[android] Setting up Gradle for api 26 (Android)

Since I have upgraded my Nexus 5x to Android O DP3 I am not able to test my applications. I get the error for not having configured my Gradle-file to work with the new API-level (26).

So I changed this and the dependencies, but I keep getting errors on ALL my support libraries like

Failed to resolve: com.android.support:design:26.0.0-beta2

Clicking on

Install repository and sync project

Pops up a progressdialog for downloading the right dependency but does not remove the error. Cleaning up project, installing repositories and then rebuilding the project won't work either.

appcompat-v7

On appcompat-v7:26.0.0-beta2 I get (before even a Gradle sync) squickly lines with the error:

When using a compileSdkVersion older than android-O revision 2,
the support library version must be 26.0.0-alpha1 or lower (was 26.0.0-beta2)

Can someone help me get the gradle file to be configured correctly for Android API 26? Any help would be appreciated.

PS: I'm using Gradle 3.0.0-alpha3 at the moment but get the same error on Gradle 2.3.2

My Gradle file:

apply plugin: 'com.android.application'

android {
compileSdkVersion 26
buildToolsVersion '26.0.0'

defaultConfig {
    applicationId "********"
    minSdkVersion 21
    targetSdkVersion 26
    versionCode 3
    versionName "2.0"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}
}

dependencies {
compile fileTree(include: ['*.jar'], dir: 'libs')
testCompile 'junit:junit:4.12'
compile 'com.android.support:appcompat-v7:26.0.0-beta2'
compile 'com.android.support:design:26.0.0-beta2'
compile 'com.github.bumptech.glide:glide:3.7.0'
compile 'com.squareup.picasso:picasso:2.5.2'
compile 'com.android.support:cardview-v7:26.0.0-beta2'
compile 'com.android.support:recyclerview-v7:26.0.0-beta2'
compile 'com.redbooth:WelcomeCoordinator:1.0.1'
compile 'com.github.kittinunf.fuel:fuel-android:1.4.0'
compile 'com.pkmmte.view:circularimageview:1.1'
compile 'com.ramotion.foldingcell:folding-cell:1.1.0'
}

you must add in your MODULE-LEVEL build.gradle file with:

//module-level build.gradle file
repositories {
    maven {
        url 'https://maven.google.com'

    }
}

see: Google's Maven repository

I have observed that when I use Android Studio 2.3.3 I MUST add repositories{maven{url 'https://maven.google.com'}} in MODULE-LEVEL build.gradle. In the case of Android Studio 3.0.0 there is no need for the addition in module-level build.gradle. It is enough the addition in project-level build.gradle which has been referred to in the other posts here, namely:

//project-level build.gradle file
allprojects {
 repositories {
    jcenter()
    maven {
        url 'https://maven.google.com/'
        name 'Google'
    }
  }
}

UPDATE 11-14-2017: The solution, that I present, was valid when I did the post. Since then, there have been various updates (even with respect to the site I refer to), and I do not know if now is valid. For one month I did my work depending on the solution above, until I upgraded to Android Studio 3.0.0

Appart from setting maven source url to your gradle, I would suggest to add both design and appcompat libraries. Currently the latest version is 26.1.0

maven {
    url "https://maven.google.com"
}

...

compile 'com.android.support:appcompat-v7:26.1.0'
compile 'com.android.support:design:26.1.0'

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

android {
    compileSdkVersion 26
    buildToolsVersion "26.0.1"
    defaultConfig {
        applicationId "com.keshav.retroft2arrayinsidearrayexamplekeshav"
        minSdkVersion 15
        targetSdkVersion 26
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
}
 compile 'com.android.support:appcompat-v7:26.0.1'
    compile 'com.android.support:recyclerview-v7:26.0.1'
    compile 'com.android.support:cardview-v7:26.0.1'

Appears to be resolved by Android Studio 3.0 Canary 4 and Gradle 3.0.0-alpha4.

You could add google() to repositories block

allprojects {
    repositories {
        jcenter()
        maven {
            url 'https://github.com/uPhyca/stetho-realm/raw/master/maven-repo'

        }
        maven {
            url "https://jitpack.io"
        }
        google()
    }
}