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OnClickListener - x,y location of event?

开发者 https://www.devze.com 2022-12-15 02:07 出处:网络
I have a custom view derived from View. I\'d like to be notified when the view is clicked, and the x,y location of where the click happened. Same for long-clicks.

I have a custom view derived from View. I'd like to be notified when the view is clicked, and the x,y location of where the click happened. Same for long-clicks.

Looks like to do this, I need to override onTouchEvent(). Is there no way to get the x,y location of the event from an OnClickListener instead, though?

If not, what's a good way of telling if a motion event is a 'real' click vs a long-click etc? The onTouchEvent generates many events in rapid s开发者_JS百科uccession etc.


Thank you. That was exactly what I was looking for. My code now is:

imageView.setOnTouchListener(new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            if (event.getAction() == MotionEvent.ACTION_DOWN){
                textView.setText("Touch coordinates : " +
                        String.valueOf(event.getX()) + "x" + String.valueOf(event.getY()));
            }
            return true;
        }
    });

which does precisely what Mark asked for...


Full example

The other answers are missing some details. Here is a full example.

public class MainActivity extends AppCompatActivity {

    // class member variable to save the X,Y coordinates
    private float[] lastTouchDownXY = new float[2];

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        // add both a touch listener and a click listener
        View myView = findViewById(R.id.my_view);
        myView.setOnTouchListener(touchListener);
        myView.setOnClickListener(clickListener);
    }

    // the purpose of the touch listener is just to store the touch X,Y coordinates
    View.OnTouchListener touchListener = new View.OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {

            // save the X,Y coordinates
            if (event.getActionMasked() == MotionEvent.ACTION_DOWN) {
                lastTouchDownXY[0] = event.getX();
                lastTouchDownXY[1] = event.getY();
            }

            // let the touch event pass on to whoever needs it
            return false;
        }
    };

    View.OnClickListener clickListener = new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // retrieve the stored coordinates
            float x = lastTouchDownXY[0];
            float y = lastTouchDownXY[1];

            // use the coordinates for whatever
            Log.i("TAG", "onLongClick: x = " + x + ", y = " + y);
        }
    };
}

Summary

  • Add a class variable to store the coordinates
  • Save the X,Y coordinates using an OnTouchListener
  • Access the X,Y coordinates in the OnClickListener


Override onTouchEvent(MotionEvent ev)

Then you can do:

ev.getXLocation()

Or something like that. Have a butches.


You can make an extension function in Kotlin, like this:

fun View.setOnClickListenerWithPoint(action: (Point) -> Unit) {
    val coordinates = Point()
    val screenPosition = IntArray(2)
    setOnTouchListener { v, event ->
        if (event.action == MotionEvent.ACTION_DOWN) {
            v.getLocationOnScreen(screenPosition)
            coordinates.set(event.x.toInt() + screenPosition[0], event.y.toInt() + screenPosition[1])
        }
        false
    }
    setOnClickListener {
        action.invoke(coordinates)
    }
}

If you need a long click - just replace setOnClickListener

I use getLocationOnScreen() because I need coordinates for RecyclerView's ViewHolder

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