Timer for Android – Make a TextView Blink

 
I am pretty sure some of you may been through the same problem where you needed a simple periodic timer for your Android app. You may use java.util.Timer but this is not a good choice as this timer creates a new thread for some reason and you don’t want to invoke multiple threads in your mobile app. So I created this simple timer that makes use of the android.os.Handler class. Below is the source code of the Timer for android. Sorry for the formatting and naming convention. I’m used to the C# conventions.

package ross.brigoli.android; import android.os.Handler; public class Timer {   private int _interval;   public int getInterval() { return _interval; }   public void setInterval(int delay) { _interval = delay; }   private Handler handler;   private Runnable _tickHandler;   private Runnable delegate;   private boolean ticking;   public boolean getIsTicking(){ return ticking; }     public Timer(int interval)   {     _interval = interval;     handler = new Handler();   }     public Timer(int interval, Runnable onTickHandler)   {     _interval = interval;     setOnTickHandler(onTickHandler);     handler = new Handler();   }     public void start(int interval, Runnable onTickHandler)   {     if (ticking) return;     _interval = interval;     setOnTickHandler(onTickHandler);     handler.postDelayed(delegate, _interval);     ticking = true;   }     public void start()   {     if (ticking) return;     handler.postDelayed(delegate, _interval);     ticking = true;   }     public void stop()   {     handler.removeCallbacks(delegate);     ticking = false;   }     public void setOnTickHandler(Runnable onTickHandler)   {     if (onTickHandler == null)       return;         _tickHandler = onTickHandler;         delegate = new Runnable() {       public void run()       {         if (_tickHandler == null) return;         _tickHandler.run();         handler.postDelayed(delegate, _interval);       }     };   } }

I used this timer to make a TextView in my Application blink, to update values in the UI from service, to monitor status, etc. with the following code:

boolean blinkOn = false;   Timer tmrBlink = new Timer(500, new Runnable() {     public void run() {       if (blinkOn)       {         ((TextView) findViewById(R.id.widget46)).setVisibility(View.VISIBLE);       }       else       {         ((TextView) findViewById(R.id.widget46)).setVisibility(View.INVISIBLE);       }       blinkOn = !blinkOn;     }       });