Android自定义GestureDetector实现手势ImageView

public abstract class BaseGestureDetector { protected final Context mContext; protected boolean mGestureInProgress; protected MotionEvent mPrevEvent; protected MotionEvent mCurrEvent; protected float mCurrPressure; protected float mPrevPressure; protected long mTimeDelta; /** * 上一次event的pressure／这一次的pressure，这是一个什么概念呢？ * 我们想象一下当你手指按下然后滑动并且到离开屏幕， * 手指触碰到屏幕的压力会越来越小，直到手指移开屏幕 */ protected static final float PRESSURE_THRESHOLD = 0.67f; public BaseGestureDetector(Context context) { mContext = context;  } /** * 跟ScaleGesture一样，我们也把事件的处理放在此方法中 * @param event * @return */ public boolean onTouchEvent(MotionEvent event){ //为了获取到ACTION_POINTER_UP等事件必须加上& MotionEvent.ACTION_MASK final int actionCode = event.getAction() & MotionEvent.ACTION_MASK; /** * 是否调用handleInProgressEvent方法 */ if (!mGestureInProgress) { //如果mGestureInProgress为false的时候，执行开始操作 handleStartProgressEvent(actionCode, event); } else { //处理手势 handleInProgressEvent(actionCode, event); } return true; } /** * 准备处理手势 * @param actionCode * @param event */ protected abstract void handleStartProgressEvent(int actionCode, MotionEvent event); /** * 正在处理手势 * @param actionCode * @param event */ protected abstract void handleInProgressEvent(int actionCode, MotionEvent event); /** * 更新event的状态，保存之前的event，获取当前event * @param curr */ protected void updateStateByEvent(MotionEvent curr){ final MotionEvent prev = mPrevEvent; // Reset mCurrEvent if (mCurrEvent != null) { mCurrEvent.recycle(); mCurrEvent = null; } mCurrEvent = MotionEvent.obtain(curr); // 之前的event跟现在的event之间的时间差 mTimeDelta = curr.getEventTime() - prev.getEventTime(); // 之前的event跟腺癌的event之间的手指压力值 mCurrPressure = curr.getPressure(curr.getActionIndex()); mPrevPressure = prev.getPressure(prev.getActionIndex()); } /** * 重置所有状态 */ protected void resetState() { if (mPrevEvent != null) { mPrevEvent.recycle(); mPrevEvent = null; } if (mCurrEvent != null) { mCurrEvent.recycle(); mCurrEvent = null; } mGestureInProgress = false; } /** * Returns {@code true} if a gesture is currently in progress. * @return {@code true} if a gesture is currently in progress, {@code false} otherwise. */ public boolean isInProgress() { return mGestureInProgress; } /** * Return the time difference in milliseconds between the previous accepted * GestureDetector event and the current GestureDetector event. *  * @return Time difference since the last move event in milliseconds. */ public long getTimeDelta() { return mTimeDelta; } /** * Return the event time of the current GestureDetector event being * processed. *  * @return Current GestureDetector event time in milliseconds. */ public long getEventTime() { return mCurrEvent.getEventTime(); }}

public class MoveGestureDetector extends BaseGestureDetector{ @Override protected void handleStartProgressEvent(int actionCode, MotionEvent event){ ｝ @Override protected void handleInProgressEvent(int actionCode, MotionEvent event){  }｝

public interface OnScaleGestureListener { public boolean onScale(ScaleGestureDetector detector); public boolean onScaleBegin(ScaleGestureDetector detector); public void onScaleEnd(ScaleGestureDetector detector); } public static class SimpleOnScaleGestureListener implements OnScaleGestureListener { public boolean onScale(ScaleGestureDetector detector) { return false; } public boolean onScaleBegin(ScaleGestureDetector detector) { return true; } public void onScaleEnd(ScaleGestureDetector detector) { // Intentionally empty } }

/** * 仿照ScaleGestureDetector我们也定义三个方法 */ public interface OnMoveGestureListener { /** * 移动的时候回调 */ public boolean onMove(MoveGestureDetector detector); /** * 移动开始的时候回调 */ public boolean onMoveBegin(MoveGestureDetector detector); /** * 移动结束的时候回调 */ public void onMoveEnd(MoveGestureDetector detector); } public static class SimpleOnMoveGestureListener implements OnMoveGestureListener { public boolean onMove(MoveGestureDetector detector) { return false; } public boolean onMoveBegin(MoveGestureDetector detector) { return true; } public void onMoveEnd(MoveGestureDetector detector) { // Do nothing, overridden implementation may be used } }

 public MatrixImageView(Context context, AttributeSet attrs) { super(context, attrs); initView(); //创建一个缩放手势监测器 scaleDetector=new ScaleGestureDetector(context,onScaleGestureListener); //创建一个MoveGestureDetector moveGestureDetector=new MoveGestureDetector(context,onMoveGestureListener); }

 @Override public boolean onTouchEvent(MotionEvent event) { //把事件给scaleDetector scaleDetector.onTouchEvent(event); //把事件给moveGestureDetector moveGestureDetector.onTouchEvent(event); return true; }

private MoveGestureDetector.SimpleOnMoveGestureListener onMoveGestureListener=new MoveGestureDetector.SimpleOnMoveGestureListener(){ @Override public boolean onMove(MoveGestureDetector detector) { return super.onMove(detector); } };

 */public class MoveGestureDetector extends BaseGestureDetector { /** * 仿照ScaleGestureDetector我们也定义三个方法 */ public interface OnMoveGestureListener { /** * 移动的时候回调 */ public boolean onMove(MoveGestureDetector detector); /** * 移动开始的时候回调 */ public boolean onMoveBegin(MoveGestureDetector detector); /** * 移动结束的时候回调 */ public void onMoveEnd(MoveGestureDetector detector); } public static class SimpleOnMoveGestureListener implements OnMoveGestureListener { public boolean onMove(MoveGestureDetector detector) { return false; } public boolean onMoveBegin(MoveGestureDetector detector) { return true; } public void onMoveEnd(MoveGestureDetector detector) { // Do nothing, overridden implementation may be used } } private static final PointF FOCUS_DELTA_ZERO = new PointF(); private final OnMoveGestureListener mListener; private PointF mCurrFocusInternal; private PointF mPrevFocusInternal;  private PointF mFocusExternal = new PointF(); private PointF mFocusDeltaExternal = new PointF(); public MoveGestureDetector(Context context, OnMoveGestureListener listener) { super(context); mListener = listener; } @Override protected void handleStartProgressEvent(int actionCode, MotionEvent event){ switch (actionCode) { //当手指按下的时候 case MotionEvent.ACTION_DOWN: //重置一下所有状态（currevent跟preevent） resetState(); // In case we missed an UP/CANCEL event //获取当前event作为mPrevEvent mPrevEvent = MotionEvent.obtain(event); //重置两次event的时间间隔 mTimeDelta = 0; //更新state updateStateByEvent(event); break; case MotionEvent.ACTION_MOVE: //回调onMoveBegin，mGestureInProgress决定是否继续处理事件（执行handleInProgressEvent） //mGestureInProgress由调用者决定 mGestureInProgress = mListener.onMoveBegin(this); break; } } /** * 处理移动事件 */ @Override protected void handleInProgressEvent(int actionCode, MotionEvent event){  switch (actionCode) { //当抬起或者取消的时候 case MotionEvent.ACTION_UP: case MotionEvent.ACTION_CANCEL: //回调onMoveEnd，move处理结束 mListener.onMoveEnd(this); //重置所有的state resetState(); break; case MotionEvent.ACTION_MOVE: //更新状态 updateStateByEvent(event); //当上一次event的press值／这一次event值大于临界值的时候开始触发onMove //因为如果CurrPressure / mPrevPressure很小的话，可能手指已经离开屏幕了 if (mCurrPressure / mPrevPressure > PRESSURE_THRESHOLD) { /** * 回调onMove方法，并获取updatePrevious * updatePrevious标记是由调用者决定， * updatePrevious是否更新之前的event， * 如果为false的话mPrevEvent一直是我们在down的时候赋值的event * 如果为true的话，每次move事件处理完都会把最新的event赋给mPrevEvent */ final boolean updatePrevious = mListener.onMove(this); if (updatePrevious) { mPrevEvent.recycle(); mPrevEvent = MotionEvent.obtain(event); } } break; } } /** * 参考ScaleGestureDetector * move核心处理方法 * 重写父类的updateStateByEvent * */ protected void updateStateByEvent(MotionEvent curr) { super.updateStateByEvent(curr); final MotionEvent prev = mPrevEvent; // 获取当前所有手指的中心点 mCurrFocusInternal = determineFocalPoint(curr); //获取之前event所有手指的中心点 mPrevFocusInternal = determineFocalPoint(prev); //判断是否有手指中途添加或者移除 boolean mSkipNextMoveEvent = prev.getPointerCount() != curr.getPointerCount(); //有移除的话mFocusDeltaExternal就等于空（0，0），没有的话就算出前面event跟当前event中心点距离 mFocusDeltaExternal = mSkipNextMoveEvent ? FOCUS_DELTA_ZERO : new PointF(mCurrFocusInternal.x - mPrevFocusInternal.x, mCurrFocusInternal.y - mPrevFocusInternal.y); //累加距离值 mFocusExternal.x += mFocusDeltaExternal.x; mFocusExternal.y += mFocusDeltaExternal.y;  } /** * 获取所有手指的中间点坐标（参考ScaleGestureDetector） */ private PointF determineFocalPoint(MotionEvent e){ // Number of fingers on screen final int pCount = e.getPointerCount();  float x = 0f; float y = 0f; for(int i = 0; i < pCount; i++){ x += e.getX(i); y += e.getY(i); } return new PointF(x/pCount, y/pCount); } /** * 获取距离值累加过后的值 */ public float getFocusX() { return mFocusExternal.x; } public float getFocusY() { return mFocusExternal.y; } /** * 获取上一个事件到下一个事件之间的x跟y的距离值 */ public PointF getFocusDelta() { return mFocusDeltaExternal; }}

package com.leo.gestureimageview;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Matrix;import android.util.AttributeSet;import android.util.DisplayMetrics;import android.view.MotionEvent;import android.view.ScaleGestureDetector;import android.widget.ImageView;import com.leo.gestureimageview.GestureDetectors.MoveGestureDetector;public class MatrixImageView extends ImageView { private Matrix currMatrix; private float scaleFactor=1f;//当前图片的缩放值 private float transX,transY; private ScaleGestureDetector scaleDetector; private MoveGestureDetector moveGestureDetector; public MatrixImageView(Context context, AttributeSet attrs) { super(context, attrs); initView(); //创建一个缩放手势监测器 scaleDetector=new ScaleGestureDetector(context,onScaleGestureListener); //创建一个MoveGestureDetector moveGestureDetector=new MoveGestureDetector(context,onMoveGestureListener); } private void initView() { currMatrix = new Matrix(); DisplayMetrics dm = getResources().getDisplayMetrics(); Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.test); bitmap = Bitmap.createScaledBitmap(bitmap, dm.widthPixels, dm.heightPixels, true); setImageBitmap(bitmap); } @Override public boolean onTouchEvent(MotionEvent event) { //把事件给scaleDetector scaleDetector.onTouchEvent(event); //把事件给moveGestureDetector moveGestureDetector.onTouchEvent(event); return true; } private void setMatrix(){ currMatrix.reset(); currMatrix.postScale(scaleFactor,scaleFactor,getMeasuredWidth()/2,getMeasuredHeight()/2); currMatrix.postTranslate(transX,transY); setImageMatrix(currMatrix); } private ScaleGestureDetector.SimpleOnScaleGestureListener onScaleGestureListener=new ScaleGestureDetector.SimpleOnScaleGestureListener(){ @Override public boolean onScale(ScaleGestureDetector detector) { scaleFactor *= detector.getScaleFactor(); // scale change since previous event // Don't let the object get too small or too large. scaleFactor = Math.max(0.1f, Math.min(scaleFactor, 10.0f)); setMatrix(); /** * 因为getScaleFactor＝当前两个手指之间的距离（preEvent）／手指按下时候两个点的距离(currEvent) * 这里如果返回true的话，会在move操作的时候去更新之前的event, * 如果为false的话，不会去更新之前按下时候保存的event */ return true; } }; private MoveGestureDetector.SimpleOnMoveGestureListener onMoveGestureListener=new MoveGestureDetector.SimpleOnMoveGestureListener(){ @Override public boolean onMove(MoveGestureDetector detector) { transX=detector.getFocusX(); transY=detector.getFocusY(); setMatrix(); return true; } };}

public class RotateGestureDetector extends TwoFingerGestureDetector { /** * Listener which must be implemented which is used by RotateGestureDetector * to perform callbacks to any implementing class which is registered to a * RotateGestureDetector via the constructor. *  * @see SimpleOnRotateGestureListener */ public interface OnRotateGestureListener { public boolean onRotate(RotateGestureDetector detector); public boolean onRotateBegin(RotateGestureDetector detector); public void onRotateEnd(RotateGestureDetector detector); } /** * Helper class which may be extended and where the methods may be * implemented. This way it is not necessary to implement all methods * of OnRotateGestureListener. */ public static class SimpleOnRotateGestureListener implements OnRotateGestureListener { public boolean onRotate(RotateGestureDetector detector) { return false; } public boolean onRotateBegin(RotateGestureDetector detector) { return true; } public void onRotateEnd(RotateGestureDetector detector) { // Do nothing, overridden implementation may be used } } private final OnRotateGestureListener mListener; private boolean mSloppyGesture; public RotateGestureDetector(Context context, OnRotateGestureListener listener) { super(context); mListener = listener; } @Override protected void handleStartProgressEvent(int actionCode, MotionEvent event){ switch (actionCode) { case MotionEvent.ACTION_POINTER_DOWN: // At least the second finger is on screen now resetState(); // In case we missed an UP/CANCEL event mPrevEvent = MotionEvent.obtain(event); mTimeDelta = 0; updateStateByEvent(event); // See if we have a sloppy gesture mSloppyGesture = isSloppyGesture(event); if(!mSloppyGesture){ // No, start gesture now mGestureInProgress = mListener.onRotateBegin(this); }  break; case MotionEvent.ACTION_MOVE: if (!mSloppyGesture) { break; } // See if we still have a sloppy gesture mSloppyGesture = isSloppyGesture(event); if(!mSloppyGesture){ // No, start normal gesture now mGestureInProgress = mListener.onRotateBegin(this); } break; case MotionEvent.ACTION_POINTER_UP: if (!mSloppyGesture) { break; } break;  } } @Override protected void handleInProgressEvent(int actionCode, MotionEvent event){  switch (actionCode) { case MotionEvent.ACTION_POINTER_UP: // Gesture ended but  updateStateByEvent(event); if (!mSloppyGesture) { mListener.onRotateEnd(this); } resetState(); break; case MotionEvent.ACTION_CANCEL: if (!mSloppyGesture) { mListener.onRotateEnd(this); } resetState(); break; case MotionEvent.ACTION_MOVE: updateStateByEvent(event); // Only accept the event if our relative pressure is within // a certain limit. This can help filter shaky data as a // finger is lifted. if (mCurrPressure / mPrevPressure > PRESSURE_THRESHOLD) { final boolean updatePrevious = mListener.onRotate(this); if (updatePrevious) { mPrevEvent.recycle(); mPrevEvent = MotionEvent.obtain(event); } } break; } } @Override protected void resetState() { super.resetState(); mSloppyGesture = false; } /** * Return the rotation difference from the previous rotate event to the current * event.  *  * @return The current rotation //difference in degrees. */ public float getRotationDegreesDelta() { double diffRadians = Math.atan2(mPrevFingerDiffY, mPrevFingerDiffX) - Math.atan2(mCurrFingerDiffY, mCurrFingerDiffX); return (float) (diffRadians * 180 / Math.PI); }}

package com.leo.gestureimageview;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Matrix;import android.graphics.PointF;import android.util.AttributeSet;import android.util.DisplayMetrics;import android.view.MotionEvent;import android.view.ScaleGestureDetector;import android.widget.ImageView;import com.leo.gestureimageview.GestureDetectors.MoveGestureDetector;import com.leo.gestureimageview.GestureDetectors.RotateGestureDetector;public class MatrixImageView2 extends ImageView { private Matrix mMatrix = new Matrix(); private float mScaleFactor =1f; private float mRotationDegrees = 0.f; private float mFocusX = 0.f; private float mFocusY = 0.f; private ScaleGestureDetector mScaleDetector; private RotateGestureDetector mRotateDetector; private MoveGestureDetector mMoveDetector; public MatrixImageView2(Context context, AttributeSet attrs) { super(context, attrs); initView(); } private void initView() { //初始化模式为初始状态 DisplayMetrics dm = getResources().getDisplayMetrics(); //给ImageView设置一张图片（此处为了测试直接在imageview里面设置了一张测试图片） Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.test); bitmap = Bitmap.createScaledBitmap(bitmap, dm.widthPixels, dm.heightPixels, true); setImageBitmap(bitmap); mScaleDetector = new ScaleGestureDetector(getContext(), new ScaleListener()); mRotateDetector = new RotateGestureDetector(getContext(), new RotateListener()); mMoveDetector = new MoveGestureDetector(getContext(), new MoveListener()); mFocusX = dm.widthPixels/2f; mFocusY = dm.heightPixels/2f; } @Override public boolean onTouchEvent(MotionEvent event) { //把缩放事件给mScaleDetector mScaleDetector.onTouchEvent(event); //把旋转事件个mRotateDetector mRotateDetector.onTouchEvent(event); //把移动事件给mMoveDetector mMoveDetector.onTouchEvent(event); return true; } private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener { @Override public boolean onScale(ScaleGestureDetector detector) { mScaleFactor *= detector.getScaleFactor(); // scale change since previous event // Don't let the object get too small or too large. mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 10.0f)); changeMatrix(); return true; } } private class RotateListener extends RotateGestureDetector.SimpleOnRotateGestureListener { @Override public boolean onRotate(RotateGestureDetector detector) { mRotationDegrees -= detector.getRotationDegreesDelta(); changeMatrix(); return true; } } private class MoveListener extends MoveGestureDetector.SimpleOnMoveGestureListener { @Override public boolean onMove(MoveGestureDetector detector) { PointF d = detector.getFocusDelta(); mFocusX += d.x; mFocusY += d.y; changeMatrix(); return true; } } private void changeMatrix(){ float scaledImageCenterX = (getDrawable().getIntrinsicWidth()*mScaleFactor)/2; float scaledImageCenterY = (getDrawable().getIntrinsicHeight()*mScaleFactor)/2; mMatrix.reset(); mMatrix.postScale(mScaleFactor, mScaleFactor); mMatrix.postRotate(mRotationDegrees, scaledImageCenterX, scaledImageCenterY); mMatrix.postTranslate(mFocusX - scaledImageCenterX, mFocusY - scaledImageCenterY); setImageMatrix(mMatrix); }}

<uk.co.senab.photoview.PhotoView android:clickable="true" android:layout_width="match_parent" android:layout_height="match_parent" android:scaleType="fitxy" />

public class PhotoView extends ImageView implements IPhotoView { private PhotoViewAttacher mAttacher; private ScaleType mPendingScaleType; public PhotoView(Context context) { this(context, null); } public PhotoView(Context context, AttributeSet attr) { this(context, attr, 0); } public PhotoView(Context context, AttributeSet attr, int defStyle) { super(context, attr, defStyle); super.setScaleType(ScaleType.MATRIX); init(); } protected void init() { if (null == mAttacher || null == mAttacher.getImageView()) { mAttacher = new PhotoViewAttacher(this); } if (null != mPendingScaleType) { setScaleType(mPendingScaleType); mPendingScaleType = null; } } @Override public void setRotationTo(float rotationDegree) { mAttacher.setRotationTo(rotationDegree); } @Override public void setRotationBy(float rotationDegree) { mAttacher.setRotationBy(rotationDegree); } @Override public boolean canZoom() { return mAttacher.canZoom(); } @Override public RectF getDisplayRect() { return mAttacher.getDisplayRect(); } @Override public void getDisplayMatrix(Matrix matrix) { mAttacher.getDisplayMatrix(matrix); } @Override public boolean setDisplayMatrix(Matrix finalRectangle) { return mAttacher.setDisplayMatrix(finalRectangle); } @Override public float getMinimumScale() { return mAttacher.getMinimumScale(); } @Override public float getMediumScale() { return mAttacher.getMediumScale(); } @Override public float getMaximumScale() { return mAttacher.getMaximumScale(); } @Override public float getScale() { return mAttacher.getScale(); } @Override public ScaleType getScaleType() { return mAttacher.getScaleType(); } @Override public Matrix getImageMatrix() { return mAttacher.getImageMatrix(); } @Override public void setAllowParentInterceptOnEdge(boolean allow) { mAttacher.setAllowParentInterceptOnEdge(allow); } @Override public void setMinimumScale(float minimumScale) { mAttacher.setMinimumScale(minimumScale); } @Override public void setMediumScale(float mediumScale) { mAttacher.setMediumScale(mediumScale); } @Override public void setMaximumScale(float maximumScale) { mAttacher.setMaximumScale(maximumScale); } @Override public void setScaleLevels(float minimumScale, float mediumScale, float maximumScale) { mAttacher.setScaleLevels(minimumScale, mediumScale, maximumScale); } @Override // setImageBitmap calls through to this method public void setImageDrawable(Drawable drawable) { super.setImageDrawable(drawable); if (null != mAttacher) { mAttacher.update(); } } @Override public void setImageResource(int resId) { super.setImageResource(resId); if (null != mAttacher) { mAttacher.update(); } } @Override public void setImageURI(Uri uri) { super.setImageURI(uri); if (null != mAttacher) { mAttacher.update(); } } @Override protected boolean setFrame(int l, int t, int r, int b) { boolean changed = super.setFrame(l, t, r, b); if (null != mAttacher) { mAttacher.update(); } return changed; } @Override public void setOnMatrixChangeListener(OnMatrixChangedListener listener) { mAttacher.setOnMatrixChangeListener(listener); } @Override public void setOnLongClickListener(OnLongClickListener l) { mAttacher.setOnLongClickListener(l); } @Override public void setOnPhotoTapListener(OnPhotoTapListener listener) { mAttacher.setOnPhotoTapListener(listener); } @Override public void setOnViewTapListener(OnViewTapListener listener) { mAttacher.setOnViewTapListener(listener); } @Override public void setScale(float scale) { mAttacher.setScale(scale); } @Override public void setScale(float scale, boolean animate) { mAttacher.setScale(scale, animate); } @Override public void setScale(float scale, float focalX, float focalY, boolean animate) { mAttacher.setScale(scale, focalX, focalY, animate); } @Override public void setScaleType(ScaleType scaleType) { if (null != mAttacher) { mAttacher.setScaleType(scaleType); } else { mPendingScaleType = scaleType; } } @Override public void setZoomable(boolean zoomable) { mAttacher.setZoomable(zoomable); } @Override public Bitmap getVisibleRectangleBitmap() { return mAttacher.getVisibleRectangleBitmap(); } @Override public void setZoomTransitionDuration(int milliseconds) { mAttacher.setZoomTransitionDuration(milliseconds); } @Override public IPhotoView getIPhotoViewImplementation() { return mAttacher; } @Override public void setOnDoubleTapListener(GestureDetector.OnDoubleTapListener newOnDoubleTapListener) { mAttacher.setOnDoubleTapListener(newOnDoubleTapListener); } @Override public void setOnScaleChangeListener(PhotoViewAttacher.OnScaleChangeListener onScaleChangeListener) { mAttacher.setOnScaleChangeListener(onScaleChangeListener); } @Override public void setOnSingleFlingListener(PhotoViewAttacher.OnSingleFlingListener onSingleFlingListener) { mAttacher.setOnSingleFlingListener(onSingleFlingListener); } @Override protected void onDetachedFromWindow() { mAttacher.cleanup(); mAttacher = null; super.onDetachedFromWindow(); } @Override protected void onAttachedToWindow() { init(); super.onAttachedToWindow(); }}

 public PhotoViewAttacher(ImageView imageView, boolean zoomable) { mImageView = new WeakReference<>(imageView); imageView.setDrawingCacheEnabled(true); imageView.setOnTouchListener(this); ViewTreeObserver observer = imageView.getViewTreeObserver(); if (null != observer) observer.addOnGlobalLayoutListener(this); // Make sure we using MATRIX Scale Type setImageViewScaleTypeMatrix(imageView); if (imageView.isInEditMode()) { return; } // Create Gesture Detectors... mScaleDragDetector = VersionedGestureDetector.newInstance( imageView.getContext(), this); mGestureDetector = new GestureDetector(imageView.getContext(), new GestureDetector.SimpleOnGestureListener() { // forward long click listener @Override public void onLongPress(MotionEvent e) { if (null != mLongClickListener) { mLongClickListener.onLongClick(getImageView()); } } @Override public boolean onFling(MotionEvent e1, MotionEvent e2,  float velocityX, float velocityY) { if (mSingleFlingListener != null) { if (getScale() > DEFAULT_MIN_SCALE) { return false; } if (MotionEventCompat.getPointerCount(e1) > SINGLE_TOUCH  || MotionEventCompat.getPointerCount(e2) > SINGLE_TOUCH) { return false; } return mSingleFlingListener.onFling(e1, e2, velocityX, velocityY); } return false; } }); mGestureDetector.setOnDoubleTapListener(new DefaultOnDoubleTapListener(this)); mBaseRotation = 0.0f; // Finally, update the UI so that we're zoomable setZoomable(zoomable); }

@Override public boolean onTouch(View v, MotionEvent ev) { boolean handled = false; if (mZoomEnabled && hasDrawable((ImageView) v)) { ViewParent parent = v.getParent(); switch (ev.getAction()) { case ACTION_DOWN: // First, disable the Parent from intercepting the touch // event if (null != parent) { parent.requestDisallowInterceptTouchEvent(true); } else { LogManager.getLogger().i(LOG_TAG, "onTouch getParent() returned null"); } // If we're flinging, and the user presses down, cancel // fling cancelFling(); break; case ACTION_CANCEL: case ACTION_UP: // If the user has zoomed less than min scale, zoom back // to min scale if (getScale() < mMinScale) { RectF rect = getDisplayRect(); if (null != rect) { v.post(new AnimatedZoomRunnable(getScale(), mMinScale,  rect.centerX(), rect.centerY())); handled = true; } } break; } // Try the Scale/Drag detector if (null != mScaleDragDetector) { boolean wasScaling = mScaleDragDetector.isScaling(); boolean wasDragging = mScaleDragDetector.isDragging(); handled = mScaleDragDetector.onTouchEvent(ev); boolean didntScale = !wasScaling && !mScaleDragDetector.isScaling(); boolean didntDrag = !wasDragging && !mScaleDragDetector.isDragging(); mBlockParentIntercept = didntScale && didntDrag; } // Check to see if the user double tapped if (null != mGestureDetector && mGestureDetector.onTouchEvent(ev)) { handled = true; } } return handled; }

@Override public void setScale(float scale, float focalX, float focalY, boolean animate) { ImageView imageView = getImageView(); if (null != imageView) { // Check to see if the scale is within bounds if (scale < mMinScale || scale > mMaxScale) { LogManager .getLogger() .i(LOG_TAG, "Scale must be within the range of minScale and maxScale"); return; } if (animate) { imageView.post(new AnimatedZoomRunnable(getScale(), scale, focalX, focalY)); } else { mSuppMatrix.setScale(scale, scale, focalX, focalY); checkAndDisplayMatrix(); } } }