Refresh view after TextView.setText

Question

I have a TextView that is updated but I cannot see the refresh until i minimize and reopen the application. here is the code that performs that.

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    bleAdapter = ((BluetoothManager) getSystemService(BLUETOOTH_SERVICE)).getAdapter();
    Set<BluetoothDevice> pairedDevices = bleAdapter.getBondedDevices();

    for (BluetoothDevice device : pairedDevices) {

        device.connectGatt(this, true, new BluetoothGattCallback() {

            @Override
            public void onConnectionStateChange(BluetoothGatt gatt, int status, int newState) {
                super.onConnectionStateChange(gatt, status, newState);
                TextView state;

                switch (newState) {

                    case BluetoothProfile.STATE_CONNECTED: 
                        state = (TextView)findViewById(R.id.state);
                        state.setText("Connected = True");
                        state.setTextColor(Color.GREEN);
                        break;

                    case BluetoothProfile.STATE_DISCONNECTED:
                        state = (TextView)findViewById(R.id.state);
                        state.setText("Connected = False");
                        state.setTextColor(Color.RED);
                        break;
                }
            }
        });
    }
}

What I need to refresh that TextView? I'm doing anything else wrong?

Answer 1

You should update the TextView in the main (ui) thread, like this

    runOnUiThread(new Runnable() {
        public void run() {
            state.setText("Connected = False");
            state.setTextColor(Color.RED);
        }
    });

or if you project is configured to support java 8 you can write it more concisely

    runOnUiThread(() -> {
       state.setText("Connected = False");
       state.setTextColor(Color.RED);
    });