与项目’：app’中的依赖’com.android.support:support-annotat

第一个解决方案：在此行添加gradle模块的依赖项

compile 'com.android.support:support-annotations:27.1.1'

并同步你的项目

注意：如果您使用Android studio 3更改编译实现

第二种解决方案：配置文档https://developer.android.com/studio/build/gradle-tips.html#configure-project-wide-properties中的项目范围属性

在project gradle中添加以下行：

// This block encapsulates custom properties and makes them available to all
// modules in the project.
ext {
    // The following are only a few examples of the types of properties you can define.
    compileSdkVersion = 26
    // You can also use this to specify versions for dependencies. Having consistent
    // versions between modules can avoid behavior conflicts.
    supportLibVersion = "27.1.1"
}

然后访问此部分,将compileSdkVersionline更改为

compileSdkVersion rootProject.ext.compileSdkVersion

并在依赖项部分更改导入的库如下所示：

compile "com.android.support:appcompat-v7:${rootProject.ext.supportLibVersion}"

并同步你的项目

注意：如果您使用Android studio 3更改编译实现

对于编译和实现之间的区别,请看这个
What’s the difference between implementation and compile in gradle