Android 室内定位系列:<1>地图构建

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

[java] view plaincopyprint?

1. package WangLi.Graphics.PathTest;  
2.   
3. import android.app.Activity;  
4. import android.content.Context;  
5. import android.graphics.Canvas;  
6. import android.graphics.Color;  
7. import android.graphics.ComposePathEffect;  
8. import android.graphics.CornerPathEffect;  
9. import android.graphics.DashPathEffect;  
10. import android.graphics.DiscretePathEffect;  
11. import android.graphics.Paint;  
12. import android.graphics.Path;  
13. import android.graphics.PathDashPathEffect;  
14. import android.graphics.PathEffect;  
15. import android.graphics.SumPathEffect;  
16. import android.os.Bundle;  
17. import android.view.View;  
18.   
19. public class PathTest extends Activity {  
20.     /** Called when the activity is first created. */  
21.     @Override  
22.     public void onCreate(Bundle savedInstanceState) {  
23.         super.onCreate(savedInstanceState);  
24.         setContentView(new MyView(this));  
25.     }  
26.     class MyView extends View  
27.     {  
28.         float phase;  
29.         PathEffect[] effects = new PathEffect[7];  
30.         int[] colors;  
31.         private Paint paint;  
32.         Path path;  
33.         public MyView(Context context) {  
34.             super(context);  
35.             paint = new Paint();  
36.             paint.setStyle(Paint.Style.STROKE);  
37.             paint.setStrokeWidth(4);  
38.             //创建,并初始化Path  
39.             path = new Path();  
40.             path.moveTo(0, 0);  
41.             for(int i = 1; i<= 15; i++)  
42.             {  
43.                 //生成15个点,随机生成它们的坐标,并将它们连成一条Path  
44.                 path.lineTo(i*20, (float)Math.random()*60);  
45.             }  
46.             //初始化七个颜色  
47.             colors = new int[] {  
48.                     Color.BLACK,Color.BLUE,Color.CYAN,  
49.                     Color.GREEN,Color.MAGENTA,Color.RED,Color.YELLOW  
50.             };  
51.         }  
52.         protected void onDraw(Canvas canvas)  
53.         {  
54.             //将背景填充成白色  
55.             canvas.drawColor(Color.WHITE);  
56.             //-------下面开始初始化7中路径的效果  
57.             //使用路径效果  
58.             effects[0] = null;  
59.             //使用CornerPathEffect路径效果  
60.             effects[1] = new CornerPathEffect(10);  
61.             //初始化DiscretePathEffect  
62.             effects[2] = new DiscretePathEffect(3.0f,5.0f);  
63.             //初始化DashPathEffect  
64.             effects[3] = new DashPathEffect(new float[]{20,10,5,10},phase);  
65.             //初始化PathDashPathEffect  
66.             Path p = new Path();  
67.             p.addRect(0, 0, 8, 8, Path.Direction.CCW);  
68.             effects[4] = new PathDashPathEffect(p,12,phase,PathDashPathEffect.Style.ROTATE);  
69.             //初始化PathDashPathEffect  
70.             effects[5] = new ComposePathEffect(effects[2],effects[4]);  
71.             effects[6] = new SumPathEffect(effects[4],effects[3]);  
72.             //将画布移到8,8处开始绘制  
73.             canvas.translate(8, 8);  
74.             //依次使用7中不同路径效果,7种不同的颜色来绘制路径  
75.             for(int i = 0; i < effects.length; i++)  
76.             {  
77.                 paint.setPathEffect(effects[i]);  
78.                 paint.setColor(colors[i]);  
79.                 canvas.drawPath(path, paint);  
80.                 canvas.translate(0, 60);  
81.             }  
82.             //改变phase值,形成动画效果  
83.             phase += 1;  
84.             invalidate();  
85.         }  
86.     }  
87. }  

效果如下