当使用Android 5 Lollipop上的USB-MTP访问目录时，MediaScannerConnection＃scanFile将目录转换为文件 [英] MediaScannerConnection#scanFile converts directories into files when accessing them with USB-MTP on Android 5 Lollipop

问题描述

诸如重命名应用触发的文件之类的更改仅在重新启动Android设备后出现在USB-MTP界面上，或者在MediaScanner上注册新文件后才出现在USB-MTP界面上，如下所示（请参见在特定路径（文件夹）上触发mediascanner，如何操作？）：

Changes like renaming a file triggered by an app only appear to the USB-MTP interface after reboot of the Android device or after you registered the new file at the MediaScanner them like this (see Trigger mediascanner on specific path (folder), how to?):

file.renameTo(newFile);    
MediaScannerConnection.scanFile(context,
        new String[] { newFile.getAbsolutePath() }, null, null);

USB-MTP用于通过USB访问android设备的存储。例如。

USB-MTP is used to access the storage of an android device via USB. E.g. with the Windows Explorer.

，但是在Android 5.0.2（内部版本10.6.A.0.454）下使用Sony XPERIA Tablet Z（SGP321） ） newFile 中提供的文件夹将变为4KB的文件。我不再能够使用Windows资源管理器访问文件夹结构，也无法将文件复制到计算机上。即使重新启动平板电脑！与Android 4.4.4相同的设备不会显示此行为。看来只有USB-MTP视图损坏了。

However, with the Sony XPERIA Tablet Z (SGP321) under Android 5.0.2 (Build 10.6.A.0.454) folders supplied in newFile will become a file with 4KB. I am no more able to access the folder structure using Windows Explorer anymore, nor can I copy the file to my computer. Even after reboot of the tablet! The same device with Android 4.4.4 does not show the behavior. It appears that only the USB-MTP view is broken. The file structure accessed by an android app still looks fine.

问题：这种行为是错误还是我没有正确实现？正确的实现方法是什么？

Question: Is this behavior a bug or did I implement it incorrectly? What would be the correct implementation?

到目前为止，我已尝试解决此问题：

What I've tried so far to fix the issue:

1. 我当前的解决方法是避免目录使用 scanFile 。


2. 我可以使用不带 MediaScannerConnection＃scanFile 的android应用重命名文件，将文件转换回目录。重新启动后，我可以再次使用Windows资源管理器访问该目录。


3. 使用Windows资源管理器重命名实际上是目录的文件不会还原它们。甚至在重新启动之后。



4. 此行，如 https://stackoverflow.com中所建议/ a / 21918085/433718
   不会刷新USB-MTP视图，但也不会将目录
   转换为文件：

1. My current workaround is to avoid scanFile for directories.
2. I can convert files back into directories by renaming them with an android app without MediaScannerConnection#scanFile. After reboot, I can access the directory with Windows Explorer again.
3. Renaming files with Windows Explorer that actually are directories does not restore them. Even after Reboot.

4. This line as suggested in https://stackoverflow.com/a/21918085/433718 does not refresh USB-MTP view, but also does not convert directories into files:

context.sendBroadcast(new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE,
            Uri.fromFile(newFile.getParentFile()));

可能与以下内容有关：

Maybe related:

• https://stackoverflow.com/a/27321544/433718


• 对各种文件操作使用内容解析器例如在此答案中删除文件： Android删除文件MediaScannerConnection

• https://stackoverflow.com/a/27321544/433718
• Using content resolver for all sorts of File operations like deleting a file in this answer: Android Deleting Files MediaScannerConnection

推荐答案

我最终在以下位置创建了一个虚拟文本文件每个目录我

I ended up creating a dummy text file in each directory I wanted to make visible, and use scanFile on the file.

1）创建目录，但不要扫描目录

1) create directory, but don't "scan" directories

2）复制文件到目录

3）在文件路径上运行scanFile

3) run scanFile on the filePath

MediaScannerConnection.scanFile (_application, new String[] { filePath }, null, null);

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