I would like to handle pinch events in my Android application to zoom in and out.
I believe Android 2.0 has multi-touch functionality, and heard that Android 1.6 might or might not support it depending of the device.
What's the best way to detect pinch events, while degrading gracefully for devices that don't support it? I'm targeting Android 1.5 upwards.
A great article by Ed Burnette (Hello Android Author) on multi touch (including pinch zoom) can be found here: http://www.zdnet.com/blog/burnette/how-to-use-multi-touch-in-android-2/1747
Here's an article on the Android developer blog about taking advantage of capability of the newer APIs on devices that support them, while gracefully continuing to support older devices. http://android-developers.blogspot.com/2009/04/backward-compatibility-for-android.html
Android 1.6 does not support multi-touch, Android 2.0 and above does, that means that you would need to have different OnTouchHandlers that you can swap in based on the version of Android you detect. For more information about how to implement the pinch-zoom, have a look at this thread.
来源：https://stackoverflow.com/questions/2631567/detecting-pinch-in-android