GestureDetector detect DoubleClick on GridView items
Note: This specific problem is solved, but there are serious follow-up problems. Have a look at GestureDetector - Detect double click in GridView item's although returning false in onTouchEvent()
I want to detect double clicks on distinct items in a GridView of images. Therefore I assigned a separate OnTouchListener to each item- imageView in the getView() method of the adapter. The gestureDetector is a member variable of the adapter-class.
private GestureDetectorCompat gestureDetector;
public ImageGridViewAdapter(Context c, ArrayList<UriWrapper> startUpImages) {
mContext = c;
uriManager = new UriManager(startUpImages);
gestureDetector = new GestureDetectorCompat(mContext, new SingleTapConfirm());
}
public View getView(final int position, View recycled, ViewGroup parent) {
ViewHolder holder;
if (recycled == null) {
..... find items by id
} else{
holder = (ViewHolder) recycled.getTag();
}
// Set listener to item image
holder.image.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
// Always returns false, the gestureDetector does not detect anything
boolean ret = gestureDetector.onTouchEvent(event);
// At least the onTouch-callback gets called with the correct position
Log.e(TAG, "onTouch returned " + ret + " at position " + position);
return true;
}
});
// Use glide library to load images into the image views
Glide.with(mContext)....into(holder.image);
return recycled;
}
private class SingleTapConfirm extends GestureDetector.SimpleOnGestureListener {
@Override
public boolean onSingleTapConfirmed(MotionEvent event) {
Log.e(TAG, "onSingleTapConfirmed"); // never called..
return true;
}
@Override
public boolean onDoubleTap(MotionEvent e) {
Log.e(TAG, "onDoubleTap"); // never called..
return super.onDoubleTap(e);
}
}
The OnTouchListener 's work and get called with the correct position. However, no matter what I am doing, the methods of the GestureDetector are never called. What seems to be the issue with this code?
Update : The onTouch-callback needs to return true, now at least the GestureDetector works. However, returning true breaks the rest of the functionality, since I have a long-click-selection-mode and a global OnTouchListener for my GridView.
Second Update: Merging the item-specific OnTouchListener and the global OnTouchListener did not work properly. (swipe gestures only recognized on certain items) I hope that I can work around these two problems by creating a custom View extending ImageView and assigning the item-specific OnTouchListener there.
private GestureDetectorCompat gestureDetector;
// in your adapter constructor
gestureDetector = new GestureDetector(context, new SingleTapConfirm());
public View getView(final int position, View recycled, ViewGroup parent) {
ViewHolder holder;
if (recycled == null) {
.....find items by id
} else {
holder = (ViewHolder) recycled.getTag();
}
// Set listener to item image
holder.image.setOnTouchListener(new View.OnTouchListener() {
@Override
public boolean onTouch(View v, MotionEvent event) {
// Use lazy initialization for the gestureDetector
gestureDetector.onTouchEvent(event);
// At least the onTouch-callback gets called with the correct position
return true;
}
});
// Use glide library to load images into the image views
Glide.with(mContext)....into(holder.image);
return recycled;
}
private class SingleTapConfirm extends GestureDetector.SimpleOnGestureListener {
@Override
public boolean onSingleTapConfirmed(MotionEvent event) {
Log.e(TAG, "onSingleTapConfirmed"); // never called..
return true;
}
@Override
public boolean onDoubleTap(MotionEvent e) {
Log.e(TAG, "onDoubleTap"); // never called..
return super.onDoubleTap(e);
}
}
更新：
@Override
public boolean onTouch(View v, MotionEvent event) {anything
gestureDetector.onTouchEvent(event);
return true;
}