Android : Blocking the main thread

I am not understanding why my main UI thread is getting blocked. I have button which calls function doSomething().

    randomButton.setOnClickListener(new OnClickListener() {

                @Override
                public void onClick(View v) {
                    doSomething();    
                }
    });
}

    // My private helper funtion

    private void doSomething() {

                Thread t1 = new Thread() {

                    @Override
                    public void run() {

                        long startTime = SystemClock.uptimeMillis();
                        Log.e(TAG, "Start Time = "+startTime);
                        while((SystemClock.uptimeMillis()-startTime)<6000){// Loop for 6 seconds
                            Log.e(TAG, "Diff ="+(SystemClock.uptimeMillis()-startTime));                        
                        }    
                    }    
                };
                t1.run();
        }

The problem is when I press the button, it remains pressed for how much ever time my loop run (here 6 secs). I want it in a such a way that user can still use his UI elements even though the loop keeps running. Thats the reason I created a new Thread. Am I doing something wrong ?

Thanks