Android开发速成简洁教程十五:RadioButton及路径绘制

这个例子是绘制多边形，多义形和路径，采用单选钮RadioButton来选择Polys 和Path示例:

UI 设计为 上部分用来显示绘图内容，下部分为两个单选按钮 Polys ，Path。这样layout就和main.xml 不一样，main.xml只含一个com.pstreets.graphics2d.GuidebeeGraphics2DView。因此需在 res\layout下新建一个polys.xml：

<?xml version=”1.0″ encoding=”utf-8″?> 
<LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android” 
    android:orientation=”vertical” 
    android:background=”@drawable/white” 
 android:layout_width=”fill_parent” 
 android:layout_height=”fill_parent”> 
    <com.pstreets.graphics2d.GuidebeeGraphics2DView 
     android:id=”@+id/graphics2dview” 
     android:layout_weight=”1″ 
     android:layout_width=”fill_parent” 
     android:layout_height=”wrap_content”/> 
 <LinearLayout xmlns:android=”http://schemas.android.com/apk/res/android” 
  android:layout_width=”wrap_content” android:layout_height=”wrap_content” 
  android:orientation=”horizontal” 
   
  > 
  <RadioGroup 
     android:layout_width=”wrap_content” 
     android:orientation=”horizontal” 
     android:textSize=”20dp” 
     android:layout_height=”wrap_content”> 
   <RadioButton android:text=”Polys” 
       android:id=”@+id/radioPolys” 
    android:layout_width=”wrap_content” 
    android:textColor=”@color/black” 
    android:checked=”true” 
    android:layout_height=”wrap_content”> 
   </RadioButton> 
   <RadioButton android:text=”Path” 
        android:id=”@+id/radioPath” 
    android:layout_width=”wrap_content” 
    android:textColor=”@color/black” 
    android:layout_height=”wrap_content”> 
   </RadioButton> 
  </RadioGroup> 
 </LinearLayout> 
 
</LinearLayout> 

RadioButton 需包含在RadioGroup中做为一个分组，这里将Polys 设为选中。

定义好Layout资源后，修改 Path.java

private RadioButton radioPoly; 
    private RadioButton radioPath;    
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.polys); 
     graphic2dView 
      = (GuidebeeGraphics2DView) 
        findViewById(R.id.graphics2dview); 
     radioPath = (RadioButton) findViewById(R.id.radioPath); 
     radioPoly = (RadioButton) findViewById(R.id.radioPolys); 
     radioPath.setOnClickListener(this); 
     radioPoly.setOnClickListener(this); 
    } 

应为需要处理按键消息，所以定义了两个RadioButton对象，可以通过findViewById获取实例。因为两个RadioButton这里采用 同样的处理方法，可以让Path实现OnClickListener ，即：public class Path extends Graphics2DActivity   implements OnClickListener。完整代码如下：

1   public class Path extends Graphics2DActivity 
2      implements OnClickListener { 
3     
4       private RadioButton radioPoly; 
5       private RadioButton radioPath; 
6     
7       public void onCreate(Bundle savedInstanceState) { 
8           super.onCreate(savedInstanceState); 
9           setContentView(R.layout.polys); 
10          graphic2dView 
11           = (GuidebeeGraphics2DView) 
12             findViewById(R.id.graphics2dview); 
13          radioPath = (RadioButton) findViewById(R.id.radioPath); 
14          radioPoly = (RadioButton) findViewById(R.id.radioPolys); 
15          radioPath.setOnClickListener(this); 
16          radioPoly.setOnClickListener(this); 
17      } 
18    
19      @Override 
20      protected void drawImage() { 
21          if (radioPoly.isChecked()) { 
22              drawPolys(); 
23          } else { 
24              drawPaths(); 
25          } 
26          graphic2dView.refreshCanvas(); 
27    
28      } 
29    
30      @Override 
31      public void onClick(View view) { 
32          drawImage(); 
33      } 
34    
35      private void drawPaths() { 
36          AffineTransform mat1; 
37    
38          // The path. 
39          com.mapdigit.drawing.geometry.Path path; 
40    
41          // Colors 
42          Color redColor = new Color(0x96ff0000, true); 
43          Color greenColor = new Color(0xff00ff00); 
44          Color blueColor = new Color(0x750000ff, true); 
45    
46          String pathdata 
47             = "M 60 20 Q -40 70 60 120 Q 160 70 60 20 z"; 
48          mat1 = new AffineTransform(); 
49          mat1.translate(30, 40); 
50          mat1.rotate(-30 * Math.PI / 180.0); 
51          path = com.mapdigit.drawing.geometry.Path.fromString(pathdata); 
52          // Clear the canvas with white color. 
53          graphics2D.clear(Color.WHITE); 
54    
55          graphics2D.setAffineTransform(new AffineTransform()); 
56          SolidBrush brush = new SolidBrush(greenColor); 
57          graphics2D.fill(brush, path); 
58          graphics2D.setAffineTransform(mat1); 
59    
60          brush = new SolidBrush(blueColor); 
61          com.mapdigit.drawing.Pen pen 
62             = new com.mapdigit.drawing.Pen(redColor, 5); 
63          graphics2D.setPenAndBrush(pen, brush); 
64          graphics2D.draw(null, path); 
65          graphics2D.fill(null, path); 
66    
67      } 
68    
69      private void drawPolys() { 
70          AffineTransform mat1; 
71    
72          // Colors 
73          Color redColor = new Color(0x96ff0000, true); 
74          Color greenColor = new Color(0xff00ff00); 
75          Color blueColor = new Color(0x750000ff, true); 
76    
77          Polyline polyline; 
78          Polygon polygon; 
79          Polygon polygon1; 
80    
81          String pointsdata1 
82          = "59,45,95,63,108,105,82,139,39,140,11,107,19,65"; 
83          mat1 = new AffineTransform(); 
84          mat1.translate(30, 40); 
85          mat1.rotate(-30 * Math.PI / 180.0); 
86          polyline = new Polyline(); 
87          polygon = new Polygon(); 
88          polygon1 = new Polygon(); 
89          Point[] points = Point.fromString(pointsdata1); 
90          for (int i = 0; i < points.length; i++) { 
91              polyline.addPoint(points[i].x, points[i].y); 
92              polygon.addPoint(points[i].x, points[i].y); 
93              polygon1.addPoint(points[i].x, points[i].y); 
94          } 
95          // Clear the canvas with white color. 
96          graphics2D.clear(Color.WHITE); 
97    
98          graphics2D.setAffineTransform(new AffineTransform()); 
99          SolidBrush brush = new SolidBrush(greenColor); 
100         graphics2D.fillPolygon(brush, polygon); 
101         graphics2D.setAffineTransform(mat1); 
102   
103         brush = new SolidBrush(blueColor); 
104         com.mapdigit.drawing.Pen pen 
105            = new com.mapdigit.drawing.Pen(redColor, 5); 
106         graphics2D.setPenAndBrush(pen, brush); 
107         graphics2D.fillPolygon(null, polygon1); 
108         graphics2D.drawPolyline(null, polyline); 
109   
110     } 
111   
112 }