android - 奥利奥(写外部存储)许可

Question

根据 "developer.android.com"

If the app targets Android 8.0 (API level 26), the system grants only 
READ_EXTERNAL_STORAGE at that time; however, if the app later requests 
WRITE_EXTERNAL_STORAGE, the system immediately grants that privilege 
without prompting the user.

现在，我有 READ_EXTERNAL_STORAGE，我请求 DownloadManager 下载公共(public)下载文件夹中的文件

downloadRequest.setDestinationInExternalPublicDir(Environment.DIRECTORY_DOWNLOADS, mAttachmentItem.getFilename());

不幸的是，我得到了

E/UncaughtException: java.lang.IllegalStateException: Unable to create directory: /storage/emulated/0/data/user/0/com.abc.cba/files
                                                                           at android.app.DownloadManager$Request.setDestinationInExternalPublicDir(DownloadManager.java:699)

我已经在 list 中声明了这两个权限

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

读取权限已经授予，在运行时我正在请求写入权限，系统不提示任何消息或对话框，它总是在“onRequestPermissionsResult”中被拒绝(未授予)

public static boolean isPermissionsToAccessStorageAreGranted(Context context, Activity activity) {
    ArrayList<String> permissions = new ArrayList<>();

    if (!PermissionUtil.checkPermissions(context, Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
        permissions.add(Manifest.permission.WRITE_EXTERNAL_STORAGE);
    }

    if (!permissions.isEmpty()) {
        String[] permissionsList = permissions.toArray(new String[permissions.size()]);
        PermissionUtil.requestPermissions(activity, permissionsList,
                PermissionUtil.REQUESTCODE_ACCESS_STORAGE);
        return false;
    } else {
        return true;
    }
}


@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if(requestCode==REQUESTCODE_ACCESS_STORAGE && grantResults[0]== PackageManager.PERMISSION_GRANTED){
 /* downloadFile(); */       
    }
}

我正尝试通过 ADB 授予这两个权限，它向我显示错误:

adb shell pm grant com.abc.cba 
android.permission.WRITE_EXTERNAL_STORAGE
Operation not allowed: java.lang.SecurityException: Package com.abc.cbs 
has not requested permission android.permission.WRITE_EXTERNAL_STORAGE

adb shell pm grant com.abc.cba 
android.permission.READ_EXTERNAL_STORAGE
Operation not allowed: java.lang.SecurityException: Can't change 
android.permission.READ_EXTERNAL_STORAGE. It is required by the 
application

Answer 1

其实是外部问题。我正在使用的应用程序库之一请求 WRITE_EXTERNAL_PERMISSION 和 android:maxSdkVersion。因此，当与我的 list 合并时，它将删除整个应用程序的权限。

解决方案是添加:

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" tools:node="replace"/>