Trying to get OnFling to work

Question

I know there are plenty of questions regarding this topic. I've had a look at most of them, but still I'm not able to debug my code. It does not detect swipes. I'm a beginner to both Android programming as well as Java, so please don't be too critical.

I have a simple Linear Layout, with a Button that fills the whole layout. Everytime the button is clicked, it's value increments by 1.
I'm trying to implement left on right swipes. My basic doubt is should I implement the setOnTouchListener with the Button or the Linear Layout?

I've seen people use OnGestureListener and OnTouchListener. Which one is preferable?

public class MainActivity extends Activity implements OnClickListener{

public Button increment;
public int cnt= 0;
private static final int SWIPE_MIN_DISTANCE = 80;
private static final int SWIPE_THRESHOLD_VELOCITY = 40;
GestureDetector gestureDetector;
LinearLayout swipe_layout= (LinearLayout)findViewById(R.id.linear);

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

    increment= (Button)findViewById(R.id.numberkey);
    increment.setOnClickListener(this);
    setDisplay(0);
    gestureDetector= new GestureDetector(this, new Detector());
    increment.setOnTouchListener(new OnTouchListener() {

        @Override
        public boolean onTouch(View v, MotionEvent event) {
            gestureDetector.onTouchEvent(event);
            return true;
        }
    });

}

@Override
public void onClick(View v) 
{
    setDisplay(cnt++);
}

private void setDisplay(int i) 
{   increment.setText(String.valueOf(i));
}

class Detector extends SimpleOnGestureListener {

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


    @Override
    public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float            velocityY) {
            // right to left swipe
            if(e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY)
               Toast.makeText(MainActivity.this, "Left Swipe", Toast.LENGTH_SHORT).show();

            else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                Toast.makeText(MainActivity.this, "Right Swipe", Toast.LENGTH_SHORT).show();
            }
        return false;
    }

}

}

Thanks in advance.

But should I call onTouchListener with the layout instead of the button? the button fills the whole layout. — Chocolava, Jan 06 '13 at 08:38

score 0 · Answer 1 · answered Jan 06 '13 at 08:48

0

move

LinearLayout swipe_layout= (LinearLayout)findViewById(R.id.linear);

after setContentView(R.layout.activity_main); of Activity because you are trying to find view before setting layout for current Activity

and set onTouchListener for Layout as :

LinearLayout swipe_layout;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    swipe_layout= (LinearLayout)findViewById(R.id.linear);

    swipe_layout.setOnTouchListener(new OnTouchListener() {

     @Override
       public boolean onTouch(View v, MotionEvent event) {

         return true;
    }
  });

answered Jan 06 '13 at 08:48

ρяσѕρєя K

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Still, the swipes don't work, the toasts don't appear. It takes my swipe gestures as simply clicks. What am I doing wrong here? – Chocolava Jan 06 '13 at 09:46
@Chocolava : see [this](http://stackoverflow.com/questions/10008053/android-trouble-with-swipe-gesture) post – ρяσѕρєя K Jan 06 '13 at 09:53
No, it's not, I tried everything that guy did. Specifically, could you please tell me whether we should return true or false from the onTouch method? – Chocolava Jan 06 '13 at 18:32
Because in that thread, the code that guy wrote, he returned false from the method. – Chocolava Jan 06 '13 at 18:35
@Chocolava : yes you can also return false from onTouch. have u tried aneal answer in given thread – ρяσѕρєя K Jan 06 '13 at 18:39
Yes, I did try aneal's answer. The exception is never caught, so probably the method does not reach onFling. Returning true or false from onTouch has no meaning? It can be either? – Chocolava Jan 06 '13 at 18:42

Trying to get OnFling to work

1 Answers1