This is limitation of the Animation in Android. They fixed that in Android 3.0. Read here for more information
An excerpt:
"Finally, the previous animations changed the visual appearance of the target objects... but they didn't actually change the objects themselves. You may have run into this problem. Let's say you want to move a Button from one side of the screen to the other. You can use a TranslateAnimation to do so, and the button will happily glide along to the other side of the screen. And when the animation is done, it will gladly snap back into its original location. So you find the setFillAfter(true) method on Animation and try it again. This time the button stays in place at the location to which it was animated. And you can verify that by clicking on it - Hey! How come the button isn't clicking? The problem is that the animation changes where the button is drawn, but not where the button physically exists within the container. If you want to click on the button, you'll have to click the location that it used to live in. Or, as a more effective solution (and one just a tad more useful to your users), you'll have to write your code to actually change the location of the button in the layout when the animation finishes."