Develop Reference

Android Gallery zoom in/out

Hi I am using the Gallery widget to show images downloaded from the internet.
to show several images and I would like to have a gradual zoom while people slide up and down on the screen. I know how to implement the touch event the only thing I don't know how to make the whole gallery view grow gradually. I don't want to zoom in on one image I want the whole gallery to zoom in/out gradually.
EDIT3: I manage to zoom the visible part of the gallery but the problem is I need to find a way for the gallery to find out about it and update it's other children too.
What happens is if 3 images are visible then you start zooming and the gallery does get smaller, so do the images but what I would like in this case is more images to be visible but I don't know how to reach this desired effect. Here's the entire code:
public class Gallery1 extends Activity implements OnTouchListener {
private static final String TAG = "GalleryTest";
private float zoom=0.0f;
// Remember some things for zooming
PointF start = new PointF();
PointF mid = new PointF();
Gallery g;
LinearLayout layout2;
private ImageAdapter ad;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.gallery_1);
layout2=(LinearLayout) findViewById(R.id.layout2);
// Reference the Gallery view
g = (Gallery) findViewById(R.id.gallery);
// Set the adapter to our custom adapter (below)
ad=new ImageAdapter(this);
g.setAdapter(ad);
layout2.setOnTouchListener(this);
}
public void zoomList(boolean increase) {
Log.i(TAG, "startig animation");
AnimatorSet set = new AnimatorSet();
set.playTogether(
ObjectAnimator.ofFloat(g, "scaleX", zoom),
ObjectAnimator.ofFloat(g, "scaleY", zoom)
);
set.addListener(new AnimatorListener() {
#Override
public void onAnimationStart(Animator animation) {
}
#Override
public void onAnimationRepeat(Animator animation) {
// TODO Auto-generated method stub
}
#Override
public void onAnimationEnd(Animator animation) {
}
#Override
public void onAnimationCancel(Animator animation) {
// TODO Auto-generated method stub
}
});
set.setDuration(100).start();
}
public class ImageAdapter extends BaseAdapter {
private static final int ITEM_WIDTH = 136;
private static final int ITEM_HEIGHT = 88;
private final int mGalleryItemBackground;
private final Context mContext;
private final Integer[] mImageIds = {
R.drawable.gallery_photo_1,
R.drawable.gallery_photo_2,
R.drawable.gallery_photo_3,
R.drawable.gallery_photo_4,
R.drawable.gallery_photo_5,
R.drawable.gallery_photo_6,
R.drawable.gallery_photo_7,
R.drawable.gallery_photo_8
};
private final float mDensity;
public ImageAdapter(Context c) {
mContext = c;
// See res/values/attrs.xml for the <declare-styleable> that defines
// Gallery1.
TypedArray a = obtainStyledAttributes(R.styleable.Gallery1);
mGalleryItemBackground = a.getResourceId(
R.styleable.Gallery1_android_galleryItemBackground, 1);
a.recycle();
mDensity = c.getResources().getDisplayMetrics().density;
}
public int getCount() {
return mImageIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView;
if (convertView == null) {
convertView = new ImageView(mContext);
imageView = (ImageView) convertView;
imageView.setScaleType(ImageView.ScaleType.FIT_XY);
imageView.setLayoutParams(new Gallery.LayoutParams(
(int) (ITEM_WIDTH * mDensity + 0.5f),
(int) (ITEM_HEIGHT * mDensity + 0.5f)));
} else {
imageView = (ImageView) convertView;
}
imageView.setImageResource(mImageIds[position]);
return imageView;
}
}
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_MOVE
&& event.getPointerCount() > 1) {
midPoint(mid, event);
if(mid.y > start.y){
Log.i(TAG, "Going down (Math.abs(mid.y - start.y)= "+(Math.abs(mid.y - start.y))+" and zoom="+zoom); // going down so increase
if ((Math.abs(mid.y - start.y) > 10) && (zoom<2.5f)){
zoom=zoom+0.1f;
midPoint(start, event);
zoomList(true);
}
return true;
}else if(mid.y < start.y){
Log.i(TAG, "Going up (Math.abs(mid.y - start.y)= "+(Math.abs(mid.y - start.y))+" and zoom="+zoom); //smaller
if ((Math.abs(mid.y - start.y) > 10) &&(zoom>0.1)){
midPoint(start, event);
zoom=zoom-0.1f;
zoomList(false);
}
return true;
}
}
else if (event.getAction() == MotionEvent.ACTION_POINTER_DOWN) {
Log.e(TAG, "Pointer went down: " + event.getPointerCount());
return true;
}
else if (event.getAction() == MotionEvent.ACTION_UP) {
Log.i(TAG, "Pointer going up");
return true;
}
else if (event.getAction() == MotionEvent.ACTION_DOWN) {
Log.i(TAG, "Pointer going down");
start.set(event.getX(), event.getY());
return true;
}
return false;
// indicate event was handled or not
}
private void midPoint(PointF point, MotionEvent event) {
float x = event.getX(0) + event.getX(1);
float y = event.getY(0) + event.getY(1);
point.set(x / 2, y / 2);
}
I realise I will probably have to extend the Gallery or even another View group or create my own class but I don't know where to start: which method use the one responsible for scaling...
EDIT4: I don't know if he question is clear enough. Here is an example of states:
State one: initial state, we have 3 images in view
State 2: we detect vertical touches going up with 2 fingers = we have to zoom out
state 3: we start zooming = animation on the gallery or on the children???
state 4: gallery detects that it's 3 children are smaller
state 5: gallery adds 1 /more children according to the new available space
LAST UPDATE:
Thanks to all that have posted but I have finally reached a conclusion and that is to not use Gallery at all:
1. It's deprecated
2. It's not customizable enough for my case
If you want to animate several images at once you may want to consider using OpenGl, I am using libgdx library:
https://github.com/libgdx/libgdx

The following ScalingGallery implementation might be of help.
This gallery subclass overrides the getChildStaticTransformation(View child, Transformation t) method in which the scaling is performed. You can further customize the scaling parameters to fit your own needs.
Please note the ScalingGalleryItemLayout.java class. This is necessary because after you have performed the scaling operationg on the child views, their hit boxes are no longer valid so they must be updated from with the getChildStaticTransformation(View child, Transformation t) method.
This is done by wrapping each gallery item in a ScalingGalleryItemLayout which extends a LinearLayout. Again, you can customize this to fit your own needs if a LinearLayout does not meet your needs for layout out your gallery items.
File : /src/com/example/ScalingGallery.java
/**
* A Customized Gallery component which alters the size and position of its items based on their position in the Gallery.
*/
public class ScalingGallery extends Gallery {
public static final int ITEM_SPACING = -20;
private static final float SIZE_SCALE_MULTIPLIER = 0.25f;
private static final float ALPHA_SCALE_MULTIPLIER = 0.5f;
private static final float X_OFFSET = 20.0f;
/**
* Implemented by child view to adjust the boundaries after it has been matrix transformed.
*/
public interface SetHitRectInterface {
public void setHitRect(RectF newRect);
}
/**
* #param context
* Context that this Gallery will be used in.
* #param attrs
* Attributes for this Gallery (via either xml or in-code)
*/
public ScalingGallery(Context context, AttributeSet attrs) {
super(context, attrs);
setStaticTransformationsEnabled(true);
setChildrenDrawingOrderEnabled(true);
}
/**
* {#inheritDoc}
*
* #see #setStaticTransformationsEnabled(boolean)
*
* This is where the scaling happens.
*/
protected boolean getChildStaticTransformation(View child, Transformation t) {
child.invalidate();
t.clear();
t.setTransformationType(Transformation.TYPE_BOTH);
// Position of the child in the Gallery (... +2 +1 0 -1 -2 ... 0 being the middle)
final int childPosition = getSelectedItemPosition() - getPositionForView(child);
final int childPositionAbs = (int) Math.abs(childPosition);
final float left = child.getLeft();
final float top = child.getTop();
final float right = child.getRight();
final float bottom = child.getBottom();
Matrix matrix = t.getMatrix();
RectF modifiedHitBox = new RectF();
// Change alpha, scale and translate non-middle child views.
if (childPosition != 0) {
final int height = child.getMeasuredHeight();
final int width = child.getMeasuredWidth();
// Scale the size.
float scaledSize = 1.0f - (childPositionAbs * SIZE_SCALE_MULTIPLIER);
if (scaledSize < 0) {
scaledSize = 0;
}
matrix.setScale(scaledSize, scaledSize);
float moveX = 0;
float moveY = 0;
// Moving from right to left -- linear move since the scaling is done with respect to top-left corner of the view.
if (childPosition < 0) {
moveX = ((childPositionAbs - 1) * SIZE_SCALE_MULTIPLIER * width) + X_OFFSET;
moveX *= -1;
} else { // Moving from left to right -- sum of the previous positions' x displacements.
// X(n) = X(0) + X(1) + X(2) + ... + X(n-1)
for (int i = childPositionAbs; i > 0; i--) {
moveX += (i * SIZE_SCALE_MULTIPLIER * width);
}
moveX += X_OFFSET;
}
// Moving down y-axis is linear.
moveY = ((childPositionAbs * SIZE_SCALE_MULTIPLIER * height) / 2);
matrix.postTranslate(moveX, moveY);
// Scale alpha value.
final float alpha = (1.0f / childPositionAbs) * ALPHA_SCALE_MULTIPLIER;
t.setAlpha(alpha);
// Calculate new hit box. Since we moved the child, the hitbox is no longer lined up with the new child position.
final float newLeft = left + moveX;
final float newTop = top + moveY;
final float newRight = newLeft + (width * scaledSize);
final float newBottom = newTop + (height * scaledSize);
modifiedHitBox = new RectF(newLeft, newTop, newRight, newBottom);
} else {
modifiedHitBox = new RectF(left, top, right, bottom);
}
// update child hit box so you can tap within the child's boundary
((SetHitRectInterface) child).setHitRect(modifiedHitBox);
return true;
}
#Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
// Helps to smooth out jittering during scrolling.
// read more - http://www.unwesen.de/2011/04/17/android-jittery-scrolling-gallery/
final int viewsOnScreen = getLastVisiblePosition() - getFirstVisiblePosition();
if (viewsOnScreen <= 0) {
super.onLayout(changed, l, t, r, b);
}
}
private int mLastDrawnPosition;
#Override
protected int getChildDrawingOrder(int childCount, int i) {
//Reset the last position variable every time we are starting a new drawing loop
if (i == 0) {
mLastDrawnPosition = 0;
}
final int centerPosition = getSelectedItemPosition() - getFirstVisiblePosition();
if (i == childCount - 1) {
return centerPosition;
} else if (i >= centerPosition) {
mLastDrawnPosition++;
return childCount - mLastDrawnPosition;
} else {
return i;
}
}
}
File : /src/com/example/ScalingGalleryItemLayout.java
public class ScalingGalleryItemLayout extends LinearLayout implements SetHitRectInterface {
public ScalingGalleryItemLayout(Context context) {
super(context);
}
public ScalingGalleryItemLayout(Context context, AttributeSet attrs) {
super(context, attrs);
}
public ScalingGalleryItemLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
private Rect mTransformedRect;
#Override
public void setHitRect(RectF newRect) {
if (newRect == null) {
return;
}
if (mTransformedRect == null) {
mTransformedRect = new Rect();
}
newRect.round(mTransformedRect);
}
#Override
public void getHitRect(Rect outRect) {
if (mTransformedRect == null) {
super.getHitRect(outRect);
} else {
outRect.set(mTransformedRect);
}
}
}
File : /res/layout/ScaledGalleryItemLayout.xml
<?xml version="1.0" encoding="utf-8"?>
<com.example.ScalingGalleryItemLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/gallery_item_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:orientation="vertical"
android:padding="5dp" >
<ImageView
android:id="#+id/gallery_item_image"
android:layout_width="360px"
android:layout_height="210px"
android:layout_gravity="center"
android:antialias="true"
android:background="#drawable/gallery_item_button_selector"
android:cropToPadding="true"
android:padding="35dp"
android:scaleType="centerInside" />
<TextView
android:id="#+id/gallery_item_text"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:textColor="#drawable/white"
android:textSize="30sp" />
</com.example.ScalingGalleryItemLayout>

To keep the state of the animation after it is done, just do this on your animation:
youranim.setFillAfter(true);
Edit :
In my project, I use this method and i think, it's help you :
http://developer.sonymobile.com/wp/2011/04/12/how-to-take-advantage-of-the-pinch-to-zoom-feature-in-your-xperia%E2%84%A2-10-apps-part-1/

U can do Image Zoom pinch option for gallery also.
by using below code lines:
you can download the example.
https://github.com/alvinsj/android-image-gallery/downloads
I hope this example will help to u..if u have any queries ask me.....

This is solution
integrate gallery component in android with gesture-image library
gesture-imageView
And here is full sample code
SampleCode

Getting imageview size for Bitmap creation

I am a programmer with a Windows background and I am new to Java and Android stuff.
I want to create a widget (not an app) which displays a chart. After a long research I know I can do this with Canvas, imageviews and Bitmaps. The canvas which I paint on should be the same as the Widget Size.
How do I know the widget size (or imageview size) so that I can supply it to the function?
Bitmap.createBitmap(width_xx, height_yy, Config.ARGB_8888);
Code Snippet:
In the timer run method:
#Override
public void run() {
Bitmap bitmap = Bitmap.createBitmap(??, ??, Config.ARGB_8888);
Canvas canvas = new Canvas(bitmap);
// Create a new paint
Paint p = new Paint();
p.setAntiAlias(true);
p.setStrokeWidth(1);
// Draw circle
// Here I can use the width and height to scale the circle
canvas.drawCircle(50, 50, 7, p);
remoteViews.setImageViewBitmap(R.id.imageView, bitmap);

From what I've learnt, you can only calculate widget dimensions on Android 4.1+.
When on a lower API, you'll have to use static dimensions.
About widget dimensions: App Widget Design Guidelines
int w = DEFAULT_WIDTH, h = DEFAULT_HEIGHT;
if ( Build.VERSION.SDK_INT >= 16 ) {
Bundle options = appWidgetManager.getAppWidgetOptions(widgetId);
int maxW = options.getInt(AppWidgetManager.OPTION_APPWIDGET_MAX_WIDTH);
int maxH = options.getInt(AppWidgetManager.OPTION_APPWIDGET_MAX_HEIGHT);
int minW = options.getInt(AppWidgetManager.OPTION_APPWIDGET_MIN_WIDTH);
int minH = options.getInt(AppWidgetManager.OPTION_APPWIDGET_MIN_HEIGHT);
if ( context.getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE ) {
w = maxW;
h = minH;
} else {
w = minW;
h = maxH;
}
}

Have a look at the method:
public void onAppWidgetOptionsChanged (Context context, AppWidgetManager appWidgetManager, int appWidgetId, Bundle newOptions)
It will be called each time you start/resize the widget.
Getting the widget width/height can be done as follows:
newOptions.getInt(AppWidgetManager.OPTION_APPWIDGET_MIN_WIDTH)
newOptions.getInt(AppWidgetManager.OPTION_APPWIDGET_MAX_WIDTH)
newOptions.getInt(AppWidgetManager.OPTION_APPWIDGET_MIN_HEIGHT)
newOptions.getInt(AppWidgetManager.OPTION_APPWIDGET_MAX_HEIGHT)

I am currently using this:
private void run() {
int width = 400, height = 400;
Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(bitmap);
Paint p = new Paint();
p.setColor(Color.WHITE);
p.setStyle(Paint.Style.STROKE);
p.setStrokeWidth(1);
p.setAntiAlias(true);
c.drawCircle(width/2, height/2, radius, p);
remoteViews.setImageViewBitmap(R.id.imageView, bitmap);
ComponentName clockWidget = new ComponentName(context,
Clock_22_analog.class);
AppWidgetManager appWidgetManager = AppWidgetManager
.getInstance(context);
appWidgetManager.updateAppWidget(clockWidget, remoteViews);
}

You can use this
Bitmap image1, image2;
Bitmap bitmap = Bitmap.createBitmap(image1.getWidth(), image1.getHeight(), Bitmap.Config.ARGB_8888);
Canvas c = new Canvas(bitmap);

You can create a custom widget and set the size of wight on its onMeasure() method. And also save the size at that time so that you can use it further for image creation...

I've not worked on Widgets, but I have some experience getting ImageView's size.
Here is some code I use:
public class ViewSizes {
public int width;
public int height;
public boolean isEmpty() {
boolean result = false;
if (0 >= width || 0 >= height) {
result = true;
}
return result;
}
}
That's just a dummy class containing the size parameters.
public static ViewSizes getSizes(View view) {
ViewSizes sizes = new ViewSizes();
sizes.width = view.getWidth();
sizes.height = view.getHeight();
if (sizes.isEmpty()) {
LayoutParams params = view.getLayoutParams();
if (null != params) {
int widthSpec = View.MeasureSpec.makeMeasureSpec(params.width, View.MeasureSpec.AT_MOST);
int heightSpec = View.MeasureSpec.makeMeasureSpec(params.height, View.MeasureSpec.AT_MOST);
view.measure(widthSpec, heightSpec);
}
sizes.width = view.getMeasuredWidth();
sizes.height = view.getMeasuredHeight();
}
return sizes;
}
This method calculates the width forcing a measure cycle if such has not already happened.
public static boolean loadPhoto(ImageView view, String url, float aspectRatio) {
boolean processed = false;
ViewSizes sizes = ViewsUtils.getSizes(view);
if (!sizes.isEmpty()) {
int width = sizes.width - 2;
int height = sizes.height - 2;
if (ASPECT_RATIO_UNDEFINED != aspectRatio) {
if (height * aspectRatio > width) {
height = (int) (width / aspectRatio);
} else if (height * aspectRatio < width) {
width = (int) (height * aspectRatio);
}
}
// Do you bitmap processing here
processed = true;
}
return processed;
}
This one is probably useless for you. I give just as an example - I have an ImageView and image URL, which should be parametrized with image and height.
public class PhotoLayoutListener implements OnGlobalLayoutListener {
private ImageView view;
private String url;
private float aspectRatio;
public PhotoLayoutListener(ImageView view, String url, float aspectRatio) {
this.view = view;
this.url = url;
this.aspectRatio = aspectRatio;
}
boolean handled = false;
#Override
public void onGlobalLayout() {
if (!handled) {
PhotoUtils.loadPhoto(view, url, aspectRatio);
handled = true;
}
ViewTreeObserver viewTreeObserver = view.getViewTreeObserver();
if (viewTreeObserver.isAlive()) {
if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {
removeLayoutListenerPre16(viewTreeObserver, this);
} else {
removeLayoutListenerPost16(viewTreeObserver, this);
}
}
}
#SuppressWarnings("deprecation")
private void removeLayoutListenerPre16(ViewTreeObserver observer, OnGlobalLayoutListener listener){
observer.removeGlobalOnLayoutListener(listener);
}
#TargetApi(Build.VERSION_CODES.JELLY_BEAN)
private void removeLayoutListenerPost16(ViewTreeObserver observer, OnGlobalLayoutListener listener){
observer.removeOnGlobalLayoutListener(listener);
}
}
This is just a layout listener - I want to process the image loading once the layout phase has finished.
public static void setImage(ImageView view, String url, boolean forceLayoutLoading, float aspectRatio) {
if (null != view && null != url) {
final ViewTreeObserver viewTreeObserver = view.getViewTreeObserver();
if (forceLayoutLoading || !PhotoUtils.loadPhoto(view, url, aspectRatio)) {
if (viewTreeObserver.isAlive()) {
viewTreeObserver.addOnGlobalLayoutListener(new PhotoLayoutListener(view, url, aspectRatio));
}
}
}
}
This is the method I actually call. I give it the view and URL. The methods takes care of loading - if it can determine the view's size it starts loading immediately. Otherwise it just assigns a layout listener and start the loading process once the layout is finished.
You could strip away some parameters - forceLoading / aspectRatio should be irrelevant for you. After that change the PhotoUtils.loadPhoto method in order to create the bitmap with the width / height it has calculated.

Like Julian told us, you can get them like that with a bitmap of your image:
int width = bitmap.getWidth();
int height = bitmap.getHeight();

Making a relative layout's content larger than the screen

I am making a grid-based game that will be much larger than the screen, and the user would scroll around in it. I basically put a bunch on ImageViews inside of a custom class that extends a relative layout. The problem is that even though RelativeLayout.LayoutParams is set to the correct size I want (1280*1280). The images are crammed against the sides of the screen and don't extend past it. I have got the scrolling logic working, and when I scroll, I can see it is a rectangle of images the size of one screen. How can I make it so the images extend past the screen?
The class that extends a relative layout:
public class GameGrid extends RelativeLayout {
ImageView[][] subViews;
int rows=0, cols=0, cellsize=0;
int width, height;
//Dragging variables
float startX;
float startY;
float lastX;
float lastY;
boolean touching;
boolean dragging;
int clickedChild;
public GameGrid(Context context) {
super(context);
init();
}
public GameGrid(Context context, int rws, int cls, int clsze) {
super(context);
rows=rws;
cols=cls;
cellsize=clsze;
init();
}
public GameGrid(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public GameGrid(Context context, AttributeSet attrs, int defaultStyles) {
super(context, attrs, defaultStyles);
init();
}
public void init() {
rows=10;
cols=10;
cellsize=128;
startX = 0;
startY = 0;
lastX=0;
lastY=0;
touching = false;
dragging = false;
clickedChild = -1;
subViews = new ImageView[cols][rows];
setLayoutParams(new RelativeLayout.LayoutParams(cellsize*cols,cellsize*rows));
width=this.getLayoutParams().width;
height=this.getLayoutParams().height;
this.setMinimumWidth(width);
this.setMinimumHeight(height);
Log.i("info","****************");
Log.i("info","GameGrid Made.");
Log.i("info","width: "+width+"\nheight: "+height);
Log.i("info","****************");
makeGrid();
// this.setOnTouchListener()
}
public boolean getDragging(){
return dragging;
}
public void makeGrid() {
for(int y=0;y<rows;y++){
for(int x=0;x<cols;x++){
ImageView temp = new ImageView(getContext());
temp.setImageResource(R.drawable.water1);
temp.setScaleType(ImageView.ScaleType.FIT_XY);
RelativeLayout.LayoutParams temp2 = new RelativeLayout.LayoutParams(width/cols,height/rows);
if (x == 0 && y == 0){ //If this is the first view being made, set it relative to the parent.
temp2.addRule(RelativeLayout.ALIGN_PARENT_TOP);
temp2.addRule(RelativeLayout.ALIGN_PARENT_LEFT);
}
else if (x == 0){ //If this is in the first column, set it below the one above.
temp2.addRule(RelativeLayout.ALIGN_LEFT,subViews[0][y-1].getId());
temp2.addRule(RelativeLayout.BELOW,subViews[0][y-1].getId());
}
else { //Align the bottom with first one of that row.
temp2.addRule(RelativeLayout.RIGHT_OF,subViews[x-1][y].getId());
temp2.addRule(RelativeLayout.ALIGN_BOTTOM,subViews[0][y].getId());
}
temp.setLayoutParams(temp2);
subViews[x][y]=temp;
subViews[x][y].setId(x+y*cols+1);
// Toast.makeText(getContext(), "" + v.getId(), Toast.LENGTH_SHORT).show();
subViews[x][y].setOnTouchListener(new OnTouchListener() {
public boolean onTouch(View v,MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN)
clickedChild = v.getId();
return false;
}
});
addView(temp);
}
}
}
#Override
public boolean onTouchEvent(MotionEvent event) {
if (event.getAction() == MotionEvent.ACTION_DOWN)
{ // when the user touches the screen
startX = event.getX();
startY = event.getY();
lastX = event.getX();
lastY = event.getY();
touching = true;
dragging = false;
return true;
}
else if (event.getAction() == MotionEvent.ACTION_MOVE)
{ // when the user moves the touch
if (!dragging)
dragging = true;
int distX = (int)(event.getX()-lastX);
int distY = (int)(event.getY()-lastY);
this.scrollBy(-distX, -distY);
lastX = event.getX();
lastY = event.getY();
return true;
}
else if (event.getAction() == MotionEvent.ACTION_UP)
{ // when the user lifts the touch
if (!dragging){
if (clickedChild>0){
Toast.makeText(getContext(), "getHeight()= " + getHeight(), Toast.LENGTH_SHORT).show();
clickedChild = -1;
}
}
touching = false;
dragging = false;
return true;
}
else if (event.getAction() == MotionEvent.ACTION_CANCEL)
{ // if something gets lost in translation
startX = 0;
startY = 0;
lastX=0;
lastY=0;
touching = false;
dragging = false;
return true;
}
return false;
}
#Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec){
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int parentWidth = MeasureSpec.getSize(widthMeasureSpec);
int parentHeight = MeasureSpec.getSize(heightMeasureSpec);
this.setMeasuredDimension(parentWidth, parentHeight);
}
The Activity:
public class Attacktics2 extends Activity {
/** Called when the activity is first created. */
GameGrid grid;
int rows, cols, cellsize;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.main);
}
public void start(View view) {
view.setVisibility(View.GONE);
grid = new GameGrid(this,10,10,128);
setContentView(grid);
}
}

Since you're already doing the heavy lifting of managing all the scrolling, I'd suggest that you implement your entire layout logic yourself and not rely on RelativeLayout. Except for ScrollView and HorizontalScrollView, the stock layout classes are going to restrict their children to be within the parent bounds. Those, in turn, will be restricted to the screen dimensions. If you handle the layout logic yourself, you can position child views so that they extend off screen. It then forms a viewport into a larger grid and can just render those children that are visible within the viewport.

Jumping ImageView when dragging in Android [duplicate]

I'm not a programmer, but I'm trying to learn android development, and having a blast.
Lately I've hit a fork in the road, and I don't know that any of the directions I can identify will meet all my needs. This is where you (the experts) can help ;)
Endpoint: I want to have the user touch a ball, and drag it to any location on the screen. I would also like to animate this ball when it gets drawn, and when it gets dropped.
I can accomplish the dragging part using a custom class (that doesn't extend anything... just a class like is found in this tutorial: basic drag & drop, however, I don't know how to apply the tween animation to it since it's not a view.
I have also developed an animated version of an ImageView with my image in it, however, I can't manage to apply the same drag & drop functionality without using AbsoluteLayout, which I know is a no-no.
So... how do I move an ImageView around a ??? layout using MotionEvents, or how do I animate (using tweens defined in XML) a non-view based custom class?
Please ask questions if this is not clear. I don't know all the terminology as well as most of you might.
There is also a copy of this question on the anddev.org forums, so I'll keep this post updated with any responses I get over there.

Why can't you extend View? Then, you have complete control over how it draws because you can override the OnDraw() method. Just make the ColorBall class extend View. Change its position when you move and then invalidate just that one view and have it draw itself instead of having the DrawView class draw it.
Edit - Here is an example class
public class Card extends View
{
private Bitmap mImage;
private final Paint mPaint = new Paint();
private final Point mSize = new Point();
private final Point mStartPosition = new Point();
public Card(Context context)
{
super(context);
}
public final Bitmap getImage() { return mCardImage; }
public final void setImage(Bitmap image)
{
mImage = image;
setSize(mCardImage.getWidth(), mCardImage.getHeight());
}
#Override
protected void onDraw(Canvas canvas)
{
Point position = getPosition();
canvas.drawBitmap(mCardImage, position.x, position.y, mPaint);
}
public final void setPosition(final Point position)
{
mRegion.set(position.x, position.y, position.x + mSize.x, position.y + mSize.y);
}
public final Point getPosition()
{
Rect bounds = mRegion.getBounds();
return new Point(bounds.left, bounds.top);
}
public final void setSize(int width, int height)
{
mSize.x = width;
mSize.y = height;
Rect bounds = mRegion.getBounds();
mRegion.set(bounds.left, bounds.top, bounds.left + width, bounds.top + height);
}
public final Point getSize() { return mSize; }
#Override
public boolean onTouchEvent(MotionEvent event)
{
// Is the event inside of this view?
if(!mRegion.contains((int)event.getX(), (int)event.getY()))
{
return super.onTouchEvent(event);
}
if(event.getAction() == MotionEvent.ACTION_DOWN)
{
mStartPosition.x = (int)event.getX();
mStartPosition.y = (int)event.getY();
bringToFront();
onSelected();
return true;
}
else if(event.getAction() == MotionEvent.ACTION_MOVE)
{
int x = 0, y = 0;
if(mLock == DirectionLock.FREE || mLock == DirectionLock.HORIZONTAL_ONLY)
{
x = (int)event.getX() - mStartPosition.x;
}
if(mLock == DirectionLock.FREE || mLock == DirectionLock.VERTICAL_ONLY)
{
y = (int)event.getY() - mStartPosition.y;
}
mRegion.translate(x, y);
mStartPosition.x = (int)event.getX();
mStartPosition.y = (int)event.getY();
invalidate();
return true;
}
else
{
return super.onTouchEvent(event);
}
}
}

Android Drag/Animation of Views

I'm not a programmer, but I'm trying to learn android development, and having a blast.
Lately I've hit a fork in the road, and I don't know that any of the directions I can identify will meet all my needs. This is where you (the experts) can help ;)
Endpoint: I want to have the user touch a ball, and drag it to any location on the screen. I would also like to animate this ball when it gets drawn, and when it gets dropped.
I can accomplish the dragging part using a custom class (that doesn't extend anything... just a class like is found in this tutorial: basic drag & drop, however, I don't know how to apply the tween animation to it since it's not a view.
I have also developed an animated version of an ImageView with my image in it, however, I can't manage to apply the same drag & drop functionality without using AbsoluteLayout, which I know is a no-no.
So... how do I move an ImageView around a ??? layout using MotionEvents, or how do I animate (using tweens defined in XML) a non-view based custom class?
Please ask questions if this is not clear. I don't know all the terminology as well as most of you might.
There is also a copy of this question on the anddev.org forums, so I'll keep this post updated with any responses I get over there.

Why can't you extend View? Then, you have complete control over how it draws because you can override the OnDraw() method. Just make the ColorBall class extend View. Change its position when you move and then invalidate just that one view and have it draw itself instead of having the DrawView class draw it.
Edit - Here is an example class
public class Card extends View
{
private Bitmap mImage;
private final Paint mPaint = new Paint();
private final Point mSize = new Point();
private final Point mStartPosition = new Point();
public Card(Context context)
{
super(context);
}
public final Bitmap getImage() { return mCardImage; }
public final void setImage(Bitmap image)
{
mImage = image;
setSize(mCardImage.getWidth(), mCardImage.getHeight());
}
#Override
protected void onDraw(Canvas canvas)
{
Point position = getPosition();
canvas.drawBitmap(mCardImage, position.x, position.y, mPaint);
}
public final void setPosition(final Point position)
{
mRegion.set(position.x, position.y, position.x + mSize.x, position.y + mSize.y);
}
public final Point getPosition()
{
Rect bounds = mRegion.getBounds();
return new Point(bounds.left, bounds.top);
}
public final void setSize(int width, int height)
{
mSize.x = width;
mSize.y = height;
Rect bounds = mRegion.getBounds();
mRegion.set(bounds.left, bounds.top, bounds.left + width, bounds.top + height);
}
public final Point getSize() { return mSize; }
#Override
public boolean onTouchEvent(MotionEvent event)
{
// Is the event inside of this view?
if(!mRegion.contains((int)event.getX(), (int)event.getY()))
{
return super.onTouchEvent(event);
}
if(event.getAction() == MotionEvent.ACTION_DOWN)
{
mStartPosition.x = (int)event.getX();
mStartPosition.y = (int)event.getY();
bringToFront();
onSelected();
return true;
}
else if(event.getAction() == MotionEvent.ACTION_MOVE)
{
int x = 0, y = 0;
if(mLock == DirectionLock.FREE || mLock == DirectionLock.HORIZONTAL_ONLY)
{
x = (int)event.getX() - mStartPosition.x;
}
if(mLock == DirectionLock.FREE || mLock == DirectionLock.VERTICAL_ONLY)
{
y = (int)event.getY() - mStartPosition.y;
}
mRegion.translate(x, y);
mStartPosition.x = (int)event.getX();
mStartPosition.y = (int)event.getY();
invalidate();
return true;
}
else
{
return super.onTouchEvent(event);
}
}
}