Android runOnUiThread not executing

I have this problem. I'm trying to update my TextView from another thread and it's not letting me.

I have tried a bunch of different solutions and none of those didn't seem to help. In my while loop code is printing that "Started new loop" all the time but it's not continuing from that runOnUiThread.

Can anyone help me figure out how to update TextView from another thread?

 //second thread
protected void startKakkosThread() {
    Thread t2 = new Thread() {
        public void run() {
            while (true) {
                System.out.println("Started new loop");
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        try {
                            if(rullaavaNumero >= 0) {
                                rullaavaNumero--;
                                System.out.println(rullaavaNumero);
                                pelaajanPisteetTeksi.setText("" + rullaavaNumero);
                                sleep(1000);
                            }else{
                                rullaavaNumero = 9;
                                System.out.println(rullaavaNumero);
                                pelaajanPisteetTeksi.setText("" + rullaavaNumero);
                                sleep(1000);
                            }
                        }catch (InterruptedException e){
                            e.printStackTrace();
                        }
                    }
                });
            }
        }
    };
    t2.start();
}

Here is a quick fix, you have an infinite loop that runs faster than a thread can have a chance (time) to start. So even thus you have a sleep in side your thread with if statement, if the thread never starts then sleep have no effect.

And your sleep inside a Thread won't work like this. You want to delay your infinite while loop, therefore you need to move sleep on out of the thread in your while loop.

It is still possible to delay your thread by adding extra sleep in it, but all that depends on what you want to achieve.

Your final code would look like this:

protected void startKakkosThread() {
    Thread t2 = new Thread() {
        public void run() {
            while (true) {
                System.out.println("Started new loop");
                runOnUiThread(new Runnable() {
                    @Override
                    public void run() {
                        if (rullaavaNumero >= 0) {
                            rullaavaNumero--;
                            System.out.println(rullaavaNumero);
                            pelaajanPisteetTeksi.setText("" + rullaavaNumero);
                            // no need for sleep here
                            // sleep(1000);
                        } else {
                            rullaavaNumero = 9;
                            System.out.println(rullaavaNumero);
                            pelaajanPisteetTeksi.setText("" + rullaavaNumero);
                            // no need for sleep here
                            // sleep(1000);
                        }
                    }
                });

                // add this part
                try {
                    sleep(1000);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        }
    };
    t2.start();
}

I have test it and it works, you could also go what @cricket has suggest.

My eye saw another issue, which is not a part of your question, but good to mention. I assume you want to count from 9 to 0, if that is the case, you need to correct following line by removing = otherwise you get counts till -1, so your code line would look like this:

if(rullaavaNumero > 0) {...