Android IN Java 8 java.time

Question

我更新到最新的 Android N sdk。我唯一不明白的是为什么我不能将 java.time 导入到我的代码中？我以为Java8可以通过Android N获得。那为什么谷歌没有添加java.time包？

Answer 1

java.time 包仅在 API 26 (Android O) 中添加: https://developer.android.com/reference/java/time/package-summary.html

更新

从 Android Gradle 插件 4.0 版开始，您可以使用 java.time API 的子集(以及许多其他 Java 8 语言 API)无需您的应用需要最低 API 级别:https://developer.android.com/studio/write/java8-support#library-desugaring

The following set of APIs are supported when building your app using Android Gradle plugin 4.0.0 or higher:

• Sequential streams (java.util.stream)
• A subset of java.time
• java.util.function
• Recent additions to java.util.{Map,Collection,Comparator}
• Optionals (java.util.Optional, java.util.OptionalInt and java.util.OptionalDouble) and some other new classes useful with theabove APIs
• Some additions to java.util.concurrent.atomic (new methods on AtomicInteger, AtomicLong and AtomicReference)
• ConcurrentHashMap (with bug fixes for Android 5.0)

要启用对这些语言 API 的支持，需要在 build.gradle 文件中包含以下几行:

android {
  defaultConfig {
    // Required when setting minSdkVersion to 20 or lower
    multiDexEnabled true
  }

  compileOptions {
    // Flag to enable support for the new language APIs
    coreLibraryDesugaringEnabled true
    // Sets Java compatibility to Java 8
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
}

dependencies {
  coreLibraryDesugaring 'com.android.tools:desugar_jdk_libs:1.0.4'
}