android how to work with animations

I want animation, for example in 开发者_运维百科my screen 4 birds should be there. and at a time 3 birds are visible. They are flying continuously. How can i do that please give me answer. How bird fly with wings I cant get that one please give me answer. Thank you

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I think you need AnimationDrawable for your purpose

Here is the tutorial for this AnimationDrawable