Set a timer for the visibility of a button

I wish did fix the issue. Either use the Dispatcher to marshall it back to the UI thread, or you might want to consider using an animation instead? It would be very straightforward to setup an timeline in Blend to do this entirely in XAML.

hope this fix your issue The problem is that you're not in the UI thread when you call okButton.setVisibility(View.VISIBLE);, since you create and run your own thread. What you have to do is get your button's handler and set the visibility through the UI thread that you get via the handler.
So instead of

okButton.setVisibility(View.VISIBLE)

okButton.getHandler().post(new Runnable() {
    public void run() {
        okButton.setVisibility(View.VISIBLE);
    }
});

Hope that helps Assuming your goal is to toggle the display of the buttons each time the timer goes off, you simply do:

- (void)onTick:(NSTimer *)timer {
    _Rateapp1.hidden = !_Rateapp1.hidden;
    _ratebomb.hidden = !_ratebomb.hidden;
    _ratelab1.hidden = !_ratelab1.hidden;
}

NSTimer *t = [NSTimer scheduledTimerWithTimeInterval:10.0 target:self selector:@selector(onTick:) userInfo:nil repeats:YES];

To fix this issue , You may want to use android.os.Handler instead.

public class ExampleActivity extends ActionBarActivity
{
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_example);
        ImageView iv = (ImageView) findViewById(R.id.imageView);
        iv.setVisibility(View.VISIBLE);
        //
        new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                        iv.setVisibility(View.INVISIBLE);
                }
        }, 3000);
    }
}

To fix the issue you can do I am trying to create an App with timer in it using service, however the timer works fine but there is a problem in my code when timer completed (comes to 0:0) my button should again re enable automatically but it stays on disabled state only, I tried a lot to re enable it but did not solved. So please see my code below and tell me what should I do to re enable it? I am new to services and android , any help will be appreciated , First, make your Intent an instance variable like-

private Button btn_start;
private TextView tv_timer;
.
.
private Intent intent_service;

intent_service = new Intent(getApplicationContext(), Timer_Service.class);
.
.

if (mpref.getBoolean("finish", false)) {
     et_hours.setEnabled(false);
     btn_start.setEnabled(true);
     tv_timer.setText("");
} else {

     et_hours.setEnabled(false);
     btn_start.setEnabled(false);  // a change is here
     tv_timer.setText(str_value);
 }

mEditor.putBoolean("finish", false).commit();
.
.
startService(intent_service); // start the service

private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String str_time = intent.getStringExtra("time");
        tv_timer.setText(str_time);

    }
};

private BroadcastReceiver broadcastReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context context, Intent intent) {
        String str_time = intent.getStringExtra("time");
        tv_timer.setText(str_time);
        if (str_time.equals("00:00")) {
            stopService(intent_service); // stop service after work done
            btn_start.setEnabled(true);
        }

    }
};

if (long_hours == 0){
    mEditor.putBoolean("finish", true).commit(); // a change is here
    mTimer.cancel();
}