Android是谷歌领导的开放手机联盟开发的基于linux的开源移动操作系统。详细信息请参见Android主页。
Android平台的开发与其他平台的开发有很大的不同。所以，在开始为Android编程之前，我们建议你确保你熟悉以下关键主题:
Java编程语言，是Android操作系统的主要开发技术。此外，你可以发现Oracle文档对Java很有用。
Java Native Interface (JNI)是一种在Java虚拟机中运行本机代码的技术。此外，您还可以发现关于JNI的Oracle文档非常有用。
Android Activity和它的生命周期，这是一个基本的Android API类。
OpenCV的开发当然需要对Android摄像头有一定的了解。
android studio缓存目录更改配置
1.下载opencv
https://opencv.org/releases/
2.最好使用JDK，最好不要使用android studio自带jrd，目前JDK版本不能超过15，推荐使用JDK15，我直接用的openjdk
3.加入opencv模块，方法如下，
我试图直接导入opencv到android studio，next按钮为灰色，所以只能使用这种方法。
// Add module into Android Studio application project: // // - Android Studio way: // (will copy almost all OpenCV Android SDK into your project, ~200Mb) // // import module: Menu -> "File" -> "New" -> "Module" -> "import Gradle project": // Source directory: select this "sdk" directory // Module name: ":opencv" // // - or attach library module from OpenCV Android SDK // (without copying into application project directory, allow to share the same module between projects) // // Edit "settings.gradle" and add these lines: // // def opencvsdk='' // // You can put declaration above into gradle.properties file instead (including file in HOME directory), // // but without 'def' and apostrophe symbols ('): opencvsdk= // include ':opencv' // project(':opencv').projectDir = new File(opencvsdk + '/sdk') // // // // Add dependency into application module: // // - Android Studio way: // "Open Module Settings" (F4) -> "Dependencies" tab // // - or add "project(':opencv')" dependency into app/build.gradle: // // dependencies { // implementation fileTree(dir: 'libs', include: ['*.jar']) // ... // implementation project(':opencv') // } // // // // Load OpenCV native library before using: // // - avoid using of "OpenCVLoader.initAsync()" approach - it is deprecated // It may load library with different version (from OpenCV Android Manager, which is installed separatelly on device) // // - use "System.loadLibrary("opencv_java4")" or "OpenCVLoader.initDebug()" // TODO: Add accurate API to load OpenCV native library // // // // Native C++ support (necessary to use OpenCV in native code of application only): // // - Use find_package() in app/CMakeLists.txt: // // find_package(OpenCV 3.4 REQUIRED java) // ... // target_link_libraries(native-lib ${OpenCV_LIBRARIES}) // // - Add "OpenCV_DIR" and enable C++ exceptions/RTTI support via app/build.gradle // documentation about CMake options: https://developer.android.com/ndk/guides/cmake.html // // defaultConfig { // ... // externalNativeBuild { // cmake { // cppFlags "-std=c++11 -frtti -fexceptions" // arguments "-DOpenCV_DIR=" + opencvsdk + "/sdk/native/jni" // , "-DANDROID_ARM_NEON=TRUE" // } // } // } // // - (optional) Limit/filter ABIs to build ('android' scope of 'app/build.gradle'): // Useful information: https://developer.android.com/studio/build/gradle-tips.html (Configure separate APKs per ABI) // // splits { // abi { // enable true // universalApk false // reset() // include 'armeabi-v7a' // , 'x86', 'x86_64', 'arm64-v8a' // } // } //
