public PhotoViewAttacher(ImageView imageView) { mImageView = new WeakReference<ImageView>(imageView); imageView.setOnTouchListener(this); mViewTreeObserver = imageView.getViewTreeObserver(); mViewTreeObserver.addOnGlobalLayoutListener(this); // Make sure we using MATRIX Scale Type setImageViewScaleTypeMatrix(imageView); if (!imageView.isInEditMode()) { // 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(mImageView.get()); } } }); mGestureDetector.setOnDoubleTapListener(this); // Finally, update the UI so that we're zoomable setZoomable(true); } }
public final void onDrag(float dx, float dy) { if (DEBUG) { Log.d(LOG_TAG, String.format("onDrag: dx: %.2f. dy: %.2f", dx, dy)); } ImageView imageView = getImageView(); if (null != imageView && hasDrawable(imageView)) { mSuppMatrix.postTranslate(dx, dy); checkAndDisplayMatrix(); /** * Here we decide whether to let the ImageView's parent to start taking over the touch event. * * <p>First we check whether this function is enabled. We never want the parent to take over * if we're scaling. We then check the edge we're on, and the direction of the scroll (i.e. if * we're pulling against the edge, aka 'overscrolling', let the parent take over). */ if (mAllowParentInterceptOnEdge && !mScaleDragDetector.isScaling()) { if (mScrollEdge == EDGE_BOTH || (mScrollEdge == EDGE_LEFT && dx >= 1f) || (mScrollEdge == EDGE_RIGHT && dx <= -1f)) { imageView.getParent().requestDisallowInterceptTouchEvent(false); } } } }
@Override public final boolean onTouch(View v, MotionEvent ev) { boolean handled = false; if (mZoomEnabled) { switch (ev.getAction()) { case MotionEvent.ACTION_DOWN: // First, disable the Parent from intercepting the touch // event v.getParent().requestDisallowInterceptTouchEvent(true); // If we're flinging, and the user presses down, cancel // fling cancelFling(); break; case MotionEvent.ACTION_CANCEL: case MotionEvent.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; } // Check to see if the user double tapped if (null != mGestureDetector && mGestureDetector.onTouchEvent(ev)) { handled = true; } // Finally, try the Scale/Drag detector if (null != mScaleDragDetector && mScaleDragDetector.onTouchEvent(ev)) { handled = true; } } return handled; }