Android Path的使用

import android.app.Activity;   
import android.os.Bundle;   
import android.view.View;   
import android.content.Context;   
import android.graphics.Canvas;   
import android.graphics.Color;   
import android.graphics.Paint;   
import android.graphics.RectF;   
import android.graphics.Path;   
import android.graphics.Shader;   
import android.graphics.LinearGradient;   
//主程序中继承自Android.view.View的 MyView类，重写 MyView的onDraw（）方法，   
//一开始就会运行绘制的工作，在onDraw（）中以Paint将几何图形绘制在Canvas上，   
//以 paint.setColor() 改变图形颜色、以 paint.setStyle()的设置来控制画出的的   
//图形是空心还是实心。程序的最后一段，就是直接在Canvas写上文字，随着Paint对   
//象里的属性设置，也会有不同的外观模式。 
public class GraphicesActivity extends Activity {   
    /** Called when the activity is first created. */  
    @Override  
    public void onCreate(Bundle savedInstanceState) {   
        super.onCreate(savedInstanceState);   
        /*设置ContentView为自定义的MyVieW*/  
        MyView myView=new MyView(this);   
        setContentView(myView);   
    }   
        
    /* 自定义继承View 的MyView*/  
    private class MyView extends View {   
         public MyView(Context context){   
            super(context) ;   
         }   
            
         /*重写onDraw（）*/  
         @Override  
         protected void onDraw(Canvas canvas)   
         {      
              super.onDraw(canvas);   
              /*设置背景为白色*/  
              canvas.drawColor(Color.WHITE);   
                  
              Paint paint=new Paint();   
              /*去锯齿*/  
              paint.setAntiAlias(true);   
              /*设置paint的颜色*/  
              paint.setColor(Color.RED);   
              /*设置paint的 style 为STROKE：空心*/  
              paint.setStyle(Paint.Style.STROKE);   
              /*设置paint的外框宽度*/  
              paint.setStrokeWidth(3);   
                  
              /*画一个空心圆形*/  
              canvas.drawCircle(40, 40, 30, paint);   
              /*画一个空心正方形*/  
              canvas.drawRect(10, 90, 70, 150, paint);   
              /*画一个空心长方形*/  
              canvas.drawRect(10, 170, 70,200, paint);   
              /*画一个空心椭圆形*/  
              canvas.drawOval(new RectF(10,220,70,250), paint);   
              /*画一个空心三角形*/  
              Path path=new Path();   
              path.moveTo(10, 330);   
              path.lineTo(70,330);   
              path.lineTo(40,270);   
              path.close();   
              canvas.drawPath(path, paint);   
              /*画一个空心梯形*/  
              Path path1=new Path();   
              path1.moveTo(10, 410);   
              path1.lineTo(70,410);   
              path1.lineTo(55,350);   
              path1.lineTo(25, 350);   
              path1.close();   
              canvas.drawPath(path1, paint);   
                  
              /*设置paint的颜色*/  
              paint.setColor(Color.BLUE);   
              /*设置paint 的style为 FILL：实心*/  
              paint.setStyle(Paint.Style.FILL);   
              /*画一个实心圆*/  
              canvas.drawCircle(120,40,30, paint);   
              /*画一个实心正方形*/  
              canvas.drawRect(90, 90, 150, 150, paint);   
              /*画一个实心长方形*/  
              canvas.drawRect(90, 170, 150,200, paint);   
              /*画一个实心椭圆*/  
              RectF re2=new RectF(90,220,150,250);   
              canvas.drawOval(re2, paint);   
              /*画一个实心三角形*/  
              Path path2=new Path();   
              path2.moveTo(90, 330);   
              path2.lineTo(150,330);   
              path2.lineTo(120,270);   
              path2.close();   
              canvas.drawPath(path2, paint);   
              /*画一个实心梯形*/  
              Path path3=new Path();   
              path3.moveTo(90, 410);   
              path3.lineTo(150,410);   
              path3.lineTo(135,350);   
              path3.lineTo(105, 350);   
              path3.close();   
              canvas.drawPath(path3, paint);   
                  
              /*设置渐变色*/  
              Shader mShader=new LinearGradient(0,0,100,100,   
                      new int[]{Color.RED,Color.GREEN,Color.BLUE,Color.YELLOW},   
                      null,Shader.TileMode.REPEAT);   
              //Shader.TileMode三种模式   
              //REPEAT:沿着渐变方向循环重复   
              //CLAMP:如果在预先定义的范围外画的话，就重复边界的颜色   
              //MIRROR:与REPEAT一样都是循环重复，但这个会对称重复   
              paint.setShader(mShader);//用Shader中定义定义的颜色来话   
               
              /*画一个渐变色圆*/  
              canvas.drawCircle(200,40,30, paint);   
              /*画一个渐变色正方形*/  
              canvas.drawRect(170, 90, 230, 150, paint);   
              /*画一个渐变色长方形*/  
              canvas.drawRect(170, 170, 230,200, paint);   
              /*画一个渐变色椭圆*/  
              RectF re3=new RectF(170,220,230,250);   
              canvas.drawOval(re3, paint);   
              /*画一个渐变色三角形*/  
              Path path4=new Path();   
              path4.moveTo(170,330);   
              path4.lineTo(230,330);   
              path4.lineTo(200,270);   
              path4.close();   
              canvas.drawPath(path4, paint);   
              /*画一个渐变色梯形*/  
              Path path5=new Path();   
              path5.moveTo(170, 410);   
              path5.lineTo(230,410);   
              path5.lineTo(215,350);   
              path5.lineTo(185, 350);   
              path5.close();   
              canvas.drawPath(path5, paint);   
                  
              /*写字*/  
              paint.setTextSize(24);   
              canvas.drawText("圆形", 240, 50, paint);   
              canvas.drawText("正方形", 240, 120, paint);   
              canvas.drawText("长方形", 240, 190, paint);   
              canvas.drawText("椭圆形", 240, 250, paint);   
              canvas.drawText("三角形", 240, 320, paint);   
              canvas.drawText("梯形", 240, 390, paint);     
         }   
    }   
}