Develop Reference

Make zoom in/out using Matrix and x,y of ImageView

I have an ImageView:
<ImageView
android:id="#+id/ivHand"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:scaleType="fitXY" />
And in Activity I do the following:
ImageView ivBgHand = (ImageView) findViewById(R.id.ivHand);
Bitmap bitmap = BitmapFactory.decodeFile(photoPath); // Path from storage
ivBgHand.setImageBitmap(bitmap);
I want to make zoom in and out using Matrix and x, y coordinates where it should be zoomed (aka pivotX, pivotY). Can anyone help me with this?
(I don't want to use ScaleAnimation, because the next step will be a handling changed Matrix)

If you are looking for a simple library which handles the zoom in an imageview with no extra code, then I can recommend to use PhotoView library. It´s pretty simple.

I've found a fantastic solution! Source link.
Custom layout view:
package <your package>;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.widget.FrameLayout;
/**
* Zooming view.
*/
public class ZoomView extends FrameLayout {
public ZoomView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
// TODO Auto-generated constructor stub
}
public ZoomView(Context context, AttributeSet attrs) {
super(context, attrs);
// TODO Auto-generated constructor stub
}
public ZoomView(final Context context) {
super(context);
}
/**
* Zooming view listener interface.
*
* #author karooolek
*
*/
public interface ZoomViewListener {
void onZoomStarted(float zoom, float zoomx, float zoomy);
void onZooming(float zoom, float zoomx, float zoomy);
void onZoomEnded(float zoom, float zoomx, float zoomy);
}
// zooming
float zoom = 1.0f;
float maxZoom = 2.0f;
float smoothZoom = 1.0f;
float zoomX, zoomY;
float smoothZoomX, smoothZoomY;
private boolean scrolling; // NOPMD by karooolek on 29.06.11 11:45
// minimap variables
private boolean showMinimap = false;
private int miniMapColor = Color.WHITE;
private int miniMapHeight = -1;
private String miniMapCaption;
private float miniMapCaptionSize = 10.0f;
private int miniMapCaptionColor = Color.WHITE;
// touching variables
private long lastTapTime;
private float touchStartX, touchStartY;
private float touchLastX, touchLastY;
private float startd;
private boolean pinching;
private float lastd;
private float lastdx1, lastdy1;
private float lastdx2, lastdy2;
// drawing
private final Matrix m = new Matrix();
private final Paint p = new Paint();
// listener
ZoomViewListener listener;
private Bitmap ch;
public float getZoom() {
return zoom;
}
public float getMaxZoom() {
return maxZoom;
}
public void setMaxZoom(final float maxZoom) {
if (maxZoom < 1.0f) {
return;
}
this.maxZoom = maxZoom;
}
public void setMiniMapEnabled(final boolean showMiniMap) {
this.showMinimap = showMiniMap;
}
public boolean isMiniMapEnabled() {
return showMinimap;
}
public void setMiniMapHeight(final int miniMapHeight) {
if (miniMapHeight < 0) {
return;
}
this.miniMapHeight = miniMapHeight;
}
public int getMiniMapHeight() {
return miniMapHeight;
}
public void setMiniMapColor(final int color) {
miniMapColor = color;
}
public int getMiniMapColor() {
return miniMapColor;
}
public String getMiniMapCaption() {
return miniMapCaption;
}
public void setMiniMapCaption(final String miniMapCaption) {
this.miniMapCaption = miniMapCaption;
}
public float getMiniMapCaptionSize() {
return miniMapCaptionSize;
}
public void setMiniMapCaptionSize(final float size) {
miniMapCaptionSize = size;
}
public int getMiniMapCaptionColor() {
return miniMapCaptionColor;
}
public void setMiniMapCaptionColor(final int color) {
miniMapCaptionColor = color;
}
public void zoomTo(final float zoom, final float x, final float y) {
this.zoom = Math.min(zoom, maxZoom);
zoomX = x;
zoomY = y;
smoothZoomTo(this.zoom, x, y);
}
public void smoothZoomTo(final float zoom, final float x, final float y) {
smoothZoom = clamp(1.0f, zoom, maxZoom);
smoothZoomX = x;
smoothZoomY = y;
if (listener != null) {
listener.onZoomStarted(smoothZoom, x, y);
}
}
public ZoomViewListener getListener() {
return listener;
}
public void setListner(final ZoomViewListener listener) {
this.listener = listener;
}
public float getZoomFocusX() {
return zoomX * zoom;
}
public float getZoomFocusY() {
return zoomY * zoom;
}
#Override
public boolean dispatchTouchEvent(final MotionEvent ev) {
// single touch
if (ev.getPointerCount() == 1) {
processSingleTouchEvent(ev);
}
// // double touch
if (ev.getPointerCount() == 2) {
processDoubleTouchEvent(ev);
}
// redraw
getRootView().invalidate();
invalidate();
return true;
}
private void processSingleTouchEvent(final MotionEvent ev) {
final float x = ev.getX();
final float y = ev.getY();
final float w = miniMapHeight * (float) getWidth() / getHeight();
final float h = miniMapHeight;
final boolean touchingMiniMap = x >= 10.0f && x <= 10.0f + w
&& y >= 10.0f && y <= 10.0f + h;
if (showMinimap && smoothZoom > 1.0f && touchingMiniMap) {
processSingleTouchOnMinimap(ev);
} else {
processSingleTouchOutsideMinimap(ev);
}
}
private void processSingleTouchOnMinimap(final MotionEvent ev) {
final float x = ev.getX();
final float y = ev.getY();
final float w = miniMapHeight * (float) getWidth() / getHeight();
final float h = miniMapHeight;
final float zx = (x - 10.0f) / w * getWidth();
final float zy = (y - 10.0f) / h * getHeight();
smoothZoomTo(smoothZoom, zx, zy);
}
private void processSingleTouchOutsideMinimap(final MotionEvent ev) {
final float x = ev.getX();
final float y = ev.getY();
float lx = x - touchStartX;
float ly = y - touchStartY;
final float l = (float) Math.hypot(lx, ly);
float dx = x - touchLastX;
float dy = y - touchLastY;
touchLastX = x;
touchLastY = y;
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
touchStartX = x;
touchStartY = y;
touchLastX = x;
touchLastY = y;
dx = 0;
dy = 0;
lx = 0;
ly = 0;
scrolling = false;
break;
case MotionEvent.ACTION_MOVE:
if (scrolling || (smoothZoom > 1.0f && l > 30.0f)) {
if (!scrolling) {
scrolling = true;
ev.setAction(MotionEvent.ACTION_CANCEL);
super.dispatchTouchEvent(ev);
}
smoothZoomX -= dx / zoom;
smoothZoomY -= dy / zoom;
return;
}
break;
case MotionEvent.ACTION_OUTSIDE:
case MotionEvent.ACTION_UP:
// tap
if (l < 30.0f) {
// check double tap
if (System.currentTimeMillis() - lastTapTime < 500) {
if (smoothZoom == 1.0f) {
smoothZoomTo(maxZoom, x, y);
} else {
smoothZoomTo(1.0f, getWidth() / 2.0f,
getHeight() / 2.0f);
}
lastTapTime = 0;
ev.setAction(MotionEvent.ACTION_CANCEL);
super.dispatchTouchEvent(ev);
return;
}
lastTapTime = System.currentTimeMillis();
performClick();
}
break;
default:
break;
}
ev.setLocation(zoomX + (x - 0.5f * getWidth()) / zoom, zoomY
+ (y - 0.5f * getHeight()) / zoom);
ev.getX();
ev.getY();
super.dispatchTouchEvent(ev);
}
private void processDoubleTouchEvent(final MotionEvent ev) {
final float x1 = ev.getX(0);
final float dx1 = x1 - lastdx1;
lastdx1 = x1;
final float y1 = ev.getY(0);
final float dy1 = y1 - lastdy1;
lastdy1 = y1;
final float x2 = ev.getX(1);
final float dx2 = x2 - lastdx2;
lastdx2 = x2;
final float y2 = ev.getY(1);
final float dy2 = y2 - lastdy2;
lastdy2 = y2;
// pointers distance
final float d = (float) Math.hypot(x2 - x1, y2 - y1);
final float dd = d - lastd;
lastd = d;
final float ld = Math.abs(d - startd);
Math.atan2(y2 - y1, x2 - x1);
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
startd = d;
pinching = false;
break;
case MotionEvent.ACTION_MOVE:
if (pinching || ld > 30.0f) {
pinching = true;
final float dxk = 0.5f * (dx1 + dx2);
final float dyk = 0.5f * (dy1 + dy2);
smoothZoomTo(Math.max(1.0f, zoom * d / (d - dd)), zoomX - dxk
/ zoom, zoomY - dyk / zoom);
}
break;
case MotionEvent.ACTION_UP:
default:
pinching = false;
break;
}
ev.setAction(MotionEvent.ACTION_CANCEL);
super.dispatchTouchEvent(ev);
}
private float clamp(final float min, final float value, final float max) {
return Math.max(min, Math.min(value, max));
}
private float lerp(final float a, final float b, final float k) {
return a + (b - a) * k;
}
private float bias(final float a, final float b, final float k) {
return Math.abs(b - a) >= k ? a + k * Math.signum(b - a) : b;
}
#Override
protected void dispatchDraw(final Canvas canvas) {
// do zoom
zoom = lerp(bias(zoom, smoothZoom, 0.05f), smoothZoom, 0.2f);
smoothZoomX = clamp(0.5f * getWidth() / smoothZoom, smoothZoomX,
getWidth() - 0.5f * getWidth() / smoothZoom);
smoothZoomY = clamp(0.5f * getHeight() / smoothZoom, smoothZoomY,
getHeight() - 0.5f * getHeight() / smoothZoom);
zoomX = lerp(bias(zoomX, smoothZoomX, 0.1f), smoothZoomX, 0.35f);
zoomY = lerp(bias(zoomY, smoothZoomY, 0.1f), smoothZoomY, 0.35f);
if (zoom != smoothZoom && listener != null) {
listener.onZooming(zoom, zoomX, zoomY);
}
final boolean animating = Math.abs(zoom - smoothZoom) > 0.0000001f
|| Math.abs(zoomX - smoothZoomX) > 0.0000001f
|| Math.abs(zoomY - smoothZoomY) > 0.0000001f;
// nothing to draw
if (getChildCount() == 0) {
return;
}
// prepare matrix
m.setTranslate(0.5f * getWidth(), 0.5f * getHeight());
m.preScale(zoom, zoom);
m.preTranslate(
-clamp(0.5f * getWidth() / zoom, zoomX, getWidth() - 0.5f
* getWidth() / zoom),
-clamp(0.5f * getHeight() / zoom, zoomY, getHeight() - 0.5f
* getHeight() / zoom));
// get view
final View v = getChildAt(0);
m.preTranslate(v.getLeft(), v.getTop());
// get drawing cache if available
if (animating && ch == null && isAnimationCacheEnabled()) {
v.setDrawingCacheEnabled(true);
ch = v.getDrawingCache();
}
// draw using cache while animating
if (animating && isAnimationCacheEnabled() && ch != null) {
p.setColor(0xffffffff);
canvas.drawBitmap(ch, m, p);
} else { // zoomed or cache unavailable
ch = null;
canvas.save();
canvas.concat(m);
v.draw(canvas);
canvas.restore();
}
// draw minimap
if (showMinimap) {
if (miniMapHeight < 0) {
miniMapHeight = getHeight() / 4;
}
canvas.translate(10.0f, 10.0f);
p.setColor(0x80000000 | 0x00ffffff & miniMapColor);
final float w = miniMapHeight * (float) getWidth() / getHeight();
final float h = miniMapHeight;
canvas.drawRect(0.0f, 0.0f, w, h, p);
if (miniMapCaption != null && miniMapCaption.length() > 0) {
p.setTextSize(miniMapCaptionSize);
p.setColor(miniMapCaptionColor);
p.setAntiAlias(true);
canvas.drawText(miniMapCaption, 10.0f,
10.0f + miniMapCaptionSize, p);
p.setAntiAlias(false);
}
p.setColor(0x80000000 | 0x00ffffff & miniMapColor);
final float dx = w * zoomX / getWidth();
final float dy = h * zoomY / getHeight();
canvas.drawRect(dx - 0.5f * w / zoom, dy - 0.5f * h / zoom, dx
+ 0.5f * w / zoom, dy + 0.5f * h / zoom, p);
canvas.translate(-10.0f, -10.0f);
}
// redraw
// if (animating) {
getRootView().invalidate();
invalidate();
// }
}
}
Just keep in mind that custom view should have only one child that's why these views were wrapped in RelativeLayout
<!-- View which can change matrix of multiple views -->
<com.vitalii.semeruk.model.ZoomView
android:id="#+id/zoomView"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- Note: ZoomView should have only one child
that's why were wrapped these views in RelativeLayout -->
<RelativeLayout
android:id="#+id/relativeLayout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<!-- Captured photo -->
<com.vitalii.semeruk.model.HandView
android:id="#+id/ivBgHand"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#android:color/white"
android:scaleType="fitXY" />
<!-- Ring -->
<com.vitalii.semeruk.model.RingPinky
android:id="#+id/ivRingPinky"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</RelativeLayout>
</com.vitalii.semeruk.model.ZoomView>
Methods to use in Activity are:
zoomTo() and smoothZoomTo()
Example:
ZoomView zoomView = (ZoomView) findViewById(R.id.zoomView);
zoomView.smoothZoomTo(3f, 86, 908);
To change maximum zoom find and replace: float maxZoom = 2.0f; with value which will fit your needs.

StickerView not working properly with Zoomble RelativeLayout

Functionality i want is as below:
User can drag,rotate,scale Sticker(Image,Text) any where on the image after zoom in or zoom out
And to achieve this i have used zoomable ReativeLayout and StickerView and instead of zooming image only i am zooming whole RelativeLayout including all Child Views(Sticker,Image etc.)
Now the issue is, everything is working fine until My RelativeLayout is not zoomed, i can drag my sticker anywhere but as soon as i zoom Relative layout and try to move sticker it shows strange behavior.
Stickers are shown at correct place after zoom in but seems its touch position are being changed, so i am not able to drag Stickers after zooming layout.
I have used this Library for StickerView code, ZoomableRelativeLayout code and layout are as below
public class ZoomView extends RelativeLayout {
public ZoomView(final Context context) {
super(context);
//setOnTouchListener(touchListener);
}
public ZoomView(Context context, AttributeSet attrs) {
super(context, attrs);
// setOnTouchListener(touchListener);
}
public ZoomView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
// setOnTouchListener(touchListener);
}
/**
* Zooming view listener interface.
*
* #author karooolek
*/
public interface ZoomViewListener {
void onZoomStarted(float zoom, float zoomx, float zoomy);
void onZooming(float zoom, float zoomx, float zoomy);
void onZoomEnded(float zoom, float zoomx, float zoomy);
}
// zooming
float zoom = 1.0f;
float maxZoom = 3.0f;
float smoothZoom = 1.0f;
float zoomX, zoomY;
float smoothZoomX, smoothZoomY;
private boolean scrolling; // NOPMD by karooolek on 29.06.11 11:45
// minimap variables
private boolean showMinimap = false;
private int miniMapColor = Color.BLACK;
private int miniMapHeight = -1;
private String miniMapCaption;
private float miniMapCaptionSize = 10.0f;
private int miniMapCaptionColor = Color.WHITE;
// touching variables
private long lastTapTime;
private float touchStartX, touchStartY;
private float touchLastX, touchLastY;
private float startd;
private boolean pinching;
private float lastd;
private float lastdx1, lastdy1;
private float lastdx2, lastdy2;
// drawing
private final Matrix m = new Matrix();
private final Paint p = new Paint();
// listener
ZoomViewListener listener;
private Bitmap ch;
public float getZoom() {
return zoom;
}
public float getMaxZoom() {
return maxZoom;
}
public void setMaxZoom(final float maxZoom) {
if (maxZoom < 1.0f) {
return;
}
this.maxZoom = maxZoom;
}
public void setMiniMapEnabled(final boolean showMiniMap) {
this.showMinimap = showMiniMap;
}
public boolean isMiniMapEnabled() {
return showMinimap;
}
public void setMiniMapHeight(final int miniMapHeight) {
if (miniMapHeight < 0) {
return;
}
this.miniMapHeight = miniMapHeight;
}
public int getMiniMapHeight() {
return miniMapHeight;
}
public void setMiniMapColor(final int color) {
miniMapColor = color;
}
public int getMiniMapColor() {
return miniMapColor;
}
public String getMiniMapCaption() {
return miniMapCaption;
}
public void setMiniMapCaption(final String miniMapCaption) {
this.miniMapCaption = miniMapCaption;
}
public float getMiniMapCaptionSize() {
return miniMapCaptionSize;
}
public void setMiniMapCaptionSize(final float size) {
miniMapCaptionSize = size;
}
public int getMiniMapCaptionColor() {
return miniMapCaptionColor;
}
public void setMiniMapCaptionColor(final int color) {
miniMapCaptionColor = color;
}
public void zoomTo(final float zoom, final float x, final float y) {
this.zoom = Math.min(zoom, maxZoom);
zoomX = x;
zoomY = y;
smoothZoomTo(this.zoom, x, y);
}
public void smoothZoomTo(final float zoom, final float x, final float y) {
smoothZoom = clamp(1.0f, zoom, maxZoom);
smoothZoomX = x;
smoothZoomY = y;
if (listener != null) {
listener.onZoomStarted(smoothZoom, x, y);
}
}
public ZoomViewListener getListener() {
return listener;
}
public void setListner(final ZoomViewListener listener) {
this.listener = listener;
}
public float getZoomFocusX() {
return zoomX * zoom;
}
public float getZoomFocusY() {
return zoomY * zoom;
}
/* #Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
return false;
}*/
/*#Override
public boolean dispatchTouchEvent(final MotionEvent ev) {
// single touch
if (ev.getPointerCount() == 1) {
processSingleTouchEvent(ev);
}
// // double touch
if (ev.getPointerCount() == 2) {
processDoubleTouchEvent(ev);
}
// redraw
getRootView().invalidate();
invalidate();
return true;
}*/
OnTouchListener touchListener = new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent ev) {
// single touch
if (ev.getPointerCount() == 1) {
processSingleTouchEvent(ev);
}
// // double touch
if (ev.getPointerCount() == 2) {
processDoubleTouchEvent(ev);
}
// redraw
/* getRootView().invalidate();
invalidate();*/
return true;
}
};
public void onTouch(View v, MotionEvent ev) {
if (ev.getPointerCount() == 1) {
processSingleTouchEvent(ev);
}
// // double touch
if (ev.getPointerCount() == 2) {
processDoubleTouchEvent(ev);
}
// redraw
getRootView().invalidate();
invalidate();
}
private void processSingleTouchEvent(final MotionEvent ev) {
final float x = ev.getX();
final float y = ev.getY();
final float w = miniMapHeight * (float) getWidth() / getHeight();
final float h = miniMapHeight;
final boolean touchingMiniMap = x >= 10.0f && x <= 10.0f + w && y >= 10.0f && y <= 10.0f + h;
if (showMinimap && smoothZoom > 1.0f && touchingMiniMap) {
processSingleTouchOnMinimap(ev);
} else {
processSingleTouchOutsideMinimap(ev);
}
}
private void processSingleTouchOnMinimap(final MotionEvent ev) {
final float x = ev.getX();
final float y = ev.getY();
final float w = miniMapHeight * (float) getWidth() / getHeight();
final float h = miniMapHeight;
final float zx = (x - 10.0f) / w * getWidth();
final float zy = (y - 10.0f) / h * getHeight();
smoothZoomTo(smoothZoom, zx, zy);
}
private void processSingleTouchOutsideMinimap(final MotionEvent ev) {
final float x = ev.getX();
final float y = ev.getY();
float lx = x - touchStartX;
float ly = y - touchStartY;
final float l = (float) Math.hypot(lx, ly);
float dx = x - touchLastX;
float dy = y - touchLastY;
touchLastX = x;
touchLastY = y;
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
touchStartX = x;
touchStartY = y;
touchLastX = x;
touchLastY = y;
dx = 0;
dy = 0;
lx = 0;
ly = 0;
scrolling = false;
break;
case MotionEvent.ACTION_MOVE:
if (scrolling || (smoothZoom > 1.0f && l > 30.0f)) {
if (!scrolling) {
scrolling = true;
ev.setAction(MotionEvent.ACTION_CANCEL);
super.dispatchTouchEvent(ev);
}
smoothZoomX -= dx / zoom;
smoothZoomY -= dy / zoom;
return;
}
break;
case MotionEvent.ACTION_OUTSIDE:
case MotionEvent.ACTION_UP:
// tap
if (l < 30.0f) {
// check double tap
if (System.currentTimeMillis() - lastTapTime < 500) {
if (smoothZoom == 1.0f) {
smoothZoomTo(maxZoom, x, y);
} else {
smoothZoomTo(1.0f, getWidth() / 2.0f, getHeight() / 2.0f);
}
lastTapTime = 0;
ev.setAction(MotionEvent.ACTION_CANCEL);
super.dispatchTouchEvent(ev);
return;
}
lastTapTime = System.currentTimeMillis();
performClick();
}
break;
default:
break;
}
ev.setLocation(zoomX + (x - 0.5f * getWidth()) / zoom, zoomY + (y - 0.5f * getHeight()) / zoom);
ev.getX();
ev.getY();
// super.dispatchTouchEvent(ev);
}
private void processDoubleTouchEvent(final MotionEvent ev) {
final float x1 = ev.getX(0);
final float dx1 = x1 - lastdx1;
lastdx1 = x1;
final float y1 = ev.getY(0);
final float dy1 = y1 - lastdy1;
lastdy1 = y1;
final float x2 = ev.getX(1);
final float dx2 = x2 - lastdx2;
lastdx2 = x2;
final float y2 = ev.getY(1);
final float dy2 = y2 - lastdy2;
lastdy2 = y2;
// pointers distance
final float d = (float) Math.hypot(x2 - x1, y2 - y1);
final float dd = d - lastd;
lastd = d;
final float ld = Math.abs(d - startd);
Math.atan2(y2 - y1, x2 - x1);
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
startd = d;
pinching = false;
break;
case MotionEvent.ACTION_MOVE:
if (pinching || ld > 30.0f) {
pinching = true;
final float dxk = 0.5f * (dx1 + dx2);
final float dyk = 0.5f * (dy1 + dy2);
smoothZoomTo(Math.max(1.0f, zoom * d / (d - dd)), zoomX - dxk / zoom, zoomY - dyk / zoom);
}
break;
case MotionEvent.ACTION_UP:
default:
pinching = false;
break;
}
ev.setAction(MotionEvent.ACTION_CANCEL);
//super.dispatchTouchEvent(ev);
}
private float clamp(final float min, final float value, final float max) {
return Math.max(min, Math.min(value, max));
}
private float lerp(final float a, final float b, final float k) {
return a + (b - a) * k;
}
private float bias(final float a, final float b, final float k) {
return Math.abs(b - a) >= k ? a + k * Math.signum(b - a) : b;
}
#Override
protected void dispatchDraw(final Canvas canvas) {
// do zoom
zoom = lerp(bias(zoom, smoothZoom, 0.05f), smoothZoom, 0.2f);
smoothZoomX = clamp(0.5f * getWidth() / smoothZoom, smoothZoomX, getWidth() - 0.5f * getWidth() / smoothZoom);
smoothZoomY = clamp(0.5f * getHeight() / smoothZoom, smoothZoomY, getHeight() - 0.5f * getHeight() / smoothZoom);
zoomX = lerp(bias(zoomX, smoothZoomX, 0.1f), smoothZoomX, 0.35f);
zoomY = lerp(bias(zoomY, smoothZoomY, 0.1f), smoothZoomY, 0.35f);
if (zoom != smoothZoom && listener != null) {
listener.onZooming(zoom, zoomX, zoomY);
}
final boolean animating = Math.abs(zoom - smoothZoom) > 0.0000001f
|| Math.abs(zoomX - smoothZoomX) > 0.0000001f || Math.abs(zoomY - smoothZoomY) > 0.0000001f;
// nothing to draw
if (getChildCount() == 0) {
return;
}
// prepare matrix
m.setTranslate(0.5f * getWidth(), 0.5f * getHeight());
m.preScale(zoom, zoom);
m.preTranslate(-clamp(0.5f * getWidth() / zoom, zoomX, getWidth() - 0.5f * getWidth() / zoom),
-clamp(0.5f * getHeight() / zoom, zoomY, getHeight() - 0.5f * getHeight() / zoom));
// get view
final View v = getChildAt(0);
m.preTranslate(v.getLeft(), v.getTop());
// get drawing cache if available
if (animating && ch == null && isAnimationCacheEnabled()) {
v.setDrawingCacheEnabled(true);
ch = v.getDrawingCache();
}
// draw using cache while animating
if (animating && isAnimationCacheEnabled() && ch != null) {
p.setColor(0xffffffff);
canvas.drawBitmap(ch, m, p);
} else { // zoomed or cache unavailable
ch = null;
canvas.save();
canvas.concat(m);
v.draw(canvas);
canvas.restore();
}
// draw minimap
if (showMinimap) {
if (miniMapHeight < 0) {
miniMapHeight = getHeight() / 4;
}
canvas.translate(10.0f, 10.0f);
p.setColor(0x80000000 | 0x00ffffff & miniMapColor);
final float w = miniMapHeight * (float) getWidth() / getHeight();
final float h = miniMapHeight;
canvas.drawRect(0.0f, 0.0f, w, h, p);
if (miniMapCaption != null && miniMapCaption.length() > 0) {
p.setTextSize(miniMapCaptionSize);
p.setColor(miniMapCaptionColor);
p.setAntiAlias(true);
canvas.drawText(miniMapCaption, 10.0f, 10.0f + miniMapCaptionSize, p);
p.setAntiAlias(false);
}
p.setColor(0x80000000 | 0x00ffffff & miniMapColor);
final float dx = w * zoomX / getWidth();
final float dy = h * zoomY / getHeight();
canvas.drawRect(dx - 0.5f * w / zoom, dy - 0.5f * h / zoom, dx + 0.5f * w / zoom, dy + 0.5f * h / zoom, p);
canvas.translate(-10.0f, -10.0f);
}
// redraw
// if (animating) {
getRootView().invalidate();
invalidate();
// }
}
}
My Layout is as below
<com.nkdroid.stickerview.widgets.ZoomView
android:id="#+id/zoomableLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_below="#id/rlUndoRedo"
android:layout_centerInParent="true">
<FrameLayout
android:id="#+id/canvasView"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ui.activities.MainActivity"
android:layout_alignParentTop="true"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true">
<com.nkdroid.stickerview.widgets.DrawingView
android:id="#+id/fingerLine"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:adjustViewBounds="true"
android:contentDescription="#string/app_name"
android:scaleType="centerCrop"
android:src="#drawable/image" />
</FrameLayout>
</com.nkdroid.stickerview.widgets.ZoomView>

Android : Zoom by center pinch

So, I have ScrollView, HorizantalScrollView and BoardView for TicTacToe game.
When user zooms, while i redraw scale into categories of cells through ScalegestureDetector zoom pinch is allocated on top, left of the screen, not at the centre of pinches, how can I allocate it to the center?
here is my project in github: https://github.com/boyfox/TestTicTac.git
Project used com.android.support:appcompat-v7
Anybody have a solution to this problem?

I think that you will want to move to an implementation closer to the Android Dragging and Scaling examples (and to the similar question here).
This is the start of what you need. You can pan the view as before and now scale the view at the center of the pinch gesture. It is your base BoardView with logic to draw points on clicks from here. It should be pretty easy to draw your custom X and O icons instead of circles.
BoardView.java
public class BoardView extends View {
private static final int JUST_SCALED_DURATION = 100;
private static final int MAX_TOUCH_DURATION = 1000;
private static final int MAX_TOUCH_DISTANCE = 10;
private boolean stayedWithinTouchDistance;
private float firstTouchX, firstTouchY;
private long firstTouchTime, lastScaleTime;
private float posX, posY, lastTouchX, lastTouchY;
private ScaleGestureDetector scaleDetector;
private float minScaleFactor = 0.1f;
private float maxScaleFactor = 5.0f;
private float scaleFactor = 1.0f;
private float cellSize = 50.0f;
private int numCells = 50;
private ArrayList<Point> points;
private Paint linePaint, pointPaint;
public BoardView(Context context) {
this(context, null, 0);
}
public BoardView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public BoardView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
points = new ArrayList<>();
linePaint = new Paint();
linePaint.setAntiAlias(true);
linePaint.setColor(-65536);
linePaint.setStrokeWidth(1.0f);
pointPaint = new Paint();
pointPaint.setAntiAlias(true);
pointPaint.setColor(-65536);
pointPaint.setStrokeWidth(1.0f);
posX = linePaint.getStrokeWidth();
posY = linePaint.getStrokeWidth();
scaleDetector = new ScaleGestureDetector(context, new ScaleListener());
}
private static float distancePx(float x1, float y1, float x2, float y2) {
float dx = x1 - x2;
float dy = y1 - y2;
return (float) Math.sqrt(dx * dx + dy * dy);
}
private float distanceDp(float distancePx) {
return distancePx / getResources().getDisplayMetrics().density;
}
private Point coerceToGrid(Point point) {
point.x = (int) ((((int) (point.x / cellSize)) * cellSize) + (cellSize / 2));
point.y = (int) ((((int) (point.y / cellSize)) * cellSize) + (cellSize / 2));
return point;
}
#Override
public boolean onTouchEvent(#NonNull MotionEvent event) {
scaleDetector.onTouchEvent(event);
final int action = MotionEventCompat.getActionMasked(event);
if (action == MotionEvent.ACTION_DOWN) {
stayedWithinTouchDistance = true;
firstTouchX = lastTouchX = event.getRawX();
firstTouchY = lastTouchY = event.getRawY();
firstTouchTime = System.currentTimeMillis();
} else if (action == MotionEvent.ACTION_MOVE) {
float thisTouchX = event.getRawX();
float thisTouchY = event.getRawY();
boolean justScaled = System.currentTimeMillis() - lastScaleTime < JUST_SCALED_DURATION;
float distancePx = distancePx(firstTouchX, firstTouchY, thisTouchX, thisTouchY);
stayedWithinTouchDistance = stayedWithinTouchDistance &&
distanceDp(distancePx) < MAX_TOUCH_DISTANCE;
if (!stayedWithinTouchDistance && !scaleDetector.isInProgress() && !justScaled) {
posX += thisTouchX - lastTouchX;
posY += thisTouchY - lastTouchY;
invalidate();
}
lastTouchX = thisTouchX;
lastTouchY = thisTouchY;
} else if (action == MotionEvent.ACTION_UP) {
long touchDuration = System.currentTimeMillis() - firstTouchTime;
if (touchDuration < MAX_TOUCH_DURATION && stayedWithinTouchDistance) {
int[] location = {0, 0};
getLocationOnScreen(location);
float x = ((lastTouchX - posX - location[0]) / scaleFactor);
float y = ((lastTouchY - posY - location[1]) / scaleFactor);
points.add(coerceToGrid(new Point((int) x, (int) y)));
invalidate();
}
}
return true;
}
private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
#Override
public boolean onScale(ScaleGestureDetector detector) {
lastScaleTime = System.currentTimeMillis();
float scale = detector.getScaleFactor();
scaleFactor = Math.max(minScaleFactor, Math.min(scaleFactor * scale, maxScaleFactor));
if (scaleFactor > minScaleFactor && scaleFactor < maxScaleFactor) {
float centerX = detector.getFocusX();
float centerY = detector.getFocusY();
float diffX = centerX - posX;
float diffY = centerY - posY;
diffX = diffX * scale - diffX;
diffY = diffY * scale - diffY;
posX -= diffX;
posY -= diffY;
invalidate();
return true;
}
return false;
}
}
private float getScaledCellSize() {
return scaleFactor * cellSize;
}
private float getScaledBoardSize() {
return numCells * getScaledCellSize();
}
private void drawBoard(Canvas canvas) {
for (int i = 0; i <= numCells; i++) {
float total = getScaledBoardSize();
float offset = getScaledCellSize() * i;
canvas.drawLine(offset, 0, offset, total, linePaint);
canvas.drawLine(0, offset, total, offset, linePaint);
}
}
private void drawPoints(Canvas canvas) {
for (Point point : points) {
float x = point.x * scaleFactor;
float y = point.y * scaleFactor;
float r = getScaledCellSize() / 4;
canvas.drawCircle(x, y, r, pointPaint);
}
}
#Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
float total = getScaledBoardSize();
float edge = linePaint.getStrokeWidth();
posX = Math.max(Math.min(edge, getWidth() - total - edge), Math.min(edge, posX));
posY = Math.max(Math.min(edge, getHeight() - total - edge), Math.min(edge, posY));
canvas.save();
canvas.translate(posX, posY);
drawBoard(canvas);
drawPoints(canvas);
canvas.restore();
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.example.client.BoardView
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</FrameLayout>

android-how to move image to center of this CustomImageVIew

I needed to able zoom images inside an imageView.
I've searched and used this CustomImageVIew and it works fine.
The only problem is this, it move the image to the top left corner of the screen.
Sorry, I can't post screenshot, consider this, it's in 1/4 of the screen at top left corner.
I want to make the image to come to center of the screen
this is the class:
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.graphics.Point;
import android.graphics.PointF;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.View.OnTouchListener;
import android.widget.ImageView;
public class CustomImageVIew extends ImageView implements OnTouchListener {
private Matrix matrix = new Matrix();
private Matrix savedMatrix = new Matrix();
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
private int mode = NONE;
private PointF mStartPoint = new PointF();
private PointF mMiddlePoint = new PointF();
private Point mBitmapMiddlePoint = new Point();
private float oldDist = 1f;
private float matrixValues[] = {0f, 0f, 0f, 0f, 0f, 0f, 0f, 0f, 0f};
private float scale;
private float oldEventX = 0;
private float oldEventY = 0;
private float oldStartPointX = 0;
private float oldStartPointY = 0;
private int mViewWidth = -1;
private int mViewHeight = -1;
private int mBitmapWidth = -1;
private int mBitmapHeight = -1;
private boolean mDraggable = false;
public CustomImageVIew(Context context) {
this(context, null, 0);
}
public CustomImageVIew(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CustomImageVIew(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
this.setOnTouchListener(this);
}
#Override
public void onSizeChanged (int w, int h, int oldw, int oldh){
super.onSizeChanged(w, h, oldw, oldh);
mViewWidth = w;
mViewHeight = h;
}
public void setBitmap(Bitmap bitmap){
if(bitmap != null){
setImageBitmap(bitmap);
mBitmapWidth = bitmap.getWidth();
mBitmapHeight = bitmap.getHeight();
mBitmapMiddlePoint.x = (mViewWidth / 2) - (mBitmapWidth / 2);
mBitmapMiddlePoint.y = (mViewHeight / 2) - (mBitmapHeight / 2);
matrix.postTranslate(mBitmapMiddlePoint.x, mBitmapMiddlePoint.y);
this.setImageMatrix(matrix);
}
}
#Override
public boolean onTouch(View v, MotionEvent event){
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_DOWN:
savedMatrix.set(matrix);
mStartPoint.set(event.getX(), event.getY());
mode = DRAG;
break;
case MotionEvent.ACTION_POINTER_DOWN:
oldDist = spacing(event);
if(oldDist > 10f){
savedMatrix.set(matrix);
midPoint(mMiddlePoint, event);
mode = ZOOM;
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
mode = NONE;
break;
case MotionEvent.ACTION_MOVE:
if(mode == DRAG){
drag(event);
} else if(mode == ZOOM){
zoom(event);
}
break;
}
return true;
}
public void drag(MotionEvent event){
matrix.getValues(matrixValues);
float left = matrixValues[2];
float top = matrixValues[5];
float bottom = (top + (matrixValues[0] * mBitmapHeight)) - mViewHeight;
float right = (left + (matrixValues[0] * mBitmapWidth)) -mViewWidth;
float eventX = event.getX();
float eventY = event.getY();
float spacingX = eventX - mStartPoint.x;
float spacingY = eventY - mStartPoint.y;
float newPositionLeft = (left < 0 ? spacingX : spacingX * -1) + left;
float newPositionRight = (spacingX) + right;
float newPositionTop = (top < 0 ? spacingY : spacingY * -1) + top;
float newPositionBottom = (spacingY) + bottom;
boolean x = true;
boolean y = true;
if(newPositionRight < 0.0f || newPositionLeft > 0.0f){
if(newPositionRight < 0.0f && newPositionLeft > 0.0f){
x = false;
} else{
eventX = oldEventX;
mStartPoint.x = oldStartPointX;
}
}
if(newPositionBottom < 0.0f || newPositionTop > 0.0f){
if(newPositionBottom < 0.0f && newPositionTop > 0.0f){
y = false;
} else{
eventY = oldEventY;
mStartPoint.y = oldStartPointY;
}
}
if(mDraggable){
matrix.set(savedMatrix);
matrix.postTranslate(x? eventX - mStartPoint.x : 0, y? eventY - mStartPoint.y : 0);
this.setImageMatrix(matrix);
if(x)oldEventX = eventX;
if(y)oldEventY = eventY;
if(x)oldStartPointX = mStartPoint.x;
if(y)oldStartPointY = mStartPoint.y;
}
}
public void zoom(MotionEvent event){
matrix.getValues(matrixValues);
float newDist = spacing(event);
float bitmapWidth = matrixValues[0] * mBitmapWidth;
float bimtapHeight = matrixValues[0] * mBitmapHeight;
boolean in = newDist > oldDist;
if(!in && matrixValues[0] < 1){
return;
}
if(bitmapWidth > mViewWidth || bimtapHeight > mViewHeight){
mDraggable = true;
} else{
mDraggable = false;
}
float midX = (mViewWidth / 2);
float midY = (mViewHeight / 2);
matrix.set(savedMatrix);
scale = newDist / oldDist;
matrix.postScale(scale, scale, bitmapWidth > mViewWidth ? mMiddlePoint.x : midX, bimtapHeight > mViewHeight ? mMiddlePoint.y : midY);
this.setImageMatrix(matrix);
}
/** Determine the space between the first two fingers */
private float spacing(MotionEvent event) {
float x = event.getX(0) - event.getX(1);
float y = event.getY(0) - event.getY(1);
return (float)Math.sqrt(x * x + y * y);
}
/** Calculate the mid point of the first two fingers */
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);
}
}
this is layout xml :
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_gravity="center"
android:gravity="center"
android:background="#000" >
<mypackagename.CustomImageVIew
android:id="#+id/imageView1"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginBottom="5dp"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp"
android:layout_marginTop="5dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
android:scaleType="matrix"
/>

My guess is that you're calling setBitmap before the view is visible on screen, while it still has a width and height of zero.
There are a few options for fixing this, but generally speaking you could change the image view so it does the calculation that happens in setBitmap either the first time onSizeChanged is called with a width and height greater than zero, or the first time onDraw is called and both getWidth() and getHeight() return greater than zero. When setBitmap is called and the view already has a width and a height, do the calculation immediately.
Here's a rough (untested) illustration:
#Override
public void onSizeChanged (int w, int h, int oldw, int oldh){
super.onSizeChanged(w, h, oldw, oldh);
mViewWidth = w;
mViewHeight = h;
if (w > 0 && h > 0 && mBitmapWidth > 0 && mBitmapHeight > 0) {
centerBitmap();
}
}
public void setBitmap(Bitmap bitmap){
if(bitmap != null){
setImageBitmap(bitmap);
mBitmapWidth = bitmap.getWidth();
mBitmapHeight = bitmap.getHeight();
if (getWidth() > 0 && getHeight() > 0) {
centerBitmap();
}
}
}
private void centerBitmap() {
mBitmapMiddlePoint.x = (mViewWidth / 2) - (mBitmapWidth / 2);
mBitmapMiddlePoint.y = (mViewHeight / 2) - (mBitmapHeight / 2);
matrix.postTranslate(mBitmapMiddlePoint.x, mBitmapMiddlePoint.y);
this.setImageMatrix(matrix);
}

Take Framelayout instead of Relative layout and try..

Android ImageView, OnTouchEvent not moving it

I'm trying to make a simple app, with an imageview that can be zoomed in and out with buttons, and when zoomed, user could move around it with his fingers.
I've been reading the whole day, here and there, found different solutions. But I can't seem to make my picture move. Thing is, I want to keep the program like it is now, but just maybe change the imageview OnTouchEvent.
I'm adding my code:
public class LoadMap extends Activity {
ZoomControls zoom;
ImageView img;
ImageButton linkButton;
float startX, startY;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_load_map);
zoom = (ZoomControls) findViewById(R.id.zoomControls1);
img = (ImageView) findViewById(R.id.imageView1);
linkButton = (ImageButton) findViewById(R.id.infopoint);
startX = img.getScaleX();
startY = img.getScaleY();
img.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
if(event.getAction() == MotionEvent.ACTION_MOVE) {
RelativeLayout.LayoutParams mParams = (RelativeLayout.LayoutParams) img.getLayoutParams();
int x = (int) event.getRawX();
int y = (int) event.getRawY();
mParams.leftMargin = x;
mParams.topMargin = y;
img.setLayoutParams(mParams);
}
return false;
}
});
linkButton.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
Uri uri = Uri.parse("just some site");
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);
}
});
zoom.setOnZoomInClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
float x = img.getScaleX();
float y = img.getScaleY();
img.setScaleX((float) (x+1));
img.setScaleY((float) (y+1));
}
});
zoom.setOnZoomOutClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
// TODO Auto-generated method stub
float x = img.getScaleX();
float y = img.getScaleY();
if((x>startX) & (y>startY)) {
img.setScaleX((float) (x-1));
img.setScaleY((float) (y-1));
}
}
});
}
Is there a way to just change some things inside this method without messing my app too much and is this even possible the way I'm trying to make it work or my program logic is wrong.
img.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
if(event.getAction() == MotionEvent.ACTION_MOVE) {
RelativeLayout.LayoutParams mParams = (RelativeLayout.LayoutParams) img.getLayoutParams();
int x = (int) event.getRawX();
int y = (int) event.getRawY();
mParams.leftMargin = x;
mParams.topMargin = y;
img.setLayoutParams(mParams);
}
return false;
}
});
Sorry, if it has been asked before, but i searched alot and couldn't find anything specific for my 'problem'.
Thanks alot to whoever spends some time on my problem :).

try this code,
put this code on image setOnTouchListener,
img.setOnTouchListener(new View.OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
LayoutParams layoutParams = (LayoutParams) img
.getLayoutParams();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
break;
case MotionEvent.ACTION_MOVE:
int x_cord = (int) event.getRawX();
int y_cord = (int) event.getRawY();
if (x_cord > windowwidth) {
x_cord = windowwidth;
}
if (y_cord > windowheight) {
y_cord = windowheight;
}
layoutParams.leftMargin = x_cord - 25;
layoutParams.topMargin = y_cord - 75;
img.setLayoutParams(layoutParams);
break;
default:
break;
}
return true;
}
});
I hope it will solve your problem..

Try using a custom ImageVIew
public class ZoomableImageView extends ImageView implements OnTouchListener {
private Context mContext;
final private float MAX_SCALE = 2f;
private Matrix mMatrix;
private final float[] mMatrixValues = new float[9];
// display width height.
private int mWidth;
private int mHeight;
private int mIntrinsicWidth;
private int mIntrinsicHeight;
private float mScale;
private float mMinScale;
private float mPrevDistance;
private boolean isScaling;
private int mPrevMoveX;
private int mPrevMoveY;
private GestureDetector mDetector;
final String TAG = "ScaleImageView";
public ZoomableImageView(Context context, AttributeSet attr) {
super(context, attr);
this.mContext = context;
initialize();
}
public ZoomableImageView(Context context) {
super(context);
this.mContext = context;
initialize();
}
#Override
public void setImageBitmap(Bitmap bm) {
super.setImageBitmap(bm);
this.initialize();
}
#Override
public void setImageResource(int resId) {
super.setImageResource(resId);
this.initialize();
}
private void initialize() {
this.setScaleType(ScaleType.MATRIX);
this.mMatrix = new Matrix();
Drawable d = getDrawable();
if (d != null) {
mIntrinsicWidth = d.getIntrinsicWidth();
mIntrinsicHeight = d.getIntrinsicHeight();
setOnTouchListener(this);
}
mDetector = new GestureDetector(mContext,
new GestureDetector.SimpleOnGestureListener() {
#Override
public boolean onDoubleTap(MotionEvent e) {
maxZoomTo((int) e.getX(), (int) e.getY());
cutting();
return super.onDoubleTap(e);
}
});
}
#Override
protected boolean setFrame(int l, int t, int r, int b) {
mWidth = r - l;
mHeight = b - t;
mMatrix.reset();
int rNorm = r - l;
mScale = (float) rNorm / (float) mIntrinsicWidth;
int paddingHeight = 0;
int paddingWidth = 0;
// scaling vertical
if (mScale * mIntrinsicHeight > mHeight) {
mScale = (float) mHeight / (float) mIntrinsicHeight;
mMatrix.postScale(mScale, mScale);
paddingWidth = (r - mWidth) / 2;
paddingHeight = 0;
// scaling horizontal
} else {
mMatrix.postScale(mScale, mScale);
paddingHeight = (b - mHeight) / 2;
paddingWidth = 0;
}
mMatrix.postTranslate(paddingWidth, paddingHeight);
setImageMatrix(mMatrix);
mMinScale = mScale;
zoomTo(mScale, mWidth / 2, mHeight / 2);
cutting();
return super.setFrame(l, t, r, b);
}
protected float getValue(Matrix matrix, int whichValue) {
matrix.getValues(mMatrixValues);
return mMatrixValues[whichValue];
}
protected float getScale() {
return getValue(mMatrix, Matrix.MSCALE_X);
}
public float getTranslateX() {
return getValue(mMatrix, Matrix.MTRANS_X);
}
protected float getTranslateY() {
return getValue(mMatrix, Matrix.MTRANS_Y);
}
protected void maxZoomTo(int x, int y) {
if (mMinScale != getScale() && (getScale() - mMinScale) > 0.1f) {
// threshold 0.1f
float scale = mMinScale / getScale();
zoomTo(scale, x, y);
} else {
float scale = MAX_SCALE / getScale();
zoomTo(scale, x, y);
}
}
public void zoomTo(float scale, int x, int y) {
if (getScale() * scale < mMinScale) {
return;
}
if (scale >= 1 && getScale() * scale > MAX_SCALE) {
return;
}
mMatrix.postScale(scale, scale);
// move to center
mMatrix.postTranslate(-(mWidth * scale - mWidth) / 2,
-(mHeight * scale - mHeight) / 2);
// move x and y distance
mMatrix.postTranslate(-(x - (mWidth / 2)) * scale, 0);
mMatrix.postTranslate(0, -(y - (mHeight / 2)) * scale);
setImageMatrix(mMatrix);
}
public void cutting() {
int width = (int) (mIntrinsicWidth * getScale());
int height = (int) (mIntrinsicHeight * getScale());
if (getTranslateX() < -(width - mWidth)) {
mMatrix.postTranslate(-(getTranslateX() + width - mWidth), 0);
}
if (getTranslateX() > 0) {
mMatrix.postTranslate(-getTranslateX(), 0);
}
if (getTranslateY() < -(height - mHeight)) {
mMatrix.postTranslate(0, -(getTranslateY() + height - mHeight));
}
if (getTranslateY() > 0) {
mMatrix.postTranslate(0, -getTranslateY());
}
if (width < mWidth) {
mMatrix.postTranslate((mWidth - width) / 2, 0);
}
if (height < mHeight) {
mMatrix.postTranslate(0, (mHeight - height) / 2);
}
setImageMatrix(mMatrix);
}
private float distance(float x0, float x1, float y0, float y1) {
float x = x0 - x1;
float y = y0 - y1;
return FloatMath.sqrt(x * x + y * y);
}
private float dispDistance() {
return FloatMath.sqrt(mWidth * mWidth + mHeight * mHeight);
}
#Override
public boolean onTouchEvent(MotionEvent event) {
if (mDetector.onTouchEvent(event)) {
return true;
}
int touchCount = event.getPointerCount();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
case MotionEvent.ACTION_POINTER_1_DOWN:
case MotionEvent.ACTION_POINTER_2_DOWN:
if (touchCount >= 2) {
float distance = distance(event.getX(0), event.getX(1),
event.getY(0), event.getY(1));
mPrevDistance = distance;
isScaling = true;
} else {
mPrevMoveX = (int) event.getX();
mPrevMoveY = (int) event.getY();
}
case MotionEvent.ACTION_MOVE:
if (touchCount >= 2 && isScaling) {
float dist = distance(event.getX(0), event.getX(1),
event.getY(0), event.getY(1));
float scale = (dist - mPrevDistance) / dispDistance();
mPrevDistance = dist;
scale += 1;
scale = scale * scale;
zoomTo(scale, mWidth / 2, mHeight / 2);
cutting();
} else if (!isScaling) {
int distanceX = mPrevMoveX - (int) event.getX();
int distanceY = mPrevMoveY - (int) event.getY();
mPrevMoveX = (int) event.getX();
mPrevMoveY = (int) event.getY();
mMatrix.postTranslate(-distanceX, -distanceY);
cutting();
}
break;
case MotionEvent.ACTION_UP:
case MotionEvent.ACTION_POINTER_UP:
case MotionEvent.ACTION_POINTER_2_UP:
if (event.getPointerCount() <= 1) {
isScaling = false;
}
break;
}
return true;
}
#Override
public boolean onTouch(View v, MotionEvent event) {
return super.onTouchEvent(event);
}
}

Try it that way:
img.setOnTouchListener(new OnTouchListener() {
#Override
public boolean onTouch(View v, MotionEvent event) {
// TODO Auto-generated method stub
if (event.getAction() == MotionEvent.ACTION_DOWN)
{
return true;
}
if(event.getAction() == MotionEvent.ACTION_MOVE) {
RelativeLayout.LayoutParams mParams = (RelativeLayout.LayoutParams) img.getLayoutParams();
int x = (int) event.getRawX();
int y = (int) event.getRawY();
mParams.leftMargin = x;
mParams.topMargin = y;
img.setLayoutParams(mParams);
}
return false;
}
});
You need to return true when the ACTION_DOWN event is triggered to indicate that you are interested in the subsequent calls relating to that same event.