检测手机多点触摸

来源：互联网发布：程序员盗600 编辑：程序博客网时间：2024/04/29 05:13

先创个MyView.java类：

package com.example.g160628_19_poinstouch;import android.content.Context;import android.graphics.Canvas;import android.graphics.Paint;import android.support.annotation.Nullable;import android.util.AttributeSet;import android.view.MotionEvent;import android.view.View;import java.util.ArrayList;import java.util.List;/** * Created by Administrator on 2017/7/9 0009. */public class MyView extends View{    List<Circle> circles=new ArrayList<>();    public MyView(Context context) {        super(context);    }    public MyView(Context context, @Nullable AttributeSet attrs) {        super(context, attrs);    }    public MyView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);    }    public MyView(Context context, @Nullable AttributeSet attrs, int defStyleAttr, int defStyleRes) {        super(context, attrs, defStyleAttr, defStyleRes);    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        Paint paint=new Paint();        //画了个圆        for (Circle circle : circles) {            circle.drawSelf(canvas,paint);        }    }    @Override    public boolean onTouchEvent(MotionEvent event) {        //获取手指的行为        int action=event.getAction();        int action_code=action&0xff;        //获取手指的下标index        int pointIndex=action>>8;        //获取手指的坐标        float x=event.getX(pointIndex);        float y=event.getY(pointIndex);        //获取手指的名字ID        int pointId=event.getPointerId(pointIndex);        if(action_code>=5){            action_code-=5;        }        switch (action_code) {            case 0://手指按下                //实例化园                Circle circle=new Circle(x,y,pointId);                //将园添加到集合中                circles.add(circle);                break;            case 1://手指抬起                circles.remove(get(pointId));                break;            case 2://手指按下移动                for (int i = 0; i <event.getPointerCount() ; i++) {                    int id=event.getPointerId(i);                    get(id).x=event.getX(i);                    get(id).y=event.getY(i);                }                break;        }        //重新调用onDraw   (重绘)        postInvalidate();        return true;    }    //在圆集合中找到你要移除的    public Circle get(int pointId){        for (Circle circle : circles) {            if(circle.pointId==pointId){                return circle;            }        }        return null;    }}

实体类Circle.java

package com.example.g160628_19_poinstouch;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import java.util.Random;/** * Created by Administrator on 2017/7/9 0009. */public class Circle {    public float x;    public float y;    public int r=100;    public int pointId;    int red;    int greed;    int blue;    Random random=new Random();    public Circle(float x, float y, int pointId) {        this.x = x;        this.y = y;        this.pointId = pointId;        red=random.nextInt(255);        greed=random.nextInt(255);        blue=random.nextInt(255);    }    //画自己   要有画布和画笔    public void drawSelf(Canvas canvas, Paint paint){        paint.setColor(Color.rgb(red,greed,blue));        canvas.drawCircle(x,y,r,paint);    }}

MainActivity.java类

package com.example.g160628_19_poinstouch;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;public class MainActivity extends AppCompatActivity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(new MyView(this));    }}

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