自定义随机颜色的圆形小球view随手指移动

来源：互联网发布：vba抓取网页数据编辑：程序博客网时间：2024/04/30 00:06
下面代码就可实现随机颜色的圆形小球view随手指移动效果：
package com.bwie.CustomBallView_RandomColor;import android.app.Activity;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.os.Bundle;import android.view.Display;import android.view.MotionEvent;import android.view.View;import android.view.Window;import android.view.WindowManager;import java.util.Random;//自定义颜色的圆形小球随手指移动viewpublic class BallActivity extends Activity {    private int screenW;        //屏幕宽度    private int screenH;        //屏幕高度    @Override    public void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        Display dis = this.getWindowManager().getDefaultDisplay();        // 设置全屏        requestWindowFeature(Window.FEATURE_NO_TITLE);        this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,                WindowManager.LayoutParams.FLAG_FULLSCREEN);        // 获取屏幕宽度        screenW = dis.getWidth();        // 获取屏幕高度        screenH = dis.getHeight();        setContentView(new BallView(this));    }    //自定义绘图类    class BallView extends View{        private Paint paint;        //定义画笔        private float cx = 50;      //圆点默认X坐标        private float cy = 50;      //圆点默认Y坐标        private int radius = 188;        //定义颜色数组        private int colorArray[] = {Color.BLACK,Color.BLACK,Color.GREEN,Color.YELLOW, Color.RED};        private int paintColor = colorArray[0]; //定义画笔默认颜色        public BallView(Context context) {            super(context);            //初始化画笔            initPaint();        }        private void initPaint(){            paint = new Paint();            //设置消除锯齿            paint.setAntiAlias(true);            //设置画笔颜色            paint.setColor(paintColor);        }        //重写onDraw方法实现绘图操作        @Override        protected void onDraw(Canvas canvas) {            super.onDraw(canvas);            //将屏幕设置为白色            canvas.drawColor(Color.WHITE);            //修正圆点坐标            revise();            //随机设置画笔颜色            setPaintRandomColor();            //绘制小圆作为小球            canvas.drawCircle(cx, cy, radius, paint);        }        //为画笔设置随机颜色        private void setPaintRandomColor(){            Random rand = new Random();            int randomIndex = rand.nextInt(colorArray.length);            paint.setColor(colorArray[randomIndex]);        }        //修正圆点坐标        private void revise(){            if(cx <= radius){                cx = radius;            }else if(cx >= (screenW-radius)){                cx = screenW-radius;            }            if(cy <= radius){                cy = radius;            }else if(cy >= (screenH-radius)){                cy = screenH-radius;            }        }        @Override        public boolean onTouchEvent(MotionEvent event) {            switch (event.getAction()) {                case MotionEvent.ACTION_DOWN:                    // 按下                    cx = (int) event.getX();                    cy = (int) event.getY();                    // 通知重绘                    postInvalidate();   //该方法会调用onDraw方法，重新绘图                    break;                case MotionEvent.ACTION_MOVE:                    // 移动                    cx = (int) event.getX();                    cy = (int) event.getY();                    // 通知重绘                    postInvalidate();                    break;                case MotionEvent.ACTION_UP:                    // 抬起                    cx = (int) event.getX();                    cy = (int) event.getY();                    // 通知重绘                    postInvalidate();                    break;            }            /*             * 备注1：此处一定要将return super.onTouchEvent(event)修改为return true，原因是：             * 1）父类的onTouchEvent(event)方法可能没有做任何处理，但是返回了false。             * 2)一旦返回false，在该方法中再也不会收到MotionEvent.ACTION_MOVE及MotionEvent.ACTION_UP事件。             */            //return super.onTouchEvent(event);            return true;        }    }}
阅读全文
0 0