Gradle error after android studio update

Question

Today I updated android studio to version 3.0
And after that I couldn't build project successfully.
I got these errors:

Unable to resolve dependency for ':app@release/compileClasspath': could not resolve com.android.support:appcompat-v7:27.0.1.

I tried using VPN or proxy etc. but none of them worked.
It's been a long day. I hope you may help me.

This is my build.gradle(app) :

apply plugin: 'com.android.application'

apply plugin: 'kotlin-android'

apply plugin: 'kotlin-android-extensions'

android {
compileSdkVersion 27
defaultConfig {
    applicationId "ir.hetbo.kotlin_tutorial"
    minSdkVersion 15
    targetSdkVersion 27
    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"org.jetbrains.kotlin:kotlin-stdlib-jre7:$kotlin_version"
implementation 'com.android.support:appcompat-v7:27.0.1'
implementation 'com.android.support.constraint:constraint-layout:1.0.2'
}

and this is build.gradle(project):

// Top-level build file where you can add configuration options common to 
all sub-projects/modules.

buildscript {
ext.kotlin_version = '1.1.60'
repositories {
    google()
    jcenter()
    maven {
        url "https://maven.google.com"
    }
}
dependencies {
    classpath 'com.android.tools.build:gradle:3.0.0'
    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

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

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

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

I did a lot of things to fix it but every time it failed.

I use gradle 4.3.1

And here is gradle wrapper properties :

#Sat Nov 18 10:16:45 IRST 2017
distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-4.3.1-all.zip

Answer 1

There is one build.gradle file for whole projects and one for each modules. Need to add below code in the application build.gradle file.

 buildscript {
        repositories {
            jcenter()
        }
        dependencies {
            classpath 'com.android.tools.build:gradle:2.3.2'
        }
    }

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

Answer 2

As of the new versions, the libraries are now inside the maven not inside Jcenter.

So inside your gradle file, you have to add maven like the below:

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

This link may help you: Adding support libraries

Answer 3

with the new features of gradle 4.1 and the classpath 'com.android.tools.build:gradle:3.0.0'

distributionBase=GRADLE_USER_HOME distributionPath=wrapper/dists zipStoreBase=GRADLE_USER_HOME zipStorePath=wrapper/dists distributionUrl=https://services.gradle.org/distributions/gradle-4.1-all.zip

and and this is build.gradle(project):

// Top-level build file where you can add configuration options common to 
all sub-projects/modules.

buildscript {
ext.kotlin_version = '1.1.60'
repositories {
    google()
    jcenter()

}
dependencies {
    classpath 'com.android.tools.build:gradle:3.0.0'
    classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

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

allprojects {
repositories {
    google()
    jcenter()

}
}

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

Answer 4

Try this code in build.gradle(Project) :

buildscript {
    ext.kotlin_version = '1.1.51'
    repositories {
        google()
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:3.0.0'
        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"

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

allprojects {
    repositories {
        google()
        jcenter()
    }
}

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