Thread t = new Thread(){@Override
            public void run(){
                try{
                    while(!isInterrupted()){
                        Thread.sleep(1000);
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                TextView textViewTime = findViewById(R.id.textTimer);
                                long time = System.currentTimeMillis();
                                textViewTime.setText(time);
                            }
                        });
                    }
                } catch (InterruptedException e) {
                }
            }
        };
        t.start();