代码
https://github.com/nihui/ncnn-android-yolov5
腾讯nihui大神：倪辉，女，90年生
nihui，腾讯优图实验室高级研究员，从事视觉AI算法的研究工作。主导研发和维护业界首个端侧高性能AI推理框架ncnn，以开源的力量帮助AI落地和促进产业发展。
教程视频
注意：
1、在目录ncnn-android-yolov5-master\app\src\main\jni放入ncnn文件，并修改CMakeLists.txt文件里的路径
2、在文件gradle-wrapper.properties里修改gradle版本
distributionUrl=http\://artifactory.cde.huawei.com/artifactory/gradle-distributions/gradle-6.7.1-all.zip
https://xugaoxiang.com/2021/02/02/android-ncnn-yolov5/
问题：
No variants found for ':app'. Check build files to ensure at least one variant exists
解决方法：
Android SDK版本不对
在模块build.gradle文件里的compileSdkVersion设置为28
https://blog.csdn.net/weixin_43342290/article/details/115212058
问题：
An old version of CMake is being used that cannot automatically detect
或
No toolchains found in the NDK toolchains folder for ABI with prefix: arm-linux-androideabi
解决方法：
修改工程build.gradle文件里的classpath的gradle的版本为4.2.1
https://blog.si-yee.com/2019/07/12/%E8%A7%A3%E5%86%B3Android-Studio%E2%80%94%E2%80%94No-toolchains-found-in-the-NDK-toolchains-folder-for-ABI-with-prefix-mips64el-linux-android%E9%94%99%E8%AF%AF/
问题：
EventQueue.isDispatchThread()=false Toolkit.getEventQueue()=com.intellij.ide.IdeEventQueue@4012292d
解决方法：
过一会自动好了？！
==================================================================================================================================
问题：
CMake ‘3.6.0’ was not found in PATH or by cmake.dir property. - CMake ‘3.10.2’ found in SDK did not match requested version ‘3.6.0’
解决方法：
app的build.gradle文件里
android{
? ? externalNativeBuild {
? ? ? ? cmake {
? ? ? ? ? ? version "3.22.1"
? ? ? ? }
? ? }
}
https://blog.csdn.net/miao_007/article/details/87632758
https://www.jianshu.com/p/f2a1365fca80
问题：
com.intellij.openapi.externalSystem.model.ExternalSystemException
暂无解决
https://github.com/nihui/ncnn-android-yolov5/issues/21
https://github.com/HUGHNew/Site/blob/master/blogs/Android-Yolo5.md
==================================================================================================================================
Could not find method android() for arguments [build_25zy1japkfafsu0dvxbfxezl5$_run_closure2@4d636d1d] on root project
是因为app的build.gradle文件的顶部缺少这句话
apply plugin: 'com.android.application'
https://blog.csdn.net/qq_35008279/article/details/80741085
Cause: compileSdkVersion is not specified
https://www.codeleading.com/article/12423883144/
?
===================================================
问题：
This project uses AndroidX dependencies, but the 'android.useAndroidX' property is not enabled
解决方法：
打开下图选中的文件gradle.properties，添加下面两句话
?
android.useAndroidX=true
android.enableJetifier=true
https://blog.csdn.net/weixin_44135826/article/details/105981267
?
问题：
Unable to make field private final java.lang.String java.io.File.path accessible: module java.base does not "opens java.io" to unnamed module
解决方法：
java jdk版本太高了 从16降到8
https://forum.cocos.org/t/topic/120533
问题：
lease remove usages of `jcenter()` Maven repository from your build scripts and migrate your build to other Maven repositories
解决方法：
//jcenter()
mavenCentral()
https://stackoverflow.com/questions/67418153/android-studio-gradle-please-remove-usages-of-jcenter-maven-repository-from
=========================================================================================
手动下载Gradle，放在目录"C:/Users/[你的名称]/.gradle/wrapper/dists/[一串英文]"下
https://www.jianshu.com/p/4c0415a79214
问题：
org.codehaus.groovy.control.MultipleCompilationErrorsException
解决方法：
?将 “File – Project Structure – Project ”路径下的Gradle version改为最新版本
https://blog.csdn.net/weixin_42433094/article/details/115937572
问题：
Connect to dl.google.com:443 [dl.google.com/180.163.151.33] failed: Connection timed out: connect
Using insecure protocols with repositories, without explicit opt-in, is unsupported
解决方法：
在工程build.gradle的repositories里面添加
maven {
? ? allowInsecureProtocol = true
? ? url 'https://maven.aliyun.com/repository/google'
}
maven {
? ? allowInsecureProtocol = true
? ? url 'https://maven.aliyun.com/repository/jcenter'
}
maven {
? ? allowInsecureProtocol = true
? ? url 'http://maven.aliyun.com/nexus/content/groups/public'
}
https://www.v2ex.com/t/724894
https://blog.csdn.net/qi_ming_hao_nan/article/details/114799678