android - 此编译器不支持 API 级别 31。请使用 30 或更早的 API 级别

Question

我将现有的 android 项目升级到 API 级别 31。我使用 Java 作为语言。我改变了 build.gradle

compileSdkVersion 31
defaultConfig {
    applicationId 'com.app.app'
    minSdkVersion 16
    targetSdkVersion 31
    versionCode 91
    versionName '4.0.1'
    testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    multiDexEnabled true
}

但我无法使用 AVD 或真实设备调试应用程序。我收到这个错误。

> Task :app:mergeProjectDexDebug
AGPBI: {"kind":"warning","text":"An API level of 31 is not supported by this compiler. Please use an API level of 30 or earlier","sources":[{}],"tool":"D8"}
AGPBI: {"kind":"warning","text":"An API level of 31 is not supported by this compiler. Please use an API level of 30 or earlier","sources":[{}],"tool":"D8"}
AGPBI: {"kind":"warning","text":"An API level of 31 is not supported by this compiler. Please use an API level of 30 or earlier","sources":[{}],"tool":"D8"}
AGPBI: {"kind":"warning","text":"An API level of 31 is not supported by this compiler. Please use an API level of 30 or earlier","sources":[{}],"tool":"D8"}
AGPBI: {"kind":"warning","text":"An API level of 31 is not supported by this compiler. Please use an API level of 30 or earlier","sources":[{}],"tool":"D8"}
AGPBI: {"kind":"warning","text":"An API level of 31 is not supported by this compiler. Please use an API level of 30 or earlier","sources":[{}],"tool":"D8"}
AGPBI: {"kind":"warning","text":"An API level of 31 is not supported by this compiler. Please use an API level of 30 or earlier","sources":[{}],"tool":"D8"}
AGPBI: {"kind":"warning","text":"An API level of 31 is not supported by this compiler. Please use an API level of 30 or earlier","sources":[{}],"tool":"D8"}
AGPBI: {"kind":"warning","text":"An API level of 31 is not supported by this compiler. Please use an API level of 30 or earlier","sources":[{}],"tool":"D8"}
An API level of 31 is not supported by this compiler. Please use an API level of 30 or earlier

我想我需要更新编译器，我该怎么做？

Answer 1

尝试将此添加到您的 build.gradle 文件:

android {
  ...
  compileOptions {
    sourceCompatibility JavaVersion.VERSION_1_8
    targetCompatibility JavaVersion.VERSION_1_8
  }
  kotlinOptions {
    jvmTarget = '1.8'
  }
}