Android軟件開發：在Canvas中利用Path繪制基本圖形

在Android中繪制基本的集合圖形，本程序就是自定義一個View組件，程序重寫該View組件的onDraw(Canvase)方法，然後在該Canvas上繪制大量的基本的集合圖形。

直接上代碼：

1.自定義的View組件代碼：

1. package com.infy.configuration;
3. import android.content.Context;
4. import android.graphics.Canvas;
5. import android.graphics.Color;
6. import android.graphics.LinearGradient;
7. import android.graphics.Paint;
8. import android.graphics.Path;
9. import android.graphics.RectF;
10. import android.graphics.Shader;
11. import android.util.AttributeSet;
12. import android.view.View;
14. public class MyView extends View{
16. public MyView(Context context, AttributeSet attrs) {
17. super(context, attrs);
18. }
20. @Override
21. protected void onDraw(Canvas canvas) {
22. // TODO Auto-generated method stub
23. super.onDraw(canvas);
25. //把整張畫布繪制成白色
26. canvas.drawColor(Color.WHITE);
27. Paint paint = new Paint();
29. //去鋸齒
30. paint.setAntiAlias(true);
31. paint.setColor(Color.BLUE);
32. paint.setStyle(Paint.Style.STROKE);
33. paint.setStrokeWidth(3);
35. //繪制圓形
36. canvas.drawCircle(40, 40, 30, paint);
37. //繪制正方形
38. canvas.drawRect(10, 80, 70, 140, paint);
39. //繪制矩形
40. canvas.drawRect(10, 150, 70, 190, paint);
42. RectF rel = new RectF(10,240,70,270);
43. //繪制橢圓
44. canvas.drawOval(rel, paint);
45. //定義一個Path對象，封閉一個三角形
46. Path path1 = new Path();
47. path1.moveTo(10, 340);
48. path1.lineTo(70, 340);
49. path1.lineTo(40, 290);
50. path1.close();
51. //根據Path進行繪制，繪制三角形
52. canvas.drawPath(path1, paint);
54. //定義一個Path對象，封閉一個五角星
55. Path path2 = new Path();
56. path2.moveTo(27, 360);
57. path2.lineTo(54, 360);
58. path2.lineTo(70, 392);
59. path2.lineTo(40, 420);
60. path2.lineTo(10, 392);
61. path2.close();
62. //根據Path進行繪制，繪制五角星
63. canvas.drawPath(path2, paint);
65. //設置填叢風格後進行繪制
66. paint.setStyle(Paint.Style.FILL);
67. paint.setColor(Color.RED);
68. canvas.drawCircle(120, 40, 30, paint);
69. //繪制正方形
70. canvas.drawRect(90, 80, 150, 140, paint);
71. //繪制矩形
72. canvas.drawRect(90, 150, 150, 190, paint);
74. //繪制圓角矩形
75. RectF re2 = new RectF(90,200,150,230);
76. canvas.drawRoundRect(re2, 15, 15, paint);
77. //繪制橢圓
78. RectF re21 = new RectF(90, 240, 150, 270);
79. canvas.drawOval(re21, paint);
81. Path path3 = new Path();
82. path3.moveTo(90, 340);
83. path3.lineTo(150, 340);
84. path3.lineTo(120, 290);
85. path3.close();
86. //繪制三角形
87. canvas.drawPath(path3,paint);
89. //繪制五角形
90. Path path4 = new Path();
91. path4.moveTo(106, 360);
92. path4.lineTo(134, 360);
93. path4.lineTo(150, 392);
94. path4.lineTo(120, 420);
95. path4.lineTo(90, 392);
96. path4.close();
97. canvas.drawPath(path4, paint);
99. //設置漸變器後繪制
100. //為Paint設置漸變器
101. Shader mShasder = new LinearGradient(0, 0, 40, 60, new int[]{Color.RED,Color.GREEN,Color.BLUE,Color.YELLOW}, null, Shader.TileMode.REPEAT);
102. paint.setShader(mShasder);
103. //設置陰影
104. paint.setShadowLayer(45, 10, 10, Color.GRAY);
105. //繪制圓形
106. canvas.drawCircle(200, 40, 30, paint);
107. //繪制正方形
108. canvas.drawRect(170, 80, 230, 140, paint);
109. //繪制矩形
110. canvas.drawRect(170, 150, 230, 190, paint);
112. //繪制圓角的矩形
113. RectF re31 = new RectF();
114. canvas.drawRoundRect(re31, 15, 15, paint);
116. //繪制橢圓
117. RectF re32 =new RectF();
118. canvas.drawOval(re32, paint);
120. //根據Path,繪制三角形
121. Path path5 = new Path();
122. path5.moveTo(170, 340);
123. path5.lineTo(230, 340);
124. path5.lineTo(200, 290);
125. path5.close();
126. canvas.drawPath(path5, paint);
128. //根據PAth,進行繪制五角形
129. Path path6 = new Path();
130. path6.moveTo(186, 360);
131. path6.lineTo(214, 360);
132. path6.lineTo(230, 392);
133. path6.lineTo(200, 420);
134. path6.lineTo(170, 392);
135. path6.close();
136. canvas.drawPath(path6, paint);
138. }
140. }

2. 使用一個基本的Activity來實現自定義的MyView組件，

定義一個ZiDingYiViewTes的Activity：

1. package com.infy.configuration;
3. import android.app.Activity;
4. import android.os.Bundle;
6. public class ZiDingYiViewTes extends Activity{
8. private MyView myView =null;
10. @Override
11. protected void onCreate(Bundle savedInstanceState) {
12. // TODO Auto-generated method stub
13. super.onCreate(savedInstanceState);
15. myView = new MyView(this, null);
17. setContentView(myView);
19. }
20. }

Android的Canvas既可以繪制簡單的集合圖形，也可以直接將一個Bitmap繪制到畫布上。

最後附上效果圖(多了一個橢圓)：

更多Android相關信息見Android 專題頁面 http://www.linuxidc.com/topicnews.aspx?tid=11