圆形随手指移动

来源：互联网发布：插画培训班知乎编辑：程序博客网时间：2024/05/16 11:53
package com.bwie.playbass;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.support.annotation.Nullable;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.util.AttributeSet;import android.view.Display;import android.view.MotionEvent;import android.view.View;import android.view.Window;import android.view.WindowManager;import java.util.Random;public class MainActivity extends AppCompatActivity {    private int screenW;//屏幕宽度    private int screenH;//屏幕高度    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        //setContentView(R.layout.activity_main);        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));    }    class BallView extends View{        //定义画笔        private Paint paint;        //圆点默认X坐标        private float cx=50;        //圆点默认Y坐标        private float cy=50;        //定义半径        private int radius=100;        //定义画笔颜色        private int colorArray[] ={Color.BLACK,Color.GREEN,Color.YELLOW,Color.RED};        private int paintColor = colorArray[0];        public BallView(Context context) {            super(context);            //初始化画笔            initPaint();        }        private void initPaint() {            paint=new Paint();            paint.setAntiAlias(true);            paint.setColor(paintColor);        }            //重写onDraw方法        @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            setPainRandomColor();            //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 setPainRandomColor() {            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()){                //按下                case MotionEvent.ACTION_DOWN:                    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;                //移动                case MotionEvent.ACTION_MOVE:                    cx=(int)event.getX();                    cy=(int)event.getY();                    postInvalidate();                    break;                //抬起                case MotionEvent.ACTION_POINTER_UP:                    cx=(int)event.getX();                    cy=(int)event.getY();                    postInvalidate();                    break;            }            return true;        }    }}
阅读全文
0 0