Android開發經驗之在圖片上隨意點擊移動文字

只要在圖片范圍之內，文字可隨意點擊移動。

1. package xiaosi.GetTextImage;
4. import Android.content.Context;
5. import android.content.res.Resources;
6. import android.graphics.Bitmap;
7. import android.graphics.BitmapFactory;
8. import android.graphics.Canvas;
9. import android.graphics.Paint;
10. import android.util.DisplayMetrics;
11. import android.view.MotionEvent;
12. import android.view.View;
13. import android.view.WindowManager;
15. public class GetTextImage extends View
16. {
17. private float x = 20, y = 40;
18. private static float windowWidth;
19. private static float windowHeight;
20. private static float left = 0; //圖片在屏幕中位置X坐標
21. private static float top = 0; //圖片在屏幕中位置Y坐標
22. private String str = "我愛你";
23. private DisplayMetrics dm = new DisplayMetrics(); //用於獲取屏幕的高度和寬度
24. private WindowManager windowManager;
25. private Bitmap newbitmap;
27. public GetTextImage(Context context)
28. {
29. super(context);
30. windowManager = (WindowManager) context
31. .getSystemService(Context.WINDOW_SERVICE);
32. //屏幕的寬度
33. windowWidth = windowManager.getDefaultDisplay().getWidth();
34. //屏幕的高度
35. windowHeight = windowManager.getDefaultDisplay().getHeight();
36. }
38. public void onDraw(Canvas canvas)
39. {
40. Resources res = getResources();
41. Bitmap bmp = BitmapFactory.decodeResource(res, R.drawable.b);
42. newbitmap = getTextImage(bmp, str, x, y);
43. canvas.drawBitmap(newbitmap, 0, 0, null);
44. }
45. /**
46. * 返回值: Bitmap 參數：原圖片,文字 功能: 根據給定的文字生成相應圖片
47. *
48. * @param originalMap
49. * @param text 文字
50. * @param x 點擊的X坐標
51. * @param y 點擊的Y坐標
52. * @return
53. */
54. public static Bitmap getTextImage(Bitmap originalMap, String text, float x,
55. float y)
56. {
57. float bitmapWidth = originalMap.getWidth();
58. float bitmapHeight = originalMap.getHeight();
59. // 定義畫布
60. Canvas canvas = new Canvas(originalMap);
61. // 定義畫筆
62. Paint paint = new Paint();
63. //獲得文本的長度（像素）
64. float textWidth = paint.measureText(text);
65. canvas.drawBitmap(originalMap, 0, 0, null);
67. // 如果圖片寬度小於屏幕寬度
68. if (left + bitmapWidth < windowWidth)
69. {
70. // 右邊界
71. if (x >= left + bitmapWidth - textWidth)
72. {
73. x = left + bitmapWidth - textWidth;
74. }
75. // 左邊界
76. else if (x <= left)
77. {
78. x = left;
79. }
80. }
81. else
82. {
83. // 右邊界
84. if (x >= windowWidth - textWidth)
85. {
86. x = windowWidth - textWidth;
87. }
88. // 左邊界
89. else if (x <= 0)
90. {
91. x = 0;
92. }
93. }
94. // 如果圖片高度小於屏幕高度
95. if (top + bitmapHeight < windowHeight)
96. {
97. // 下
98. if (y >= top + bitmapHeight)
99. {
100. y = top + bitmapHeight;
101. }
102. // 上
103. else if (y <= top + 10)
104. {
105. y = top + 10;
106. }
107. }
108. else
109. {
110. if (y >= windowHeight)
111. {
112. y = windowHeight;
113. }
114. else if (y <= 0)
115. {
116. y = 0;
117. }
118. }
120. // 添加字
121. canvas.drawText(text, x, y, paint);
122. return originalMap;
123. }
124. @Override
125. public boolean onTouchEvent(MotionEvent event)
126. {
127. if (event.getAction() == MotionEvent.ACTION_DOWN)
128. {
129. x = event.getX();
130. y = event.getY();
131. // 重繪
132. invalidate();
133. }
134. return true;
135. }
136. }

1. package xiaosi.GetTextImage;
3. import android.app.Activity;
4. import android.os.Bundle;
6. public class GetTextImageActivity extends Activity {
7. /** Called when the activity is first created. */
8. private GetTextImage get;
9. @Override
10. public void onCreate(Bundle savedInstanceState) {
11. super.onCreate(savedInstanceState);
12. get = new GetTextImage(this);
13. setContentView(get);
14. }
15. }