Question

我希望在我的应用上有一个ListView，它会填充我外部存储设备上的所有mp3文件。

这是onCreate方法中的代码。

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    mListView = (ListView) findViewById(R.id.listView1);
    List<DoubleString> mList = new ArrayList<DoubleString>();
    String selection = MediaStore.Audio.Media.IS_MUSIC + " != 0";
    final String sortOrder = MediaStore.Audio.AudioColumns.TITLE;
    ContentResolver resolver = getContentResolver();
    Uri uri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
    Cursor cursor = resolver.query(uri, null, selection, null, sortOrder);
    if (cursor != null && cursor.moveToFirst()) {
        int id = cursor.getColumnIndex(MediaStore.Audio.Media._ID);
        int title = cursor.getColumnIndex(MediaStore.Audio.Media.TITLE);
        int artist = cursor.getColumnIndex(MediaStore.Audio.Media.ARTIST);
        int data = cursor.getColumnIndex(MediaStore.Audio.Media.DATA);
        do {
            long mId = cursor.getLong(id);
            String mTitle = cursor.getString(title);
            String mArtist = cursor.getString(artist);
            String mData = cursor.getString(data);
            MediaMetadataRetriever retriever = new MediaMetadataRetriever();
            retriever.setDataSource(mData);
            String mimeType = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_MIMETYPE);
            if (mimeType == "audio/mpeg") {
                mList.add(new DoubleString(mId, mTitle, mArtist, mData));
            }
        }
        while (cursor.moveToNext());
    }
    final DoubleStringAdapter adapter = new DoubleStringAdapter(this, mList);
    mListView.setAdapter(adapter);

但ListView返回null，即不会在ListView上填充任何内容。

所以我的问题是：

我的代码是否适用于过滤？
或是否有任何方法可以使用MediaStore＆amp; MediaMetadataRetriever？

Answer 1

您可以通过以下使用MediaStore的代码来执行此操作。请添加外部存储权限。机器人：名称= “android.permission.WRITE_EXTERNAL_STORAGE”

代码是 -

public ArrayList<HashMap<String, String>> getSDCardAudioFiles() {
        // if you want  file path and additional details
        ArrayList<HashMap<String, String>> audioFilesDetailList = new ArrayList<HashMap<String, String>>();
        // if you want only file path
        ArrayList<String> audioFilePath =new ArrayList<String>();
        // if you want only file name
        ArrayList<String> audioFileName =new ArrayList<String>();
            Cursor mCursor = getContentResolver().query(
                    MediaStore.Audio.Media.EXTERNAL_CONTENT_URI,
                    new String[] { MediaStore.Audio.Media.DISPLAY_NAME,
                            MediaStore.Audio.Media.DATA }, null, null, null);

            int count = mCursor.getCount();

            HashMap<String, String> audioFileMap;
            while (mCursor.moveToNext()) {
                audioFileMap = new HashMap<String, String>();
                audioFileMap.put("FileName",mCursor.getString(mCursor
                                .getColumnIndexOrThrow(MediaStore.Audio.Media.DISPLAY_NAME)));
                audioFileMap.put("FilePath", mCursor.getString(mCursor
                        .getColumnIndexOrThrow(MediaStore.Audio.Media.DATA)));
                if(audioFileMap.get("FileName").endsWith(".mp3")){
                    audioFilesDetailList.add(audioFileMap);

                    // if you want only file path
                    audioFilePath.add(audioFileMap.get("FilePath"));
                     // if you want only file name 
                    audioFileName.add(audioFileMap.get("FileName"));
                }
            }
            mCursor.close();
            //return the arraylist whichever u needed
            return audioFilesDetailList;
        }

使用MediaStore＆amp; amp;过滤来自其他媒体文件的mp3文件MediaMetadataRetriever？

1 个答案: