OnTouchevent () vs onTouch ()

Question

After many experiments with onTouchEvent and onTouch, I found that onTouch works wherever you want (whether in action or in a view), until you declare the interface and correctly install the Listener! OnTouchEvent, on the other hand, only works inside the view! Is my assumption correct? Is that the real difference?

Answer 1

Yes, you're right - onTouch() used by View users to receive touch events, and onTouchEvent() used by derived View classes to receive touch events.

Answer 2

I had some confusion about how onTouchEvent () and onTouch () work (you can see my comment on this question). After some research below, I found out about this. This may be useful for beginners.

1) Implementation:

If you want to use onTouch (), you need to do three things.

1- implement OnTouchListener

2- call setOnTouchListener () in the view you want to set in order to catch the event

3- override onTouch () to handle the event

but if you want to use onTouchEvent (), you do not need to do steps 1 and 2 above. you just need to override onTouchEvent ().

2) Work:

onTouch () works in the view, view, activity mode. This means that you can use onTouch () inside a view, viewgroup or activity. These methods take two arguments [onTouch (View v, MotionEvent e)]. This allows you to filter events for different views in an action or view group. Or the activity itself can handle it. onTouchEvent () takes one argument [ onTouchEvent(MotionEvent e) ]. Thus, this can only be used inside a view that implements it or in a derived form. The derived view allows you to extend the touch behavior defined in onTouchEvent ().

I think that such options are part of a more flexible Android development philosophy, although sometimes this creates confusion for students.

Answer 3

I used ontouch () and ontouchevent (), since ontouch is used when I want to work with elements of a single kind, such as buttons, image buttons, etc. on one image (say Linringayout), whereas when I want to work on areas of the rest of the elements (like a button) I use ontouchevent.

Answer 4

In fact, onTouchEvent () will be called by the action if none of the views accepts the touch event.

And, as you say, onTouch () can be used in any class if:

• This class (i.e. Foo) implements the OnTouchListener interface and
• This class is a registered listener using view.setOnTouchListener(foo);

Answer 5

When creating a custom view, you can

@override onTouchEvent(MotionEvent e){}

while you can add onTouch to any View, ViewGroup or Activity.

onTouch(View v, MotionEvent e) { //you can filter any View touch }

onTouch is generic, and onTouchEvent is for viewing. And you can also filter your presentation using onTouch.

Answer 6

I found another difference. onTouchEvent does not seem to receive the deprecated MotionEvent.ACTION_POINTER_2_DOWN and MotionEvent.ACTION_POINTER_2_UP events.

Of course, they are quite old, and we should not use them.

This is in Android 5.1 api 22.

Answer 7

onTouchEvent is a method implemented by View , Activity, and other base classes such as LinearLayout , etc. ..

 public boolean onTouchEvent(MotionEvent event) { throw new RuntimeException("Stub!"); } 

you can override this method with any derived classes

then

onTouch () is defined by the OnTouchListener {} interface

public interface OnTouchListener { boolean onTouch(View var1, MotionEvent var2); }

so you only need to implement it when setting this interface to the class