Android通过ContentProvider传输文件

我们知道Android两个应用程序之间进行数据交互需要通过ContentProvider，而且通常都是数据库的操作。
今天项目需要使用Android的ContentProvider交互普通SD卡上的文件，于是我写了这个小例子：
AndroidManifest.xml

[html]
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.h3c.test"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk android:minSdkVersion="15" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

    <application
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name" >
        <activity
            android:label="@string/app_name"
            android:name=".NotepadTestActivity" >
            <intent-filter >
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <provider android:name=".TestContentProvider" android:authorities="com.h3c.test" />
    </application>

</manifest>

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.h3c.test"
    android:versionCode="1"
    android:versionName="1.0" >

<uses-sdk android:minSdkVersion="15" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"/>

</manifest>
TestContentProvider.java
[java]
package com.h3c.test;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.util.ArrayList;

import android.content.ContentProvider;
import android.content.ContentProviderOperation;
import android.content.ContentProviderResult;
import android.content.ContentValues;
import android.content.OperationApplicationException;
import android.content.res.AssetFileDescriptor;
import android.database.Cursor;
import android.net.Uri;
import android.os.Environment;
import android.os.ParcelFileDescriptor;
import android.util.Log;

public class TestContentProvider extends ContentProvider {

    @Override
    public int delete(Uri uri, String selection, String[] selectionArgs) {
        // TODO Auto-generated method stub
        Log.e("H3c", "delete");
        return 0;
    }

    @Override
    public String getType(Uri uri) {
        // TODO Auto-generated method stub
        Log.e("H3c", "gettype");
        return null;
    }

    @Override
    public Uri insert(Uri uri, ContentValues values) {
        // TODO Auto-generated method stub
        Log.e("H3c", "insert");
        return null;
    }

    @Override
    public boolean onCreate() {
        // TODO Auto-generated method stub
        Log.e("H3c", "create");
        return false;
    }

    @Override
    public Cursor query(Uri uri, String[] projection, String selection,
            String[] selectionArgs, String sortOrder) {
        // TODO Auto-generated method stub
        Log.e("H3c", "query");
        return null;
    }

    @Override
    public int update(Uri uri, ContentValues values, String selection,
            String[] selectionArgs) {
        // TODO Auto-generated method stub
        Log.e("H3c", "update");
  &nb

补充：移动开发 , Android ,