android studio Unable to resolve dependency for ':app@

网上主要是说 

1.修改build.gradle 文件

    buildscript {

        repositories {
            google()
            jcenter()
        }
        dependencies {
            classpath 'com.android.tools.build:gradle:3.0.0'


            // NOTE: Do not place your application dependencies here; they belong
            // in the individual module build.gradle files
        }
    }

    allprojects {
    repositories {
        jcenter()
        maven {
            url "https://maven.google.com"
        }
    }
}

    task clean(type: Delete) {
        delete rootProject.buildDir
    }

2.在C:\Users\MissZhou\.gradle\wrapper\dists\gradle-4.4-all 中自己手动下载好文件

3.setting中build,execution,deployment中Gradle取消勾选offline work

4.前三条都没用

把

compileSdkVersion 27

改成 25 其他配置的也要改

apply plugin: 'com.android.application'

android {
    compileSdkVersion 25
    defaultConfig {
        applicationId "com.example.misszhou.myapplication"
        minSdkVersion 24
        targetSdkVersion 25
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}

dependencies {
    implementation fileTree(dir: 'libs', include: ['*.jar'])
    implementation 'com.android.support:appcompat-v7:25.1.1'
    implementation 'com.android.support.constraint:constraint-layout:1.0.2'
    implementation 'com.android.support:design:25.1.1'
 //   testImplementation 'junit:junit:4.12'
   // androidTestImplementation 'com.android.support.test:runner:1.0.1'
    //androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'
}