2011.10.17——— android 多点触控

2011.10.17——— android 多点触控
参考：http://blog.csdn.net/ldj299/article/details/6422547

主要API：

event.getPointerCount()：触控点的个数getPointerId(int pointerIndex)：pointerIndex从0到getPointerCount-1,返回一个触摸点的标示getX(int pointerIndex)：通过标示来得到X坐标getY(int pointerIndex)：通过标示来得到Y坐标MotionEvent.ACTION_POINTER_1_DOWN：第一个触摸点点击事件MotionEvent.ACTION_POINTER_2_DOWN：第二个触摸点点击事件MotionEvent.ACTION_POINTER_1_UP：第一个触摸点松开事件MotionEvent.ACTION_POINTER_2_UP：第二个触摸点松开事件

测试代码如下：

自定义view

package com.lp.multi;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.util.AttributeSet;import android.util.Log;import android.view.MotionEvent;import android.view.View;public class MyView extends View{public MyView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);// TODO Auto-generated constructor stub}public MyView(Context context, AttributeSet attrs) {super(context, attrs);// TODO Auto-generated constructor stub}public MyView(Context context) {super(context);// TODO Auto-generated constructor stub}@Overrideprotected void onDraw(Canvas canvas) {Paint mPaint = new Paint();mPaint.setColor(Color.GRAY);mPaint.setTextSize(30);canvas.drawText("呵呵", 100, 200, mPaint);}@Overridepublic boolean onTouchEvent(MotionEvent event) {int pointCount = event.getPointerCount();System.out.println(pointCount);if (pointCount == 2) {final float x0 = event.getX(event.getPointerId(0));final float y0 = event.getY(event.getPointerId(0));final float x1 = event.getX(event.getPointerId(1));final float y1 = event.getY(event.getPointerId(1));switch (event.getAction()) {case MotionEvent.ACTION_POINTER_2_DOWN:System.out.println("ACTION_POINTER_2_DOWN");break;case MotionEvent.ACTION_POINTER_1_DOWN:System.out.println("ACTION_POINTER_1_DOWN");break;case MotionEvent.ACTION_POINTER_1_UP:System.out.println("ACTION_POINTER_1_UP");break;case MotionEvent.ACTION_POINTER_2_UP:System.out.println("ACTION_POINTER_2_UP");break;case MotionEvent.ACTION_MOVE: {System.out.println("ACTION_MOVE");break;}}System.out.println(x0+" "+x1+" "+y0+" "+y1);}return true;}}

注意：
onTouchEvent返回true 要不是没有效果的

Activity

package com.lp.multi;import android.app.Activity;import android.os.Bundle;public class MainActivity extends Activity {    /** Called when the activity is first created. */    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(new MyView(this));    }}

运行结果：

10-17 17:53:32.269: INFO/System.out(11675): 110-17 17:53:32.279: INFO/System.out(11675): 210-17 17:53:32.279: INFO/System.out(11675): ACTION_POINTER_2_DOWN10-17 17:53:32.279: INFO/System.out(11675): 324.3229 201.57916 88.79375 226.6212510-17 17:53:32.289: INFO/System.out(11675): 210-17 17:53:32.289: INFO/System.out(11675): ACTION_MOVE10-17 17:53:32.299: INFO/System.out(11675): 324.3229 201.57916 88.79375 226.6212510-17 17:53:32.299: INFO/System.out(11675): 210-17 17:53:32.299: INFO/System.out(11675): ACTION_POINTER_1_UP10-17 17:53:32.309: INFO/System.out(11675): 324.3229 201.57916 88.79375 226.6212510-17 17:53:32.309: INFO/System.out(11675): 1

结论：

1、ACTION_POINTER_2_DOWN和ACTION_POINTER_1_DOWN 可能只会触发一个
2、事件只触发了一个，但是坐标都是能得到的

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