[Android SQLite]數據存儲與訪問 - 外部存儲

接下來就到SD卡了吧 ^_^

不是所有的手機都有SD卡,但是Android系統本身提供了對SD卡很便捷的訪問方法

相關閱讀：

[Android SQLite]數據存儲與訪問 - 內部存儲 http://www.linuxidc.com/Linux/2011-12/50130.htm

[Android SQLite]數據存儲與訪問 - SharedPreferences http://www.linuxidc.com/Linux/2011-12/50131.htm

一般下載的數據都比較大就都放到SD卡了...具體原因,未知 哈哈

1. public class SD_Demo extends Activity implements OnClickListener
2. {
3. private StringBuilder randomNumBersString = null;
5. private TextView displayView = null;
7. @Override
8. protected void onCreate(Bundle savedInstanceState)
9. {
10. super.onCreate(savedInstanceState);
11. setContentView(R.layout.main1);
12. setupViews();
13. }
15. private void setupViews()
16. {
17. displayView = (TextView) findViewById(R.id.display);
18. findViewById(R.id.random).setOnClickListener(this);
19. findViewById(R.id.write).setOnClickListener(this);
20. randomNumBersString = new StringBuilder();
21. }
23. @Override
24. public void onClick(View v)
25. {
26. switch (v.getId())
27. {
28. case R.id.random:
29. for (int i = 0; i < 10; i++)
30. {
31. randomNumBersString.append(Math.random()+"\n");
32. }
33. displayView.setText(randomNumBersString.toString());
34. break;
36. case R.id.write:
37. String fileName = "SdcardFile-"+System.currentTimeMillis()+".txt";;
38. boolean sdCardExist = Environment.getExternalStorageState().equals(android.os.Environment.MEDIA_MOUNTED);
39. File dir = null;
40. if (sdCardExist)
41. {
42. dir = new File( Environment.getExternalStorageDirectory().toString() + File.separator + "123321");
43. if (!dir.exists())
44. {
45. dir.mkdirs();
46. }
47. }
48. if (dir.exists() && dir.canWrite())
49. {
50. File newFile = new File(dir.getAbsolutePath()+ "/" + fileName);
51. FileOutputStream fos = null;
52. try
53. {
54. newFile.createNewFile();
55. if (newFile.exists() && newFile.canWrite())
56. {
57. fos = new FileOutputStream(newFile);
58. fos.write(randomNumBersString.toString().getBytes());
59. displayView.setText(String.format("%s文件寫入SD卡", fileName)) ;
60. }
61. } catch (IOException e)
62. {
63. e.printStackTrace();
64. }finally
65. {
66. if (fos != null)
67. {
68. try
69. {
70. fos.flush();
71. fos.close();
72. } catch (IOException e)
73. {
74. e.printStackTrace();
75. }
76. }
77. }
78. }
79. break;
80. }
81. }
82. }