Question

I want to give my app a nice touch by allowing users to slide the page left or right instead of just using next/previous buttons (similar to the home screen).

What is the best way to do that? I assume I would have to override one of the Activity.on... methods and that I would also have to put my page’s main View in a ViewGroup that allows me to shift pages left and right.

Answer 1

Use GestureDetector to detect if the touch event is a scroll.

If the first event to the first call to onScroll is ACTION_DOWN then you should see if it was a dominantly horizontal scroll. If so then your scroll is started and you should shift the absolute position of the view that fills the page.

For non deprecated absolute positioning, see my answer here Android: Alternative to AbsoluteLayout (I really do need absolute positioning)

You will want to be cautions of whether you return true to consume the touch events or not.

GestureDetector does not have a callback for scrolling having stopped. You will have to check if there was an ACTION_UP before you call GestureDetector.onTouchEvent and if there was an action up and you did have an unfinished scroll then you should set the absolute position to the destination location and use a TranslateAnimation to make it look nice moving from current to destination.

Edit:

GestureDetector did not work well at all if the child views also wanted to respond to touch events. I ended up creating a subclass of FrameLayout (one of the most basic layouts and the closest thing to a non intrusive parent view) and overriding dispatchTouchEvent. I just took all the events and did the detection myself.