Android通過ContentProvider傳輸文件

我們知道Android兩個應用程序之間進行數據交互需要通過ContentProvider，而且通常都是數據庫的操作。
今天項目需要使用Android的ContentProvider交互普通SD卡上的文件，於是我寫了這個小例子：

AndroidManifest.xml

1. <?xml version="1.0" encoding="utf-8"?>
2. <manifest xmlns:android="http://schemas.android.com/apk/res/android"
3. package="com.h3c.test"
4. android:versionCode="1"
5. android:versionName="1.0" >
7. <uses-sdk android:minSdkVersion="15" />
8. <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>
10. <application
11. android:icon="@drawable/ic_launcher"
12. android:label="@string/app_name" >
13. <activity
14. android:label="@string/app_name"
15. android:name=".NotepadTestActivity" >
16. <intent-filter >
17. <action android:name="android.intent.action.MAIN" />
19. <category android:name="android.intent.category.LAUNCHER" />
20. </intent-filter>
21. </activity>
23. <provider android:name=".TestContentProvider" android:authorities="com.h3c.test" />
24. </application>
26. </manifest>

1. package com.h3c.test;
3. import java.io.File;
4. import java.io.FileNotFoundException;
5. import java.io.IOException;
6. import java.util.ArrayList;
8. import android.content.ContentProvider;
9. import android.content.ContentProviderOperation;
10. import android.content.ContentProviderResult;
11. import android.content.ContentValues;
12. import android.content.OperationApplicationException;
13. import android.content.res.AssetFileDescriptor;
14. import android.database.Cursor;
15. import android.net.Uri;
16. import android.os.Environment;
17. import android.os.ParcelFileDescriptor;
18. import android.util.Log;
20. public class TestContentProvider extends ContentProvider {
22. @Override
23. public int delete(Uri uri, String selection, String[] selectionArgs) {
24. // TODO Auto-generated method stub
25. Log.e("H3c", "delete");
26. return 0;
27. }
29. @Override
30. public String getType(Uri uri) {
31. // TODO Auto-generated method stub
32. Log.e("H3c", "gettype");
33. return null;
34. }
36. @Override
37. public Uri insert(Uri uri, ContentValues values) {
38. // TODO Auto-generated method stub
39. Log.e("H3c", "insert");
40. return null;
41. }
43. @Override
44. public boolean onCreate() {
45. // TODO Auto-generated method stub
46. Log.e("H3c", "create");
47. return false;
48. }
50. @Override
51. public Cursor query(Uri uri, String[] projection, String selection,
52. String[] selectionArgs, String sortOrder) {
53. // TODO Auto-generated method stub
54. Log.e("H3c", "query");
55. return null;
56. }
58. @Override
59. public int update(Uri uri, ContentValues values, String selection,
60. String[] selectionArgs) {
61. // TODO Auto-generated method stub
62. Log.e("H3c", "update");
63. return 0;
64. }
66. @Override
67. public AssetFileDescriptor openAssetFile(Uri uri, String mode)
68. throws FileNotFoundException {
69. // TODO Auto-generated method stub
70. Log.e("H3c", "openAssetFile");
71. return super.openAssetFile(uri, mode);
72. }
74. //此方法非常重要，一定要重寫，否則默認報FileNotFound異常
75. @Override
76. public ParcelFileDescriptor openFile(Uri uri, String mode)
77. throws FileNotFoundException {
78. // TODO Auto-generated method stub
79. File root = Environment.getExternalStorageDirectory();
80. root.mkdirs();
81. File path = new File(root, uri.getEncodedPath());
83. Log.e("H3c", "opeFile:"+path);
84. int imode = 0;
85. if (mode.contains("w")) {
86. imode |= ParcelFileDescriptor.MODE_WRITE_ONLY;
87. if (!path.exists()) {
88. try {
89. path.createNewFile();
90. } catch (IOException e) {
91. e.printStackTrace();
92. }
93. }
94. }
95. if (mode.contains("r"))
96. imode |= ParcelFileDescriptor.MODE_READ_ONLY;
97. if (mode.contains("+"))
98. imode |= ParcelFileDescriptor.MODE_APPEND;
100. return ParcelFileDescriptor.open(path, imode);
101. }
103. }

1. package com.h3c.test;
3. import java.io.File;
4. import java.io.FileInputStream;
5. import java.io.FileNotFoundException;
6. import java.io.FileOutputStream;
7. import java.io.IOException;
8. import java.io.InputStream;
9. import java.io.OutputStream;
10. import java.lang.reflect.InvocationTargetException;
11. import java.lang.reflect.Method;
13. import android.app.Activity;
14. import android.content.Context;
15. import android.content.pm.PackageManager.NameNotFoundException;
16. import android.content.res.AssetFileDescriptor;
17. import android.net.Uri;
18. import android.os.Bundle;
19. import android.util.Log;
20. import android.view.View;
21. import android.view.View.OnClickListener;
22. import android.widget.Button;
24. public class NotepadTestActivity extends Activity {
25. @Override
26. protected void onCreate(Bundle savedInstanceState) {
27. // TODO Auto-generated method stub
28. super.onCreate(savedInstanceState);
29. setContentView(R.layout.notepad);
31. Button button = (Button) findViewById(R.id.notepad);
32. button.setOnClickListener(new OnClickListener() {
34. @Override
35. public void onClick(View v) {
36. try {
37. // 直接讀文件
38. // InputStream is = getContentResolver().openInputStream(
39. // Uri.parse("file:/mnt/sdcard/h3c.txt"));
40. //
41. // File bkFile = new File("/mnt/sdcard/h3c2.txt");
42. // if (!bkFile.exists()) {
43. // bkFile.createNewFile();
44. // }
45. //
46. // FileOutputStream out = new FileOutputStream(bkFile);
47. // byte[] b = new byte[1024 * 5]; // 5KB
48. // int len;
49. // while ((len = is.read(b)) != -1) {
50. // out.write(b, 0, len);
51. // }
52. // out.flush();
53. // is.close();
54. // out.close();
56. // 直接寫文件
57. // OutputStream out = getContentResolver().openOutputStream(
58. // Uri.parse("file:/mnt/sdcard/h3c.txt"));
59. // FileInputStream in = new FileInputStream(new File(
60. // "/mnt/sdcard/h3c3.txt"));
61. //
62. // byte[] b = new byte[1024 * 5]; // 5KB
63. // int len;
64. // while ((len = in.read(b)) != -1) {
65. // out.write(b, 0, len);
66. // }
67. // out.flush();
68. //
69. // in.close();
70. // out.close();
72. // 內容流寫
73. // AssetFileDescriptor afd = getContentResolver()
74. // .openAssetFileDescriptor(
75. // Uri.parse("content://com.h3c.test/h3c.txt"),
76. // "wr");
77. // InputStream in = afd.createInputStream();
78. // File bkFile = new File("/mnt/sdcard/h3c2.txt");
79. // if (!bkFile.exists()) {
80. // bkFile.createNewFile();
81. // }
82. //
83. // FileOutputStream out = new FileOutputStream(bkFile);
84. // byte[] b = new byte[1024 * 5]; // 5KB
85. // int len;
86. // while ((len = in.read(b)) != -1) {
87. // out.write(b, 0, len);
88. // }
89. // out.flush();
90. // in.close();
91. // out.close();
93. // 內容流讀
94. AssetFileDescriptor afd = getContentResolver()
95. .openAssetFileDescriptor(
96. Uri.parse("content://com.h3c.test/h3c.txt"),
97. "wr");
98. OutputStream out = afd.createOutputStream();
99. FileInputStream in = new FileInputStream(new File(
100. "/mnt/sdcard/h3c2.txt"));
102. byte[] b = new byte[1024 * 5]; // 5KB
103. int len;
104. while ((len = in.read(b)) != -1) {
105. out.write(b, 0, len);
106. }
107. out.flush();
109. in.close();
110. out.close();
111. } catch (FileNotFoundException e) {
112. e.printStackTrace();
113. } catch (IOException e) {
114. e.printStackTrace();
115. }
116. }
117. });
119. }
120. }