Do not allow multiple instances of an activity of an Android app
<p>I'm trying to create a really simple application for Android that will play a music file (I'm really only just starting to get into Android). I have only one Activity that starts when the application starts, and it starts playing the music file. What I need is that the activity always runs (plays the music), whether you press Back or Home buttons, unless you specifically tell it to shut down from Settings menu, and if you try to run it again, it should just restore that activity to the front (basically, how every other player out there works). What happens for me, though, is that when I press back to return to the menu screen for instance, and click on the app again, it runs another instance of the activity (which I can tell, because the music doubles). What can I do to prevent this? Many thanks.</p>
