Android实现手机多点触摸画圆
本文实例为大家分享了Android实现手机多点触摸画圆的具体代码,供大家参考,具体内容如下
静态效果图:(多个手指按下和抬起的状态)
代码实现部分:
1、先写个实体类,设置相关的属性
package com.zking.laci.android19_pointstouch; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import java.util.Random; /** * Created by Laci on 2017/7/9. */ public class MyCircle { public float x; public float y; public int r=100; public int pointId; int red; int green; int blue; Random random=new Random(); public MyCircle(float x, float y, int pointId) { this.x = x; this.y = y; this.pointId = pointId; red=random.nextInt(255); green=random.nextInt(255); blue=random.nextInt(255); } public void drawSelf(Canvas canvas, Paint paint){ paint.setStyle(Paint.Style.STROKE); paint.setColor(Color.rgb(red,green,blue)); canvas.drawCircle(x,y,r,paint); } }
2、然后我们自己再写个java类,用来画圆的
package com.zking.laci.android19_pointstouch; 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 Laci on 2017/7/9. */ public class MyView extends View { List<MyCircle> lt=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(); for (MyCircle myCircle : lt) { myCircle.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; //手指的下标 int pointIndex=action>>8; //获取手指的坐标 float x=event.getX(pointIndex); float y=event.getY(pointIndex); //获取手指的名字的ID int pointId=event.getPointerId(pointIndex); if(action_code>=5){ action_code-=5; } switch (action_code) { case MotionEvent.ACTION_DOWN: //实例化园 MyCircle myCircle=new MyCircle(x,y,pointId); //将园添加到集合中 lt.add(myCircle); break; case MotionEvent.ACTION_UP: lt.remove(get(pointId)); break; case MotionEvent.ACTION_MOVE: 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 invalidate(); return true; } public MyCircle get(int pointId){ for (MyCircle myCircle : lt) { if(myCircle.pointId==pointId){ return myCircle; } } return null; } }
3、最后我们在activity中改一句代码就可以了
setContentView(new MyView(this));
最后打开真机测试就可以啦!
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持我们。
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