FileNotFoundException EACCES（权限被拒绝）

Question

我在尝试打开 FileInputStream 时遇到文件打开权限被拒绝的异常。

 File myFile = new File(Environment.getExternalStorageDirectory()
           .getAbsolutePath() + "/test/test.txt");
 try {
      FileInputStream inStream = new FileInputStream(myFile); // crash

这是堆栈跟踪：

 System.err﹕ java.io.FileNotFoundException: /storage/emulated/0/test/test.txt: open failed: EACCES (Permission denied)
 System.err﹕ at libcore.io.IoBridge.open(IoBridge.java:456)
 System.err﹕ at java.io.FileInputStream.<init>(FileInputStream.java:76)

 ...

 Caused by: android.system.ErrnoException: open failed: EACCES (Permission denied)
 at libcore.io.Posix.open(Native Method)
 at libcore.io.BlockGuardOs.open(BlockGuardOs.java:186)
 at libcore.io.IoBridge.open(IoBridge.java:442)

是的，我的清单中确实有权限：

<uses-permission android:name="ANDROID.PERMISSION.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="ANDROID.PERMISSION.WRITE_EXTERNAL_STORAGE" />

Answer 1

Android 区分大小写。将ANDROID.PERMISSION 替换为android.permission：

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

此外，您应该只需要其中一项权限。如果您打算写入外部存储，则不需要READ_EXTERNAL_STORAGE。