android - 同步gradle的问题

Question

我安装的是Android Studio 3.4，在同步gradle的时候遇到了这个问题。我无法在任何地方找到问题的解决方案。

这是我收到的错误:

"Failed to resolve: com.android.support:appcompat-v7:28.0.0 Show in Project Structure dialog Affected Modules: app""

"Failed to resolve: com.android.support.constraint:constraint-layout:1.1.3 Show in Project Structure dialog Affected Modules: app""

"Failed to resolve: com.android.support.test:runner:1.0.2 Show in Project Structure dialog Affected Modules: app"

"Failed to resolve: com.android.support.test.espresso:espresso-core:3.0.2 Show in Project Structure dialog Affected Modules: app"

Answer 1

  repositories {
        google()
        jcenter()
        maven { url 'https://maven.google.com' }
        maven { url 'https://plugins.gradle.org/m2/' }
    }

compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }

“添加你的gradle文件”