Android之图形图像之使用Path类总结

Path类可以预先在View上将N个点连成一条"路径",然后调用Canvas的drawPath(path,paint)即可沿着路径绘制图形

Android还为路径绘制提供了PathEffect来定义绘制效果,PathEffect包含如下子类

ComposePathEffect

CornerPathEffect

DashPathEffect

DiscretePathEffect

PathDashPathEffect

SumPathEffect

下面的示例将会逐一使用上面的绘制效果

  

   

    

     

    
    

     

      package WangLi.Graphics.PathTest;  
     
    
   

    

     

    
    

     
  
     
    
   

    

     

    
    

     

      import android.app.Activity;  
     
    
   

    

     

    
    

     

      import android.content.Context;  
     
    
   

    

     

    
    

     

      import android.graphics.Canvas;  
     
    
   

    

     

    
    

     

      import android.graphics.Color;  
     
    
   

    

     

    
    

     

      import android.graphics.ComposePathEffect;  
     
    
   

    

     

    
    

     

      import android.graphics.CornerPathEffect;  
     
    
   

    

     

    
    

     

      import android.graphics.DashPathEffect;  
     
    
   

    

     

    
    

     

      import android.graphics.DiscretePathEffect;  
     
    
   

    

     

    
    

     

      import android.graphics.Paint;  
     
    
   

    

     

    
    

     

      import android.graphics.Path;  
     
    
   

    

     

    
    

     

      import android.graphics.PathDashPathEffect;  
     
    
   

    

     

    
    

     

      import android.graphics.PathEffect;  
     
    
   

    

     

    
    

     

      import android.graphics.SumPathEffect;  
     
    
   

    

     

    
    

     

      import android.os.Bundle;  
     
    
   

    

     

    
    

     

      import android.view.View;  
     
    
   

    

     

    
    

     
  
     
    
   

    

     

    
    

     

      public class PathTest extends Activity {  
     
    
   

    

     

    
    

     

       /** Called when the activity is first created. */  
     
    
   

    

     

    
    

     

       @Override  
     
    
   

    

     

    
    

     

       public void onCreate(Bundle savedInstanceState) {  
     
    
   

    

     

    
    

     

       super.onCreate(savedInstanceState);  
     
    
   

    

     

    
    

     

       setContentView(new MyView(this));  
     
    
   

    

     

    
    

     

       }  
     
    
   

    

     

    
    

     

       class MyView extends View  
     
    
   

    

     

    
    

     

       {  
     
    
   

    

     

    
    

     

       float phase;  
     
    
   

    

     

    
    

     

       PathEffect[] effects = new PathEffect[7];  
     
    
   

    

     

    
    

     

       int[] colors;  
     
    
   

    

     

    
    

     

       private Paint paint;  
     
    
   

    

     

    
    

     

       Path path;  
     
    
   

    

     

    
    

     

       public MyView(Context context) {  
     
    
   

    

     

    
    

     

       super(context);  
     
    
   

    

     

    
    

     

       paint = new Paint();  
     
    
   

    

     

    
    

     

       paint.setStyle(Paint.Style.STROKE);  
     
    
   

    

     

    
    

     

       paint.setStrokeWidth(4);  
     
    
   

    

     

    
    

     

       //创建,并初始化Path  
     
    
   

    

     

    
    

     

       path = new Path();  
     
    
   

    

     

    
    

     

       path.moveTo(0, 0);  
     
    
   

    

     

    
    

     

       for(int i = 1; i<= 15; i++) 
     
    
   

    

     

    
    

     

       { 
     
    
   

    

     

    
    

     

       //生成15个点,随机生成它们的坐标,并将它们连成一条Path 
     
    
   

    

     

    
    

     

       path.lineTo(i*20, (float)Math.random()*60); 
     
    
   

    

     

    
    

     

       } 
     
    
   

    

     

    
    

     

       //初始化七个颜色 
     
    
   

    

     

    
    

     

       colors = new int[] { 
     
    
   

    

     

    
    

     

       Color.BLACK,Color.BLUE,Color.CYAN, 
     
    
   

    

     

    
    

     

       Color.GREEN,Color.MAGENTA,Color.RED,Color.YELLOW 
     
    
   

    

     

    
    

     

       }; 
     
    
   

    

     

    
    

     

       } 
     
    
   

    

     

    
    

     

       protected void onDraw(Canvas canvas) 
     
    
   

    

     

    
    

     

       { 
     
    
   

    

     

    
    

     

       //将背景填充成白色 
     
    
   

    

     

    
    

     

       canvas.drawColor(Color.WHITE); 
     
    
   

    

     

    
    

     

       //-------下面开始初始化7中路径的效果 
     
    
   

    

     

    
    

     

       //使用路径效果 
     
    
   

    

     

    
    

     

       effects[0] = null; 
     
    
   

    

     

    
    

     

       //使用CornerPathEffect路径效果 
     
    
   

    

     

    
    

     

       effects[1] = new CornerPathEffect(10); 
     
    
   

    

     

    
    

     

       //初始化DiscretePathEffect 
     
    
   

    

     

    
    

     

       effects[2] = new DiscretePathEffect(3.0f,5.0f); 
     
    
   

    

     

    
    

     

       //初始化DashPathEffect 
     
    
   

    

     

    
    

     

       effects[3] = new DashPathEffect(new float[]{20,10,5,10},phase); 
     
    
   

    

     

    
    

     

       //初始化PathDashPathEffect 
     
    
   

    

     

    
    

     

       Path p = new Path(); 
     
    
   

    

     

    
    

     

       p.addRect(0, 0, 8, 8, Path.Direction.CCW); 
     
    
   

    

     

    
    

     

       effects[4] = new PathDashPathEffect(p,12,phase,PathDashPathEffect.Style.ROTATE); 
     
    
   

    

     

    
    

     

       //初始化PathDashPathEffect 
     
    
   

    

     

    
    

     

       effects[5] = new ComposePathEffect(effects[2],effects[4]); 
     
    
   

    

     

    
    

     

       effects[6] = new SumPathEffect(effects[4],effects[3]); 
     
    
   

    

     

    
    

     

       //将画布移到8,8处开始绘制 
     
    
   

    

     

    
    

     

       canvas.translate(8, 8); 
     
    
   

    

     

    
    

     

       //依次使用7中不同路径效果,7种不同的颜色来绘制路径 
     
    
   

    

     

    
    

     

       for(int i = 0; i < effects.length; i++) 
     
    
   

    

     

    
    

     

       { 
     
    
   

    

     

    
    

     

       paint.setPathEffect(effects[i]); 
     
    
   

    

     

    
    

     

       paint.setColor(colors[i]); 
     
    
   

    

     

    
    

     

       canvas.drawPath(path, paint); 
     
    
   

    

     

    
    

     

       canvas.translate(0, 60); 
     
    
   

    

     

    
    

     

       } 
     
    
   

    

     

    
    

     

       //改变phase值,形成动画效果 
     
    
   

    

     

    
    

     

       phase += 1; 
     
    
   

    

     

    
    

     

       invalidate(); 
     
    
   

    

     

    
    

     

       } 
     
    
   

    

     

    
    

     

       } 
     
    
   

    

     

    
    

     

      } 
     
    
  
 

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原文链接：chenyu.blog.csdn.net/article/details/50484174