MediaStore - 功能无法找到所有歌曲

Question

我有来自developer.android的这个功能，但它找不到所有歌曲，只有少数。请给我一些线索。

public void getAllSongs() {
    ContentResolver contentResolver = getContentResolver();
    Uri uri = android.provider.MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
    Cursor cursor = contentResolver.query(uri, null, null, null, null);
    if (cursor == null) {
        // query failed, handle error.
    } else if (!cursor.moveToFirst()) {
        // no media on the device
    } else {
        int titleColumn = cursor.getColumnIndex(android.provider.MediaStore.Audio.Media.TITLE);
        int idColumn = cursor.getColumnIndex(android.provider.MediaStore.Audio.Media._ID);
        do {
            long thisId = cursor.getLong(idColumn);
            String thisTitle = cursor.getString(titleColumn);
            songs.add(thisId + "||"+thisTitle);// ...process entry...
        } while (cursor.moveToNext());
    }
}

Answer 1

我使用以下内容获取所有曲目：

using NAudio.CoreAudioApi;
using NAudio.Wave;
using System;
using System.Collections.Generic;
using System.Windows;

namespace WpfApp2
{
    /// <summary>
    /// Interaction logic for MainWindow.xaml
    /// </summary>
    public partial class MainWindow : Window
    {
        public MainWindow()
        {
            InitializeComponent();

            foreach (KeyValuePair<string, MMDevice> device in GetInputAudioDevices())
            {
                Console.WriteLine("Name: {0}, State: {1}", device.Key, device.Value.State);
            }
        }

        public Dictionary<string, MMDevice> GetInputAudioDevices()
        {
            Dictionary<string, MMDevice> retVal = new Dictionary<string, MMDevice>();
            MMDeviceEnumerator enumerator = new MMDeviceEnumerator();
            int waveInDevices = WaveIn.DeviceCount;
            for (int waveInDevice = 0; waveInDevice < waveInDevices; waveInDevice++)
            {
                WaveInCapabilities deviceInfo = WaveIn.GetCapabilities(waveInDevice);
                foreach (MMDevice device in enumerator.EnumerateAudioEndPoints(DataFlow.Capture, DeviceState.All))
                {
                    if (device.FriendlyName.StartsWith(deviceInfo.ProductName))
                    {
                        retVal.Add(device.FriendlyName, device);
                        break;
                    }
                }
            }

            return retVal;
        }
    }
}