Android Studio C ++ NDK库示例 [英] Android Studio C++ NDK library example

问题描述

我想下载一些使用C或C ++的Android Studio NDK项目的工作示例，该示例将编译为.so库(或我可以从其中提取.so的APK). 我已经尝试过将ndkbuild与Android.mk一起使用，也尝试将CMake与CMakeLists.txt一起使用，以及Windows上的官方和非官方教程...

I would like to download some working example of Android Studio NDK project with C or C++ which will be compiled to .so library (or APK from which I can extract .so). I have tried ndkbuild with Android.mk build and also CMake with CMakeLists.txt, official and unofficial tutorials on Windows...

如果我在同一个应用程序(java)上的android上尝试使用它们，则可以正常运行，但是我想在Android上的Unity3D中使用NDK，并且我一直在获取DllNotFoundException.

If I try them on android from same app (java), it is working but I want to use NDK in Unity3D on android and I keep getting DllNotFoundException.

我上传了 Android 和

I uploaded my Android and Unity projects to github.

推荐答案

首先，此处是您要查找的示例Android Project插件.

First of all, here is a sample Android Project plugin you are looking for.

知道自己如何做到这一点非常重要.

It's very important to know how to do this yourself.

这以前很难做到，但是最新的 Android Studio 使现在更容易使用C/C ++或轻松生成 .so 库.将 Android Studio 更新到最新版本，然后按照以下步骤创建C ++插件.

This used to be hard to do before but the latest Android Studio made it easier to now use C/C++ or generate .so library easily. Update Android Studio to the latest version then follow steps below to create a C++ plugin.

1 .在Android Studio中创建一个新项目

1.Create a new Project in Android Studio

2 .选中包含C ++支持以启用C ++.

2.Check the Include C++ suport to enable C++.

3 .在下拉菜单中，检查 C ++ Standard 下拉菜单中的 C ++ 11 .您将需要C ++ 11才能真正使用最有用的C ++功能.另外，如果需要，请启用exception或frtti.

3.On the Dropdown Menu, check C++ 11 on the C++ Standard drop-down menu. You will need C++ 11 to actually use most useful C++ features. Also, enable exception or frtti if you need them.

就是这样.

构建插件时:

调试库应该位于:

\app\build\intermediates\cmake\debug\obj\

发布库应位于:

\app\build\intermediates\cmake\debug\obj\

如果您仅看到调试而不是插件的发行版，请在此处查看如何使其显示

If you only see the debug but not the release version of the plugin, check here for how to make it appear.

在Android上获取 DllNotFoundException 的可能原因:

Possible reasons you are getting DllNotFoundException on Android:

1 .您没有将C/C ++函数包装在extern "C"周围.您必须对 .cpp 文件中的每个功能执行此操作，或者对 .h 文件中的功能执行此操作.

1.You did not wrap the C/C++ function around extern "C". You must do this for each function in the .cpp file or you do it in the function in the .h file.

2 .您将插件放在错误的Unity文件夹中.

2.You put the plugin in the wrong Unity folder.

在<ProjectDirectory>\app\build\intermediates\cmake\release\obj处生成的armeabi-v7a和x86插件应放置在Unity项目的Assets\Plugins\Android\libs\armeabi-v7a\和Assets\Plugins\Android\libs\x86\处.

The armeabi-v7a and x86 plugins generated at <ProjectDirectory>\app\build\intermediates\cmake\release\obj should be placed at Assets\Plugins\Android\libs\armeabi-v7a\ and Assets\Plugins\Android\libs\x86\ in the Unity project.

请确保正确拼写这些内容.有关更多信息，请参见此.

Make sure to spell these correctly. See this for more information about this.

3 .您从C#端加载错误.

3.You are loading it incorrectly from the C# side.

假设插件的名称是libScreenshot.a，不包括lib前缀，也不在加载.a时添加.a./p>

Let's say that the name of the plugin is libScreenshot.a, do not include the lib prefix, also do not add the .a when loading it.

[DllImport("Screenshot", CallingConvention = CallingConvention.Cdecl)]
    public static extern void takeScreenshot();

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