Android的NDK和摇篮：每构建类型不同Android.mk [英] Android NDK and Gradle: Different Android.mk per build type

问题描述

我的本地库包含日志，我想在编译时删除。

My native library contains logs which I would like to remove at compile time. Logs are shown by defining the pre-processor macro ENABLE_DEBUG in LOCAL_CFLAGS like so:

include $(CLEAR_VARS)
LOCAL_MODULE    := native-stuff
LOCAL_SRC_FILES := Native.cpp
LOCAL_LDLIBS := -llog
LOCAL_CFLAGS := -DENABLE_DEBUG
include $(BUILD_SHARED_LIBRARY)

我通过Android的工作室建设有摇篮的应用程序，我想有没有 LOCAL_CFLAGS另一个Android.mk文件：= -DENABLE_DEBUG 的发布版本，有效地禁用日志记录。

I'm building the app with Gradle via Android Studio and I would like to have another Android.mk file without LOCAL_CFLAGS := -DENABLE_DEBUG for release builds, effectively disabling logging.

我试着在的src 创建文件夹发布/ JNI 来做到这一点，并把Android的副本。 MK没有CFLAGS。它建立并成功部署，但我还是看到了日志。这里是我的的build.gradle ：

I tried to do it by creating the folders release/jni under src and put a copy of Android.mk without the CFLAGS. It builds and deploys successfully, but I still see the logs. Here is my build.gradle:

apply plugin: 'com.android.library'

android {
    compileSdkVersion 21
    buildToolsVersion "21.1.2"

    defaultConfig {
        minSdkVersion 17
        targetSdkVersion 21
        versionCode 1
        versionName "1.0"
    }

    sourceSets {
        main {
            //Tell Gradle where to put the compiled shared library
            jniLibs.srcDir 'src/main/libs'

            //disable automatic ndk-build call
            jni.srcDirs = [];
        }
        release {
            jni.srcDirs = [];
        }
    }

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

    // Tell Gradle the run the ndkBuild task when compiling
    tasks.withType(JavaCompile) {
        compileTask -> compileTask.dependsOn ndkBuild
    }

    // This task utilizes the Android.mk file defined in src/main/jni so that you
    // have more control over the build parameters (like library inclusion)
    // The system must define property 'androidNdkHome' in ~/.gradle/gradle.properties file
    // to point to NDK path
    task ndkBuild(type: Exec) {
        commandLine "$androidNdkHome/ndk-build", '-C', file('src/main/jni').absolutePath
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:support-v4:21.0.2'
}

我的项目结构如下所示：

My project structure looks like this:

src/
   main/
       jni/
          Android.mk
   release/
       jni/
          Android.mk

是否有可能做我想做什么？

Is it possible to do what I want?

推荐答案

我觉得我有一个解决方案在这里。它并不像pretty因为我本来希望它是（特别是因为它涉及创建一个临时文件），但我测试了它和它的工作如预期。

I think I've got a solution here. It's not as pretty as I would have liked it to be (esp. as it involves creating a temporary file), but I've tested it and it's working as intended.

我写这个使用其他的 Application.mk 的调试版本，名为 Application-debug.mk 的。你可以把 APP_CFLAGS：= -DENABLE_DEBUG 里面做你想做的。

I've written this to use another Application.mk for debug builds, called Application-debug.mk. You can put APP_CFLAGS := -DENABLE_DEBUG inside to do what you want.

它如何工作的注释是在code。如果它是一个应用程序生成的文件，可以使用 applicationVariants.all 而不是 libraryVariants.all ：

Comments on how it works are in the code. If it's for an application build file, use applicationVariants.all instead of libraryVariants.all:

android.libraryVariants.all { variant ->  // executes this block for each variant, current and futures
    def task = tasks.create(name: "ndk${variant.buildType.name.capitalize()}Build") { //create ndkReleaseBuild and ndkDebugBuild tasks
        doLast {
            exec { //execute all this block when the task is executed. (A Build task gets only the commandLine to be executed, so here we're using doLast.exec instead)
                def extraParameter = ""
                def rebuildFlag = ""

                if (variant.buildType.name == "debug")
                    extraParameter = "NDK_APPLICATION_MK=" + file('src/main/jni/Application-debug.mk').absolutePath //reference to another Application.mk to use when doing a debug build.

                def lastBuildFile = file('src/main/jni/.lastbuild.tmp') //save the last build type to a temp file, to avoid triggering rebuilds all the time.
                if (!lastBuildFile.exists())
                    lastBuildFile.createNewFile()

                def lastBuildType = lastBuildFile.text
                if (lastBuildType != variant.buildType.name) {
                    println "== ndk build variant has changed, triggering full rebuild. =="
                    rebuildFlag = "-B"
                }

                if (Os.isFamily(Os.FAMILY_WINDOWS)) {
                    commandLine 'ndk-build.cmd', rebuildFlag, '-C', file('src/main').absolutePath, extraParameter
                } else {
                    commandLine 'ndk-build', rebuildFlag, '-C', file('src/main').absolutePath, extraParameter
                }

                lastBuildFile.write(variant.buildType.name)
            }
        }
    }
    variant.javaCompile.dependsOn task
}

我推这个code作为依据，以及： HTTPS：//gist.github。 COM / ph0b / 92f1f664c453869636f8

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