Android开发实例之多点触控程序

event.getAction() //获取触控动作比如ACTION_DOWN  event.getPointerCount(); //获取触控点的数量，比如2则可能是两个手指同时按压屏幕  event.getPointerId(nID); //对于每个触控的点的细节，我们可以通过一个循环执行getPointerId方法获取索引  event.getX(nID); //获取第nID个触控点的x位置  event.getY(nID); //获取第nID个点触控的y位置  event.getPressure(nID); //LCD可以感应出用户的手指压力，当然具体的级别由驱动和物理硬件决定的  event.getDownTime() //按下开始时间  event.getEventTime() // 事件结束时间  event.getEventTime()-event.getDownTime()); //总共按下时花费时间 

public class MyView extends SurfaceView implements SurfaceHolder.Callback{    MultitouchVisible father;        private static final int MAX_TOUCHPOINTS = 10;     private static final String START_TEXT = "请随便触摸屏幕进行测试";     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 MyView(MultitouchVisible father) {      super(father);      // TODO Auto-generated constructor stub      this.father=father;      SurfaceHolder holder = getHolder();       holder.addCallback(this);       setFocusable(true); // 确保我们的View能获得输入焦点       setFocusableInTouchMode(true); // 确保能接收到触屏事件       init();     }     private void init() {        // 初始化10个不同颜色的画笔        textPaint.setColor(Color.WHITE);        colors[0] = Color.BLUE;        colors[1] = Color.RED;        colors[2] = Color.GREEN;        colors[3] = Color.YELLOW;        colors[4] = Color.CYAN;        colors[5] = Color.MAGENTA;        colors[6] = Color.DKGRAY;        colors[7] = Color.WHITE;        colors[8] = Color.LTGRAY;        colors[9] = Color.GRAY;        for (int i = 0; i < MAX_TOUCHPOINTS; i++) {         touchPaints[i] = new Paint();          touchPaints[i].setColor(colors[i]);       }    }      /*    * 处理触屏事件     */      @Override      public boolean onTouchEvent(MotionEvent event) {      // 获得屏幕触点数量        int pointerCount = event.getPointerCount();       if (pointerCount > MAX_TOUCHPOINTS) {          pointerCount = MAX_TOUCHPOINTS;          }        // 锁定Canvas,开始进行相应的界面处理        Canvas c = getHolder().lockCanvas();       if (c != null) {         c.drawColor(Color.BLACK);         if (event.getAction() == MotionEvent.ACTION_UP) {            // 当手离开屏幕时，清屏            }        else {            // 先在屏幕上画一个十字，然后画一个圆            for (int i = 0; i < pointerCount; i++) {             // 获取一个触点的坐标，然后开始绘制              int id = event.getPointerId(i);              int x = (int) event.getX(i);              int y = (int) event.getY(i);              drawCrosshairsAndText(x, y, touchPaints[id], i, id, c);            }            for (int i = 0; i < pointerCount; i++) {              int id = event.getPointerId(i);              int x = (int) event.getX(i);              int y = (int) event.getY(i);              drawCircle(x, y, touchPaints[id], c);           }        }        // 画完后，unlock          getHolder().unlockCanvasAndPost(c);      }      return true;    }      /**     * 画十字及坐标信息     */      private void drawCrosshairsAndText(int x, int y, Paint paint, int ptr,int id, Canvas c) {       c.drawLine(0, y, width, y, paint);        c.drawLine(x, 0, x, height, paint);        int textY = (int) (5 + 20 * ptr);        c.drawText("x" + ptr + "=" + x, 10 , textY, textPaint);        c.drawText("y" + ptr + "=" + y, 70 , textY, textPaint);        c.drawText("id" + ptr + "=" + id, width - 55 , textY, textPaint);     }     /**     * 画圆    */      private void drawCircle(int x, int y, Paint paint, Canvas c) {        c.drawCircle(x, y, 40 , paint);      }     @Override   public void surfaceChanged(SurfaceHolder holder, int format, int width,        int height) {      // TODO Auto-generated method stub      this.width = width;       this.height = height;       textPaint.setTextSize(14);       Canvas c = getHolder().lockCanvas();       if (c != null) {        // 背景黑色         c.drawColor(Color.BLACK);         float tWidth = textPaint.measureText(START_TEXT);         c.drawText(START_TEXT, width / 2 - tWidth / 2, height / 2, textPaint);         getHolder().unlockCanvasAndPost(c);       }     }    @Override   public void surfaceCreated(SurfaceHolder holder) {      // TODO Auto-generated method stub          }     @Override   public void surfaceDestroyed(SurfaceHolder holder) {      // TODO Auto-generated method stub          }  } 

public class MultitouchVisible extends Activity {    /** Called when the activity is first created. */   @Override   public void onCreate(Bundle savedInstanceState) {      super.onCreate(savedInstanceState);      //隐藏标题栏       requestWindowFeature(Window.FEATURE_NO_TITLE);       //设置成全屏       getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,       WindowManager.LayoutParams.FLAG_FULLSCREEN);       //设置为上面的MTView       setContentView(new MyView(this));     }  }