android set visibility of a button on timer

Question

Hi, I have an app that shows a disclaimer at the beginning of the program. I want a button to remain invisible for a set amount of time, and then become visible. I set up a thread that sleeps for 5 seconds, and then tries to make the button visible. However ,I get this error when I execute my code:

08-02 21:34:07.868: ERROR/AndroidRuntime(1401): android.view.ViewRoot$CalledFromWrongThreadException: Only the original thread that created a view hierarchy can touch its views.

How can I count 5 seconds, and then make the button visible? THanks.

Thread splashTread = new Thread() {
           @Override
           public void run() {
            try {
                   int waited = 0;
                   while(_active && (!_ok2)) {
                       sleep(100);
                       if(_active) {
                           waited += 100;
                           if(waited >= _splashTime)
                           {
                            turnButtonOn();
                           }

                       }
                   }
               } catch(InterruptedException e) {
                   // do nothing
               } finally {
                   finish();
                   startActivity(new Intent("com.lba.mixer.Choose"));

               }
    };
    splashTread.start();


      public static void turnButtonOn() {

okButton.setVisibility(View.VISIBLE); }

Answer 1

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)

Do

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