The code which David Hedlund has posted gave me the error:
Unable to add window — token null is not valid
If you are getting the same error use the below code. It works!!
runOnUiThread(new Runnable() {
@Override
public void run() {
if (!isFinishing()){
new AlertDialog.Builder(YourActivity.this)
.setTitle("Your Alert")
.setMessage("Your Message")
.setCancelable(false)
.setPositiveButton("ok", new OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// Whatever...
}
}).show();
}
}
});