Error_(27, 13) Failed to resolve_ com.android.support_appcompat-v7_30.+ _a href=_install.m2.repo__In

Error:(27, 13) Failed to resolve: com.android.support:appcompat-v7:30.+
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解决办法：

我的 sdk 工具版本是26.1.1

然后点击Show in File

android {
    compileSdkVersion 30
    buildToolsVersion "30.0.2"
    defaultConfig {
        applicationId "com.bg.myapplication"
        minSdkVersion 19
        targetSdkVersion 30
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:30.+'

按照注释修改

android {
    compileSdkVersion 26//修改
    buildToolsVersion "30.0.2"
    defaultConfig {
        applicationId "com.bg.myapplication"
        minSdkVersion 19
        targetSdkVersion 26//修改
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:26.+'//修改