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;
}
