我得到了
open failed: EACCES(权限被拒绝)
myOutput = new FileOutputStream(outFileName);
我检查了根目录，并尝试了android.permission.WRITE_EXTERNAL_STORAGE。
我该如何解决这个问题?
try {
InputStream myInput;
myInput = getAssets().open("XXX.db");
// Path to the just created empty db
String outFileName = "/data/data/XX/databases/"
+ "XXX.db";
// Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
// Transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
// Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
buffer = null;
outFileName = null;
}
catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
我在运行CM 12.1的三星Galaxy Note 3上也遇到了同样的问题。我的问题是我有
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"
android:maxSdkVersion="18"/>
而且必须用它来拍摄和存储用户照片。当我试图在ImageLoader中加载这些相同的照片时，我得到了(权限被拒绝)错误。解决方案是显式添加
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>
因为上面的权限只限制写权限到API版本18，以及它的读权限。
在我的例子中，我使用的是一个文件选择器库，它返回到外部存储的路径，但它从/root/开始。即使在运行时授予WRITE_EXTERNAL_STORAGE权限，我仍然得到错误EACCES(权限被拒绝)。
因此，使用Environment.getExternalStorageDirectory()来获取外部存储的正确路径。
例子:
无法写入:/root/storage/emulated/0/newfile.txt
可以写:/storage/emulated/0/newfile.txt
boolean externalStorageWritable = isExternalStorageWritable();
File file = new File(filePath);
boolean canWrite = file.canWrite();
boolean isFile = file.isFile();
long usableSpace = file.getUsableSpace();
Log.d(TAG, "externalStorageWritable: " + externalStorageWritable);
Log.d(TAG, "filePath: " + filePath);
Log.d(TAG, "canWrite: " + canWrite);
Log.d(TAG, "isFile: " + isFile);
Log.d(TAG, "usableSpace: " + usableSpace);
/* Checks if external storage is available for read and write */
public boolean isExternalStorageWritable() {
String state = Environment.getExternalStorageState();
if (Environment.MEDIA_MOUNTED.equals(state)) {
return true;
}
return false;
}
输出1:
externalStorageWritable: true
filePath: /root/storage/emulated/0/newfile.txt
isFile: false
usableSpace: 0
输出2:
externalStorageWritable: true
filePath: /storage/emulated/0/newfile.txt
isFile: true
usableSpace: 1331007488
2022 Kotlin请求许可的方式:
private val writeStoragePermissionResult =
registerForActivityResult(ActivityResultContracts.RequestMultiplePermissions()) { permissions ->}
private fun askForStoragePermission(): Boolean =
if (hasPermissions(
requireContext(),
Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.WRITE_EXTERNAL_STORAGE
)
) {
true
} else {
writeStoragePermissionResult.launch(
arrayOf(
Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.WRITE_EXTERNAL_STORAGE,
)
)
false
}
fun hasPermissions(context: Context, vararg permissions: String): Boolean = permissions.all {
ActivityCompat.checkSelfPermission(context, it) == PackageManager.PERMISSION_GRANTED
}
