public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        final TextView textView = findViewById(R.id.text);
        final Button runOn = findViewById(R.id.runOn);
        runOn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                new Thread() {
                    public void run() {
                        while (i++ < 1000) {
                            try {
                                runOnUiThread(new Runnable() {
                                    @Override
                                    public void run() {

                                        textView.setText("#" + i);
                                    }
                                });
                                Thread.sleep(300);
                            } catch (InterruptedException e) {
                                e.printStackTrace();
                            }
                        }
                    }
                }.start();
            }
        });
    }

private void runThread() {

        new Thread() {
            public void run() {
                while (i++ < 1000) {
                    try {
                        runOnUiThread(new Runnable() {

                            @Override
                            public void run() {
                                textView.setText("#" + i);
                            }
                        });
                        Thread.sleep(300);
                    } catch (InterruptedException e) {
                        e.printStackTrace();
                    }
                }
            }
        }.start();
    }