Android-Zoom a imageView when it got Focused

I am new Android. I have declared the imageView in xml file.I want to get zoom in and out when the image is get focused.there is an开发者_如何学编程y way to zoom a static image view in android. Thanks in advance.

you can use this method to zoom in and zoom out :http://developer.android.com/reference/android/graphics/Bitmap.html#createScaledBitmap%28android.graphics.Bitmap,%20int,%20int,%20boolean%29