Swipe run by Activity Do OnBackPress

Question

It can capture the left swipe action to right and run a command by the activity? In the case of an activity would identify the swipe (left to right) and run the command onBackPress(); I need to identify swipe at the view and I hold other components in the activity and do not know how to identify whether the action is the activity or component.

Answer 1

With the following code it can have a listener that responds to the back gesture. It is possible with a View setOnTouchListener have this ability to identify the movement and perform the action.

Execution

        android.view.GestureDetector gestureDetector = new android.view.GestureDetector(this, new GestureDetector(Activity.this));
        View.OnTouchListener gestureListener = new View.OnTouchListener() {
            public boolean onTouch(View v, MotionEvent event) {
                return gestureDetector.onTouchEvent(event);
            }
        };

        view.setOnTouchListener(gestureListener);

GestureDetector.java

public class GestureDetector extends android.view.GestureDetector.SimpleOnGestureListener {

    private static final int SWIPE_MIN_DISTANCE = 120;
    private static final int SWIPE_MAX_OFF_PATH = 250;
    private static final int SWIPE_THRESHOLD_VELOCITY = 200;
    private final Activity activity;

    public GestureDetector(Activity activity){
        this.activity = activity;
    }

    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {
        try {
            if (Math.abs(e1.getY() - e2.getY()) > SWIPE_MAX_OFF_PATH)
                return false;
            if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                activity.onBackPressed();
            }
        } catch (Exception e) {
            // nothing
        }
        return false;
    }

    @Override
    public boolean onDown(MotionEvent e) {
        return true;
    }
}