android - Check whether activity is active

Question

I'm having a problem with a listener in a certain activity.

The problem is that this listener contains an alert.show(); which can be called after we try to push a new activity (which then gives an exception).

e.g.: I'm listening in activity A for a signal from an other phone. I press back and try to run a new activity B but the program crashes because of the alert.show() A's listener.

ERROR/AndroidRuntime(3573): android.view.WindowManager$BadTokenException: Unable to add window -- token android.os.BinderProxy@476c21c0 is not valid; is your activity running?

Can I check in A's listener whether this activity is active and then show the alert or not depending on this value?

Answer 1

There might be an easier way I can't think of but one way is to implement it yourself. On onResume() you set a member variable mIsRunning to true and on onPause() back to false. Using this boolean you should know not to call alert.show() on your callback.