CODEWITHSUNDEEP
android
Pushpendra Kuntal
Pushpendra Kuntal

Reputation: 6196

Android onGestureListener and onTouchListner

I am working in android. I have some functionality which is to be done on these following methods:-

1. MotionEvent.ACTION_DOWN
2. MotionEvent.ACTION_UP
3. MotionEvent.ACTION_MOVE

and i also want to do fling() on that image.

For above requirement i implemented onGestureListener and onTouchListener in my application, but these are not working properly. onTouchListener is working but onGestureListener is not working. When i remove onTouchListner code then onGestureListener is working correctly.

So please suggest me what should i do for this. I want to implement these four methods in my application.

1. MotionEvent.ACTION_DOWN
2. MotionEvent.ACTION_UP
3. MotionEvent.ACTION_MOVE
4. onFling

Upvotes: 3

Views: 6449

Answers (2)

Sean
Sean

Reputation: 196

Just as a word of advice coming from a fellow Android developer who has chased down the primrose path of the swipe or fling event... When writing a listener or trying to implement the OnGestureListener class be sure to have import android.view.GestureDetector.OnGestureListener in your imports.

Otherwise the OnGesturListener will be using a GestureOverlayView's imports and that's not what it seems you are looking for. Those are helpful especially when trying to implement gesture captures using the Gestures application and importing the saved gestures and creating a Gestures Library for your application during run time to then "predict" what the user is doing by running some fancy algorithm in the background and seeing who deviates the least from the user's input. Which turns out to be an array of locations that came in from the OS as the dragged their little stubby fingers across the flat screen... It's a different approach than just trying to capture a fling, or long press. Which seems as what the users are looking for above and not some fancy multi-press gesture capture, which this approach makes very simple. This technique is also very helpful in video games and giving possibly a "backdoor" to any people out there who like to develop games. Or in the 9-5 world, to put a Support or Admin backdoor into your mobile application to hide some settings or logs from everyday users. In which one can also use the above intended techniques but then you have to get an array of points, or locations across the screen and it gets tedious for any non-math people or self taught developers. Hope I contributed or helped anyone. No one mentioned this to me when I was learning this and I never found it in any of the several books I have read about Android also.

Upvotes: 0

Deva
Deva

Reputation: 3949

You can acheive this by implementing the OnGestureListener from your activity overriding the below methods

// For touch 
public boolean onSingleTapUp(MotionEvent event) { return false; }

// For Fling 
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
        float velocityY) {
    return false;
}

Hope this helps.

EDIT 1: Detailed explanation:

1> implement the OnGestureListener from your activity

public class MyActivity implements OnGestureListener

2> create an instance of GestureDetector:

private GestureDetector gestureScanner;

And at onCreate:

// Avoid a deprecated constructor 
// (http://developer.android.com/reference/android/view/GestureDetector.html)
gestureScanner = new GestureDetector(this, this);

3> Override the below methods:

@Override
public boolean onTouchEvent(MotionEvent event) {
    return gestureScanner.onTouchEvent(event);
}

@Override
public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX,
        float velocityY) {
    /* on scroll to the next page in story */

    if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE
            && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
        // ...
    }
    /* on scroll to the previous page in story */
    else if (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE
            && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
        // ...
    }

    return false;
}

@Override
public boolean onSingleTapUp(MotionEvent event) {
    return false;
}

EDIT 2: For handling Move Override the onScroll method have a look at the details here

Upvotes: 7

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