Android View Scrolling Performance Troubleshooting

I'm currently experiencing some scrolling issues in a few of my views. The performance on the Galaxy Tab (7 inch) is rather poor. Rather than trying to explain my view hierarchy here, I was wondering if anyone had any general gui开发者_Python百科dance on how to troubleshoot scroll performance issues on Android. I'm interested in any approaches or gotchas that I should be aware of when building views, and how to find the trouble spots that's causing the laggy scrolling

I these few suggestions would help you,

1- Use an efficient ListAdapter (taking advantage of the ConvertView in getView() method) as such: http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/view/List14.html

2- If you are loading images over the net, thread your loader and set images to views asynchronously.

3- And if you're rendering images in your list items, keep a cache in the form of an HashMap; i.e. HashMap where integer would be the position and Drawable would be the materialized images. Use the Drawables availabe in the Cache in your getView() method and only load images if the Drawable is null when you ask for a particular index/position.

As you may already know, list items are rendered (getView() is called) every time the the item at the index is scrolled to the visible screen; so caching images and using the convertView (the view already been created once) would make your adapter and list efficient.

You could even put some system.outs in your getView() method to see the difference.

I hope these help

Best

-serkan