Develop Reference

Android onTouch multi-touch not receiving all touch events

I am using an Android SurfaceView and listening for multi-touch events. I am able to detect multiple touches but it seems that the ACTION_POINTER_UP touch event is not getting fired. Here is a quick snip of my code.
public class GameView extends SurfaceView implements Runnable {
...
#Override
public boolean onTouchEvent(MotionEvent motionEvent) {
Log.i("pointer count", Integer.toString(motionEvent.getPointerCount()));
return true;
}
...
}
When I put 2 fingers on the screen the pointer count log out is 2. If I remove one of my fingers the pointer count log out is not 1 and stays at 2. It only goes to 1 if I move my finger that is still on the screen. Why is this and how to I firkin fix it? thanks!
EDIT
This problem occurs on my One Plus One and my friends Samsung Galaxy Note 2. It is interesting that when I put it on my Samsung Galaxy s4 the problem did not occur.

Do not use getAction() == MotionEvent.ACTION_POINTER_UP as the action will also contain the pointer index.
getActionMasked() will strip out this information, and could be used for comparison.
See http://developer.android.com/reference/android/view/MotionEvent.html#getActionMasked()

Is there a offset between onTouchEvent and onTouchListener?

I have developed a game that shoots when player touches the screen by using onTouchListener for my custom SurfaceView and Thread.
But now I want to change the approach and instead of onTouchListener I added onTouchEvent to the SurfaceView o my Activity.
The problem is that I get some kind of offset when I click on the emulator.
Everything is working great, except that offset keeps appearing and I don't understand why.
Also let me mention that my app is running in landscape mode, maybe this is relevant.
I suspect that it isn't working properly because onTouchListener was added to the view and depended on it, but onTouchEvent doesn't depend on the view.
Also my view doesn't have any padding or margin properties, it is full-screen view (fill_parent).
Does anyone have any ideas on this?

I have done my application, and everything works correctly now, but i still do not know what the problem was.
After lots of debugging of my application the onTouchEvent returned random Y values that were always higher than the ones that the onTouchListener returned. And i am not sure why this is hapening since my view that recognizes the onTouchListener is a full-screen view.
So i figured out a way to get passed this by doing some math.
The first function that the android calls is the onTouch method which gives the correct values but just for one touch. I needed it to give right values even on the MotionEvent.ACTION_MOVE so i noticed that MotionEvent.ACTION_MOVE is actually doing correctly depending on the first touch recognized by the onTouchEvent.
So i just got the coordinate Y from the onTouch and the different coordinate with the offset from onTouchEvent calculated the difference and in every onTouchEvent from there, until the user lifts up their finger, i just subtract that difference and that gives me the correct value.
If anyone else has this problem, and doesn't know how to fix it, here is my code, maybe it will be helpful.
#Override
public boolean onTouchEvent(MotionEvent arg1) {
/*you can only touch when the thread is running*/
if(game.state() != STATE_PAUSE){
if(arg1.getAction() == MotionEvent.ACTION_DOWN){
coordinateX = arg1.getX();
coordinateY = arg1.getY();
differenceY = Math.abs(coordinateY - touchedY);
coordinateY = coordinateY - differenceY;
shootingIsOkay = true;
game.setDrawCircle(coordinateX,coordinateY);
}
if(arg1.getAction() == MotionEvent.ACTION_MOVE){
coordinateX = arg1.getX();
coordinateY = arg1.getY();
coordinateY = coordinateY - differenceY;
shootingIsOkay = true;
game.setDrawCircle(coordinateX,coordinateY);
}
if(arg1.getAction() == MotionEvent.ACTION_UP){
shootingIsOkay = false;
}
}
return false;
}
And the onTouch method that is called from the onTouchListener that depends on the view is just simple, here:
#Override
public boolean onTouch(View arg0, MotionEvent arg1) {
touchedY = arg1.getY();
return false;
}
If anyone knows how to fix this problem, please post your answer, i am very curious why this is happening

Disable GestureDetector in Activity

In my app, I have an activity that uses onTouchEvent() to calculate screen input. But on some phones, eg. Samsung Galaxy S4 the event is aborted in favor of GestureDetector, with the log message:
GestureDetector(23138): [Surface touch Event] Palm swipe start, x:565.0 m:450.0 s:54.0 TILT_TO_ZOOM_XVAR: 180.0
The problem disappears when the user turns Movements and Gestures off in the Android Phone Settings menu, but this is to hard to find to be convenient.
How can I disable this, without forcing the user to exit the app or change the phone settings?

I don't know if it works, but my first idea is requestDisallowInterceptTouchEvent() may help you ( http://developer.android.com/reference/android/view/ViewParent.html#requestDisallowInterceptTouchEvent%28boolean%29 ).
public boolean onTouch(View v, MotionEvent e) {
if(e.getAction() == MotionEvent.ACTION_DOWN){
viewPager.getParent().requestDisallowInterceptTouchEvent(true);
}
}

Why is getPointerCount() always returning 1?

An experiment in learning Android is to detect two-finger presses. I have an app that changes a custom ImageView to a random pic on a touch. That works fine. I now want it to only change the picture when two or more fingers press. I have an IF statement to only randomize the picture if pointerCount>1. It doesn't do anything.
I have my ASUS Transformer TF101 connected to the PC. I have a simple custom ImageView with an onTouch event.
public boolean onTouchEvent(MotionEvent event) {
int number =event.getPointerCount();
if (number > 1){
*randomise pic*
I examine the value of 'number' during a debug step-through (Log.d doesn't work for me from this ASUS :() and it's always 1 no matter how many fingers I touch with.
Any ideas?

(X) return false;
(X) return super.onTouchEvent(event);
(O) return true;

Dragging across an android button

I would like an android button to be triggered if a user drags across it and releases his finger on it in addition to the standard activation if it is clicked and released.
I was trying to use the ACTION_MOVE MotionEvent, but this event is only triggered between ACTION_DOWN and ACTION_UP events. I also think that ACTION_OUTSIDE might be a solution. Is there a way to do this?
Here is my code with the actions taken stripped out (b is a button):
b.setOnTouchListener(new View.OnTouchListener() {
public boolean onTouch(View v, MotionEvent event) {
if (event.getAction()== MotionEvent.ACTION_DOWN){
//Tiggers correctly
} else if (event.getAction() == MotionEvent.ACTION_MOVE) {
//Triggers correctly between events, but not when the finger is dragged ontop outside of the element
} else if (event.getAction() == MotionEvent.ACTION_OUTSIDE){
//Can't get this to trigger in any case but I think it might be the solution
} else if (event.getAction() == MotionEvent.ACTION_UP){
//Triggers correctly
}
}
return false;
}
});

ACTION_OUTSIDE can be triggered only when your touch area is extended by the ViewRoot.
If you think about dragging, you have 2 options, but for both of them you can detect rectangle, where your button positioned on screen View.getHitRect(Rect) and then, basing on this knowledge you can decide wheter MotionEvent is inside Rect or not.
Otherwise you can create DragLayer and implement all logic there.

You might want to give the Gesture Listener a try. There is a rather good description about how to use it here.
It seems like you need to extend Button and add possibilities for gesture detection in order to accomplish this.