报错信息：

The specified Android SDK Build Tools version (31.0.0) is ignored, as it is below the minimum supported version (31.0.。) for Android Gradle Plugin 4.2.2.

Android SDK Build Tools 30.0.2 will be used.

现在的版本信息

android {
    compileSdkVersion 31
    buildToolsVersion "31.0.0"

    defaultConfig {
        applicationId "com.example.monitormemory"
        minSdkVersion 16
        targetSdkVersion 31
        versionCode 1
        versionName "1.0"

        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    } 

降低版本号试试：

compileSdkVersion 30
buildToolsVersion "30.0.0"
targetSdkVersion 30 

继续报错

The specified Android SDK Build Tools version (30.0.0) is ignored, as it is below the minimum supported version (30.0.2) for Android Gradle Plugin 4.2.2.

Android SDK Build Tools 30.0.2 will be used.

按照提示修改为30.0.2

compileSdkVersion 30
buildToolsVersion "30.0.2"
targetSdkVersion 30

终于编译成功了，666，记录下，以免忘记