Android Custom View Performance

Question

This is the situation - My root layout is scrollview - A custom view with multiple drawing operations is embedded in the layout My problem is that if the layout is scrolled then customview.ondraw() is being called multiple times. Since there are many operations in the ondraw() I am getting a performance hit.

What is the best strategy out of this?

score 1 · Accepted Answer · answered Dec 23 '12 at 16:40

1

See the docs on View.setDrawingCacheEnabled(). Note you have to call getDrawingCache() in your onDraw implementation, and draw the returned bitmap if getDrawingCache() returns a non-null value. I'm not sure whether ScrollView will take care of calling setDrawingCacheEnabled automatically. You'll have to try it and find out. I think it does; but you still need to call getDrawingCache() in your onDraw routine.

That takes care of the non-hardware accelerated cases.

For hardware accelerated views, see the docs for setLayerType. It's far from a given that caching hardware accelerated views actually provides a performance improvement, so do this cautiously.

answered Dec 23 '12 at 16:40

Robin Davies

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Let me try this. I will get back. – Lakshman Chilukuri Dec 24 '12 at 02:39
setDrawingCacheEnabled() is the right approach. I used the variation suggested in http://stackoverflow.com/questions/3046766/android-drawing-cache. Thanks. – Lakshman Chilukuri Dec 24 '12 at 05:15
for the setLayerType approach, you may check this http://developer.android.com/training/custom-views/optimizing-view.html – Nevin Chen Jan 31 '15 at 01:48

score 0 · Answer 2 · answered Dec 23 '12 at 16:42

Forgot the name of the methods in Android, but there is a Swing demo with a split pane.

If there is a flag set to true ( update continuously) than the split panel is drawing wile you move the spit components. The same effect is at scroll too. You can use a draw, continuously and another only when the scrolling finished. The same thing is at iOS too.

You need to find which are those methods and embed your custom view drawing when is needed.

Android Custom View Performance

2 Answers2