java - 无法创建目录

Question

我正在尝试将下载的文件写入存储，但出现错误。这是我的代码 -

request.setDestinationInExternalPublicDir("/songs", "name-of-the-file.mp3");

日志 -

03-25 12:40:47.230 10480-10480/com.xxxx.ytm.yyyy E/AndroidRuntime: FATAL EXCEPTION: main

Process: com.xxxx.ytm.yyyy, PID: 10480
java.lang.IllegalStateException: Unable to create directory: /storage/emulated/0/songs

    at android.app.DownloadManager$Request.setDestinationInExternalPublicDir(DownloadManager.java:538)
    at com.antimatter.ytm.youtubemp3.MainActivity$1.onClick(MainActivity.java:84)
    at android.view.View.performClick(View.java:5198)
    at android.view.View$PerformClick.run(View.java:21147)
    at android.os.Handler.handleCallback(Handler.java:739)
    at android.os.Handler.dispatchMessage(Handler.java:95)
    at android.os.Looper.loop(Looper.java:148)
    at android.app.ActivityThread.main(ActivityThread.java:5417)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)

为了记录，这是代码的其余部分 -

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
// To work and download on main thread

DownloadManager.Request request = new DownloadManager.Request(Uri.parse(downl));
request.setDestinationInExternalPublicDir("/songs", "name-of-the-file.mp3");

DownloadManager manager = (DownloadManager) getSystemService(Context.DOWNLOAD_SERVICE);
    manager.enqueue(request);

我已经添加了以下权限 -

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.READ_PHONE_STATE" />

Answer 1

最有可能发生的情况是您没有写入 SD 卡的权限、SD 卡不存在或者您没有访问正确的 . 首先确保你有一张SD卡。 其次，不同制造商的存储路径有所不同，因此不要对其进行硬编码。尝试以下操作来创建目录

String pathTofile=Environment.getExternalStorageDirectory().getAbsolutePath(); String fullpath=pathTofile+”你定义的目录路径”

以上应该有效。

如果没有，请尝试以下链接

`/storage/emulated/legacy/` vs `/storage/emulated/0/` vs `data/data/myApp'