Android的资产，C，JNI [英] Android assets, C, JNI

问题描述

如何访问一个Android的资产，如.txt文件，从C用JNI？

How do you access an Android asset, such as a .txt file, from C with the JNI?

我想文件：///android_asset/myFile.txt，并在本地MYFILE.TXT与MYFILE.TXT在与C实现文件的JNI文件夹重复

I'm trying "file:///android_asset/myFile.txt", and locally "myFile.txt" with a duplicate of myFile.txt in the jni folder with the C implementation file.

推荐答案

与资产的事情是，你不能直接访问它们的文件。这是因为在资产从对APK直接读取。他们并没有解压缩到安装时给定的文件夹。

The thing with assets is that you can't access them directly as files. This is because the assets are read directly from the APK. They're not unzipped to a given folder upon installation.

这是Android 2.3开始，有一个C API来访问资产。看看＆LT;安卓/ asset_manager.h＆GT; 和 assetManager 字段＆LT ;安卓/ native_activity.h＆GT; 。我从来没有用这个，虽然，我不知道，你可以使用这个资产管理API，如果你不依赖于原生的活动。不管怎样，这不会在Android 2.2及以下的工作。

Starting from Android 2.3, there is a C API to access assets. Have a look at <android/asset_manager.h> and the assetManager field in <android/native_activity.h>. I've never used this though, and I'm not sure that you can use this asset manager API if you don't rely on a native activity. And anyway, this won't work on Android 2.2 and below.

所以，我看到三个选项：

So I see three options:

• 您可以提取的资产注入一些目录，但是这将需要额外的空间
• 您可以（bunlde和）使用类似libzip读取来自APK资产的纯C。
• 或者，避免捆绑额外的图书馆，我个人的preference是读取C数据，使用JNI，从Java 的InputStream 对象返回 AssetManager.open（）。这需要一点code，但它的伟大工程。

• you could extract the assets into some directory but this will take extra space
• you could (bunlde and) use something like libzip to read the assets from the APK in pure C.
• or, to avoid bundling an extra library, my personal preference is to read data in C, using JNI, from the Java InputStream object returned by AssetManager.open(). It takes a little code but it works great.

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