从扩展文件读取MP3(Reading mp3 from expansion file)

从扩展文件读取MP3文件

我创建一个名称和扩展文件

“main.1.com.example.app.obb”

它包含音频文件名“about_eng.mp3”

现在的问题我写了下面的代码读取和播放MP3文件

    private final static String EXP_PATH = "/Android/obb/";

static String[] getAPKExpansionFiles(Context ctx, int mainVersion, int patchVersion) {
    String packageName = ctx.getPackageName();
    Vector<String> ret = new Vector<String>();
    if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {
        // Build the full path to the app's expansion files
        File root = Environment.getExternalStorageDirectory();
        File expPath = new File(root.toString() + EXP_PATH + packageName);

        // Check that expansion file path exists
        if (expPath.exists()) {
            if ( mainVersion > 0 ) {
                String strMainPath = expPath + File.separator + "main." +
                        mainVersion + "." + packageName + ".obb";
                File main = new File(strMainPath);
                if ( main.isFile() ) {
                        ret.add(strMainPath);
                }
            }
            if ( patchVersion > 0 ) {
                String strPatchPath = expPath + File.separator + "patch." +
                        mainVersion + "." + packageName + ".obb";
                File main = new File(strPatchPath);
                if ( main.isFile() ) {
                        ret.add(strPatchPath);
                }
            }
        }
    }
    String[] retArray = new String[ret.size()];
    ret.toArray(retArray);
    return retArray;
}
@Override
protected void onCreate(Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onCreate(savedInstanceState);
    // Get a ZipResourceFile representing a merger of both the main and patch files

    try {
        ZipResourceFile expansionFile = APKExpansionSupport.getAPKExpansionZipFile(this,1,1);
        if(expansionFile!=null){

            AssetFileDescriptor fd = expansionFile.getAssetFileDescriptor("about_eng.mp3");
                //or
            MediaPlayer mediaPlayer = new MediaPlayer();
            mediaPlayer.setDataSource( fd.getFileDescriptor(), 
                    fd.getStartOffset(),fd.getLength());
            mediaPlayer.prepare();
            mediaPlayer.start();

            }




    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }

    // Get an input stream for a known file inside the expansion file ZIPs


}

但是，在这条线总是抛出异常

 mediaPlayer.setDataSource( fd.getFileDescriptor(), 
                    fd.getStartOffset(),fd.getLength());
            mediaPlayer.prepare();

因为变量fd是空。

任何机构可以帮我解决这个

Answer 1:

我用Google搜索，发现我们shold不得不作出的.zip用0% (No compression)是在提及http://developer.android.com/google/play/expansion-files.html

Tip: If you're packaging media files into a ZIP, you can use media playback calls on the files with offset and length controls (such as MediaPlayer.setDataSource() and SoundPool.load()) without the need to unpack your ZIP. In order for this to work, you must not perform additional compression on the media files when creating the ZIP packages. For example, when using the zip tool, you should use the -n option to specify the file suffixes that should not be compressed: zip -n .mp4;.ogg main_expansion media_files

所以如何用winrar制作0％压缩ZIP？

看到这里的压缩方法

所以我们应该要上传此拉链在Play商店。

所以你不需要使用ZipHelper.java是在其他SO答复中提到

只是简单地使用

ZipResourceFile expansionFile=null;

            try {
                expansionFile = APKExpansionSupport.getAPKExpansionZipFile(getApplicationContext(),3,0);

                     AssetFileDescriptor fd = expansionFile.getAssetFileDescriptor("test.mp3");
                     MediaPlayer mPlayer = new MediaPlayer();
                     mPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
                     mPlayer.setDataSource(fd.getFileDescriptor(),fd.getStartOffset(),fd.getLength());
                     mPlayer.prepare();
                     mPlayer.start();

            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

Answer 2:

尝试使用expansionFile.getAssetFileDescriptor("main_expansion/about_eng.mp3")

如果它不工作，调用此：

ZipResourceFile.ZipEntryRO [] entries = expansionFile.getAllEntries();

并期待在文件名：

entries[0].mFileName; 。

这可能是一个暗示的路径应该是什么样子等。

我知道这个问题是旧的，但也许它可以帮助别人。

Answer 3:

要读取MP3，与媒体播放器，你可以做到这3种方式

例如。 我的应用程序包的名字是

com.bluewindsolution.android.sampleapp

那么我的扩展文件

main.1.com.bluewindsolution.android.sampleapp.obb

详细，你可以跟随在这里

。[主|补丁] <扩充版本> <包名称> .obb

---

从扩展您可以通过3种方式获得它：

通过AssetFileDescriptor

// this one work with image file, media file
// Get a ZipResourceFile representing a specific expansion file
// mainContext, version no. of your main expansion, version no of your patch
ZipResourceFile expansionFile = APKExpansionSupport.getAPKExpansionZipFile(this, 1, 0); 
AssetFileDescriptor afd_img1 = expansionFile.getAssetFileDescriptor("your_path/your_file.jpg");
AssetFileDescriptor afd_mpbg = expansionFile.getAssetFileDescriptor("your_path/your_file.mp3");

// to set image
ImageView imageView1 = (ImageView)findViewById(R.id.iv1); 
imageView1.setImageBitmap(BitmapFactory.decodeFileDescriptor(afd_iv1.getFileDescriptor()));

// to set sound
try {
    mpbg.setDataSource(afd_mpbg.getFileDescriptor(), afd_mpbg.getStartOffset(), afd_mpbg.getDeclaredLength());
    mpbg.prepareAsync();
    mpbg.start();
} catch (IllegalStateException e) {
    Log.w("Error=====", "Failed to prepare media player", e);
}

---

通过的InputStream

// this one work with image file, media file
// Get a ZipResourceFile representing a specific expansion file

ZipResourceFile expansionFile = new ZipResourceFile(filePathToMyZip);

// Get an input stream for a known file inside the expansion file ZIPs

InputStream fileStream = expansionFile.getInputStream(pathToFileInsideZip);

---

通过乌里

//this one can use in almost thing such as jpg, mp3, mp4, pdf, etc.

//you need to create new class to override APEZProvider
public class ZipFileContentProvider extends APEZProvider {
    @Override
    public String getAuthority() {
        return "com.bluewindsolution.android.sampleapp";
    }
}

//you need to add <provider> in AndroidManifest.xml
<provider
 android:name="com.bluewindsolution.android.sampleapp.ZipFileContentProvider"
   android:authorities="com.bluewindsolution.android.sampleapp" 
      android:exported="false"
      android:multiprocess="true"
    >
    <meta-data android:name="mainVersion"
              android:value="1"></meta-data>
</provider>

//after that you can use it any time by this code:
String filename2 = "image/i_commu_a_1_1_1_1.jpg"; // suppose you store put your file in directory in .obb
String uriString2 = "content://com.bluewindsolution.android.sampleapp" +  File.separator + filename2;
Uri uri2 = Uri.parse(uriString2);
imageView2.setImageURI(uri2);

// Filename inside my expansion file
String filename = "video/v_do_1_1_1.mp4"; // suppose you store put your file in directory in .obb
String uriString = "content://com.bw.sample_extension_download_main" +  File.separator + filename;
Uri uri = Uri.parse(uriString);

v1 = (VideoView)findViewById(R.id.videoView1);
v1.setVideoURI(uri);
v1.start();

文章来源: Reading mp3 from expansion file