewRightPosition(verticalMovementFactor);
int left = right - mainViewLayoutParams.width;
int bottom = top + mainViewLayoutParams.height;
mainView.layout(left, top, right, bottom);
}
This is the code I use for moving the view. The mainView itself has correct touch positions, the child views inside this view are the problem. Is there anything I'm missing?
EDIT
Here is the view i'm using.
public class MinimizableView extends RelativeLayout {
private static final int DEFAULT_MINIMIZED_MARGIN = 2;
private static final int DEFAULT_SCALE_FACTOR = 2;
private static final int MIN_SLIDING_DISTANCE_ON_CLICK = 10;
private View mainView;
private View unmovableView;
private ArrayList<View> otherViews;
private ArrayList<Integer> initialPositions;
private LayoutParams mainViewLayoutParams;
private int verticalDragRange;
private int mainViewOriginalWidth;
private int mainViewOriginalHeight;
private float scaleFactor = DEFAULT_SCALE_FACTOR;
private float minimizedMargin;
private boolean firstLayoutPass = true;
private int mainViewInitialPosition;
private float lastTouchActionDownXPosition;
private ViewDragHelper viewDragHelper;
private MinimizableViewListener listener;
public interface MinimizableViewListener {
void onMinimized();
void onMaximized();
void onClosed();
}
public MinimizableView(Context context) {
super(context);
init(context);
}
public MinimizableView(Context context, AttributeSet attrs) {
super(context, attrs);
init(context);
}
public MinimizableView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init(context);
}
private void init(Context context) {
minimizedMargin = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, DEFAULT_MINIMIZED_MARGIN, getResources().getDisplayMetrics());
ViewCompat.requestApplyInsets(this);
}
private ViewDragHelper.Callback viewDragHelperCallback = new ViewDragHelper.Callback() {
private static final int MINIMUM_DX_FOR_HORIZONTAL_DRAG = 5;
private static final int MINIMUM_DY_FOR_VERTICAL_DRAG = 15;
private static final float X_MIN_VELOCITY = 1500;
private static final float Y_MIN_VELOCITY = 1000;
#Override
public boolean tryCaptureView(View child, int pointerId) {
return child.equals(mainView);
}
#Override
public void onViewPositionChanged(View changedView, int left, int top, int dx, int dy) {
if (!isMainViewAtBottom()) {
float verticalMovementFactor = (top - mainViewInitialPosition) / (float) verticalDragRange;
changeDragViewScale(verticalMovementFactor);
changeDragViewPosition(top, verticalMovementFactor);
changeSecondViewAlpha(verticalMovementFactor);
changeSecondViewPosition(verticalMovementFactor);
changeUnmovableViewAlpha(verticalMovementFactor);
}
}
#Override
public void onViewReleased(View releasedChild, float xvel, float yvel) {
super.onViewReleased(releasedChild, xvel, yvel);
if (isMainViewAtBottom() && !isViewAtRight(releasedChild)) {
triggerOnReleaseActionsWhileHorizontalDrag(xvel);
} else {
triggerOnReleaseActionsWhileVerticalDrag(yvel);
}
}
#Override
public int clampViewPositionVertical(View child, int top, int dy) {
int newTop = verticalDragRange + mainViewInitialPosition;
if (isMinimized() && Math.abs(dy) >= MINIMUM_DY_FOR_VERTICAL_DRAG || (!isMinimized() && !isMainViewAtBottom())) {
final int topBound = getPaddingTop() + mainViewInitialPosition;
final int bottomBound = verticalDragRange + mainViewInitialPosition;
newTop = Math.min(Math.max(top, topBound), bottomBound);
}
return newTop;
}
#Override
public int clampViewPositionHorizontal(View child, int left, int dx) {
int newLeft = mainView.getLeft();
if ((isMinimized() && Math.abs(dx) > MINIMUM_DX_FOR_HORIZONTAL_DRAG) || (isMainViewAtBottom() && !isViewAtRight(mainView))) {
newLeft = left;
}
return newLeft;
}
private void triggerOnReleaseActionsWhileHorizontalDrag(float xvel) {
if (xvel < 0 && xvel <= -X_MIN_VELOCITY) {
closeToLeft();
} else if (xvel > 0 && xvel >= X_MIN_VELOCITY) {
closeToRight();
} else {
if (isNextToLeftBound(mainView)) {
closeToLeft();
} else if (isNextToRightBound(mainView)) {
closeToRight();
} else {
minimize();
}
}
}
private void triggerOnReleaseActionsWhileVerticalDrag(float xvel) {
if (xvel < 0 && xvel <= -Y_MIN_VELOCITY) {
maximize();
} else if (xvel > 0 && xvel >= Y_MIN_VELOCITY) {
minimize();
} else {
if (isDragViewAboveTheMiddle(mainView)) {
maximize();
} else {
minimize();
}
}
}
};
private void changeDragViewScale(float verticalMovementFactor) {
mainViewLayoutParams.width = (int) (mainViewOriginalWidth * (1 - (verticalMovementFactor / scaleFactor)));
mainViewLayoutParams.height = (int) (mainViewOriginalHeight * (1 - (verticalMovementFactor / scaleFactor)));
mainView.setLayoutParams(mainViewLayoutParams);
}
private void changeDragViewPosition(int top, float verticalMovementFactor) {
int right = calculateViewRightPosition(verticalMovementFactor);
int left = right - mainViewLayoutParams.width;
int bottom = top + mainViewLayoutParams.height;
mainView.layout(left, top, right, bottom);
}
private void changeSecondViewAlpha(float verticalMovementFactor) {
for (int i = 0; i < otherViews.size(); i++) {
otherViews.get(i).setAlpha(1 - verticalMovementFactor);
}
}
private void changeSecondViewPosition(float verticalMovementFactor) {
int newTop;
int initialTop;
for (int i = 0; i < otherViews.size(); i++) {
initialTop = initialPositions.get(i);
newTop = (int) (initialTop + ((getBottom() - initialTop) * verticalMovementFactor));
otherViews.get(i).setY(newTop);
}
}
private void changeUnmovableViewAlpha(float verticalMovementFactor) {
unmovableView.setAlpha(1 - verticalMovementFactor);
}
private int calculateViewRightPosition(float verticalMoveFactor) {
return (int) (mainViewOriginalWidth - minimizedMargin * verticalMoveFactor);
}
private boolean isDragViewAboveTheMiddle(View view) {
int parentHeight = getHeight();
float viewYPosition = view.getY() + (view.getHeight() * 0.5f);
return viewYPosition < (parentHeight * 0.5);
}
private boolean isMainViewAtTop() {
return mainView.getTop() == mainViewInitialPosition;
}
private boolean isMainViewAtBottom() {
return mainView.getBottom() >= getBottom() - getPaddingBottom() - minimizedMargin - 1;
}
private boolean isViewAtRight(View view) {
return view.getRight() + minimizedMargin + 10 >= getWidth() - 10;
}
private void closeToLeft() {
if (viewDragHelper.smoothSlideViewTo(mainView, -mainViewOriginalWidth, getHeight() - getMinHeightPlusMargin())) {
ViewCompat.postInvalidateOnAnimation(this);
}
if (listener != null) {
listener.onClosed();
}
}
private int getMinHeightPlusMargin() {
return (int) (mainViewOriginalHeight * (1 - 1 / scaleFactor) + minimizedMargin);
}
private int getMinWidthPlusMargin() {
return (int) (mainViewOriginalWidth * (1 - 1 / scaleFactor) + minimizedMargin);
}
private void closeToRight() {
if (viewDragHelper.smoothSlideViewTo(mainView, mainViewOriginalWidth, getHeight() - getMinHeightPlusMargin())) {
ViewCompat.postInvalidateOnAnimation(this);
}
if (listener != null) {
listener.onClosed();
}
}
private boolean isNextToLeftBound(View view) {
return (view.getLeft() - minimizedMargin) < getWidth() * 0.05;
}
private boolean isNextToRightBound(View view) {
return (view.getLeft() - minimizedMargin) > getWidth() * 0.75;
}
private boolean isViewHit(View view, int x, int y) {
int[] viewLocation = new int[2];
view.getLocationOnScreen(viewLocation);
int[] parentLocation = new int[2];
this.getLocationOnScreen(parentLocation);
int screenX = parentLocation[0] + x;
int screenY = parentLocation[1] + y;
return screenX >= viewLocation[0]
&& screenX < viewLocation[0] + view.getWidth()
&& screenY >= viewLocation[1]
&& screenY < viewLocation[1] + view.getHeight();
}
private static final int INVALID_POINTER = -1;
private int activePointerId;
#Override
public boolean onTouchEvent(MotionEvent event) {
int actionMasked = MotionEventCompat.getActionMasked(event);
if ((actionMasked & MotionEventCompat.ACTION_MASK) == MotionEvent.ACTION_DOWN) {
activePointerId = MotionEventCompat.getPointerId(event, actionMasked);
}
if (activePointerId == INVALID_POINTER) {
return false;
}
viewDragHelper.processTouchEvent(event);
if (isClosed()) {
return false;
}
boolean isDragViewHit = isViewHit(mainView, (int) event.getX(), (int) event.getY());
boolean isSecondViewHit = false;
for (int i = 0; i < otherViews.size(); i++) {
if (isViewHit(otherViews.get(i), (int) event.getX(), (int) event.getY())) {
isSecondViewHit = true;
break;
}
}
analyzeTouchToMaximizeIfNeeded(event, isDragViewHit);
if (isMaximized()) {
mainView.dispatchTouchEvent(event);
} else {
mainView.dispatchTouchEvent(cloneMotionEventWithAction(event, MotionEvent.ACTION_CANCEL));
}
return isDragViewHit || isSecondViewHit;
}
private void analyzeTouchToMaximizeIfNeeded(MotionEvent ev, boolean isDragViewHit) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
lastTouchActionDownXPosition = ev.getX();
break;
case MotionEvent.ACTION_UP:
float clickOffset = ev.getX() - lastTouchActionDownXPosition;
if (shouldMaximizeOnClick(ev, clickOffset, isDragViewHit)) {
if (isMinimized()) {
maximize();
}
}
break;
default:
break;
}
}
public boolean shouldMaximizeOnClick(MotionEvent ev, float deltaX, boolean isDragViewHit) {
return (Math.abs(deltaX) < MIN_SLIDING_DISTANCE_ON_CLICK) && ev.getAction() != MotionEvent.ACTION_MOVE && isDragViewHit;
}
private MotionEvent cloneMotionEventWithAction(MotionEvent event, int action) {
return MotionEvent.obtain(event.getDownTime(), event.getEventTime(), action, event.getX(), event.getY(), event.getMetaState());
}
#Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
if (!isEnabled()) {
return false;
}
switch (MotionEventCompat.getActionMasked(ev) & MotionEventCompat.ACTION_MASK) {
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
viewDragHelper.cancel();
return false;
case MotionEvent.ACTION_DOWN:
int index = MotionEventCompat.getActionIndex(ev);
activePointerId = MotionEventCompat.getPointerId(ev, index);
if (activePointerId == INVALID_POINTER) {
return false;
}
break;
default:
break;
}
boolean interceptTap = viewDragHelper.isViewUnder(mainView, (int) ev.getX(), (int) ev.getY());
return viewDragHelper.shouldInterceptTouchEvent(ev) || interceptTap;
}
#Override
protected void onFinishInflate() {
super.onFinishInflate();
otherViews = new ArrayList<>();
initialPositions = new ArrayList<>();
int childCount = getChildCount();
for (int i = 0; i < childCount; i++) {
View child = getChildAt(i);
if (child instanceof DragView) {
mainView = child;
} else if (child instanceof UnmovableView) {
unmovableView = child;
} else {
otherViews.add(child);
}
}
viewDragHelper = ViewDragHelper.create(this, 1, viewDragHelperCallback);
mainViewLayoutParams = (LayoutParams) mainView.getLayoutParams();
}
#Override
public void computeScroll() {
if (!isInEditMode() && viewDragHelper.continueSettling(true)) {
ViewCompat.postInvalidateOnAnimation(this);
}
}
#Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
if (isInEditMode() || firstLayoutPass) {
super.onLayout(changed, left, top, right, bottom);
mainViewInitialPosition = mainView.getTop();
verticalDragRange = getMeasuredHeight() - mainViewInitialPosition - getMinHeightPlusMargin() - getPaddingTop() - getPaddingBottom();
for (int i = 0; i < otherViews.size(); i++) {
initialPositions.add(otherViews.get(i).getTop());
}
firstLayoutPass = false;
} else if (isMainViewAtTop()) {
mainView.layout(left, mainViewInitialPosition, right, mainViewInitialPosition + mainViewOriginalHeight);
changeUnmovableViewAlpha(0);
setLayoutPositions(0, left, right, bottom, true);
} else {
setLayoutPositions(mainView.getTop() / (float) verticalDragRange, left, right, bottom, false);
}
}
private void setLayoutPositions(float offsetFactor, int left, int right, int bottom, boolean setY) {
int newTop;
int initialTop;
for (int i = 0; i < otherViews.size(); i++) {
View view = otherViews.get(i);
initialTop = initialPositions.get(i);
newTop = (int) (initialTop + ((bottom - initialTop) * offsetFactor));
view.layout(left, newTop, right, newTop + view.getHeight());
if (setY) {
view.setY(newTop);
}
}
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (mainViewOriginalWidth == 0) {
mainViewOriginalWidth = mainView.getMeasuredWidth();
mainViewOriginalHeight = mainView.getMeasuredHeight();
}
}
private boolean smoothSlideTo(float slideOffset) {
final int topBound = mainViewInitialPosition + getPaddingTop();
int x = (int) (slideOffset * (getWidth() - getMinWidthPlusMargin()));
int y = (int) ((slideOffset * verticalDragRange) + topBound);
if (viewDragHelper.smoothSlideViewTo(mainView, x, y)) {
ViewCompat.postInvalidateOnAnimation(this);
return true;
}
return false;
}
#Override
public void setPadding(int left, int top, int right, int bottom) {
super.setPadding(left, top, right, bottom);
mainViewInitialPosition = mainView.getTop();
verticalDragRange = getMeasuredHeight() - mainViewInitialPosition - getMinHeightPlusMargin() - getPaddingTop() - getPaddingBottom();
for (int i = 0; i < otherViews.size(); i++) {
initialPositions.add(otherViews.get(i).getTop());
}
}
// --------- PUBLIC METHODS ---------- //
public void maximize() {
smoothSlideTo(0);
if (listener != null) {
listener.onMaximized();
}
}
public void minimize() {
smoothSlideTo(1);
if (listener != null) {
listener.onMinimized();
}
}
public boolean isMinimized() {
return isMainViewAtBottom() && isViewAtRight(mainView);
}
public boolean isMaximized() {
return mainView.getTop() == mainViewInitialPosition;
}
public boolean isClosed() {
return mainView.getRight() <= 0 && mainView.getLeft() >= getWidth();
}
public void setMinimizableViewListener(MinimizableViewListener listener) {
this.listener = listener;
}
public void hide() {
changeDragViewScale(1);
changeDragViewPosition(verticalDragRange + mainViewInitialPosition - getMinHeightPlusMargin(), 1);
minimize();
setVisibility(GONE);
}
public void show() {
setVisibility(VISIBLE);
post(new Runnable() {
#Override
public void run() {
maximize();
}
});
}
}
As you can see the I have overridden the onTouch method and it works fine. I also have a button inside the mainView which is also a RelativeLayout.
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/activity_main"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.lycatv.dragviewtest.MainActivity">
<android.support.v7.widget.Toolbar
android:id="#+id/actionBar1"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/actionBar1"
android:fitsSystemWindows="true"
android:text="Hello World!" />
<com.lycatv.dragviewtest.MinimizableView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:paddingBottom="56dp">
<com.lycatv.dragviewtest.UnmovableView
android:id="#+id/actionBar"
android:layout_width="match_parent"
android:layout_height="wrap_content">
<android.support.v7.widget.Toolbar
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimaryDark" />
</com.lycatv.dragviewtest.UnmovableView>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#+id/actionBar"
android:background="#1a1e39" />
<FrameLayout
android:id="#+id/frameLayout1"
android:layout_width="match_parent"
android:layout_height="48dp"
android:layout_below="#+id/actionBar" />
<com.lycatv.dragviewtest.DragView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="#+id/frameLayout1">
<ImageView
android:layout_width="match_parent"
android:layout_height="200dp"
android:src="#000000" />
<CheckBox
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:text="CheckBox"
android:textColor="#android:color/white" />
</com.lycatv.dragviewtest.DragView>
</com.lycatv.dragviewtest.MinimizableView>
The CheckBox does not work when you press on it. Instead it works when you press above it. By whatever amount it is offset from the top.

I won't pretend to understand everything your code is doing. However, I did notice something in onLayout that is almost certainly wrong. The code you posted is this:
#Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
if (isInEditMode() || firstLayoutPass) {
super.onLayout(changed, left, top, right, bottom);
mainViewInitialPosition = mainView.getTop();
verticalDragRange = getMeasuredHeight() - mainViewInitialPosition - getMinHeightPlusMargin() - getPaddingTop() - getPaddingBottom();
for (int i = 0; i < otherViews.size(); i++) {
initialPositions.add(otherViews.get(i).getTop());
}
firstLayoutPass = false;
} else if (isMainViewAtTop()) {
mainView.layout(left, mainViewInitialPosition, right, mainViewInitialPosition + mainViewOriginalHeight);
changeUnmovableViewAlpha(0);
setLayoutPositions(0, left, right, bottom, true);
} else {
setLayoutPositions(mainView.getTop() / (float) verticalDragRange, left, right, bottom, false);
}
}
The almost-certain error in this code is in your use of the layout method here:
mainView.layout(left, mainViewInitialPosition, right, mainViewInitialPosition + mainViewOriginalHeight);
You are using the parameter values left and right to layout your mainView (and the child views via setLayoutPositions). This is wrong. Keep in mind that left, top, right and bottom are the relative positions of your parent view (MinimizableView); they should not be used directly to layout your child views, as the child views are relative to MinimizableView, not to the parent of MinimizableView.
For example, when you layout mainView, the values you pass into layout() are interpreted as being relative to MinimizableView. This means the left offset should be 0 (plus padding), not left. Diddo for right. You layout call should look more like:
mainView.layout(0, 0, mainView.getMeasuredWidth(), mainView.getMeasuredHeight());
Note that the above does not account for padding.

how to fill adapter to viewpage fully without going aside?

I am trying to change viewpage rotation 90 to get vertical swapping. but my adapter going aside. i am unable fix it. help me to fit layout correctly.
Here is my view pager
<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.view.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/pager"
android:layout_alignParentTop="true"
android:layout_width="800dp"
android:layout_height="480dp"
android:background="#a07fe0">
</android.support.v4.view.ViewPager>
Here is my layout of adapter
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#ff0000"
android:layout_centerInParent="true"
android:orientation="horizontal"
android:rotation="270">
<ImageView
android:id="#+id/screen"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_gravity="start"
android:src="#drawable/makescr1"/>
</LinearLayout>

Use This class.
public class VerticalPager extends ViewGroup {
public static final String TAG = "VerticalPager";
private static final int INVALID_SCREEN = -1;
public static final int SPEC_UNDEFINED = -1;
private static final int TOP = 0;
private static final int BOTTOM = 1;
/**
* The velocity at which a fling gesture will cause us to snap to the next screen
*/
private static final int SNAP_VELOCITY = 1000;
private int pageHeight;
private int measuredHeight;
private boolean mFirstLayout = true;
private int mCurrentPage;
private int mNextPage = INVALID_SCREEN;
private Scroller mScroller;
private VelocityTracker mVelocityTracker;
private int mTouchSlop;
private int mMaximumVelocity;
private float mLastMotionY;
private float mLastMotionX;
private final static int TOUCH_STATE_REST = 0;
private final static int TOUCH_STATE_SCROLLING = 1;
private int mTouchState = TOUCH_STATE_REST;
private boolean mAllowLongPress;
private Set<OnScrollListener> mListeners = new HashSet<OnScrollListener>();
VerticalPageChange mpageChangeListener;
/**
* Used to inflate the Workspace from XML.
*
* #param context The application's context.
* #param attrs The attribtues set containing the Workspace's customization values.
*/
public VerticalPager(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public VerticalPager(Context context, AttributeSet attrs,
VerticalPageChange mpageChangeListener) {
this(context, attrs, 0);
this.mpageChangeListener=mpageChangeListener;
}
/**
* Used to inflate the Workspace from XML.
*
* #param context The application's context.
* #param attrs The attribtues set containing the Workspace's customization values.
* #param defStyle Unused.
*/
public VerticalPager(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
//TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.com_deezapps_widget_HorizontalPager);
//pageHeightSpec = a.getDimensionPixelSize(R.styleable.com_deezapps_widget_HorizontalPager_pageWidth, SPEC_UNDEFINED);
//a.recycle();
init(context);
}
/**
* Initializes various states for this workspace.
*/
private void init(Context context) {
mScroller = new Scroller(getContext(), new DecelerateInterpolator());
mCurrentPage = 0;
final ViewConfiguration configuration = ViewConfiguration.get(getContext());
mTouchSlop = configuration.getScaledTouchSlop();
mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
}
/**
* Returns the index of the currently displayed page.
*
* #return The index of the currently displayed page.
*/
int getCurrentPage() {
return mCurrentPage;
}
/**
* Sets the current page.
*
* #param currentPage
*/
public void setCurrentPage(int currentPage) {
mCurrentPage = Math.max(0, Math.min(currentPage, getChildCount()));
scrollTo(getScrollYForPage(mCurrentPage), 0);
invalidate();
}
public int getPageHeight() {
return pageHeight;
}
// public void setPageHeight(int pageHeight) {
// this.pageHeightSpec = pageHeight;
// }
/**
* Gets the value that getScrollX() should return if the specified page is the current page (and no other scrolling is occurring).
* Use this to pass a value to scrollTo(), for example.
* #param whichPage
* #return
*/
private int getScrollYForPage(int whichPage) {
int height = 0;
for(int i = 0; i < whichPage; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != View.GONE) {
height += child.getHeight();
}
}
return height - pageHeightPadding();
}
#Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
postInvalidate();
} else if (mNextPage != INVALID_SCREEN) {
mCurrentPage = mNextPage;
mNextPage = INVALID_SCREEN;
clearChildrenCache();
}
}
#Override
protected void dispatchDraw(Canvas canvas) {
// ViewGroup.dispatchDraw() supports many features we don't need:
// clip to padding, layout animation, animation listener, disappearing
// children, etc. The following implementation attempts to fast-track
// the drawing dispatch by drawing only what we know needs to be drawn.
final long drawingTime = getDrawingTime();
// todo be smarter about which children need drawing
final int count = getChildCount();
for (int i = 0; i < count; i++) {
drawChild(canvas, getChildAt(i), drawingTime);
}
for (OnScrollListener mListener : mListeners) {
int adjustedScrollY = getScrollY() + pageHeightPadding();
mListener.onScroll(adjustedScrollY);
if (adjustedScrollY % pageHeight == 0) {
mListener.onViewScrollFinished(adjustedScrollY / pageHeight);
}
}
}
int pageHeightPadding() {
return ((getMeasuredHeight() - pageHeight) / 2);
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
pageHeight = getMeasuredHeight();
final int count = getChildCount();
for (int i = 0; i < count; i++) {
getChildAt(i).measure(MeasureSpec.makeMeasureSpec(getMeasuredWidth(), MeasureSpec.EXACTLY),
MeasureSpec.makeMeasureSpec(pageHeight, MeasureSpec.UNSPECIFIED));
}
if (mFirstLayout) {
scrollTo(getScrollYForPage(mCurrentPage), 0);
mFirstLayout = false;
}
}
#Override
protected void onLayout(boolean changed, int left, int top, int right, int bottom) {
measuredHeight = 0;
final int count = getChildCount();
int height;
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
if (child.getVisibility() != View.GONE) {
if(i == 0) {
child.getHeight();
child.layout(0, measuredHeight, right - left, measuredHeight + (int)(pageHeight*.96));
measuredHeight += (pageHeight*.96);
} else {
height = pageHeight * (int)Math.ceil((double)child.getMeasuredHeight()/(double)pageHeight);
height = Math.max(pageHeight, height);
child.layout(0, measuredHeight, right - left, measuredHeight + height);
measuredHeight += height;
}
}
}
}
#Override
public boolean requestChildRectangleOnScreen(View child, Rect rectangle, boolean immediate) {
int screen = indexOfChild(child);
if (screen != mCurrentPage || !mScroller.isFinished()) {
return true;
}
return false;
}
#Override
protected boolean onRequestFocusInDescendants(int direction, Rect previouslyFocusedRect) {
int focusableScreen;
try
{
if (mNextPage != INVALID_SCREEN) {
focusableScreen = mNextPage;
} else {
focusableScreen = mCurrentPage;
}
getChildAt(focusableScreen).requestFocus(direction, previouslyFocusedRect);
}
catch(Exception e)
{
e.printStackTrace();
}
return false;
}
#Override
public boolean dispatchUnhandledMove(View focused, int direction) {
if (direction == View.FOCUS_LEFT) {
if (getCurrentPage() > 0) {
snapToPage(getCurrentPage() - 1);
return true;
}
} else if (direction == View.FOCUS_RIGHT) {
if (getCurrentPage() < getChildCount() - 1) {
snapToPage(getCurrentPage() + 1);
return true;
}
}
return super.dispatchUnhandledMove(focused, direction);
}
#Override
public void addFocusables(ArrayList<View> views, int direction) {
getChildAt(mCurrentPage).addFocusables(views, direction);
if (direction == View.FOCUS_LEFT) {
if (mCurrentPage > 0) {
getChildAt(mCurrentPage - 1).addFocusables(views, direction);
}
} else if (direction == View.FOCUS_RIGHT){
if (mCurrentPage < getChildCount() - 1) {
getChildAt(mCurrentPage + 1).addFocusables(views, direction);
}
}
}
#Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
//Log.d(TAG, "onInterceptTouchEvent::action=" + ev.getAction());
/*
* This method JUST determines whether we want to intercept the motion.
* If we return true, onTouchEvent will be called and we do the actual
* scrolling there.
*/
/*
* Shortcut the most recurring case: the user is in the dragging
* state and he is moving his finger. We want to intercept this
* motion.
*/
final int action = ev.getAction();
if ((action == MotionEvent.ACTION_MOVE) && (mTouchState != TOUCH_STATE_REST)) {
//Log.d(TAG, "onInterceptTouchEvent::shortcut=true");
return true;
}
final float y = ev.getY();
final float x = ev.getX();
switch (action) {
case MotionEvent.ACTION_MOVE:
/*
* mIsBeingDragged == false, otherwise the shortcut would have caught it. Check
* whether the user has moved far enough from his original down touch.
*/
if (mTouchState == TOUCH_STATE_REST) {
checkStartScroll(x, y);
}
break;
case MotionEvent.ACTION_DOWN:
// Remember location of down touch
mLastMotionX = x;
mLastMotionY = y;
mAllowLongPress = true;
/*
* If being flinged and user touches the screen, initiate drag;
* otherwise don't. mScroller.isFinished should be false when
* being flinged.
*/
mTouchState = mScroller.isFinished() ? TOUCH_STATE_REST : TOUCH_STATE_SCROLLING;
break;
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
// Release the drag
clearChildrenCache();
mTouchState = TOUCH_STATE_REST;
break;
}
/*
* The only time we want to intercept motion events is if we are in the
* drag mode.
*/
return mTouchState != TOUCH_STATE_REST;
}
private void checkStartScroll(float x, float y) {
/*
* Locally do absolute value. mLastMotionX is set to the y value
* of the down event.
*/
final int xDiff = (int) Math.abs(x - mLastMotionX);
final int yDiff = (int) Math.abs(y - mLastMotionY);
boolean xMoved = xDiff > mTouchSlop;
boolean yMoved = yDiff > mTouchSlop;
if (xMoved || yMoved) {
if (yMoved) {
// Scroll if the user moved far enough along the X axis
mTouchState = TOUCH_STATE_SCROLLING;
enableChildrenCache();
}
// Either way, cancel any pending longpress
if (mAllowLongPress) {
mAllowLongPress = false;
// Try canceling the long press. It could also have been scheduled
// by a distant descendant, so use the mAllowLongPress flag to block
// everything
final View currentScreen = getChildAt(mCurrentPage);
currentScreen.cancelLongPress();
}
}
}
void enableChildrenCache() {
setChildrenDrawingCacheEnabled(true);
setChildrenDrawnWithCacheEnabled(true);
}
void clearChildrenCache() {
setChildrenDrawnWithCacheEnabled(false);
}
#Override
public boolean onTouchEvent(MotionEvent ev) {
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(ev);
final int action = ev.getAction();
final float x = ev.getX();
final float y = ev.getY();
switch (action) {
case MotionEvent.ACTION_DOWN:
/*
* If being flinged and user touches, stop the fling. isFinished
* will be false if being flinged.
*/
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
// Remember where the motion event started
mLastMotionY = y;
break;
case MotionEvent.ACTION_MOVE:
if (mTouchState == TOUCH_STATE_REST) {
checkStartScroll(y, x);
} else if (mTouchState == TOUCH_STATE_SCROLLING) {
// Scroll to follow the motion event
int deltaY = (int) (mLastMotionY - y);
mLastMotionY = y;
// Apply friction to scrolling past boundaries.
final int count = getChildCount();
if (getScrollY() < 0 || getScrollY() + pageHeight > getChildAt(count - 1).getBottom()) {
deltaY /= 2;
}
scrollBy(0, deltaY);
}
break;
case MotionEvent.ACTION_UP:
if (mTouchState == TOUCH_STATE_SCROLLING) {
final VelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
int velocityY = (int) velocityTracker.getYVelocity();
final int count = getChildCount();
// check scrolling past first or last page?
if(getScrollY() < 0) {
snapToPage(0);
} else if(getScrollY() > measuredHeight - pageHeight) {
snapToPage(count - 1, BOTTOM);
} else {
for(int i = 0; i < count; i++) {
final View child = getChildAt(i);
if(child.getTop() < getScrollY() &&
child.getBottom() > getScrollY() + pageHeight) {
// we're inside a page, fling that bitch
mNextPage = i;
mScroller.fling(getScrollX(), getScrollY(), 0, -velocityY, 0, 0, child.getTop(), child.getBottom() - getHeight());
invalidate();
break;
} else if(child.getBottom() > getScrollY() && child.getBottom() < getScrollY() + getHeight()) {
// stuck in between pages, oh snap!
if(velocityY < -SNAP_VELOCITY) {
snapToPage(i + 1);
} else if(velocityY > SNAP_VELOCITY) {
snapToPage(i, BOTTOM);
} else if(getScrollY() + pageHeight/2 > child.getBottom()) {
snapToPage(i + 1);
} else {
snapToPage(i, BOTTOM);
}
break;
}
}
}
if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
}
mTouchState = TOUCH_STATE_REST;
break;
case MotionEvent.ACTION_CANCEL:
mTouchState = TOUCH_STATE_REST;
}
return true;
}
private void snapToPage(final int whichPage, final int where) {
enableChildrenCache();
boolean changingPages = whichPage != mCurrentPage;
mNextPage = whichPage;
View focusedChild = getFocusedChild();
if (focusedChild != null && changingPages && focusedChild == getChildAt(mCurrentPage)) {
focusedChild.clearFocus();
}
final int delta;
if(getChildAt(whichPage).getHeight() <= pageHeight || where == TOP) {
delta = getChildAt(whichPage).getTop() - getScrollY();
} else {
delta = getChildAt(whichPage).getBottom() - pageHeight - getScrollY();
}
mScroller.startScroll(0, getScrollY(), 0, delta, 400);
invalidate();
mpageChangeListener.onPageChange(whichPage);
}
public void snapToPage(final int whichPage) {
snapToPage(whichPage, TOP);
// mpageChangeListener.onPageChange(whichPage);
}
#Override
protected Parcelable onSaveInstanceState() {
final SavedState state = new SavedState(super.onSaveInstanceState());
state.currentScreen = mCurrentPage;
return state;
}
#Override
protected void onRestoreInstanceState(Parcelable state) {
SavedState savedState = (SavedState) state;
super.onRestoreInstanceState(savedState.getSuperState());
if (savedState.currentScreen != INVALID_SCREEN) {
mCurrentPage = savedState.currentScreen;
}
}
public void scrollUp() {
if (mNextPage == INVALID_SCREEN && mCurrentPage > 0 && mScroller.isFinished()) {
snapToPage(mCurrentPage - 1);
}
}
public void scrollDown() {
if (mNextPage == INVALID_SCREEN && mCurrentPage < getChildCount() - 1 && mScroller.isFinished()) {
snapToPage(mCurrentPage + 1);
}
}
public int getScreenForView(View v) {
int result = -1;
if (v != null) {
ViewParent vp = v.getParent();
int count = getChildCount();
for (int i = 0; i < count; i++) {
if (vp == getChildAt(i)) {
return i;
}
}
}
return result;
}
/**
* #return True is long presses are still allowed for the current touch
*/
public boolean allowLongPress() {
return mAllowLongPress;
}
public static class SavedState extends BaseSavedState {
int currentScreen = -1;
SavedState(Parcelable superState) {
super(superState);
}
private SavedState(Parcel in) {
super(in);
currentScreen = in.readInt();
}
#Override
public void writeToParcel(Parcel out, int flags) {
super.writeToParcel(out, flags);
out.writeInt(currentScreen);
}
public static final Parcelable.Creator<SavedState> CREATOR =
new Parcelable.Creator<SavedState>() {
public SavedState createFromParcel(Parcel in) {
return new SavedState(in);
}
public SavedState[] newArray(int size) {
return new SavedState[size];
}
};
}
public void addOnScrollListener(OnScrollListener listener) {
mListeners.add(listener);
}
public void removeOnScrollListener(OnScrollListener listener) {
mListeners.remove(listener);
}
/**
* Implement to receive events on scroll position and page snaps.
*/
public static interface OnScrollListener {
/**
* Receives the current scroll X value. This value will be adjusted to assume the left edge of the first
* page has a scroll position of 0. Note that values less than 0 and greater than the right edge of the
* last page are possible due to touch events scrolling beyond the edges.
* #param scrollX Scroll X value
*/
void onScroll(int scrollX);
/**
* Invoked when scrolling is finished (settled on a page, centered).
* #param currentPage The current page
*/
void onViewScrollFinished(int currentPage);
}
public interface VerticalPageChange
{
public void onPageChange(int position);
}
}
i have add page dynamically. inside getView() of BaseAdapter.
final VerticalPager verticalPage = new VerticalPager(Act_ItemView.this, null, mVerticalPagechangeListener);
// setDotIndicatorView(p.arr_images.size());
for (int i = 0; i < p.arr_images.size(); i++)
{
final String image_url = p.arr_images.get(i).image_method;
PhotoView imageView = new PhotoView(Act_ItemView.this);
imageView.setLayoutParams(new ViewGroup.LayoutParams(width, height));
imageView.setAllowParentInterceptOnEdge(true);
// imageView.setScaleType(ScaleType.CENTER_CROP);
imageLoader1.displayImage(image_url, imageView, options1, animateFirstListener1);
verticalPage.setHorizontalScrollBarEnabled(false);
verticalPage.addView(imageView);
verticalPage.setTag(i);
}
linearLayoutMain.addView(verticalPage);
here is listner implemented
VerticalPager.VerticalPageChange mVerticalPagechangeListener = new VerticalPager.VerticalPageChange()
{
#Override
public void onPageChange(int position)
{
try
{
int pagePosition1 = viewPager.getCurrentItem();
setindicator(position);
array_index[pagePosition1] = position;
} catch (Exception e)
{
e.printStackTrace();
}
}
};

Android ViewPager when swiping on last screen

Im having trouble figuring out how to capture a swipe event on the last page of a view pager.
Basically the requirement is that when the user is on the last page, and they try to swipe to get to the next page, the activity should close.
I've tried doing this onPageScrolled but I cant seem to differentiate a left or right swipe when in there. When on the last page, the user should still maintain the functionality to move to the previous page.
So basically the case is
When on last page
if swipe prev (do normal behaviour)
if swipe next (finish activity)
Can anyone provide any suggestions?
Thanks

Here is working solution!!
Required variables
....
private boolean isLastPageSwiped;
private int counterPageScroll;
....
Inside onPageScrolled of ViewPager
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
//Here 6 is last position
if (position == 6 && positionOffset == 0 && !isLastPageSwiped){
if(counterPageScroll != 0){
isLastPageSwiped=true;
//Next Activity here
}
counterPageScroll++;
}else{
counterPageScroll=0;
}
}

You should include an fake blank page to your ViewPager, when user swipes your actual last page, it comes to this fake one. When this fake one is visible finish the Activity.
You should try this way, if it does not work, I can give you an example code.

I am probably really late, but then this might help someone else down the line. I got the snippet from a question on stackoverflow, where in i am just tweaking the code a little bit.
Answer from here.
ViewPager.OnPageChangeListener pagerListener = new ViewPager.OnPageChangeListener() {
boolean lastPageChange = false;
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels){
int lastIdx = mPgScreenAdapter.getCount() - 1;
Log.d(TAG, "pos:" + position);
if(lastPageChange && position == lastIdx) {}
}
#Override
public void onPageSelected( int i) {
pgText.setCurrentItem(i/2);
}
#Override
public void onPageScrollStateChanged(int state) {
int lastIdx = mPgScreenAdapter.getCount() - 1;
int curItem = pgScreen.getCurrentItem();
if(curItem==lastIdx && state==1){
lastPageChange = true;
// i put this here since onPageScroll gets called a couple of times.
finish();
}else {
lastPageChange = false;
}
}
};

int lastPosition;
int currentPosition;
//View pager assign
ViewPager viewPager = findViewById(R.id.viewPager);
//PageIndicatorView external https://github.com/romandanylyk
PageIndicatorView pageIndicatorView = findViewById(R.id.pageIndicatorView);
//customise pageIndicatorView design
pageIndicatorView.setAnimationType(AnimationType.THIN_WORM);
pageIndicatorView.setViewPager(viewPager);
//BannerAdapter is an custom adapter for viewpage i made.
//assign data here
BannerAdapter pagerAdapter = new BannerAdapter(this, banner, new OnClickListener() {
#Override
public void onClick() {
}
});
viewPager.setAdapter(pagerAdapter);
//listener for View Pager
//this is where process of making the infinite loop
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
//assign position so that can be manipulated
currentPosition = position;
}
#Override
public void onPageSelected(int position) {
//set pager indicator position here
pageIndicatorView.setSelection(position);
}
#Override
public void onPageScrollStateChanged(int state) {
//check state 0 mean no ongoing process
if(state == 0){
//check currentPosition == lastPosition to detect that scroll cant scroll anymore
if(currentPosition == lastPosition){
int lastitem = banner.size() - 1;
//check position if either last item/first item
//and set viewpager current page as follow
if(currentPosition == lastitem){
viewPager.setCurrentItem(0);
}else if(currentPosition == 0){
viewPager.setCurrentItem(lastitem);
}
}else{
lastPosition = currentPosition;
}
Log.d("ScrollState", "currentPosition: " + currentPosition);
}
/*empty*/
}
});

I also tried my luck to find solution. Here is working code.Hope it will help someone else:-
pager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
}
#Override
public void onPageScrollStateChanged(int state) {
if (state == ViewPager.SCROLL_STATE_IDLE) {
int curr = pager.getCurrentItem();
int lastReal = pager.getAdapter().getCount() - 1;
if (curr < lastReal) {
counter = 0;
} else if (curr == lastReal) {
counter++;
if (counter == 2) {
pager.setOffscreenPageLimit(0);
pager.setCurrentItem(0, false);
counter = 0;
}
}
}
}
});
pagerIndicator.setViewPager(pager);
I used counter as global variable.
Thanks!

I created an abstract listener based on the solutions here. I wanted to do something when swiping right on the last page, or left on the first page.
import android.support.v4.view.ViewPager;
abstract class PageChangeToUnavailablePageListener implements ViewPager.OnPageChangeListener {
private int finalPageIndex;
private boolean finalPageVisible = false;
private boolean firstPageVisible = true;
private int lastScrollState = 0;
abstract void onUnavailablePageChangeOnLastPage();
abstract void onUnavailablePageChangeOnFirstPage();
public PageChangeToUnavailablePageListener(int finalPageIndex) {
this.finalPageIndex = finalPageIndex;
}
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int i) {
firstPageVisible = (i == 0);
finalPageVisible = (i == finalPageIndex);
}
#Override
public void onPageScrollStateChanged(int state) {
// The normal state sequence for changing pages is
// DRAGGING (user starts drag), SETTLING (next page is chosen), IDLE (animation is complete).
// No next page is chosen when dragging right on last page, or left on first page.
// In this case the SETTLING state is missing and the sequence is (DRAGGING, IDLE).
if (lastScrollState == ViewPager.SCROLL_STATE_DRAGGING && state == ViewPager.SCROLL_STATE_IDLE) {
// The user scrolled to an unavailable page.
if (finalPageVisible) {
onUnavailablePageChangeOnLastPage();
} else if (firstPageVisible) {
onUnavailablePageChangeOnFirstPage();
}
}
lastScrollState = state;
}
}

Hope you got an answer, i came across the same issue and this is what i did:
Incase you are using a viewpager and an activity with a class extending FragmentStatePagerAdapter you can use the getItem(int position) method to check if you reached the last page. This is also if you declared the NUM_PAGES and you can use it to detect the user has reached the last page.

in Activity:
private static int MAX_LAYOUTS = 3;
private boolean isLastPageSwiped;
private int counterPageScroll;
In onCreate:
ViewPager.OnPageChangeListener viewPagerPageChangeListener = new ViewPager.OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
}
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
if (position == MAX_LAYOUTS - 1 && positionOffset == 0 && !isLastPageSwiped) {
if (counterPageScroll != 0) {
isLastPageSwiped = true;
Intent intent = new Intent(OldActivity.this, NewActivity.class);
startActivity(intent);
}
counterPageScroll++;
} else {
counterPageScroll = 0;
}
}
#Override
public void onPageScrollStateChanged(int arg0) {
}
};
viewPager.addOnPageChangeListener(viewPagerPageChangeListener);

i have also solution for these(in kotlin),
Example my tabview has 3 pages.
......
private var isLastPageSwiped = false
private var indexPageScroll = 0
......
override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {
super.onPageScrolled(position, positionOffset, positionOffsetPixels)
if (position == 2 && positionOffset == 0f && !isLastPageSwiped) {
if (indexPageScroll != 0) {
isLastPageSwiped = true
//Next Activity here
//You can perform your action on last page scroll.
}
indexPageScroll++
} else {
indexPageScroll = 0
}
}

Implementing Circular Scrolling In PagerAdapter

I am using PagerAdapter for horizontal swiping for showing newspaper pages in my app.
Currently I want to implement the circular scrolling in this app.Right now what I have done is whenever I am getting on last page I try to set the currentItem to first pagei.e that functionality working for last page to first page,but the problem is that how can I go to last page from first page.
Here I am pasting my code related to pagerAdapter & onPageChangeListener:-
awesomeAdapter = new AwesomePagerAdapter(awesomePager);
awesomePager.setAdapter(awesomeAdapter);
awesomePager.setPageMargin(10);
awesomePager.setOnPageChangeListener(new OnPageChangeListener() {
int lastPosition;
float posOffset = 0;
#Override
public void onPageSelected(int position) {
viewerPage = position;
CommonLogic.logMessage("Viewer Page:- "+ viewerPage, TAG, Log.VERBOSE);
posOffset = 0;
}
#Override
public void onPageScrolled(int position,float positionOffset,int positionOffsetPixels) {
if (positionOffset == 0 && positionOffsetPixels == 0 && position != 0) {
lastPosition = position;
}
posOffset -= positionOffset;
CommonLogic.logMessage(" Position:- "
+ position + " Position Offset:- " + positionOffset
+ " Position Offset Variable:- "
+ posOffset
+ " Position Offset Pixels:- "
+ positionOffsetPixels
+ " Last Position " + lastPosition,
TAG, Log.VERBOSE);
CommonLogic.logMessage(" Last Position "
+ lastPosition, TAG, Log.VERBOSE);
}
#Override
public void onPageScrollStateChanged(int state) {
// To Detect the Last Page & This Sets it to first page.This working fine.
if (state == ViewPager.SCROLL_STATE_DRAGGING && viewerPage == (uris.size() - 1)) {
CommonLogic.logMessage("Scroll State Changed ", TAG,Log.VERBOSE);
postDelayed(new Runnable() {
#Override
public void run() {
awesomePager.setCurrentItem(0, true);
}
}, 200);
}
// I have also used this to detect whether the user is on first & try to move on last page,but it is not working well.
else if (state == ViewPager.SCROLL_STATE_DRAGGING && (lastPosition == 0 || lastPosition == (uris.size() - 1)) && viewerPage == 0 && posOffset <= 0) {
CommonLogic.logMessage( "Scroll State Changed ", TAG,Log.VERBOSE);
postDelayed(new Runnable() {
#Override
public void run() {
awesomePager.setCurrentItem((uris.size() - 1), true);
}
}, 200);
}
}
}
});
Also the PagerAdapter i.e AwesomweAdapter in my case,is also as folllows:-
private class AwesomePagerAdapter extends PagerAdapter {
ViewPager pdfContainer;
DocumentNewView documentNewView;
CustomViewPager customViewPager;
public AwesomePagerAdapter(CustomViewPager awesomePager) {
this.customViewPager = awesomePager;
}
#Override
public int getItemPosition(Object object) {
return POSITION_NONE;
}
#Override
public int getCount() {
return uris.size();
}
public DocumentNewView addViewAt(int position, DocumentNewView mainView) {
CommonLogic.logMessage("Position of View:- " + position, TAG,
Log.VERBOSE);
pdfContainer.addView(mainView);
return mainView;
}
/**
* Create the page for the given position. The adapter is responsible
* for adding the view to the container given here, although it only
* must ensure this is done by the time it returns from
* {#link #finishUpdate()}.
*
* #param container
* The containing View in which the page will be shown.
* #param position
* The page position to be instantiated.
* #return Returns an Object representing the new page. This does not
* need to be a View, but can be some other container of the
* page.
*/
#Override
public Object instantiateItem(View collection, int position) {
CommonLogic
.logMessage("Instantiate Item Called ", TAG, Log.VERBOSE);
documentNewView = new DocumentNewView(cxt, display, customViewPager);
documentNewView.setPdfContext(new PdfContext());
CodecDocument codecDocument = documentNewView.open(uris
.get(position));
documentNewView.renderDocument(codecDocument);
documentNewView.setMaxZoom(4f);
documentNewView.setVerticalScrollBarEnabled(true);
codecDocument = null;
this.pdfContainer = (ViewPager) collection;
return addViewAt(position, documentNewView);
}
/**
* Remove a page for the given position. The adapter is responsible for
* removing the view from its container, although it only must ensure
* this is done by the time it returns from {#link #finishUpdate()}.
*
* #param container
* The containing View from which the page will be removed.
* #param position
* The page position to be removed.
* #param object
* The same object that was returned by
* {#link #instantiateItem(View, int)}.
*/
#Override
public void destroyItem(View collection, int position, Object view) {
pdfContainer.removeView((DocumentNewView) view);
}
/**
* Called when the a change in the shown pages has been completed. At
* this point you must ensure that all of the pages have actually been
* added or removed from the container as appropriate.
*
* #param container
* The containing View which is displaying this adapter's
* page views.
*/
#Override
public void finishUpdate(View arg0) {
CommonLogic.logMessage("Finish Update Called ", TAG, Log.VERBOSE);
}
#Override
public void restoreState(Parcelable arg0, ClassLoader arg1) {
}
#Override
public Parcelable saveState() {
return null;
}
#Override
public void startUpdate(View arg0) {
CommonLogic.logMessage("State Update Called ", TAG, Log.VERBOSE);
}
#Override
public boolean isViewFromObject(View view, Object object) {
return view == ((DocumentNewView) object);
}
Please give me any suggestions/changes in my code (if applicable) for it.
Thanks in Advance.

I could achieve this by overriding onPageSelected method of OnPageChangeListener. Consider you have three pages in this order A<->B<->C. To goal is to reach C if we scroll right from A and similarly to reach A if we scroll left from C.
To do this, define your to have 5 pages (3+2), and organize the pages as follows:
C<->A<->B<->C<->A
Now in the onPageSelected method, check and if position if 0, change it to 3 (getCount()-2) and if position is 4 (getCount()-1), change it to 1. Make sure to use the method:
setCurrentItem(item, smoothScroll)
Here is complete code for CircularPagerAdaptor Class :
package zolender.adapters;
import android.content.Context;
import android.os.Parcelable;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.view.LayoutInflater;
import android.view.View;
public class CircularPagerAdapter extends PagerAdapter{
private int[] pageIDsArray;
private int count;
public CircularPagerAdapter(final ViewPager pager, int... pageIDs) {
super();
int actualNoOfIDs = pageIDs.length;
count = actualNoOfIDs + 2;
pageIDsArray = new int[count];
for (int i = 0; i < actualNoOfIDs; i++) {
pageIDsArray[i + 1] = pageIDs[i];
}
pageIDsArray[0] = pageIDs[actualNoOfIDs - 1];
pageIDsArray[count - 1] = pageIDs[0];
pager.setOnPageChangeListener(new OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
int pageCount = getCount();
if (position == 0){
pager.setCurrentItem(pageCount-2,false);
} else if (position == pageCount-1){
pager.setCurrentItem(1,false);
}
}
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
// TODO Auto-generated method stub
}
#Override
public void onPageScrollStateChanged(int state) {
// TODO Auto-generated method stub
}
});
}
public int getCount() {
return count;
}
public Object instantiateItem(View container, int position) {
LayoutInflater inflater = (LayoutInflater) container.getContext()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
int pageId = pageIDsArray[position];
View view = inflater.inflate(pageId, null);
((ViewPager) container).addView(view, 0);
return view;
}
#Override
public void destroyItem(View container, int position, Object object) {
((ViewPager) container).removeView((View) object);
}
#Override
public void finishUpdate(View container) {
// TODO Auto-generated method stub
}
#Override
public boolean isViewFromObject(View view, Object object) {
return view == ((View) object);
}
#Override
public void restoreState(Parcelable state, ClassLoader loader) {
// TODO Auto-generated method stub
}
#Override
public Parcelable saveState() {
// TODO Auto-generated method stub
return null;
}
#Override
public void startUpdate(View container) {
// TODO Auto-generated method stub
}
}
And here is how you can use it:
myPager = (ViewPager) findViewById(R.id.myfivepanelpager);
PagerAdapter adapter = new CircularPagerAdapter(myPager, new int[]{R.layout.farleft, R.layout.left, R.layout.middle, R.layout.right, R.layout.farright});
myPager.setAdapter(adapter);
myPager.setCurrentItem(3);

I also needed a circular ViewPager. This is what I've done. I assume you get pageCount value from somewhere.
...
pager = (ViewPager) findViewById(R.id.pager);
//Gesture detection
final GestureDetector gestureDetector = new GestureDetector(new MyGestureDetector());
pager.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
return gestureDetector.onTouchEvent(event);
}
});
//pagelistener is just for getting selected page
pager.setOnPageChangeListener(new OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
selectedPage = position;
}
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageScrollStateChanged(int state) {
}
});
and here is the GestureDetector.
Copied from here
class MyGestureDetector extends SimpleOnGestureListener {
#Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
int SWIPE_MIN_DISTANCE = Utils.ConvertToPixel(mContext, 50);
int SWIPE_MAX_OFF_PATH = Utils.ConvertToPixel(mContext, 250);
int SWIPE_THRESHOLD_VELOCITY = Utils.ConvertToPixel(mContext, 200);
try {
if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
return false;
// right to left swipe
if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE
&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY
&& selectedPage == (pageCount - 1)) {
pager.setCurrentItem(0);
return true;
} else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE
&& Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY
&& selectedPage == 0) {
pager.setCurrentItem(pageCount - 1);
return true;
}
} catch (Exception e) {
// nothing
}
return false;
}
}

Expanding on Z0lenDer's answer, when using a regular ViewPager where you don't need to free the memory for each associated view, it's more efficient to store the created views rather than the layout IDs. This is necessary if wanting to get rid of any delay and flicker when the item is being switched.
There's also an issue with the animation when using onPageSelected, as it doesn't let the slide finish before doing the switch. The only way I found to avoid this is to only perform the switch once the scroll state has changed to SCROLL_STATE_IDLE and just setting the current item in onPageSelected.
private int currentPage = 0;
...
pager.setOnPageChangeListener(new OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
currentPage = position;
}
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageScrollStateChanged(int state) {
// TODO Auto-generated method stub
Log.d(TAG, "onPageScrollStateChanged: " + state);
if (state == ViewPager.SCROLL_STATE_IDLE) {
int pageCount = getCount();
if (currentPage == 0){
pager.setCurrentItem(pageCount-2,false);
} else if (currentPage == pageCount-1){
pager.setCurrentItem(1,false);
}
}
}
});

Try this
((ViewPager) container)
.setOnPageChangeListener(new OnPageChangeListener() {
#Override
public void onPageSelected(int position) {
Log.i("TAG", "pos::" + position);
}
#Override
public void onPageScrollStateChanged(int state) {
// TODO Auto-generated method stub
int currentPage = pager.getCurrentItem();
Log.i("TAG", "currentPage::" + currentPage);
Log.i("TAG", "currentState::" + currentState);
Log.i("TAG", "previousState::" + previousState);
if (currentPage == 4 || currentPage == 0) {
previousState = currentState;
currentState = state;
if (previousState == 1 && currentState == 0) {
pager.setCurrentItem(currentPage == 0 ? 4 : 0);
}
}
}
#Override
public void onPageScrolled(int arg0, float arg1,
int arg2) {
// TODO Auto-generated method stub
}
});
return
This should be placed inside
#Override
public Object instantiateItem(final View container, int position) {}

I used it this way,
fragment layouts in adapter 0>1>2>3>4>5,
0 & 5 are dummy
viewPager.setAdapter(adapter);
viewPager.setCurrentItem(1, false); //going to page 1;
final int[] pagePosition = new int[1];
viewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
#Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
}
#Override
public void onPageSelected(int position) {
pagePosition[0] = position;
}
#Override
public void onPageScrollStateChanged(int state) { //state changes from 2 to 0 during a swipe
if (state == 0 && pagePosition[0] == 0){
viewPager.setCurrentItem(4, false);
} else if (state == 0 && pagePosition[0] == 5){
viewPager.setCurrentItem(1, false);
}
}
});

Well this helped
private class CircularViewPagerHandler implements ViewPager.OnPageChangeListener {
private ViewPager mViewPager;
private int mCurrentPosition;
private int mScrollState;
private int mPreviousPosition;
public CircularViewPagerHandler(final ViewPager viewPager) {
mViewPager = viewPager;
}
#Override
public void onPageSelected(final int position) {
mCurrentPosition = position;
mPreviousPosition = position-1;
}
#Override
public void onPageScrollStateChanged(final int state) {
if (state == ViewPager.SCROLL_STATE_IDLE) {
setNextItemIfNeeded();
}
mScrollState = state;
}
private void setNextItemIfNeeded() {
if (!isScrollStateSettling()) {
handleSetNextItem();
}
}
private boolean isScrollStateSettling() {
return mScrollState == ViewPager.SCROLL_STATE_SETTLING; //indicated page is settling to it's final position
}
private void handleSetNextItem() {
final int lastPosition = mViewPager.getAdapter().getCount() - 1;
if (mCurrentPosition == 0) {
mViewPager.setCurrentItem(lastPosition,false);
} else if (mCurrentPosition == lastPosition) {
mViewPager.setCurrentItem(0, false);
}
}
#Override
public void onPageScrolled(final int position, final float positionOffset, final int positionOffsetPixels) {
}
}
It was #tobi_b's answer

Unable to start activity with java.lang.NullPointerException on Fling

When I am trying to fling example this error faced. with java Null pointer exception.
My java code
public class LearnCount extends Activity {
private FlingGallery mGallery;
public boolean onTouchEvent(MotionEvent event) {
return mGallery.onGalleryTouchEvent(event);
}
private String[] teststr = {
"test1","test2","test3","test4","test5"
};
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);
setContentView(R.layout.main);
LinearLayout productHolder = (LinearLayout) findViewById(R.id.linearLayoutOfCount);
mGallery = new FlingGallery(this);
mGallery.setAdapter(new ArrayAdapter<String>(getApplicationContext(),
android.R.layout.simple_list_item_1, teststr) {
public View getView(int position, View convertView, ViewGroup parent) {
System.out.println(mGallery.getCurrentPosition() + " position");
if (convertView != null
&& convertView instanceof GalleryViewItem) {
GalleryViewItem galleryView = (GalleryViewItem) convertView;
//galleryView.pImage.setImageResource(mImageIds[position]);
galleryView.b.setText(teststr[position]);
return galleryView;
}
GalleryViewItem gvi = new GalleryViewItem(getApplicationContext(), position);
gvi.b.setText(teststr[position]);
return gvi;
}
});
productHolder.addView(mGallery);
}
public class GalleryViewItem extends TableLayout {
private TextView b;
public GalleryViewItem(Context context, int position) {
super(context);
LayoutInflater inflater = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View v = inflater.inflate(R.layout.test, null);
b = (TextView) v.findViewById(R.id.test);
this.addView(v);
}
}
public class FlingGallery extends FrameLayout {
// Constants
private final int swipe_min_distance = 120;
private final int swipe_max_off_path = 250;
private final int swipe_threshold_veloicty = 400;
// Properties
private int mViewPaddingWidth = 0;
private int mAnimationDuration = 250;
private float mSnapBorderRatio = 0.5f;
private boolean mIsGalleryCircular = false;
// Members
private int mGalleryWidth = 0;
private boolean mIsTouched = false;
private boolean mIsDragging = false;
private float mCurrentOffset = 0.0f;
private long mScrollTimestamp = 0;
private int mFlingDirection = 0;
public int mCurrentPosition = 0;
private int mCurrentViewNumber = 0;
private Context mContext;
private Adapter mAdapter;
private FlingGalleryView[] mViews;
private FlingGalleryAnimation mAnimation;
private GestureDetector mGestureDetector;
private Interpolator mDecelerateInterpolater;
public FlingGallery(Context context) {
super(context);
mContext = context;
mAdapter = null;
mViews = new FlingGalleryView[3];
mViews[0] = new FlingGalleryView(0, this);
mViews[1] = new FlingGalleryView(1, this);
mViews[2] = new FlingGalleryView(2, this);
mAnimation = new FlingGalleryAnimation();
mGestureDetector = new GestureDetector(new FlingGestureDetector());
mDecelerateInterpolater = AnimationUtils.loadInterpolator(mContext,
android.R.anim.decelerate_interpolator);
}
public void setPaddingWidth(int viewPaddingWidth) {
mViewPaddingWidth = viewPaddingWidth;
}
public void setAnimationDuration(int animationDuration) {
mAnimationDuration = animationDuration;
}
public void setSnapBorderRatio(float snapBorderRatio) {
mSnapBorderRatio = snapBorderRatio;
}
public int getCurrentPosition() {
return mCurrentPosition;
}
public void setIsGalleryCircular(boolean isGalleryCircular) {
if (mIsGalleryCircular != isGalleryCircular) {
mIsGalleryCircular = isGalleryCircular;
if (mCurrentPosition == getFirstPosition()) {
// We need to reload the view immediately to the left to
// change it to circular view or blank
mViews[getPrevViewNumber(mCurrentViewNumber)]
.recycleView(getPrevPosition(mCurrentPosition));
}
if (mCurrentPosition == getLastPosition()) {
// We need to reload the view immediately to the right to
// change it to circular view or blank
mViews[getNextViewNumber(mCurrentViewNumber)]
.recycleView(getNextPosition(mCurrentPosition));
}
}
}
public int getGalleryCount() {
return (mAdapter == null) ? 0 : mAdapter.getCount();
}
public int getFirstPosition() {
return 0;
}
public int getLastPosition() {
return (getGalleryCount() == 0) ? 0 : getGalleryCount() - 1;
}
private int getPrevPosition(int relativePosition) {
int prevPosition = relativePosition - 1;
if (prevPosition < getFirstPosition()) {
prevPosition = getFirstPosition() - 1;
if (mIsGalleryCircular == true) {
prevPosition = getLastPosition();
}
}
return prevPosition;
}
private int getNextPosition(int relativePosition) {
int nextPosition = relativePosition + 1;
if (nextPosition > getLastPosition()) {
nextPosition = getLastPosition() + 1;
if (mIsGalleryCircular == true) {
nextPosition = getFirstPosition();
}
}
return nextPosition;
}
private int getPrevViewNumber(int relativeViewNumber) {
return (relativeViewNumber == 0) ? 2 : relativeViewNumber - 1;
}
private int getNextViewNumber(int relativeViewNumber) {
return (relativeViewNumber == 2) ? 0 : relativeViewNumber + 1;
}
protected void onLayout(boolean changed, int left, int top, int right,
int bottom) {
super.onLayout(changed, left, top, right, bottom);
// Calculate our view width
mGalleryWidth = right - left;
if (changed == true) {
// Position views at correct starting offsets
mViews[0].setOffset(0, 0, mCurrentViewNumber);
mViews[1].setOffset(0, 0, mCurrentViewNumber);
mViews[2].setOffset(0, 0, mCurrentViewNumber);
}
}
public void setAdapter(Adapter adapter) {
mAdapter = adapter;
mCurrentPosition = 0;
mCurrentViewNumber = 0;
// Load the initial views from adapter
mViews[0].recycleView(mCurrentPosition);
mViews[1].recycleView(getNextPosition(mCurrentPosition));
mViews[2].recycleView(getPrevPosition(mCurrentPosition));
// Position views at correct starting offsets
mViews[0].setOffset(0, 0, mCurrentViewNumber);
mViews[1].setOffset(0, 0, mCurrentViewNumber);
mViews[2].setOffset(0, 0, mCurrentViewNumber);
}
private int getViewOffset(int viewNumber, int relativeViewNumber) {
// Determine width including configured padding width
int offsetWidth = mGalleryWidth + mViewPaddingWidth;
// Position the previous view one measured width to left
if (viewNumber == getPrevViewNumber(relativeViewNumber)) {
return offsetWidth;
}
// Position the next view one measured width to the right
if (viewNumber == getNextViewNumber(relativeViewNumber)) {
return offsetWidth * -1;
}
return 0;
}
void movePrevious() {
// Slide to previous view
mFlingDirection = 1;
processGesture();
}
void moveNext() {
// Slide to next view
mFlingDirection = -1;
processGesture();
}
public boolean onKeyDown(int keyCode, KeyEvent event) {
switch (keyCode) {
case KeyEvent.KEYCODE_DPAD_LEFT:
movePrevious();
return true;
case KeyEvent.KEYCODE_DPAD_RIGHT:
moveNext();
return true;
case KeyEvent.KEYCODE_DPAD_CENTER:
case KeyEvent.KEYCODE_ENTER:
}
return super.onKeyDown(keyCode, event);
}
public boolean onGalleryTouchEvent(MotionEvent event) {
boolean consumed = mGestureDetector.onTouchEvent(event);
if (event.getAction() == MotionEvent.ACTION_UP) {
if (mIsTouched || mIsDragging) {
processScrollSnap();
processGesture();
}
}
return consumed;
}
void processGesture() {
int newViewNumber = mCurrentViewNumber;
int reloadViewNumber = 0;
int reloadPosition = 0;
mIsTouched = false;
mIsDragging = false;
if (mFlingDirection > 0) {
if (mCurrentPosition > getFirstPosition()
|| mIsGalleryCircular == true) {
// Determine previous view and outgoing view to recycle
newViewNumber = getPrevViewNumber(mCurrentViewNumber);
mCurrentPosition = getPrevPosition(mCurrentPosition);
reloadViewNumber = getNextViewNumber(mCurrentViewNumber);
reloadPosition = getPrevPosition(mCurrentPosition);
}
}
if (mFlingDirection < 0) {
if (mCurrentPosition < getLastPosition()
|| mIsGalleryCircular == true) {
// Determine the next view and outgoing view to recycle
newViewNumber = getNextViewNumber(mCurrentViewNumber);
mCurrentPosition = getNextPosition(mCurrentPosition);
reloadViewNumber = getPrevViewNumber(mCurrentViewNumber);
reloadPosition = getNextPosition(mCurrentPosition);
}
}
if (newViewNumber != mCurrentViewNumber) {
mCurrentViewNumber = newViewNumber;
// Reload outgoing view from adapter in new position
mViews[reloadViewNumber].recycleView(reloadPosition);
}
// Ensure input focus on the current view
mViews[mCurrentViewNumber].requestFocus();
// Run the slide animations for view transitions
mAnimation.prepareAnimation(mCurrentViewNumber);
this.startAnimation(mAnimation);
// Reset fling state
mFlingDirection = 0;
//checkNextBackButton(mCurrentPosition);
System.out.println("positionFiling" + mCurrentPosition);
}
void processScrollSnap() {
// Snap to next view if scrolled passed snap position
float rollEdgeWidth = mGalleryWidth * mSnapBorderRatio;
int rollOffset = mGalleryWidth - (int) rollEdgeWidth;
int currentOffset = mViews[mCurrentViewNumber].getCurrentOffset();
if (currentOffset <= rollOffset * -1) {
// Snap to previous view
mFlingDirection = 1;
}
if (currentOffset >= rollOffset) {
// Snap to next view
mFlingDirection = -1;
}
}
public class FlingGalleryView {
private int mViewNumber;
private FrameLayout mParentLayout;
private FrameLayout mInvalidLayout = null;
private LinearLayout mInternalLayout = null;
private View mExternalView = null;
public FlingGalleryView(int viewNumber, FrameLayout parentLayout) {
mViewNumber = viewNumber;
mParentLayout = parentLayout;
// Invalid layout is used when outside gallery
mInvalidLayout = new FrameLayout(mContext);
mInvalidLayout.setLayoutParams(new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
// Internal layout is permanent for duration
mInternalLayout = new LinearLayout(mContext);
mInternalLayout.setLayoutParams(new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT));
mParentLayout.addView(mInternalLayout);
}
public void recycleView(int newPosition) {
if (mExternalView != null) {
mInternalLayout.removeView(mExternalView);
}
if (mAdapter != null) {
if (newPosition >= getFirstPosition()
&& newPosition <= getLastPosition()) {
mExternalView = mAdapter.getView(newPosition,
mExternalView, mInternalLayout);
} else {
mExternalView = mInvalidLayout;
}
}
if (mExternalView != null) {
mInternalLayout.addView(mExternalView,
new LinearLayout.LayoutParams(
LayoutParams.FILL_PARENT,
LayoutParams.FILL_PARENT));
}
}
public void setOffset(int xOffset, int yOffset,
int relativeViewNumber) {
// Scroll the target view relative to its own position relative
// to currently displayed view
mInternalLayout.scrollTo(getViewOffset(mViewNumber,
relativeViewNumber)
+ xOffset, yOffset);
}
public int getCurrentOffset() {
// Return the current scroll position
return mInternalLayout.getScrollX();
}
public void requestFocus() {
mInternalLayout.requestFocus();
}
}
public class FlingGalleryAnimation extends Animation {
private boolean mIsAnimationInProgres;
private int mRelativeViewNumber;
private int mInitialOffset;
private int mTargetOffset;
private int mTargetDistance;
public FlingGalleryAnimation() {
mIsAnimationInProgres = false;
mRelativeViewNumber = 0;
mInitialOffset = 0;
mTargetOffset = 0;
mTargetDistance = 0;
}
public void prepareAnimation(int relativeViewNumber) {
// If we are animating relative to a new view
if (mRelativeViewNumber != relativeViewNumber) {
if (mIsAnimationInProgres == true) {
// We only have three views so if requested again to
// animate in same direction we must snap
int newDirection = (relativeViewNumber == getPrevViewNumber(mRelativeViewNumber)) ? 1
: -1;
int animDirection = (mTargetDistance < 0) ? 1 : -1;
// If animation in same direction
if (animDirection == newDirection) {
// Ran out of time to animate so snap to the target
// offset
mViews[0].setOffset(mTargetOffset, 0,
mRelativeViewNumber);
mViews[1].setOffset(mTargetOffset, 0,
mRelativeViewNumber);
mViews[2].setOffset(mTargetOffset, 0,
mRelativeViewNumber);
}
}
// Set relative view number for animation
mRelativeViewNumber = relativeViewNumber;
}
// Note: In this implementation the targetOffset will always be
// zero
// as we are centering the view; but we include the calculations
// of
// targetOffset and targetDistance for use in future
// implementations
mInitialOffset = mViews[mRelativeViewNumber].getCurrentOffset();
mTargetOffset = getViewOffset(mRelativeViewNumber,
mRelativeViewNumber);
mTargetDistance = mTargetOffset - mInitialOffset;
// Configure base animation properties
this.setDuration(mAnimationDuration);
this.setInterpolator(mDecelerateInterpolater);
// Start/continued animation
mIsAnimationInProgres = true;
}
protected void applyTransformation(float interpolatedTime,
Transformation transformation) {
// Ensure interpolatedTime does not over-shoot then calculate
// new offset
interpolatedTime = (interpolatedTime > 1.0f) ? 1.0f
: interpolatedTime;
int offset = mInitialOffset
+ (int) (mTargetDistance * interpolatedTime);
for (int viewNumber = 0; viewNumber < 3; viewNumber++) {
// Only need to animate the visible views as the other view
// will always be off-screen
if ((mTargetDistance > 0 && viewNumber != getNextViewNumber(mRelativeViewNumber))
|| (mTargetDistance < 0 && viewNumber != getPrevViewNumber(mRelativeViewNumber))) {
mViews[viewNumber].setOffset(offset, 0,
mRelativeViewNumber);
}
}
}
public boolean getTransformation(long currentTime,
Transformation outTransformation) {
if (super.getTransformation(currentTime, outTransformation) == false) {
// Perform final adjustment to offsets to cleanup animation
mViews[0].setOffset(mTargetOffset, 0, mRelativeViewNumber);
mViews[1].setOffset(mTargetOffset, 0, mRelativeViewNumber);
mViews[2].setOffset(mTargetOffset, 0, mRelativeViewNumber);
// Reached the animation target
mIsAnimationInProgres = false;
return false;
}
// Cancel if the screen touched
if (mIsTouched || mIsDragging) {
// Note that at this point we still consider ourselves to be
// animating
// because we have not yet reached the target offset; its
// just that the
// user has temporarily interrupted the animation with a
// touch gesture
return false;
}
return true;
}
}
private class FlingGestureDetector extends GestureDetector.SimpleOnGestureListener {
public boolean onDown(MotionEvent e) {
// Stop animation
mIsTouched = true;
// Reset fling state
mFlingDirection = 0;
return true;
}
public boolean onScroll(MotionEvent e1, MotionEvent e2,
float distanceX, float distanceY) {
if (e2.getAction() == MotionEvent.ACTION_MOVE) {
if (mIsDragging == false) {
// Stop animation
mIsTouched = true;
// Reconfigure scroll
mIsDragging = true;
mFlingDirection = 0;
mScrollTimestamp = System.currentTimeMillis();
mCurrentOffset = mViews[mCurrentViewNumber]
.getCurrentOffset();
}
float maxVelocity = mGalleryWidth
/ (mAnimationDuration / 1000.0f);
long timestampDelta = System.currentTimeMillis()
- mScrollTimestamp;
float maxScrollDelta = maxVelocity
* (timestampDelta / 1000.0f);
float currentScrollDelta = e1.getX() - e2.getX();
if (currentScrollDelta < maxScrollDelta * -1)
currentScrollDelta = maxScrollDelta * -1;
if (currentScrollDelta > maxScrollDelta)
currentScrollDelta = maxScrollDelta;
int scrollOffset = Math.round(mCurrentOffset
+ currentScrollDelta);
// We can't scroll more than the width of our own frame
// layout
if (scrollOffset >= mGalleryWidth)
scrollOffset = mGalleryWidth;
if (scrollOffset <= mGalleryWidth * -1)
scrollOffset = mGalleryWidth * -1;
mViews[0].setOffset(scrollOffset, 0, mCurrentViewNumber);
mViews[1].setOffset(scrollOffset, 0, mCurrentViewNumber);
mViews[2].setOffset(scrollOffset, 0, mCurrentViewNumber);
}
return false;
}
public boolean onFling(MotionEvent e1, MotionEvent e2,
float velocityX, float velocityY) {
if (Math.abs(e1.getY() - e2.getY()) <= swipe_max_off_path) {
if (e2.getX() - e1.getX() > swipe_min_distance
&& Math.abs(velocityX) > swipe_threshold_veloicty) {
movePrevious();
}
if (e1.getX() - e2.getX() > swipe_min_distance
&& Math.abs(velocityX) > swipe_threshold_veloicty) {
moveNext();
}
}
return false;
}
public void onLongPress(MotionEvent e) {
// Finalise scrolling
mFlingDirection = 0;
processGesture();
}
public void onShowPress(MotionEvent e) {
}
public boolean onSingleTapUp(MotionEvent e) {
// Reset fling state
mFlingDirection = 0;
return false;
}
}
}
}
My log cat error message is:
I am the beginner for android, something wrong my code?

LinearLayout productHolder = (LinearLayout) findViewById(R.id.linearLayoutOfCount);
Is returning null. Make sure you are referencing the correct id.