android: how to create different “screens” and nav between them using touch-and-drag?

Question

Can i create the same kind of navigation that I have on the main screens? That is, I want different screens that I can navigate between using the touch-and-drag? I haven\'t

Answer 1

There is nothing built-in, but you can use ViewFlipper, GestureDetector and Animation to "fake it" (you wont get the tactile drag of the home screen using this method):

public class SwipeExample extends Activity {

    private static final int LEFT = 0;
    private static final int RIGHT = 1;

    ViewFlipper flipper;
    GestureDetector gestureDetector;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        flipper = (ViewFlipper) findViewById(R.id.flipper);
        gestureDetector = new GestureDetector(new MyGestureDetector());

    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        if (gestureDetector.onTouchEvent(event))
            return true;
        else
            return false;
    }

    private Animation animateInFrom(int fromDirection) {

        Animation inFrom = null;

        switch (fromDirection) {
        case LEFT:
            inFrom = new TranslateAnimation(
                    Animation.RELATIVE_TO_PARENT, -1.0f, 
                    Animation.RELATIVE_TO_PARENT, 0.0f,
                    Animation.RELATIVE_TO_PARENT, 0.0f,
                    Animation.RELATIVE_TO_PARENT, 0.0f);
            break;
        case RIGHT:
            inFrom = new TranslateAnimation(
                    Animation.RELATIVE_TO_PARENT, +1.0f, 
                    Animation.RELATIVE_TO_PARENT, 0.0f,
                    Animation.RELATIVE_TO_PARENT, 0.0f,
                    Animation.RELATIVE_TO_PARENT, 0.0f);
            break;
        }

        inFrom.setDuration(250);
        inFrom.setInterpolator(new AccelerateInterpolator());
        return inFrom;
    }

    private Animation animateOutTo(int toDirection) {

        Animation outTo = null;

        switch (toDirection) {
        case LEFT:
            outTo = new TranslateAnimation(
                    Animation.RELATIVE_TO_PARENT, 0.0f,
                    Animation.RELATIVE_TO_PARENT, -1.0f,
                    Animation.RELATIVE_TO_PARENT, 0.0f,
                    Animation.RELATIVE_TO_PARENT, 0.0f);
            break;
        case RIGHT:
            outTo = new TranslateAnimation(
                    Animation.RELATIVE_TO_PARENT, 0.0f,
                    Animation.RELATIVE_TO_PARENT, +1.0f,
                    Animation.RELATIVE_TO_PARENT, 0.0f,
                    Animation.RELATIVE_TO_PARENT, 0.0f);
            break;
        }

        outTo.setDuration(250);
        outTo.setInterpolator(new AccelerateInterpolator());
        return outTo;
    }

    class MyGestureDetector extends SimpleOnGestureListener {

        // from:
        // http://www.codeshogun.com/blog/2009/04/16/how-to-implement-swipe-action-in-android/

        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;

        @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 (e1.getX() - e2.getX() > SWIPE_MIN_DISTANCE
                        && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                    // right to left swipe
                    flipper.setInAnimation(animateInFrom(RIGHT));
                    flipper.setOutAnimation(animateOutTo(LEFT));
                    flipper.showNext();
                } else if (e2.getX() - e1.getX() > SWIPE_MIN_DISTANCE
                        && Math.abs(velocityX) > SWIPE_THRESHOLD_VELOCITY) {
                    // left to right swipe
                    flipper.setInAnimation(animateInFrom(LEFT));
                    flipper.setOutAnimation(animateOutTo(RIGHT));
                    flipper.showPrevious();
                }
            } catch (Exception e) {}
            return false;
        }
    }

}