Question

I want to implement swiping between two pages. The first page is a ListFragment, with a couple of items. I want to be able to swipe a single item and switch to another Activity to do some processing of that ListItem.

I’ve implemented Activity switching using ViewPager – which seems the most reasonable way to handle this. However I don’t know how to get the swiped item from the ListFragment when switched to the other screen.

I know there is onListItemClick(), but don’t know if it allows to fetch item index after swipe. According to what I’ve found – it doesn’t.

Any ideas?

Answer 1

I’ve managed to do this using the following overloaded ViewPager class:

import android.R;
import android.content.Context;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.Log;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.widget.ListView;
import org.ftang.model.Program;

public class TouchingViewPager extends ViewPager {

    private GestureDetector gestureScanner;

    public TouchingViewPager(Context context) {
        super(context);
        gestureScanner = new GestureDetector(simpleOnGestureListener);
    }

    public TouchingViewPager(Context context, AttributeSet attrs) {
        super(context, attrs);
        gestureScanner = new GestureDetector(simpleOnGestureListener);
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        int currentItem = getCurrentItem();
        gestureScanner.onTouchEvent(ev);
        return super.onTouchEvent(ev);
    }

    GestureDetector.SimpleOnGestureListener simpleOnGestureListener = new GestureDetector.SimpleOnGestureListener() {

        public boolean onDown(Math event) {
            return true;
        }

        public boolean onFling(MotionEvent event1, MotionEvent event2, float velocityX, float velocityY) {
            Log.d(null,"Fling");
            int MAJOR_MOVE = 120;
            if (event1 == null) event1 = MotionEvent.obtain(0, 0, 0, 0, 0, 0);
            int dx = (int) (event2.getX() - event1.getX());
            // don't accept the fling if it's too short
            // as it may conflict with a button push
            if (Math.abs(dx) > MAJOR_MOVE && Math.abs(velocityX) > Math.abs(velocityY)) {
                if (velocityX > 0) {
                    // nothing
                } else {
                    ListView liveView = (ListView) findViewById(R.id.list);
                    Program program = (Program) liveView.getAdapter()
                            .getItem(liveView.pointToPosition((int)event1.getX(), (int)event1.getY()));
                    program.getName();
                } 
                return true;
            } else {
                return false;
            }
        }

    };
}

Note that I’m calling gestureScanner once again in onTouchEvent. I suppose I could wire somehow the custom getsutureScanner so that it would be handling all the touch events. However since I’m not familiar with how ViewPager events are handled, I’ve decided to call my own handler side by side.

If there is a better way to do this – please let me know.