权限被拒绝

Question

编辑：因为我已经要求允许在运行时我的问题是不重复的Android permission doesn't work even if I have declared it

EDIT2：写入文件到Environment.getexternalstoragedirectory是确定的，但到SD卡给出了错误

嘿我试着写与RandomAccessFile MP3文件到SD卡，这是我的代码：

public void save(String newFilename) throws IOException, NotSupportedException { 
    if (file.compareTo(new File(newFilename)) == 0) { 
     throw new IllegalArgumentException("Save filename same as source filename"); 
    } 
    RandomAccessFile saveFile = new RandomAccessFile(newFilename, "rw"); 
    try { 
     if (hasId3v2Tag()) { 
      saveFile.write(id3v2Tag.toBytes()); 
     } 
     saveMpegFrames(saveFile); 
     if (hasCustomTag()) { 
      saveFile.write(customTag); 
     } 
     if (hasId3v1Tag()) { 
      saveFile.write(id3v1Tag.toBytes()); 
     } 
    } finally { 
     saveFile.close(); 
    } 
} 

private void saveMpegFrames(RandomAccessFile saveFile) throws IOException { 
    int filePos = xingOffset; 
    if (filePos < 0) filePos = startOffset; 
    if (filePos < 0) return; 
    if (endOffset < filePos) return; 
    RandomAccessFile randomAccessFile = new RandomAccessFile(this.file.getPath(), "r"); 
    byte[] bytes = new byte[bufferLength]; 
    try { 
     randomAccessFile.seek(filePos); 
     while (true) { 
      int bytesRead = randomAccessFile.read(bytes, 0, bufferLength); 
      if (filePos + bytesRead <= endOffset) { 
       saveFile.write(bytes, 0, bytesRead); 
       filePos += bytesRead; 
      } else { 
       saveFile.write(bytes, 0, endOffset - filePos + 1); 
       break; 
      } 
     } 
    } finally { 
     randomAccessFile.close(); 
    } 
} 

，我在logcat收到此错误：

java.io.FileNotFoundException: /storage/15D5-14F7/Musics/Music/Dream On.mp3: open failed: EACCES (Permission denied) 

但我有写入和读取权限为什么会发生这种情况？

Answer 1

java.io.FileNotFoundException: /storage/15D5-14F7/Musics/Music/Dream On.mp3: open failed: EACCES (Permission denied) 

这似乎是在 removable storage的位置

。您无权读取或写入Android 4.4及更高版本设备上可移动存储上的任意位置。

，但我有写和读权限

，你可能读和/或写权限external storage。外部存储不是可移动存储。

Answer 2

如果你写这个权限，你可以访问权限。但是上面的棉花糖，你必须包括如何处理运行时权限。

这是解决方案链接。

https://blog.xamarin.com/requesting-runtime-permissions-in-android-marshmallow/