C ++ Template类继承,如何成员类型规范?

时间:2016-08-05 02:55:11

标签: c++ templates c++11 template-meta-programming

    <meta-data
        android:name="com.google.android.gms.version"
        android:value="@integer/google_play_services_version" />

此代码问题为apply plugin: "com.android.application" import com.android.build.OutputFile /** * The react.gradle file registers a task for each build variant (e.g. bundleDebugJsAndAssets * and bundleReleaseJsAndAssets). * These basically call `react-native bundle` with the correct arguments during the Android build * cycle. By default, bundleDebugJsAndAssets is skipped, as in debug/dev mode we prefer to load the * bundle directly from the development server. Below you can see all the possible configurations * and their defaults. If you decide to add a configuration block, make sure to add it before the * `apply from: "../../node_modules/react-native/react.gradle"` line. * * project.ext.react = [ * // the name of the generated asset file containing your JS bundle * bundleAssetName: "index.android.bundle", * * // the entry file for bundle generation * entryFile: "index.android.js", * * // whether to bundle JS and assets in debug mode * bundleInDebug: false, * * // whether to bundle JS and assets in release mode * bundleInRelease: true, * * // whether to bundle JS and assets in another build variant (if configured). * // See http://tools.android.com/tech-docs/new-build-system/user-guide#TOC-Build-Variants * // The configuration property can be in the following formats * // 'bundleIn${productFlavor}${buildType}' * // 'bundleIn${buildType}' * // bundleInFreeDebug: true, * // bundleInPaidRelease: true, * // bundleInBeta: true, * * // the root of your project, i.e. where "package.json" lives * root: "../../", * * // where to put the JS bundle asset in debug mode * jsBundleDirDebug: "$buildDir/intermediates/assets/debug", * * // where to put the JS bundle asset in release mode * jsBundleDirRelease: "$buildDir/intermediates/assets/release", * * // where to put drawable resources / React Native assets, e.g. the ones you use via * // require('./image.png')), in debug mode * resourcesDirDebug: "$buildDir/intermediates/res/merged/debug", * * // where to put drawable resources / React Native assets, e.g. the ones you use via * // require('./image.png')), in release mode * resourcesDirRelease: "$buildDir/intermediates/res/merged/release", * * // by default the gradle tasks are skipped if none of the JS files or assets change; this means * // that we don't look at files in android/ or ios/ to determine whether the tasks are up to * // date; if you have any other folders that you want to ignore for performance reasons (gradle * // indexes the entire tree), add them here. Alternatively, if you have JS files in android/ * // for example, you might want to remove it from here. * inputExcludes: ["android/**", "ios/**"] * ] */ apply from: "../../node_modules/react-native/react.gradle" /** * Set this to true to create two separate APKs instead of one: * - An APK that only works on ARM devices * - An APK that only works on x86 devices * The advantage is the size of the APK is reduced by about 4MB. * Upload all the APKs to the Play Store and people will download * the correct one based on the CPU architecture of their device. */ def enableSeparateBuildPerCPUArchitecture = false /** * Run Proguard to shrink the Java bytecode in release builds. */ def enableProguardInReleaseBuilds = false android { compileSdkVersion 23 buildToolsVersion "23.0.1" defaultConfig { applicationId "com.obv" minSdkVersion 16 targetSdkVersion 22 versionCode 1 versionName "1.0" ndk { abiFilters "armeabi-v7a", "x86" } } splits { abi { reset() enable enableSeparateBuildPerCPUArchitecture universalApk false // If true, also generate a universal APK include "armeabi-v7a", "x86" } } buildTypes { release { minifyEnabled enableProguardInReleaseBuilds proguardFiles getDefaultProguardFile("proguard-android.txt"), "proguard-rules.pro" } } // applicationVariants are e.g. debug, release applicationVariants.all { variant -> variant.outputs.each { output -> // For each separate APK per architecture, set a unique version code as described here: // http://tools.android.com/tech-docs/new-build-system/user-guide/apk-splits def versionCodes = ["armeabi-v7a":1, "x86":2] def abi = output.getFilter(OutputFile.ABI) if (abi != null) { // null for the universal-debug, universal-release variants output.versionCodeOverride = versionCodes.get(abi) * 1048576 + defaultConfig.versionCode } } } packagingOptions { exclude 'META-INF/DEPENDENCIES.txt' exclude 'META-INF/LICENSE.txt' exclude 'META-INF/NOTICE.txt' exclude 'META-INF/NOTICE' exclude 'META-INF/LICENSE' exclude 'META-INF/DEPENDENCIES' exclude 'META-INF/notice.txt' exclude 'META-INF/license.txt' exclude 'META-INF/dependencies.txt' exclude 'META-INF/LGPL2.1' } } dependencies { compile fileTree(dir: "libs", include: ["*.jar"]) compile "com.android.support:appcompat-v7:23.0.1" compile "com.facebook.react:react-native:+" // From node_modules compile 'com.google.android.gms:play-services-maps:9.4.0' compile 'com.airbnb.android:react-native-maps:0.7.1' } // Run this once to be able to run the application with BUCK // puts all compile dependencies into folder libs for BUCK to use task copyDownloadableDepsToLibs(type: Copy) { from configurations.compile into 'libs' } 。 它在BTree编译时转换为template <typename _datTy> class ANode{ typedef ANode<_datTy> _nodeTy; public: std::vector<_nodeTy> childVector; }; template <typename _datTy, class _nodeTy = ANode> ATree { public : void doSomeThing() { auto iter = _root.childVector.begin(); } protected: _nodeTy _root; }; template <typename _datTy> class BNode : public ANode<_datTy> { typedef BNode<_datTy> _nodeTy; public: bool somethingExtends; }; template <typename _datTy> BTree : public ATree<_datTy, BNode<_datTy>> { ... }; BTree<char> test; test.doSomeThing();

但我真的很想要这个, 在ATree编译时{,1}} 关于BTree编译时的std::vector<_nodeTy> childVector

我不会在当前架构点上使用像std::vector<Anode<_datTy>>这样的基类指针。

怎么知道这个问题? 谢谢你的阅读。

1 个答案:

答案 0 :(得分:1)

您正在寻找Curiously recurring template pattern。这些方面的东西:

template <typename NodeType>   
class XNode{
public:
    std::vector<NodeType> childVector;
};

template <typename DataType>   
class ANode : public XNode<ANode<DataType>> {};

template <typename DataType>   
class BNode : public XNode<BNode<DataType>> {};