Develop Reference

Translate Animation Android

I have a RecyclerView with Images inside. I need to move clicked image to the center of the screen. And there should be no depend on the images's start point, it should move to the center of the screen.
I've tried to do this using XML code - it does't work correct, TranslateAnimation object - it doesn't work correct. In both variants image's movement depends on the images's start position and final points of all images are different.
I don't know how to do this. Please help me)

Try the following code. The code uses Listview, but the same logic can be applied for RecyclerView.
The approach here is to create a new imageview in the parent layout of the listview overlapping the image that was clicked. Then translate the newly created imageview to the center of the screen.
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
root = (RelativeLayout) findViewById(R.id.main_root);
listView = (ListView) findViewById(R.id.list);
MyAdapter adapter = new MyAdapter(MainActivity.this, web, imageId);
listView.setAdapter(adapter);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
ImageView imgView = (ImageView) view.findViewById(R.id.grid_image);
// Get location of window with respect to window.
int location[] = new int[2];
imgView.getLocationInWindow(location);
// Create a new image view overlapping
// the image view that was clicked.
ImageView imgView2 = new ImageView(MainActivity.this);
imgView2.setImageDrawable(imgView.getDrawable());
// To make it overlap, use the location values of
// the clicked image as left and top margin for the
// new image.
RelativeLayout.LayoutParams params = new RelativeLayout.LayoutParams(
imgView.getWidth(), imgView.getHeight());
params.leftMargin = location[0];
params.topMargin = location[1] - getStatusBarHeight();
// Add the new image view to the root view of the activity.
root.addView(imgView2, params);
translateToCenter(imgView2, location);
}
});
}
/**
* To translate the new image view to the center of the screen.
* #param view
* #param originalLoc
*/
private void translateToCenter(View view , int originalLoc[])
{
int xMove = root.getWidth() / 2 - view.getWidth() / 2 - originalLoc[0];
int yMove = root.getHeight() / 2 - view.getHeight() / 2 - originalLoc[1];
TranslateAnimation anim = new TranslateAnimation( 0, xMove , 0, yMove );
anim.setDuration(1000);
anim.setFillAfter( true );
view.startAnimation(anim);
}
/**
* To get the status bar height.
* #return
*/
private int getStatusBarHeight() {
int result = 0;
int resourceId = getResources().getIdentifier(
"status_bar_height", "dimen", "android");
if (resourceId > 0) {
result = getResources().getDimensionPixelSize(resourceId);
}
return result;
}

PopupWindow or PopupMenu? Or something else?

I'm trying to create very similar layout like Google Play Books. I need to create an PopupMenu or PopupWindow, which will be displayed at the same position like in the picture below.
I am not sure, if it is PopupMenu or PopupWindow or something else. This "window" is displayed when I click on the item from menu.
In case, that I change an orientation to landscape mode, in ActionBar is a new icon, which displays this "window". The picture below shows this situation:
I have two questions:
Is this a PopupMenu, PopupWindow or something else?
How can I determine the position of this "window" in case, that it is the PopupWindow and I need to show it?

You have to create an OnClickListener like this:
button.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
int[] location = new int[2];
v.getLocationOnScreen(location);
// Initialize the Point with x, and y positions
Point point = new Point();
point.x = location[0];
point.y = location[1];
popupWindow(v, point);
}
});
The method for popupWindow(View view, Point point):
private ArrayAdapter<String> adapterTypeSelection;
private void popupWindow(View v, Point p) {
// int popupwindowWidth =
// UnitConverterClass.convertDpToPx(180,getActivity());
int popupwindowHeight = LinearLayout.LayoutParams.WRAP_CONTENT;
LayoutInflater layoutInflater = (LayoutInflater) getActivity()
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View layout = layoutInflater.inflate(
R.layout.dashboard_profile_popup_window, null);
// Creating the PopupWindow
final PopupWindow pwindow = new PopupWindow(getActivity());
pwindow.setContentView(layout);
// pwindow.showAsDropDown(v);
// pwindow.setWidth(popupwindowWidth);
pwindow.setHeight(popupwindowHeight);
pwindow.setFocusable(true);
String[] types = {"hello", "hi"};
adapterTypeSelection = new ArrayAdapter<String>(getActivity(),
R.layout.<your layout for the popupwindow>,
R.id.textView, types);
ListView listview = (ListView) pwindow.getContentView().findViewById(
R.id.listview_popwindow);
listview.setAdapter(adapterTypeSelection);
listview.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
TextView temp = (TextView) parent.getChildAt(position)
.findViewById(R.id.textView);
if (temp.getText()
.toString()
.equals("hello"))) {
//hello
} else {
//hi
}
pwindow.dismiss();
}
});
pwindow.setOnDismissListener(new OnDismissListener() {
#Override
public void onDismiss() {
//TODO dismiss settings
}
});
pwindow.setWidth(<width>);
pwindow.setBackgroundDrawable(<resource for background>);
// int OFFSET_X = UnitConverterClass.convertDpToPx(180, getActivity());
// int OFFSET_Y = UnitConverterClass.convertDpToPx(30, getActivity());
// pwindow.showAtLocation(layout, Gravity.NO_GRAVITY,
// p.x + OFFSET_X, p.y + OFFSET_Y);
pwindow.showAtLocation(layout, Gravity.NO_GRAVITY, p.x, p.y);
}
Hope this helps to make a PopupWindow in the position you want to show it.

Gallery like view with center image zoom

Here I need a gallery like view with only three images to be shown at a time on screen. In this the middle image will be larger than the two other images on its sides.
If the user scrolls the view next images will slide on screen as it does in gallery and at a time only three images will be shown out of which the center image should automatically zoom when it is shown on screen and remaining two should be smaller than it.
Here I can't use gallery because it is depreciated in android.
I was able to make a gallery like view with help of viewpager using code on this link. It shows only three images on screen at a time, which fits my one requirement. But i am not able to get the central image that is visible on screen and zoom it. Although I was able to get the clicked image on screen.
Can someone please tell me where do I need to modify this code and what I need to add in it to get the image that is in center from the images shown on screen and zoom it.
I know that there is no center image on screen according to viewpager and it is just showing three images on screen at a time because of modifications in code.
I have also tried:-
GridView with horizontal scroll
HorizontalScrollView with horizontal linear layout
but viewpager seems to be a better solution, because it stops the scrolling with only three items on screen because of viewpager's inherent properties.
and If someone knows any other method to achieve it, please tell me and I'll try it.
P.S. For anyone who wants the full code, I have added it as an answer, which has zoom capability also. Just few additions in accepted answer. :)

Following code will help you to make a gallery like view which will have center lock. It responds to touch and swipe both. It shows three images on the screen at a time and the center image is zoomed.
import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.HorizontalScrollView;
import android.widget.ImageView;
import android.widget.LinearLayout;
public class CenteringHorizontalScrollView extends HorizontalScrollView implements View.OnTouchListener {
private Context mContext;
private static final int SWIPE_PAGE_ON_FACTOR = 10;
private int mActiveItem;
private float mPrevScrollX;
private boolean mStart;
private int mItemWidth;
View targetLeft, targetRight;
ImageView leftImage, rightImage;
public CenteringHorizontalScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
mContext=context;
mItemWidth = 100; // or whatever your item width is.
setOnTouchListener(this);
}
#Override
public boolean onTouch(View v, MotionEvent event) {
int x = (int) event.getRawX();
boolean handled = false;
switch (event.getAction()) {
case MotionEvent.ACTION_MOVE:
if (mStart) {
mPrevScrollX = x;
mStart = false;
}
break;
case MotionEvent.ACTION_UP:
mStart = true;
int minFactor = mItemWidth / SWIPE_PAGE_ON_FACTOR;
if ((mPrevScrollX - (float) x) > minFactor) {
if (mActiveItem < getMaxItemCount() - 1) {
mActiveItem = mActiveItem + 1;
}
}else if (((float) x - mPrevScrollX) > minFactor) {
if (mActiveItem > 0) {
mActiveItem = mActiveItem - 1;
}
}
scrollToActiveItem();
handled = true;
break;
}
return handled;
}
private int getMaxItemCount() {
return ((LinearLayout) getChildAt(0)).getChildCount();
}
private LinearLayout getLinearLayout() {
return (LinearLayout) getChildAt(0);
}
/**
* Centers the current view the best it can.
*/
public void centerCurrentItem() {
if (getMaxItemCount() == 0)
return;
int currentX = getScrollX();
View targetChild;
int currentChild = -1;
do {
currentChild++;
targetChild = getLinearLayout().getChildAt(currentChild);
} while (currentChild < getMaxItemCount() && targetChild.getLeft() < currentX);
if (mActiveItem != currentChild) {
mActiveItem = currentChild;
scrollToActiveItem();
}
}
/**
* Scrolls the list view to the currently active child.
*/
private void scrollToActiveItem() {
int maxItemCount = getMaxItemCount();
if (maxItemCount == 0)
return;
int targetItem = Math.min(maxItemCount - 1, mActiveItem);
targetItem = Math.max(0, targetItem);
mActiveItem = targetItem;
// Scroll so that the target child is centered
View targetView = getLinearLayout().getChildAt(targetItem);
ImageView centerImage = (ImageView)targetView;
int height=300;//set size of centered image
LinearLayout.LayoutParams flparams = new LinearLayout.LayoutParams(height, height);
centerImage.setLayoutParams(flparams);
//get the image to left of the centered image
if((targetItem-1)>=0){
targetLeft = getLinearLayout().getChildAt(targetItem-1);
leftImage = (ImageView)targetLeft;
int width=250;//set the size of left image
LinearLayout.LayoutParams leftParams = new LinearLayout.LayoutParams(width,width);
leftParams.setMargins(0, 30, 0, 0);
leftImage.setLayoutParams(leftParams);
}
//get the image to right of the centered image
if((targetItem+1)<maxItemCount){
targetRight = getLinearLayout().getChildAt(targetItem+1);
rightImage = (ImageView)targetRight;
int width=250;//set the size of right image
LinearLayout.LayoutParams rightParams = new LinearLayout.LayoutParams(width,width);
rightParams.setMargins(0, 30, 0, 0);
rightImage.setLayoutParams(rightParams);
}
int targetLeft = targetView.getLeft();
int childWidth = targetView.getRight() - targetLeft;
int width = getWidth() - getPaddingLeft() - getPaddingRight();
int targetScroll = targetLeft - ((width - childWidth) / 2);
super.smoothScrollTo(targetScroll, 0);
}
/**
* Sets the current item and centers it.
* #param currentItem The new current item.
*/
public void setCurrentItemAndCenter(int currentItem) {
mActiveItem = currentItem;
scrollToActiveItem();
}
}
In your xml add the horizontal scroll view like follow:-
<com.yourpackagename.CenteringHorizontalScrollView
android:id="#+id/HSVImage"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="#+id/Horizontalalternative">
<LinearLayout
android:id="#+id/linearImage"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
</LinearLayout>
</com.yourpackagename.CenteringHorizontalScrollView>
Define a Linear layout in your activity.
LinearLayout imageGallery;
Then get it as follows:-
imageGallery=(LinearLayout)findViewById(R.id.linearImage);
Now you have to add imageView to your LinearLayout. Here I assume that you have images in your drawable folder and you have made an array of ids of your images that you want to add to gallery. So you can do it via following method in your activity:-
for(int i=0; i<lengthOfImageIdArray; i++){
ImageView image=new ImageView(YourActivityName.this);
image.setBackgroundResource(yourArrayName[i]);
imageGallery.addView(image);
}
You can also set the width of images dynamically, so that they fit every screen, with only little extra effort.

Override setPrimaryItem in your ViewPager and make the center item bigger.
What was the issue with using a HorizontalScrollView with a LinearLayout? If it's centering you may be able to do something similar to this (assuming you've
/**
* A centering HSV loosely based on http://iotasol.blogspot.com/2011/08/creating-custom-horizontal-scroll-view.html
*/
public class CenteringHorizontalScrollView extends HorizontalScrollView implements View.OnTouchListener {
private static final int SWIPE_PAGE_ON_FACTOR = 10;
private int mActiveItem;
private float mPrevScrollX;
private boolean mStart;
private int mItemWidth;
public CenteringHorizontalScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
mItemWidth = 100; // or whatever your item width is.
setOnTouchListener(this);
}
#Override
public boolean onTouch(View v, MotionEvent event) {
int x = (int) event.getRawX();
boolean handled = false;
switch (event.getAction()) {
case MotionEvent.ACTION_MOVE:
if (mStart) {
mPrevScrollX = x;
mStart = false;
}
break;
case MotionEvent.ACTION_UP:
mStart = true;
int minFactor = mItemWidth / SWIPE_PAGE_ON_FACTOR;
if ((mPrevScrollX - (float) x) > minFactor) {
if (mActiveItem < getMaxItemCount() - 1) {
mActiveItem = mActiveItem + 1;
}
}
else if (((float) x - mPrevScrollX) > minFactor) {
if (mActiveItem > 0) {
mActiveItem = mActiveItem - 1;
}
}
scrollToActiveItem();
handled = true;
break;
}
return handled;
}
private int getMaxItemCount() {
return ((LinearLayout) getChildAt(0)).getChildCount();
}
private LinearLayout getLinearLayout() {
return (LinearLayout) getChildAt(0);
}
/**
* Centers the current view the best it can.
*/
public void centerCurrentItem() {
if (getMaxItemCount() == 0) {
return;
}
int currentX = getScrollX();
View targetChild;
int currentChild = -1;
do {
currentChild++;
targetChild = getLinearLayout().getChildAt(currentChild);
} while (currentChild < getMaxItemCount() && targetChild.getLeft() < currentX);
if (mActiveItem != currentChild) {
mActiveItem = currentChild;
scrollToActiveItem();
}
}
/**
* Scrolls the list view to the currently active child.
*/
private void scrollToActiveItem() {
int maxItemCount = getMaxItemCount();
if (maxItemCount == 0) {
return;
}
int targetItem = Math.min(maxItemCount - 1, mActiveItem);
targetItem = Math.max(0, targetItem);
mActiveItem = targetItem;
// Scroll so that the target child is centered
View targetView = getLinearLayout().getChildAt(targetItem);
int targetLeft = targetView.getLeft();
int childWidth = targetView.getRight() - targetLeft;
int width = getWidth() - getPaddingLeft() - getPaddingRight();
int targetScroll = targetLeft - ((width - childWidth) / 2);
super.smoothScrollTo(targetScroll, 0);
}
/**
* Sets the current item and centers it.
* #param currentItem The new current item.
*/
public void setCurrentItemAndCenter(int currentItem) {
mActiveItem = currentItem;
scrollToActiveItem();
}
}

Help with Android UI ListView problems

To understand this question, first read how this method works.
I am trying to implements a drag and drop ListView, it's going alright but have run into
a road block. So I don't have to handled everything, I am intercepting(but returning false) MotionEvents sent to the ListView, letting it handle scrolling and stuff. When I want to start dragging a item, I then return true and handled all the dragging stuff. Everything is working fine except for one thing. The drag(drag and drop) is started when it is determined that a long press as a occurred(in onInterceptTouchEvent). I get the Bitmap for the image that I drag around like so. itemPositition being the index of the item that was selected.
(omitting irrelevant parts)
...
View dragItem = mListView.getChildAt(itemPosition);
dragItem.setDrawingCacheEnabled(true);
Bitmap bitmap = Bitmap.createBitmap(dragItem.getDrawingCache());
mDragImage = new ImageView(mContext);
mDragImage.setImageBitmap(bitmap);
...
The problem is, mDragImage is a solid black like this.
But, if I don't let ListView handle anything. As in, I start the drag on ACTION_DOWN and stop on ACTION_UP, mDragImage looks has expected(but I obviously lose scrolling abilities).
Since the drag is started with a long press, the ListView is given the opportunity to do things before the long press occurs. This is my guess as to why this is happening. When a item is pressed, it is highlighted by the ListView. Somewhere in doing so, it is messing with the bitmap. So when I go to get it, it's in a weird state(all black).
I see two options for fixing this, neither of which I know how to do.
Create a image from scratch.
Handle the highlighting myself(if that is the problem).
Option two seems a better one to me, except that I looked at the documentation and the source code and could not find out how to do so. Here are some things I have done/tried.
I set setOnItemClickListener(...) and
setOnItemSelectedListener(...) with a empty method(highlighting
still happens). (Before anyone suggests it, calling
setOnClickListener results in a runtime error.)
I also looked into trying to get the ListView to make a new item
(for option 2), but could not find a way.
Spent 45ish minutes looking through the source code and
documentation trying to pinpoint where the highlighting was
happening(I never found it).
Any help fixing this would be appreciated.
(EDIT1 START)
So I don't actually know if onLongClickListener is working, I made an error before thinking it was. I am trying to set it up right now, will update when I find out if it does.
(EDIT1 END)
Last minute edit before post. I tried using onLongClickListener just now, and the image is good. I would still like to know if there is another way. How I have to use onLongClickListener to get things working is ugly, but it works. I also spent so much time trying to figure this out, it would be nice to find out the answer. I still want to be able to change/handle the highlight color, the default orangeish color is not pretty. Oh and sorry about the length of the post. I could not think of way of making it shorter, while supplying all the information I thought was needed.

use this code, it's allows operation drug and drop in ListView:
public class DraggableListView extends ListView {
private static final String LOG_TAG = "tasks365";
private static final int END_OF_LIST_POSITION = -2;
private DropListener mDropListener;
private int draggingItemHoverPosition;
private int dragStartPosition; // where was the dragged item originally
private int mUpperBound; // scroll the view when dragging point is moving out of this bound
private int mLowerBound; // scroll the view when dragging point is moving out of this bound
private int touchSlop;
private Dragging dragging;
private GestureDetector longPressDetector;
public DraggableListView(Context context, AttributeSet attrs) {
this(context, attrs, android.R.attr.listViewStyle);
}
public DraggableListView(final Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
touchSlop = ViewConfiguration.get(context).getScaledTouchSlop();
longPressDetector = new GestureDetector(getContext(), new SimpleOnGestureListener() {
#Override
public void onLongPress(final MotionEvent e) {
int x = (int) e.getX();
final int y = (int) e.getY();
int itemnum = pointToPosition(x, y);
if (itemnum == AdapterView.INVALID_POSITION) {
return;
}
if (dragging != null) {
dragging.stop();
dragging = null;
}
final View item = getChildAt(itemnum - getFirstVisiblePosition());
item.setPressed(false);
dragging = new Dragging(getContext());
dragging.start(y, ((int) e.getRawY()) - y, item);
draggingItemHoverPosition = itemnum;
dragStartPosition = draggingItemHoverPosition;
int height = getHeight();
mUpperBound = Math.min(y - touchSlop, height / 3);
mLowerBound = Math.max(y + touchSlop, height * 2 / 3);
}
});
setOnItemLongClickListener(new OnItemLongClickListener() {
#SuppressWarnings("unused")
public boolean onItemLongClick(AdapterView<?> paramAdapterView, View paramView, int paramInt, long paramLong) {
// Return true to let AbsListView reset touch mode
// Without this handler, the pressed item will keep highlight.
return true;
}
});
}
/* pointToPosition() doesn't consider invisible views, but we need to, so implement a slightly different version. */
private int myPointToPosition(int x, int y) {
if (y < 0) {
return getFirstVisiblePosition();
}
Rect frame = new Rect();
final int count = getChildCount();
for (int i = 0; i < count; i++) {
final View child = getChildAt(i);
child.getHitRect(frame);
if (frame.contains(x, y)) {
return getFirstVisiblePosition() + i;
}
}
if ((x >= frame.left) && (x < frame.right) && (y >= frame.bottom)) {
return END_OF_LIST_POSITION;
}
return INVALID_POSITION;
}
#Override
public boolean onTouchEvent(MotionEvent ev) {
if (longPressDetector.onTouchEvent(ev)) {
return true;
}
if ((dragging == null) || (mDropListener == null)) {
// it is not dragging, or there is no drop listener
return super.onTouchEvent(ev);
}
int action = ev.getAction();
switch (ev.getAction()) {
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_CANCEL:
dragging.stop();
dragging = null;
if (mDropListener != null) {
if (draggingItemHoverPosition == END_OF_LIST_POSITION) {
mDropListener.drop(dragStartPosition, getCount() - 1);
} else if (draggingItemHoverPosition != INVALID_POSITION) {
mDropListener.drop(dragStartPosition, draggingItemHoverPosition);
}
}
resetViews();
break;
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_MOVE:
int x = (int) ev.getX();
int y = (int) ev.getY();
dragging.drag(x, y);
int position = dragging.calculateHoverPosition();
if (position != INVALID_POSITION) {
if ((action == MotionEvent.ACTION_DOWN) || (position != draggingItemHoverPosition)) {
draggingItemHoverPosition = position;
doExpansion();
}
scrollList(y);
}
break;
}
return true;
}
private void doExpansion() {
int expanItemViewIndex = draggingItemHoverPosition - getFirstVisiblePosition();
if (draggingItemHoverPosition >= dragStartPosition) {
expanItemViewIndex++;
}
// Log.v(LOG_TAG, "Dragging item hovers over position " + draggingItemHoverPosition + ", expand item at index "
// + expanItemViewIndex);
View draggingItemOriginalView = getChildAt(dragStartPosition - getFirstVisiblePosition());
for (int i = 0;; i++) {
View itemView = getChildAt(i);
if (itemView == null) {
break;
}
ViewGroup.LayoutParams params = itemView.getLayoutParams();
int height = LayoutParams.WRAP_CONTENT;
if (itemView.equals(draggingItemOriginalView)) {
height = 1;
} else if (i == expanItemViewIndex) {
height = itemView.getHeight() + dragging.getDraggingItemHeight();
}
params.height = height;
itemView.setLayoutParams(params);
}
}
/**
* Reset view to original height.
*/
private void resetViews() {
for (int i = 0;; i++) {
View v = getChildAt(i);
if (v == null) {
layoutChildren(); // force children to be recreated where needed
v = getChildAt(i);
if (v == null) {
break;
}
}
ViewGroup.LayoutParams params = v.getLayoutParams();
params.height = LayoutParams.WRAP_CONTENT;
v.setLayoutParams(params);
}
}
private void resetScrollBounds(int y) {
int height = getHeight();
if (y >= height / 3) {
mUpperBound = height / 3;
}
if (y <= height * 2 / 3) {
mLowerBound = height * 2 / 3;
}
}
private void scrollList(int y) {
resetScrollBounds(y);
int height = getHeight();
int speed = 0;
if (y > mLowerBound) {
// scroll the list up a bit
speed = y > (height + mLowerBound) / 2 ? 16 : 4;
} else if (y < mUpperBound) {
// scroll the list down a bit
speed = y < mUpperBound / 2 ? -16 : -4;
}
if (speed != 0) {
int ref = pointToPosition(0, height / 2);
if (ref == AdapterView.INVALID_POSITION) {
//we hit a divider or an invisible view, check somewhere else
ref = pointToPosition(0, height / 2 + getDividerHeight() + 64);
}
View v = getChildAt(ref - getFirstVisiblePosition());
if (v != null) {
int pos = v.getTop();
setSelectionFromTop(ref, pos - speed);
}
}
}
public void setDropListener(DropListener l) {
mDropListener = l;
}
public interface DropListener {
void drop(int from, int to);
}
class Dragging {
private Context context;
private WindowManager windowManager;
private WindowManager.LayoutParams mWindowParams;
private ImageView mDragView;
private Bitmap mDragBitmap;
private int coordOffset;
private int mDragPoint; // at what offset inside the item did the user grab it
private int draggingItemHeight;
private int x;
private int y;
private int lastY;
public Dragging(Context context) {
this.context = context;
windowManager = (WindowManager) context.getSystemService("window");
}
/**
* #param y
* #param offset - the difference in y axis between screen coordinates and coordinates in this view
* #param view - which view is dragged
*/
public void start(int y, int offset, View view) {
this.y = y;
lastY = y;
this.coordOffset = offset;
mDragPoint = y - view.getTop();
draggingItemHeight = view.getHeight();
mDragView = new ImageView(context);
mDragView.setBackgroundResource(android.R.drawable.alert_light_frame);
// Create a copy of the drawing cache so that it does not get recycled
// by the framework when the list tries to clean up memory
view.setDrawingCacheEnabled(true);
mDragBitmap = Bitmap.createBitmap(view.getDrawingCache());
mDragView.setImageBitmap(mDragBitmap);
mWindowParams = new WindowManager.LayoutParams();
mWindowParams.gravity = Gravity.TOP;
mWindowParams.x = 0;
mWindowParams.y = y - mDragPoint + coordOffset;
mWindowParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
| WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
| WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN;
mWindowParams.format = PixelFormat.TRANSLUCENT;
mWindowParams.windowAnimations = 0;
windowManager.addView(mDragView, mWindowParams);
}
public void drag(int x, int y) {
lastY = this.y;
this.x = x;
this.y = y;
mWindowParams.y = y - mDragPoint + coordOffset;
windowManager.updateViewLayout(mDragView, mWindowParams);
}
public void stop() {
if (mDragView != null) {
windowManager.removeView(mDragView);
mDragView.setImageDrawable(null);
mDragView = null;
}
if (mDragBitmap != null) {
mDragBitmap.recycle();
mDragBitmap = null;
}
}
public int getDraggingItemHeight() {
return draggingItemHeight;
}
public int calculateHoverPosition() {
int adjustedY = (int) (y - mDragPoint + (Math.signum(y - lastY) + 2) * draggingItemHeight / 2);
// Log.v(LOG_TAG, "calculateHoverPosition(): lastY=" + lastY + ", y=" + y + ", adjustedY=" + adjustedY);
int pos = myPointToPosition(0, adjustedY);
if (pos >= 0) {
if (pos >= dragStartPosition) {
pos -= 1;
}
}
return pos;
}
}
}

Android: how to check if a View inside of ScrollView is visible?

I have a ScrollView which holds a series of Views. I would like to be able to determine if a view is currently visible (if any part of it is currently displayed by the ScrollView). I would expect the below code to do this, surprisingly it does not:
Rect bounds = new Rect();
view.getDrawingRect(bounds);
Rect scrollBounds = new Rect(scroll.getScrollX(), scroll.getScrollY(),
scroll.getScrollX() + scroll.getWidth(), scroll.getScrollY() + scroll.getHeight());
if(Rect.intersects(scrollBounds, bounds))
{
//is visible
}

This works:
Rect scrollBounds = new Rect();
scrollView.getHitRect(scrollBounds);
if (imageView.getLocalVisibleRect(scrollBounds)) {
// Any portion of the imageView, even a single pixel, is within the visible window
} else {
// NONE of the imageView is within the visible window
}

Use View#getHitRect instead of View#getDrawingRect on the view you're testing. You can use View#getDrawingRect on the ScrollView instead of calculating explicitly.
Code from View#getDrawingRect:
public void getDrawingRect(Rect outRect) {
outRect.left = mScrollX;
outRect.top = mScrollY;
outRect.right = mScrollX + (mRight - mLeft);
outRect.bottom = mScrollY + (mBottom - mTop);
}
Code from View#getHitRect:
public void getHitRect(Rect outRect) {
outRect.set(mLeft, mTop, mRight, mBottom);
}

If you want to detect that the view is FULLY visible:
private boolean isViewVisible(View view) {
Rect scrollBounds = new Rect();
mScrollView.getDrawingRect(scrollBounds);
float top = view.getY();
float bottom = top + view.getHeight();
if (scrollBounds.top < top && scrollBounds.bottom > bottom) {
return true;
} else {
return false;
}
}

This extension help detect view fully visible.
It also work if your View is a child of child of ... of ScrollView (eg: ScrollView -> LinearLayout -> ContraintLayout -> ... -> YourView).
fun ScrollView.isViewVisible(view: View): Boolean {
val scrollBounds = Rect()
this.getDrawingRect(scrollBounds)
var top = 0f
var temp = view
while (temp !is ScrollView){
top += (temp).y
temp = temp.parent as View
}
val bottom = top + view.height
return scrollBounds.top < top && scrollBounds.bottom > bottom
}
Note
1) view.getY() and view.getX() return the x,y value to FIRST PARENT.
2) Here is example about how getDrawingRect will return
Link

My Solution is use NestedScrollView Scroll element:
final Rect scrollBounds = new Rect();
scroller.getHitRect(scrollBounds);
scroller.setOnScrollChangeListener(new NestedScrollView.OnScrollChangeListener() {
#Override
public void onScrollChange(NestedScrollView v, int scrollX, int scrollY, int oldScrollX, int oldScrollY) {
if (myBtn1 != null) {
if (myBtn1.getLocalVisibleRect(scrollBounds)) {
if (!myBtn1.getLocalVisibleRect(scrollBounds)
|| scrollBounds.height() < myBtn1.getHeight()) {
Log.i(TAG, "BTN APPEAR PARCIALY");
} else {
Log.i(TAG, "BTN APPEAR FULLY!!!");
}
} else {
Log.i(TAG, "No");
}
}
}
});
}

To expand a bit on Bill Mote's answer using getLocalVisibleRect, you may want to check if the view is only partially visible:
Rect scrollBounds = new Rect();
scrollView.getHitRect(scrollBounds);
if (!imageView.getLocalVisibleRect(scrollBounds)
|| scrollBounds.height() < imageView.getHeight()) {
// imageView is not within or only partially within the visible window
} else {
// imageView is completely visible
}

public static int getVisiblePercent(View v) {
if (v.isShown()) {
Rect r = new Rect();
v.getGlobalVisibleRect(r);
double sVisible = r.width() * r.height();
double sTotal = v.getWidth() * v.getHeight();
return (int) (100 * sVisible / sTotal);
} else {
return -1;
}
}

I faced the same problem today. While Googling and reading Android reference I found this post and a method I ended up using instead;
public final boolean getLocalVisibleRect (Rect r)
Nice of them not to only providing Rect but also boolean indicating if View visible at all. On negative side this method is undocumented :(

I you want to detect if your View is fully visible, try with this method:
private boolean isViewVisible(View view) {
Rect scrollBounds = new Rect();
mScrollView.getDrawingRect(scrollBounds);
float top = view.getY();
float bottom = top + view.getHeight();
if (scrollBounds.top < top && scrollBounds.bottom > bottom) {
return true; //View is visible.
} else {
return false; //View is NOT visible.
}
}
Strictly speaking you can get the visibility of a view with:
if (myView.getVisibility() == View.VISIBLE) {
//VISIBLE
} else {
//INVISIBLE
}
The posible constant values of the visibility in a View are:
VISIBLE
This view is visible. Use with setVisibility(int) and android:visibility.
INVISIBLE
This view is invisible, but it still takes up space for layout purposes. Use with setVisibility(int) and android:visibility.
GONE
This view is invisible, and it doesn't take any space for layout purposes. Use with setVisibility(int) and android:visibility.

Kotlin way;
An extension for listing scroll view's scroll and get an action if child view visible on screen.
#SuppressLint("ClickableViewAccessibility")
fun View.setChildViewOnScreenListener(view: View, action: () -> Unit) {
val visibleScreen = Rect()
this.setOnTouchListener { _, motionEvent ->
if (motionEvent.action == MotionEvent.ACTION_MOVE) {
this.getDrawingRect(visibleScreen)
if (view.getLocalVisibleRect(visibleScreen)) {
action()
}
}
false
}
}
Use this extension function for any scrollable view
nestedScrollView.setChildViewOnScreenListener(childView) {
action()
}

You can use the FocusAwareScrollView which notifies when view becomes visible :
FocusAwareScrollView focusAwareScrollView = (FocusAwareScrollView) findViewById(R.id.focusAwareScrollView);
if (focusAwareScrollView != null) {
ArrayList<View> viewList = new ArrayList<>();
viewList.add(yourView1);
viewList.add(yourView2);
focusAwareScrollView.registerViewSeenCallBack(viewList, new FocusAwareScrollView.OnViewSeenListener() {
#Override
public void onViewSeen(View v, int percentageScrolled) {
if (v == yourView1) {
// user have seen view1
} else if (v == yourView2) {
// user have seen view2
}
}
});
}
Here is class :
import android.content.Context;
import android.graphics.Rect;
import android.support.v4.widget.NestedScrollView;
import android.util.AttributeSet;
import android.view.View;
import java.util.ArrayList;
import java.util.List;
public class FocusAwareScrollView extends NestedScrollView {
private List<OnScrollViewListener> onScrollViewListeners = new ArrayList<>();
public FocusAwareScrollView(Context context) {
super(context);
}
public FocusAwareScrollView(Context context, AttributeSet attrs) {
super(context, attrs);
}
public FocusAwareScrollView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
public interface OnScrollViewListener {
void onScrollChanged(FocusAwareScrollView v, int l, int t, int oldl, int oldt);
}
public interface OnViewSeenListener {
void onViewSeen(View v, int percentageScrolled);
}
public void addOnScrollListener(OnScrollViewListener l) {
onScrollViewListeners.add(l);
}
public void removeOnScrollListener(OnScrollViewListener l) {
onScrollViewListeners.remove(l);
}
protected void onScrollChanged(int l, int t, int oldl, int oldt) {
for (int i = onScrollViewListeners.size() - 1; i >= 0; i--) {
onScrollViewListeners.get(i).onScrollChanged(this, l, t, oldl, oldt);
}
super.onScrollChanged(l, t, oldl, oldt);
}
#Override
public void requestChildFocus(View child, View focused) {
super.requestChildFocus(child, focused);
}
private boolean handleViewSeenEvent(View view, int scrollBoundsBottom, int scrollYOffset,
float minSeenPercentage, OnViewSeenListener onViewSeenListener) {
int loc[] = new int[2];
view.getLocationOnScreen(loc);
int viewBottomPos = loc[1] - scrollYOffset + (int) (minSeenPercentage / 100 * view.getMeasuredHeight());
if (viewBottomPos <= scrollBoundsBottom) {
int scrollViewHeight = this.getChildAt(0).getHeight();
int viewPosition = this.getScrollY() + view.getScrollY() + view.getHeight();
int percentageSeen = (int) ((double) viewPosition / scrollViewHeight * 100);
onViewSeenListener.onViewSeen(view, percentageSeen);
return true;
}
return false;
}
public void registerViewSeenCallBack(final ArrayList<View> views, final OnViewSeenListener onViewSeenListener) {
final boolean[] viewSeen = new boolean[views.size()];
FocusAwareScrollView.this.postDelayed(new Runnable() {
#Override
public void run() {
final Rect scrollBounds = new Rect();
FocusAwareScrollView.this.getHitRect(scrollBounds);
final int loc[] = new int[2];
FocusAwareScrollView.this.getLocationOnScreen(loc);
FocusAwareScrollView.this.setOnScrollChangeListener(new NestedScrollView.OnScrollChangeListener() {
boolean allViewsSeen = true;
#Override
public void onScrollChange(NestedScrollView v, int x, int y, int oldx, int oldy) {
for (int index = 0; index < views.size(); index++) {
//Change this to adjust criteria
float viewSeenPercent = 1;
if (!viewSeen[index])
viewSeen[index] = handleViewSeenEvent(views.get(index), scrollBounds.bottom, loc[1], viewSeenPercent, onViewSeenListener);
if (!viewSeen[index])
allViewsSeen = false;
}
//Remove this if you want continuous callbacks
if (allViewsSeen)
FocusAwareScrollView.this.setOnScrollChangeListener((NestedScrollView.OnScrollChangeListener) null);
}
});
}
}, 500);
}
}

I ended up implementing a combination of two of the Java answers ( #bill-mote https://stackoverflow.com/a/12428154/3686125 and #denys-vasylenko https://stackoverflow.com/a/25528434/3686125 ) in my project as a set of Kotlin extensions, which support either standard vertial ScrollView or HorizontalScrollView controls.
I just tossed these in a Kotlin file named Extensions.kt, no class, just methods.
I used these to determine which item to snap to when a user stops scrolling in various scrollviews in my project:
fun View.isPartiallyOrFullyVisible(horizontalScrollView: HorizontalScrollView) : Boolean {
val scrollBounds = Rect()
horizontalScrollView.getHitRect(scrollBounds)
return getLocalVisibleRect(scrollBounds)
}
fun View.isPartiallyOrFullyVisible(scrollView: ScrollView) : Boolean {
val scrollBounds = Rect()
scrollView.getHitRect(scrollBounds)
return getLocalVisibleRect(scrollBounds)
}
fun View.isFullyVisible(horizontalScrollView: HorizontalScrollView) : Boolean {
val scrollBounds = Rect()
horizontalScrollView.getDrawingRect(scrollBounds)
val left = x
val right = left + width
return scrollBounds.left < left && scrollBounds.right > right
}
fun View.isFullyVisible(scrollView: ScrollView) : Boolean {
val scrollBounds = Rect()
scrollView.getDrawingRect(scrollBounds)
val top = y
val bottom = top + height
return scrollBounds.top < top && scrollBounds.bottom > bottom
}
fun View.isPartiallyVisible(horizontalScrollView: HorizontalScrollView) : Boolean = isPartiallyOrFullyVisible(horizontalScrollView) && !isFullyVisible(horizontalScrollView)
fun View.isPartiallyVisible(scrollView: ScrollView) : Boolean = isPartiallyOrFullyVisible(scrollView) && !isFullyVisible(scrollView)
Example usage, iterating through scrollview's LinearLayout children and logging outputs:
val linearLayoutChild: LinearLayout = getChildAt(0) as LinearLayout
val scrollView = findViewById(R.id.scroll_view) //Replace with your scrollview control or synthetic accessor
for (i in 0 until linearLayoutChild.childCount) {
with (linearLayoutChild.getChildAt(i)) {
Log.d("ScrollView", "child$i left=$left width=$width isPartiallyOrFullyVisible=${isPartiallyOrFullyVisible(scrollView)} isFullyVisible=${isFullyVisible(scrollView)} isPartiallyVisible=${isPartiallyVisible(scrollView)}")
}
}

My way:
scrollView.viewTreeObserver?.addOnScrollChangedListener {
scrollView.getDrawingRect(Rect())
myViewInsideScrollView.getLocalVisibleRect(Rect())
}

I know its very late. But i have a good solution. Below is the code snippet for getting view visibility percentage in scroll view.
First of all set touch listener on scroll view for getting callback for scroll stop.
#Override
public boolean onTouch(View v, MotionEvent event) {
switch ( event.getAction( ) ) {
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
new Handler().postDelayed(new Runnable() {
#Override
public void run() {
if(mScrollView == null){
mScrollView = (ScrollView) findViewById(R.id.mScrollView);
}
int childCount = scrollViewRootChild.getChildCount();
//Scroll view location on screen
int[] scrollViewLocation = {0,0};
mScrollView.getLocationOnScreen(scrollViewLocation);
//Scroll view height
int scrollViewHeight = mScrollView.getHeight();
for (int i = 0; i < childCount; i++){
View child = scrollViewRootChild.getChildAt(i);
if(child != null && child.getVisibility() == View.VISIBLE){
int[] viewLocation = new int[2];
child.getLocationOnScreen(viewLocation);
int viewHeight = child.getHeight();
getViewVisibilityOnScrollStopped(scrollViewLocation, scrollViewHeight,
viewLocation, viewHeight, (String) child.getTag(), (childCount - (i+1)));
}
}
}
}, 150);
break;
}
return false;
}
In above code snippet, we are getting call backs for scroll view touch events and post a runnable after 150 millis(Not mandatory) after getting the callback for scroll stopped. In that runnable we will get location of scroll view on the screen and scroll view height. Then get the direct child viewgroup instance of scroll view and get the child counts. In my case direct child of scroll view is LinearLayout named scrollViewRootChild. Then iterate all the child views of scrollViewRootChild. In above code snippet you can see I am getting the location of the child on the screen in a integer array named viewLocation, get height of view in variable name viewHeight. Then i called a private method getViewVisibilityOnScrollStopped. You can get the understanding of the internal working of this method by reading documentation.
/**
* getViewVisibilityOnScrollStopped
* #param scrollViewLocation location of scroll view on screen
* #param scrollViewHeight height of scroll view
* #param viewLocation location of view on screen, you can use the method of view claas's getLocationOnScreen method.
* #param viewHeight height of view
* #param tag tag on view
* #param childPending number of views pending for iteration.
*/
void getViewVisibilityOnScrollStopped(int[] scrollViewLocation, int scrollViewHeight, int[] viewLocation, int viewHeight, String tag, int childPending) {
float visiblePercent = 0f;
int viewBottom = viewHeight + viewLocation[1]; //Get the bottom of view.
if(viewLocation[1] >= scrollViewLocation[1]) { //if view's top is inside the scroll view.
visiblePercent = 100;
int scrollBottom = scrollViewHeight + scrollViewLocation[1]; //Get the bottom of scroll view
if (viewBottom >= scrollBottom) { //If view's bottom is outside from scroll view
int visiblePart = scrollBottom - viewLocation[1]; //Find the visible part of view by subtracting view's top from scrollview's bottom
visiblePercent = (float) visiblePart / viewHeight * 100;
}
}else{ //if view's top is outside the scroll view.
if(viewBottom > scrollViewLocation[1]){ //if view's bottom is outside the scroll view
int visiblePart = viewBottom - scrollViewLocation[1]; //Find the visible part of view by subtracting scroll view's top from view's bottom
visiblePercent = (float) visiblePart / viewHeight * 100;
}
}
if(visiblePercent > 0f){
visibleWidgets.add(tag); //List of visible view.
}
if(childPending == 0){
//Do after iterating all children.
}
}
If you feel any improvement in this code please contribute.

Using #Qberticus answer which was to the point but great btw, I compined a bunch of codes to check if whenever a scrollview is called and got scrolled it trigger the #Qberticus answer and you can do whatever you want, in my case I have a social network containing videos so when the view is drawed on the screen I play the video same idea like facebook and Instagram.
Here's the code:
mainscrollview.getViewTreeObserver().addOnScrollChangedListener(new OnScrollChangedListener() {
#Override
public void onScrollChanged() {
//mainscrollview is my scrollview that have inside it a linearlayout containing many child views.
Rect bounds = new Rect();
for(int xx=1;xx<=postslayoutindex;xx++)
{
//postslayoutindex is the index of how many posts are read.
//postslayoutchild is the main layout for the posts.
if(postslayoutchild[xx]!=null){
postslayoutchild[xx].getHitRect(bounds);
Rect scrollBounds = new Rect();
mainscrollview.getDrawingRect(scrollBounds);
if(Rect.intersects(scrollBounds, bounds))
{
vidPreview[xx].startPlaywithoutstoppping();
//I made my own custom video player using textureview and initialized it globally in the class as an array so I can access it from anywhere.
}
else
{
}
}
}
}
});