Android programming development multitouch implementation method

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public class MTView extends SurfaceView implements  {
  private static final int MAX_TOUCHPOINTS = 10;
  private static final String START_TEXT = "Please touch the screen for testing";
  private Paint textPaint = new Paint();
  private Paint touchPaints[] = new Paint[MAX_TOUCHPOINTS];
  private int colors[] = new int[MAX_TOUCHPOINTS];
  private int width, height;
  private float scale = 1.0f;
  public MTView(Context context) {
    super(context);
    SurfaceHolder holder = getHolder();
    (this);
    setFocusable(true); // Make sure our View gets input focus    setFocusableInTouchMode(true); // Make sure to receive touch screen events    init();
  }
  private void init() {
    // Initialize 10 different colors of brushes    ();
    colors[0] = ;
    colors[1] = ;
    colors[2] = ;
    colors[3] = ;
    colors[4] = ;
    colors[5] = ;
    colors[6] = ;
    colors[7] = ;
    colors[8] = ;
    colors[9] = ;
    for (int i = 0; i < MAX_TOUCHPOINTS; i++) {
      touchPaints[i] = new Paint();
      touchPaints[i].setColor(colors[i]);
    }
  }
  /*
    * Handle touch screen events
    */
  @Override
  public boolean onTouchEvent(MotionEvent event) {
    // Get the number of screen contacts    int pointerCount = ();
    if (pointerCount > MAX_TOUCHPOINTS) {
      pointerCount = MAX_TOUCHPOINTS;
    }
    // Lock Canvas and start the corresponding interface processing    Canvas c = getHolder().lockCanvas();
    if (c != null) {
      ();
      if (() == MotionEvent.ACTION_UP) {
        // Clear the screen when your hand leaves the screen      } else {
        // First draw a cross on the screen, then draw a circle        for (int i = 0; i < pointerCount; i++) {
          // Get the coordinates of a contact and start drawing          int id = (i);
          int x = (int) (i);
          int y = (int) (i);
          drawCrosshairsAndText(x, y, touchPaints[id], i, id, c);
        }
        for (int i = 0; i < pointerCount; i++) {
          int id = (i);
          int x = (int) (i);
          int y = (int) (i);
          drawCircle(x, y, touchPaints[id], c);
        }
      }
      // After drawing, unlock      getHolder().unlockCanvasAndPost(c);
    }
    return true;
  }
  /**
    * Draw cross and coordinate information
    *
    * @param x
    * @param y
    * @param paint
    * @param ptr
    * @param id
    * @param c
    */
  private void drawCrosshairsAndText(int x, int y, Paint paint, int ptr,
      int id, Canvas c) {
    (0, y, width, y, paint);
    (x, 0, x, height, paint);
    int textY = (int) ((15 + 20 * ptr) * scale);
    ("x" + ptr + "=" + x, 10 * scale, textY, textPaint);
    ("y" + ptr + "=" + y, 70 * scale, textY, textPaint);
    ("id" + ptr + "=" + id, width - 55 * scale, textY, textPaint);
  }
  /**
    * Draw a circle
    *
    * @param x
    * @param y
    * @param paint
    * @param c
    */
  private void drawCircle(int x, int y, Paint paint, Canvas c) {
    (x, y, 40 * scale, paint);
  }
  /*
    * When entering the program, draw the background black, and then write "START_TEXT" to the screen
    */
  public void surfaceChanged(SurfaceHolder holder, int format, int width,
      int height) {
     = width;
     = height;
    if (width > height) {
       = width / 480f;
    } else {
       = height / 480f;
    }
    (14 * scale);
    Canvas c = getHolder().lockCanvas();
    if (c != null) {
      // Black background      ();
      float tWidth = (START_TEXT);
      (START_TEXT, width / 2 - tWidth / 2, height / 2,
          textPaint);
      getHolder().unlockCanvasAndPost(c);
    }
  }
  public void surfaceCreated(SurfaceHolder holder) {
  }
  public void surfaceDestroyed(SurfaceHolder holder) {
  }
}

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public class MultitouchVisible extends Activity {
  @Override
  public void onCreate(Bundle savedInstanceState) {
    (savedInstanceState);
    //Hide the title bar    requestWindowFeature(Window.FEATURE_NO_TITLE);
    //Set to full screen    getWindow().setFlags(.FLAG_FULLSCREEN,
        .FLAG_FULLSCREEN);
    //Set as MTView above    setContentView(new MTView(this));
  }
}