Android软件开发：在Canvas中利用Path绘制基本图形

1.自定义的View组件代码：

    package com.infy.configuration;  
      
    import android.content.Context;  
    import android.graphics.Canvas;  
    import android.graphics.Color;  
    import android.graphics.LinearGradient;  
    import android.graphics.Paint;  
    import android.graphics.Path;  
    import android.graphics.RectF;  
    import android.graphics.Shader;  
    import android.util.AttributeSet;  
    import android.view.View;  
      
    public class MyView extends View{  
      
        public MyView(Context context, AttributeSet attrs) {  
            super(context, attrs);  
        }  
      
        @Override  
        protected void onDraw(Canvas canvas) {  
            // TODO Auto-generated method stub   
            super.onDraw(canvas);  
              
            //把整张画布绘制成白色   
            canvas.drawColor(Color.WHITE);  
            Paint paint = new Paint();  
              
            //去锯齿   
            paint.setAntiAlias(true);  
            paint.setColor(Color.BLUE);  
            paint.setStyle(Paint.Style.STROKE);  
            paint.setStrokeWidth(3);  
              
            //绘制圆形   
            canvas.drawCircle(40, 40, 30, paint);  
            //绘制正方形   
            canvas.drawRect(10, 80, 70, 140, paint);  
            //绘制矩形   
            canvas.drawRect(10, 150, 70, 190, paint);  
      
            RectF rel = new RectF(10,240,70,270);  
            //绘制椭圆   
            canvas.drawOval(rel, paint);  
            //定义一个Path对象，封闭一个三角形   
            Path path1 = new Path();  
            path1.moveTo(10, 340);  
            path1.lineTo(70, 340);  
            path1.lineTo(40, 290);  
            path1.close();  
            //根据Path进行绘制，绘制三角形   
            canvas.drawPath(path1, paint);  
              
            //定义一个Path对象，封闭一个五角星   
            Path path2 = new Path();  
            path2.moveTo(27, 360);  
            path2.lineTo(54, 360);  
            path2.lineTo(70, 392);  
            path2.lineTo(40, 420);  
            path2.lineTo(10, 392);  
            path2.close();  
            //根据Path进行绘制，绘制五角星   
            canvas.drawPath(path2, paint);  
              
            //设置填丛风格后进行绘制   
            paint.setStyle(Paint.Style.FILL);  
            paint.setColor(Color.RED);  
            canvas.drawCircle(120, 40, 30, paint);  
            //绘制正方形   
            canvas.drawRect(90, 80, 150, 140, paint);  
            //绘制矩形   
            canvas.drawRect(90, 150, 150, 190, paint);  
              
            //绘制圆角矩形   
            RectF re2 = new RectF(90,200,150,230);  
            canvas.drawRoundRect(re2, 15, 15, paint);  
            //绘制椭圆   
            RectF re21 = new RectF(90, 240, 150, 270);  
            canvas.drawOval(re21, paint);  
              
            Path path3 = new Path();  
            path3.moveTo(90, 340);  
            path3.lineTo(150, 340);  
            path3.lineTo(120, 290);  
            path3.close();  
            //绘制三角形   
            canvas.drawPath(path3,paint);  
              
            //绘制五角形   
            Path path4 = new Path();  
            path4.moveTo(106, 360);  
            path4.lineTo(134, 360);  
            path4.lineTo(150, 392);  
            path4.lineTo(120, 420);  
            path4.lineTo(90, 392);  
            path4.close();  
            canvas.drawPath(path4, paint);  
              
            //设置渐变器后绘制   
            //为Paint设置渐变器   
            Shader mShasder = new LinearGradient(0, 0, 40, 60, new int[]{Color.RED,Color.GREEN,Color.BLUE,Color.YELLOW}, null, Shader.TileMode.REPEAT);  
            paint.setShader(mShasder);  
            //设置阴影   
            paint.setShadowLayer(45, 10, 10, Color.GRAY);  
            //绘制圆形   
            canvas.drawCircle(200, 40, 30, paint);  
            //绘制正方形   
            canvas.drawRect(170, 80, 230, 140, paint);  
            //绘制矩形   
            canvas.drawRect(170, 150, 230, 190, paint);  
              
            //绘制圆角的矩形   
            RectF re31 = new RectF();  
            canvas.drawRoundRect(re31, 15, 15, paint);  
              
            //绘制椭圆   
            RectF re32 =new RectF();  
            canvas.drawOval(re32, paint);  
              
            //根据Path,绘制三角形   
            Path path5 = new Path();  
            path5.moveTo(170, 340);  
            path5.lineTo(230, 340);  
            path5.lineTo(200, 290);  
            path5.close();  
            canvas.drawPath(path5, paint);  
              
            //根据PAth,进行绘制五角形   
            Path path6 = new Path();  
            path6.moveTo(186, 360);  
            path6.lineTo(214, 360);  
            path6.lineTo(230, 392);  
            path6.lineTo(200, 420);  
            path6.lineTo(170, 392);  
            path6.close();  
            canvas.drawPath(path6, paint);  
             
        }  
      
    }  

2. 使用一个基本的Activity来实现自定义的MyView组件，

定义一个ZiDingYiViewTes的Activity：

    package com.infy.configuration;  
      
    import android.app.Activity;  
    import android.os.Bundle;  
      
    public class ZiDingYiViewTes extends Activity{  
          
        private MyView myView =null;  
      
        @Override  
        protected void onCreate(Bundle savedInstanceState) {  
            // TODO Auto-generated method stub   
            super.onCreate(savedInstanceState);  
              
            myView = new MyView(this, null);  
              
            setContentView(myView);  
              
        }  
    }  

Android的Canvas既可以绘制简单的集合图形，也可以直接将一个Bitmap绘制到画布上。

最后附上效果图(多了一个椭圆)：

转自：http://www.linuxidc.com/Linux/2012-05/61204.htm