如何使用Android NDK和Gradle构建单个APK

Question

如何使用Android NDK和Gradle构建单个APK

4

我正在开发一款新的Android应用程序，使用OpenCV（使用C++而不是Java），我对opencv和NDK都很陌生。我已经使用下面的Gradle文件构建（并运行）成功，并且在Android Studio中我可以选择一个变体并进行构建（例如x86）。

我的问题有两个：

Is there a way I can have a variant that builds an APK supporting all architectures? (I know file size will be bigger)

Can i achieve a build without specifying all the same libs for each variant. Is there any way I can make the build system just pick up the libraries each time since they are all inside the project and organised by architecture name?

apply plugin: 'com.android.application'

android {
compileSdkVersion 21
buildToolsVersion "21.0.0"

defaultConfig {
    applicationId "uk.co.xxx.androidcppimagereader"
    minSdkVersion 17
    targetSdkVersion 21
    versionCode 1
    versionName "1.0"
}

def libsDir = projectDir.path + "/libs/"

productFlavors {
    x86 {
        versionCode Integer.parseInt("3" + defaultConfig.versionCode)
        ndk {
            abiFilter "x86"
            moduleName "Processing"
            stl "gnustl_static"
            cFlags "-I/opt/local/include/opencv -I/opt/local/include"
            ldLibs libsDir + "x86/libopencv_core.a"
            ldLibs libsDir + "x86/libopencv_ts.a"
            ldLibs libsDir + "x86/libopencv_contrib.a"
            ldLibs libsDir + "x86/libopencv_ml.a"
            ldLibs libsDir + "x86/libopencv_java.so"
            ldLibs "log"
            ldLibs "z", "jnigraphics"
        }
    }
    armv7 {
        versionCode Integer.parseInt("2" + defaultConfig.versionCode)
        ndk {
            abiFilter "armeabi-v7a"
            moduleName "Processing"
            stl "gnustl_static"
            cFlags "-I/opt/local/include/opencv -I/opt/local/include"
            ldLibs libsDir + "armeabi-v7a/libopencv_core.a"
            ldLibs libsDir + "armeabi-v7a/libopencv_ts.a"
            ldLibs libsDir + "armeabi-v7a/libopencv_contrib.a"
            ldLibs libsDir + "armeabi-v7a/libopencv_ml.a"
            ldLibs libsDir + "armeabi-v7a/libopencv_java.so"
            ldLibs "log"
            ldLibs "z", "jnigraphics"
        }
    }
    arm {
        versionCode Integer.parseInt("1" + defaultConfig.versionCode)
        ndk {
            abiFilter "armeabi"
            moduleName "Processing"
            stl "gnustl_static"
            cFlags "-I/opt/local/include/opencv -I/opt/local/include"
            ldLibs libsDir + "armeabi/libopencv_core.a"
            ldLibs libsDir + "armeabi/libopencv_ts.a"
            ldLibs libsDir + "armeabi/libopencv_contrib.a"
            ldLibs libsDir + "armeabi/libopencv_ml.a"
            ldLibs libsDir + "armeabi/libopencv_java.so"
            ldLibs "log"
            ldLibs "z",  "jnigraphics"
        }
    }

}

    buildTypes {
         release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:21.0.3'
}

- user2022581

2个回答

1

为了正确链接库，您需要根据不同的架构声明不同的ldLibs，就像您目前正在做的那样。

不幸的是，如果您同时为所有架构构建，则无法使用当前插件从gradle中执行此操作。

在我看来，最好的解决方案是停用内置（目前已弃用）的ndk支持，改用常规的Android.mk / Application.mk文件。您的build.gradle将如下所示：

import org.apache.tools.ant.taskdefs.condition.Os

apply plugin: 'com.android.application'

android {
    compileSdkVersion 21
    buildToolsVersion "21.1"

    defaultConfig {
        applicationId "uk.co.xxx.androidcppimagereader"
        minSdkVersion 17
        targetSdkVersion 21
        versionCode 1
        versionName "1.0"
    }

    sourceSets.main {
        jniLibs.srcDir 'src/main/libs' //set libs as default directory for .so files inclusion, instead of jniLibs
        jni.srcDirs = [] //disable automatic ndk-build call
    }

    // call regular ndk-build(.cmd) script from app directory
    task ndkBuild(type: Exec) {
        if (Os.isFamily(Os.FAMILY_WINDOWS)) {
            commandLine 'ndk-build.cmd', '-C', file('src/main').absolutePath
        } else {
            commandLine 'ndk-build', '-C', file('src/main').absolutePath
        }
    }

    tasks.withType(JavaCompile) {
        compileTask -> compileTask.dependsOn ndkBuild
    }
}

- ph0b

谢谢。所以...如果我使用makefile，那么它应该构建所有架构，然后将输出库复制到src/main/libs中吗？我是NDK开发的新手，对Android.mk的输出结构稍有不清楚。 - user2022581

没错。看看NDK内部的示例，了解如何编写Android.mk和Application.mk文件。 - ph0b

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- G3M · Accepted Answer

在build.gradle文件中定义所有你计划在你的apk中包含的架构之后，使用关键字“fat”。这将构建一个FAT二进制文件。观看此视频以获取更多细节：https://www.youtube.com/watch?v=kFtxo7rr2HQ

arm {
    versionCode Integer.parseInt("1" + defaultConfig.versionCode)
    ndk {
        abiFilter "armeabi"
        moduleName "Processing"
        stl "gnustl_static"
        cFlags "-I/opt/local/include/opencv -I/opt/local/include"
        ldLibs libsDir + "armeabi/libopencv_core.a"
        ldLibs libsDir + "armeabi/libopencv_ts.a"
        ldLibs libsDir + "armeabi/libopencv_contrib.a"
        ldLibs libsDir + "armeabi/libopencv_ml.a"
        ldLibs libsDir + "armeabi/libopencv_java.so"
        ldLibs "log"
        ldLibs "z",  "jnigraphics"
    }
    fat // <- HERE
}

buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}