Jython

// RobotControl.java

package robotcontrol.app;

import ch.aplu.android.*;
import android.graphics.Color;
import android.bluetooth.*;
import ch.aplu.android.bluetooth.*;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;


public class RobotControl extends GameGrid
  implements GGPushButtonListener
{
  private GGPushButton forward;
  private GGPushButton backward;
  private GGPushButton left;
  private GGPushButton right;
  private GGPushButton stop;
  private GGTextField tf;
  private BluetoothClient bc;
  private DataInputStream dis;
  private DataOutputStream dos;

  public RobotControl()
  {
    super(21, 21, 0);
    setScreenOrientation(PORTRAIT);
  }

  public void main()
  {
    String serverName = askName();
    getBg().clear(Color.BLUE);
    new GGTextField("RobotControl",
      new Location(0, 1), true).show();
    addButtons();
    tf = new GGTextField("Trying to connect...", new Location(4, 19), true);
    tf.show();
      
    // Search device   
    BluetoothDevice serverDevice = searchDevice(serverName);
    if (serverDevice != null)
    {
      bc = new BluetoothClient(serverDevice);
      boolean rc = bc.connect();
      if (!rc)
      {
         tf.hide();
         tf = new GGTextField("Connection failed", new Location(4, 19), true);
         tf.show();
         return;
      }
      tf.hide();
      tf = new GGTextField("Connection established", new Location(3, 19), true);
      tf.show();
      dis = new DataInputStream(bc.getInputStream());
      dos = new DataOutputStream(bc.getOutputStream());
      enableButtons();
  }  
  }
  
  private String askName()
  {
    GGPreferences prefs = new GGPreferences(this);
    String oldName = prefs.retrieveString("BluetoothName");
    String newName = null;
    while (newName == null || newName.equals(""))
    {
      newName = GGInputDialog.show(this, "RobotControl", 
        "Enter Bluetooth Name",
        oldName == null ? "raspberrypi" : oldName);
    }
    prefs.storeString("BluetoothName", newName);
    return newName;
  }  

  private void addButtons()
  {
    forward = new GGPushButton("forward");   
    addActor(forward, new Location(10, 5));
    backward = new GGPushButton("backward");
    addActor(backward, new Location(10, 15));
    left = new GGPushButton("left");
    addActor(left, new Location(3, 10));
    right = new GGPushButton("right");
    addActor(right, new Location(17, 10));
    stop = new GGPushButton("stop");
    addActor(stop, new Location(10, 10));
  }

  private void enableButtons()
  {
    forward.addPushButtonListener(this);
    backward.addPushButtonListener(this);
    left.addPushButtonListener(this);
    right.addPushButtonListener(this);
    stop.addPushButtonListener(this);
  }

  public void onPause()
  {
    super.onPause();
  }
  
   public void buttonPressed(GGPushButton button)
  {
    if (button == forward)
      sendMessage("FORWARD");
    if (button == backward)
      sendMessage("BACKWARD");
    if (button == left)
      sendMessage("LEFT");
    if (button == right)
      sendMessage("RIGHT");
    if (button == stop)
      sendMessage("STOP");
  }

  public void buttonReleased(GGPushButton button)
  {
  }

  public void buttonClicked(GGPushButton button)
  {
  }
  
  public void buttonRepeated(GGPushButton button)
  {   
  }
  
  private void sendMessage(String msg)
  {
    try
    {
     dos.writeBytes(msg + "\0");
     dos.flush();
    }
    catch (IOException ex)
    {
      tf.hide();
      tf = new GGTextField("Connection lost", new Location(3, 19), true);
      tf.show();
    }
  }  

  private BluetoothDevice searchDevice(String btName)
  {
    BluetoothAdapter adapter =
      BluetoothDiscovery.getBluetoothAdapter(this);
    if (adapter == null)
      return null;

    if (!adapter.isEnabled())
    {
      requestBluetoothEnable();
      if (!adapter.isEnabled())
        return null;
    }
    BluetoothDiscovery bd = new BluetoothDiscovery(this);
    BluetoothDevice device = bd.getPairedDevice(btName);
    return device;
  }
}
	onStateChanged(): Im Callback onStateChanged() wird beim Empfang eines Befehls die entsprechende Funktion aufgerufen.
	display.showText("LI"): Falls der Pi2Go über ein Display verfügt, können kurze Meldungen (4 Zeichen) angezeigt werden. Noch viel besser ist es ein OLED 1306 anzuschliessen, mit dem mehrere Textzeilen angezeigt werden können. Das gleiche Programm mit OLED-Display finden Sie hier.
Datenübertragung über Bluetooth
