将静态库链接到 Android 中的 JNI 共享库

Question

我是 Android 新手，如果这看起来有点幼稚，请原谅我。我有两个预构建的静态库，feta (../../feta/build/libfeta.a) 和 mish (../../mish/build/libmish.a)，并且我有共享的 JNI 库。使用 JNI 库工作得很好，但我试图通过 JNI 库访问 feta 和 mish。这两个库与 Android 项目一起不断更改和更新，因此每次构建它们时复制它们并不是一个真正的选择（如果这甚至可以解决链接问题），而且我更不喜欢简单地复制源文件到 Android 项目中。

我试过搜索，但是大部分答案都是使用旧版系统，要我修改Android.mk，我没有。我正在使用最新版本的 Android Studio，它使用 Gradle 插件。

我尝试在各种设置中使用十多个教程和 Stackoverflow 答案中的所有配置，但没有成功。

如果您回答，请提供完整且有效的build.gradle，这样我就不会遇到与其他答案相同的问题（谢谢！）。

我只是在遵循this 教程后问过这个问题，所以所有文件都会反映这一点。

这是我得到的构建错误：

Error:A problem occurred configuring project ':app'.
> The following model rules could not be applied due to unbound inputs and/or subjects:
    android.sources { ... } @ app/build.gradle line 58, column 5
      subject:
        - android.sources Object [*]
    repositories { ... } @ app/build.gradle line 39, column 5
      subject:
        - repositories Object [*]
  [*] - indicates that a model item could not be found for the path or type.

这是我在app 模块中的build.gradle 文件：

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    buildToolsVersion "25.0.2"
    defaultConfig {
        applicationId "com.neonorb.mish_android"
        minSdkVersion 15
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        externalNativeBuild {
            cmake {
                cppFlags "-std=c++14 -Wno-implicit-exception-spec-mismatch"
            }
        }
        ndk {
            // ${targetPlatform.getName()}
            // ${buildType.getName()}
            stl "c++_static"
            abiFilters "x86_64"
        }
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    externalNativeBuild {
        cmake {
            path "CMakeLists.txt"
        }
    }
}

model {
    repositories {
        libs(PrebuiltLibraries) {
            feta {
                headers.srcDir "../../feta/include/"
                binaries.withType(StaticLibraryBinary) {
                    staticLibraryFile = file("../../feta/build/libfeta.a")
                }
            }
        }
        libs(PrebuiltLibraries) {
            mish {
                headers.srcDir "../../mish/include/"
                binaries.withType(StaticLibraryBinary) {
                    staticLibraryFile = file("../../mish/build/libmish.a")
                }
            }
        }
    }

    android.sources {
        main {
            jni {
                dependencies {
                    library "feta" linkage "static"
                    library "mish" linkage "static"
                }
            }
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.1.0'
    compile 'com.google.android.gms:play-services-ads:10.0.1'
    compile 'com.android.support:design:25.1.0'
    testCompile 'junit:junit:4.12'
}

这是根 (mish-android) 目录一：

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.3'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

这是我的CMakeLists.txt：

# Sets the minimum version of CMake required to build the native
# library. You should either keep the default value or only pass a
# value of 3.4.0 or lower.

cmake_minimum_required(VERSION 3.4.1)

# Creates and names a library, sets it as either STATIC
# or SHARED, and provides the relative paths to its source code.
# You can define multiple libraries, and CMake builds it for you.
# Gradle automatically packages shared libraries with your APK.

add_library( # Sets the name of the library.
             mish-android

             # Sets the library as a shared library.
             SHARED

             # Provides a relative path to your source file(s).
             # Associated headers in the same location as their source
             # file are automatically included.
             src/main/cpp/mish.cpp )

# Searches for a specified prebuilt library and stores the path as a
# variable. Because system libraries are included in the search path by
# default, you only need to specify the name of the public NDK library
# you want to add. CMake verifies that the library exists before
# completing its build.

find_library( # Sets the name of the path variable.
              log-lib

              # Specifies the name of the NDK library that
              # you want CMake to locate.
              log )

# Specifies libraries CMake should link to your target library. You
# can link multiple libraries, such as libraries you define in the
# build script, prebuilt third-party libraries, or system libraries.

target_link_libraries( # Specifies the target library.
                       mish-android

                       # Links the target library to the log library
                       # included in the NDK.
                       ${log-lib} )

如果有帮助的话，这是我的目录结构。

Answer 1

事实证明，我需要升级我的 Gradle 插件。我能够删除CMakeLists.txt。我还需要将我的 Gradle 包装器版本升级到 3.2 以支持新的实验性插件。

这是我的根build.gradle：

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        //classpath 'com.android.tools.build:gradle:2.2.3'
        classpath 'com.android.tools.build:gradle-experimental:0.9.0-beta1'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

task clean(type: Delete) {
    delete rootProject.buildDir
}

这是我的appbuild.gradle：

apply plugin: 'com.android.model.application'

model {
    android {
        compileSdkVersion 25
        buildToolsVersion "25.0.2"
        defaultConfig {
            applicationId "com.neonorb.mish_android"
            minSdkVersion.apiLevel 15
            targetSdkVersion.apiLevel 25
            versionCode 1
            versionName "1.0"
            testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        }
        ndk {
            moduleName "mish-android"
            ldLibs.add("log")
            cppFlags.add("-std=c++14")
            cppFlags.add("-Wno-implicit-exception-spec-mismatch")
            // ${targetPlatform.getName()}
            // ${buildType.getName()}
            stl "c++_static"
            abiFilters.addAll(["x86_64"])
            // only build for x86_64 because that's all Feta and Mish support atm
        }
        buildTypes {
            release {
                minifyEnabled false
                proguardFiles.add(file("proguard-rules.pro"))
            }
        }
        sources {
            main {
                jni {
                    source {
                        srcDir "src"
                    }
                    dependencies {
                        library "feta" linkage "static"
                        library "mish" linkage "static"
                    }
                }
            }
        }
    }
    repositories {
        libs(PrebuiltLibraries) {
            feta {
                headers.srcDir "../../feta/include/"
                binaries.withType(StaticLibraryBinary) {
                    staticLibraryFile = file("../../feta/build/libfeta.a")
                }
            }
        }
        libs(PrebuiltLibraries) {
            mish {
                headers.srcDir "../../mish/include/"
                binaries.withType(StaticLibraryBinary) {
                    staticLibraryFile = file("../../mish/build/libmish.a")
                }
            }
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:25.1.0'
    testCompile 'junit:junit:4.12'
}