打开失败:安卓(6.0.1)系统应用程序中的EACCES(权限被拒绝)

Question

我开发了一个android系统应用程序，可以将文件从/sdcard/download/test.txt复制到/cache/xyz/location。

我可以将文件复制到/cache/，但bot到/cache/xyz/location，

获取以下错误：

java.io.FileNotFoundException：/cache/xyz/test.txt：打开失败：EACCES(权限被拒绝(

File packageFile = new File(Environment.getDownloadCacheDirectory() + "/xyz/test.txt");
File downloadedFile = new File(Environment.getExternalStorageDirectory() + "/test.txt");
if (packageFile.exists()) {
Log.d(TAG, "TEST -> File in Cache Exists");

} else {
Log.d(TAG, "TEST -> File in Cache is Empty");
}
packageFile.canWrite();
if (downloadedFile.exists()) {
Log.d(TAG, "TEST -> packageFile in downloadedFile Exists");
FileChannel source = null;
FileChannel dest = null;
try {
source = (new FileInputStream(downloadedFile)).getChannel();
dest = (new FileOutputStream(packageFile)).getChannel();
count += dest.transferFrom(source, count, size-count);


catch (Exception e) {
Log.d(TAG, "TEST -> Failed to copy update file into internal storage: " + e);
}

} else {
Log.d(TAG, "TEST -> File DO NOT Exists");
}

清单：

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

Answer 1

对于API 23+，您需要请求读/写权限，即使它们已经在清单中。

// Storage Permissions
private static final int REQUEST_EXTERNAL_STORAGE = 1;
private static String[] PERMISSIONS_STORAGE = {
Manifest.permission.READ_EXTERNAL_STORAGE,
Manifest.permission.WRITE_EXTERNAL_STORAGE
};
/**
* Checks if the app has permission to write to device storage
*
* If the app does not has permission then the user will be prompted to grant permissions
*
* @param activity
*/
public static void verifyStoragePermissions(Activity activity) {
// Check if we have write permission
int permission = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE);
if (permission != PackageManager.PERMISSION_GRANTED) {
// We don't have permission so prompt the user
ActivityCompat.requestPermissions(
activity,
PERMISSIONS_STORAGE,
REQUEST_EXTERNAL_STORAGE
);
}
}

通过：异常'；打开失败：EACCES(权限被拒绝('；在安卓上