android - 在具有Android 10（Q）和targetSdkVersion = 29的ExoPlayer上播放歌曲的正确方法是什么？(What is the correct way to play songs on ExoPlayer with Android 10 (Q) and targetSdkVersion = 29?)

Question

With the recent changes on Android 10 (Q), trying to play a song from the user's device on an app (that targets sdk version 29 and runs Android 10 ) using ExoPlayer, prints the following log on the console and fails (the song is not played):

(随着Android 10（Q）的最新更改，尝试使用ExoPlayer在用户的设备上播放歌曲（目标版本为sdk版本29 ，运行Android 10 ），并在控制台上打印以下日志，但失败（歌曲为未播放）：)

E/libprocessgroup: Error encountered killing process cgroup uid 99420 pid 20294: Permission denied
    com.google.android.exoplayer2.upstream.FileDataSource$FileDataSourceException: java.io.FileNotFoundException: /storage/emulated/0/Music/Nirvana/[1989] - Bleach/01 - Blew.mp3: open failed: EACCES (Permission denied)
        at com.google.android.exoplayer2.upstream.FileDataSource.open(FileDataSource.java:73)
        at com.google.android.exoplayer2.upstream.DefaultDataSource.open(DefaultDataSource.java:257)
        at com.google.android.exoplayer2.upstream.StatsDataSource.open(StatsDataSource.java:83)
        at com.google.android.exoplayer2.source.ProgressiveMediaPeriod$ExtractingLoadable.load(ProgressiveMediaPeriod.java:939)
        at com.google.android.exoplayer2.upstream.Loader$LoadTask.run(Loader.java:394)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641)
        at java.lang.Thread.run(Thread.java:919)
     Caused by: java.io.FileNotFoundException: /storage/emulated/0/Music/Nirvana/[1989] - Bleach/01 - Blew.mp3: open failed: EACCES (Permission denied)
        at libcore.io.IoBridge.open(IoBridge.java:496)
        at java.io.RandomAccessFile.<init>(RandomAccessFile.java:289)
        at java.io.RandomAccessFile.<init>(RandomAccessFile.java:152)
        at com.google.android.exoplayer2.upstream.FileDataSource.open(FileDataSource.java:65)
        at com.google.android.exoplayer2.upstream.DefaultDataSource.open(DefaultDataSource.java:257) 
        at com.google.android.exoplayer2.upstream.StatsDataSource.open(StatsDataSource.java:83) 
        at com.google.android.exoplayer2.source.ProgressiveMediaPeriod$ExtractingLoadable.load(ProgressiveMediaPeriod.java:939) 
        at com.google.android.exoplayer2.upstream.Loader$LoadTask.run(Loader.java:394) 
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
        at java.lang.Thread.run(Thread.java:919) 
     Caused by: android.system.ErrnoException: open failed: EACCES (Permission denied)
        at libcore.io.Linux.open(Native Method)
        at libcore.io.ForwardingOs.open(ForwardingOs.java:167)
        at libcore.io.BlockGuardOs.open(BlockGuardOs.java:252)
        at libcore.io.ForwardingOs.open(ForwardingOs.java:167)
        at android.app.ActivityThread$AndroidOs.open(ActivityThread.java:7255)
        at libcore.io.IoBridge.open(IoBridge.java:482)
        at java.io.RandomAccessFile.<init>(RandomAccessFile.java:289) 
        at java.io.RandomAccessFile.<init>(RandomAccessFile.java:152) 
        at com.google.android.exoplayer2.upstream.FileDataSource.open(FileDataSource.java:65) 
        at com.google.android.exoplayer2.upstream.DefaultDataSource.open(DefaultDataSource.java:257) 
        at com.google.android.exoplayer2.upstream.StatsDataSource.open(StatsDataSource.java:83) 
        at com.google.android.exoplayer2.source.ProgressiveMediaPeriod$ExtractingLoadable.load(ProgressiveMediaPeriod.java:939) 
        at com.google.android.exoplayer2.upstream.Loader$LoadTask.run(Loader.java:394) 
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1167) 
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:641) 
        at java.lang.Thread.run(Thread.java:919) 

One way that I found on the Internet to solve that problem is to add the following attribute on the Manifest's <application> tag:

(我在Internet上找到的解决该问题的方法之一是在清单的<application>标记上添加以下属性：)

android:requestLegacyExternalStorage="true"

The problem with that solution is that it seems to be temporary and might get deprecated soon.

(该解决方案的问题在于它似乎是临时的，可能很快就会弃用。)

---

What is the correct way to deal with those changes under those specifications?

(在这些规范下应对这些更改的正确方法是什么？)

  ask by Augusto Carmo translate from so

Answer 1

See https://stackoverflow.com/a/59037794/2373819

(参见https://stackoverflow.com/a/59037794/2373819)

But looking at the Exoplayer Source Code.

(但是看一下Exoplayer源代码。)

https://github.com/google/ExoPlayer/blob/release-v2/library/core/src/main/java/com/google/android/exoplayer2/upstream/FileDataSource.java

(https://github.com/google/ExoPlayer/blob/release-v2/library/core/src/main/java/com/google/android/exoplayer2/upstream/FileDataSource.java)

Says

(说)

file = new RandomAccessFile(dataSpec.uri.getPath(), "r");

And in API 29 and above file paths are not accessible in public files.

(在API 29及更高版本中，公共文件中不能访问文件路径。)

You should raise a bug in ExoPlayer to use Java a fileDescriptor from a contentresolver instead

(您应该在ExoPlayer中引发一个错误，以使用Java从contentresolver使用fileDescriptor)