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

[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"/>

    <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>
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"); 
        return 0; 
    } 
 
    @Override 
    public AssetFileDescriptor openAssetFile(Uri uri, String mode) 
            throws FileNotFoundException { 
        // TODO Auto-generated method stub  
        Log.e("H3c", "openAssetFile"); 
        return super.openAssetFile(uri, mode); 
    } 
 
    //此方法非常重要，一定要重寫，否則默認報FileNotFound異常  
    @Override 
    public ParcelFileDescriptor openFile(Uri uri, String mode) 
            throws FileNotFoundException { 
        // TODO Auto-generated method stub  
        File root = Environment.getExternalStorageDirectory(); 
        root.mkdirs(); 
        File path = new File(root, uri.getEncodedPath()); 
 
        Log.e("H3c", "opeFile:"+path); 
        int imode = 0; 
        if (mode.contains("w")) { 
            imode |= ParcelFileDescriptor.MODE_WRITE_ONLY; 
            if (!path.exists()) { 
                try { 
                    path.createNewFile(); 
                } catch (IOException e) { 
                    e.printStackTrace(); 
                } 
            } 
        } 
        if (mode.contains("r")) 
            imode |= ParcelFileDescriptor.MODE_READ_ONLY; 
        if (mode.contains("+")) 
            imode |= ParcelFileDescriptor.MODE_APPEND; 
 
        return ParcelFileDescriptor.open(path, imode); 
    } 
 
} 

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");
        return 0;
    }

    @Override
    public AssetFileDescriptor openAssetFile(Uri uri, String mode)
            throws FileNotFoundException {
        // TODO Auto-generated method stub
        Log.e("H3c", "openAssetFile");
        return super.openAssetFile(uri, mode);
    }

    //此方法非常重要，一定要重寫，否則默認報FileNotFound異常
    @Override
    public ParcelFileDescriptor openFile(Uri uri, String mode)
            throws FileNotFoundException {
        // TODO Auto-generated method stub
        File root = Environment.getExternalStorageDirectory();
        root.mkdirs();
        File path = new File(root, uri.getEncodedPath());

        Log.e("H3c", "opeFile:"+path);
        int imode = 0;
        if (mode.contains("w")) {
            imode |= ParcelFileDescriptor.MODE_WRITE_ONLY;
            if (!path.exists()) {
                try {
                    path.createNewFile();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        if (mode.contains("r"))
            imode |= ParcelFileDescriptor.MODE_READ_ONLY;
        if (mode.contains("+"))
            imode |= ParcelFileDescriptor.MODE_APPEND;

        return ParcelFileDescriptor.open(path, imode);
    }

}

NotepadTestActivity.java
[java]
package com.h3c.test; 
 
import java.io.File; 
import java.io.FileInputStream; 
import java.io.FileNotFoundException; 
import java.io.FileOutputStream; 
import java.io.IOException; 
import java.io.InputStream; 
import java.io.OutputStream; 
import java.lang.reflect.InvocationTargetException; 
import java.lang.reflect.Method; 
 
import android.app.Activity; 
import android.content.Context; 
import android.content.pm.PackageManager.NameNotFoundException; 
import android.content.res.AssetFileDescriptor; 
import android.net.Uri; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
 
public class NotepadTestActivity extends Activity { 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
        // TODO Auto-generated method stub  
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.notepad); 
 
        Button button = (Button) findViewById(R.id.notepad); 
        button.setOnClickListener(new OnClickListener() { 
 
            @Override 
            public void onClick(View v) { 
                try { 
                    // 直接讀文件  
                    // InputStream is = getContentResolver().openInputStream(  
                    // Uri.parse("file:/mnt/sdcard/h3c.txt"));  
                    //  
                    // File bkFile = new File("/mnt/sdcard/h3c2.txt");  
                    // if (!bkFile.exists()) {  
                    // bkFile.createNewFile();  
                    // }  
                    //                      
                    // FileOutputStream out = new FileOutputStream(bkFile);  
                    // byte[] b = new byte[1024 * 5]; // 5KB  
                    // int len;  
                    // while ((len = is.read(b)) != -1) {  
                    // out.write(b, 0, len);  
                    // }  
                    // out.flush();  
                    // is.close();  
                    // out.close();  
 
                    // 直接寫文件  
                    // OutputStream out = getContentResolver().openOutputStream(  
                    // Uri.parse("file:/mnt/sdcard/h3c.txt"));  
                    // FileInputStream in = new FileInputStream(new File(  
                    // "/mnt/sdcard/h3c3.txt"));  
                    //  
                    // byte[] b = new byte[1024 * 5]; // 5KB  
                    // int len;  
                    // while ((len = in.read(b)) != -1) {  
                    // out.write(b, 0, len);  
                    // }  
                    // out.flush();  
                    //                      
                    // in.close();  
                    // out.close();  
 
                    // 內容流寫  
                    // AssetFileDescriptor afd = getContentResolver()  
                    // .openAssetFileDescriptor(  
                    // Uri.parse("content://com.h3c.test/h3c.txt"),  
                    // "wr");  
                    // InputStream in = afd.createInputStream();  
                    // File bkFile = new File("/mnt/sdcard/h3c2.txt");  
                    // if (!bkFile.exists()) {  
                    // bkFile.createNewFile();  
                    // }  
                    //  
                    // FileOutputStream out = new FileOutputStream(bkFile);  
                    // byte[] b = new byte[1024 * 5]; // 5KB  
                    // int len;  
                    // while ((len = in.read(b)) != -1) {  
                    // out.write(b, 0, len);  
                    // }  
                    // out.flush();  
                    // in.close();  
                    // out.close();  
 
                    // 內容流讀  
                    AssetFileDescriptor afd = getContentResolver() 
                            .openAssetFileDescriptor( 
                                    Uri.parse("content://com.h3c.test/h3c.txt"), 
                                    "wr"); 
                    OutputStream out = afd.createOutputStream(); 
                    FileInputStream in = new FileInputStream(new File( 
                            "/mnt/sdcard/h3c2.txt")); 
 
                    byte[] b = new byte[1024 * 5]; // 5KB  
                    int len; 
                    while ((len = in.read(b)) != -1) { 
                        out.write(b, 0, len); 
                    } 
                    out.flush(); 
 
                    in.close(); 
                    out.close(); 
                } catch (FileNotFoundException e) { 
                    e.printStackTrace(); 
                } catch (IOException e) { 
                    e.printStackTrace(); 
                } 
            } 
        }); 
 
    } 
} 

package com.h3c.test;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

import android.app.Activity;
import android.content.Context;
import android.content.pm.PackageManager.NameNotFoundException;
import android.content.res.AssetFileDescriptor;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class NotepadTestActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.notepad);

        Button button = (Button) findViewById(R.id.notepad);
        button.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                try {
                    // 直接讀文件
                    // InputStream is = getContentResolver().openInputStream(
                    // Uri.parse("file:/mnt/sdcard/h3c.txt"));
                    //
                    // File bkFile = new File("/mnt/sdcard/h3c2.txt");
                    // if (!bkFile.exists()) {
                    // bkFile.createNewFile();
                    // }
                    //                   
                    // FileOutputStream out = new FileOutputStream(bkFile);
                    // byte[] b = new byte[1024 * 5]; // 5KB
                    // int len;
                    // while ((len = is.read(b)) != -1) {
                    // out.write(b, 0, len);
                    // }
                    // out.flush();
                    // is.close();
                    // out.close();

                    // 直接寫文件
                    // OutputStream out = getContentResolver().openOutputStream(
                    // Uri.parse("file:/mnt/sdcard/h3c.txt"));
                    // FileInputStream in = new FileInputStream(new File(
                    // "/mnt/sdcard/h3c3.txt"));
                    //
                    // byte[] b = new byte[1024 * 5]; // 5KB
                    // int len;
                    // while ((len = in.read(b)) != -1) {
                    // out.write(b, 0, len);
                    // }
                    // out.flush();
                    //                   
                    // in.close();
                    // out.close();

                    // 內容流寫
                    // AssetFileDescriptor afd = getContentResolver()
                    // .openAssetFileDescriptor(
                    // Uri.parse("content://com.h3c.test/h3c.txt"),
                    // "wr");
                    // InputStream in = afd.createInputStream();
                    // File bkFile = new File("/mnt/sdcard/h3c2.txt");
                    // if (!bkFile.exists()) {
                    // bkFile.createNewFile();
                    // }
                    //
                    // FileOutputStream out = new FileOutputStream(bkFile);
                    // byte[] b = new byte[1024 * 5]; // 5KB
                    // int len;
                    // while ((len = in.read(b)) != -1) {
                    // out.write(b, 0, len);
                    // }
                    // out.flush();
                    // in.close();
                    // out.close();

                    // 內容流讀
                    AssetFileDescriptor afd = getContentResolver()
                            .openAssetFileDescriptor(
                                    Uri.parse("content://com.h3c.test/h3c.txt"),
                                    "wr");
                    OutputStream out = afd.createOutputStream();
                    FileInputStream in = new FileInputStream(new File(
                            "/mnt/sdcard/h3c2.txt"));

                    byte[] b = new byte[1024 * 5]; // 5KB
                    int len;
                    while ((len = in.read(b)) != -1) {
                        out.write(b, 0, len);
                    }
                    out.flush();

                    in.close();
                    out.close();
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        });

    }
}

 作者：h3c4lenovo