如何通过NDK访问Android Lollipop DocumentFile文件? [英] How to access Android Lollipop DocumentFile files via NDK?

问题描述

如何访问从 DocumentFile 生成的文件在本机JNI代码中的Android KitKat/Lollipop中，因此我可以使用fopen，fread等. 我特别要求它通过NDK访问外部SD卡文件.

How is it possible to access files which are generated from a DocumentFile in Android KitKat/Lollipop in Native JNI Code, so I can use fopen, fread, etc. I'm particular asking this to access the external SD-Card files via the NDK.

推荐答案

您可以使用文件描述符:

You can use file descriptors:

ParcelFileDescriptor filePfd;
DocumentFile file;
filePfd = getContentResolver().openFileDescriptor(file.getUri(), "w");
int fd = filePfd.getFd();

此int fd可以传递给JNI并用作常规的C ++文件描述符:

This int fd can be passed to JNI and used as usual C++ file descriptor:

FILE* file = NULL;
file = fdopen(fd, "r+b");

您需要访问SD卡上文件或目录的权限

And you need permission to access to file or directory on SD-card

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