[android] Failed to resolve: com.android.support:appcompat-v7:26.0.0

I am having this issue in Android studio.

Error:(22, 13) Failed to resolve: com.android.support:appcompat-v7:26.0.0
<a href="install.m2.repo">Install Repository and sync project</a><br><a href="openFile:C:/Users/username/AndroidStudioProjects/ElectroSave/app/build.gradle">Show in File</a><br><a href="open.dependency.in.project.structure">Show in Project Structure dialog</a>

This is my Gradle code:

apply plugin: 'com.android.application'

android {
       compileSdkVersion 26
      buildToolsVersion "25.0.2"
    defaultConfig {
    applicationId "com.example.noelly.myapplication"
    minSdkVersion 19
    targetSdkVersion 25
    versionCode 1
    versionName "1.0"
}
   buildTypes {
      release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 
'proguard-rules.pro'




 dependencies {
     compile fileTree(dir: 'libs', include: ['*.jar'])
     compile 'com.android.support:appcompat-v7:26.0.0'
}

1 - in build.gradle change my supportLibVersion to 26.0.0

2 - in app/build.gradle use :

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

3 - cd android

4 - ./gradlew clean

5 - ./gradlew assembleRelease

My issue got resolved with the help of following steps:

For gradle 3.0.0 and above version

1. add google() below jcenter()
2. Change the compileSdkVersion to 26 and buildToolsVersion to 26.0.2
3. Change to gradle-4.2.1-all.zip in the gradle_wrapper.properties file

1. Add this in build.gradle(Project:projectname)

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

2. Add this in build.gradle(Module:app)

   dependencies {
     compile 'com.android.support:appcompat-v7:26.1.0'
   }
   

If you already use jitpack.io or any repository. You can add google repository like this:

allprojects {
    repositories {
        maven { url "https://jitpack.io" }
        maven { url "https://maven.google.com" }
    }
}

Go to SDK path: SDK\extras\android\m2repository\com\android\support\appcompat-v7 to see correct dependency name, then change name if your dependency is alpha version:

dependencies {
  compile fileTree(dir: 'libs', include: ['*.jar'])
  compile 'com.android.support:appcompat-v7:26.0.0'
}

to :

dependencies {
  compile fileTree(dir: 'libs', include: ['*.jar'])
  compile 'com.android.support:appcompat-v7:26.0.0-alpha1'
}

Can you control internet access ? If you dont have internet access, your ide doesnt download package then you encountered this problem.

I was facing the same issue but I switched 26.0.0-beta1 dependencies to 26.1.0 and it's working now.

Adding the below content in the main gradle has solved the problem for me:

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

To use support libraries starting from version 26.0.0 you need to add Google's Maven repository to your project's build.gradle file as described here: https://developer.android.com/topic/libraries/support-library/setup.html

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

For Android Studio 3.0.0 and above:

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

If you are using Android Studio 3.0, add the Google maven repository as shown below:

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

File -> Project Structure -> Modules (app) -> Open Dependencies Tab -> Remove all then use + to add from the proposed list.

change

compile 'com.android.support:appcompat-v7:26.0'

to

`compile 'com.android.support:appcompat-v7:26.+'`

worked for me fine.

you forgot to add add alpha1 in module area

compile 'com.android.support:appcompat-v7:26.0.0-alpha1'

use maven repository in project area that's it

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

Please be noted, we need to add google maven to use support library starting from revision 25.4.0. As in the release note says:

Important: The support libraries are now available through Google's Maven repository. You do not need to download the support repository from the SDK Manager. For more information, see Support Library Setup.

Read more at Support Library Setup.

Play services and Firebase dependencies since version 11.2.0 are also need google maven. Read Some Updates to Apps Using Google Play services and Google APIs Android August 2017 - version 11.2.0 Release note.

So you need to add the google maven to your root build.gradle like this:

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

For Gradle build tools plugin version 3.0.0, you can use google() repository (more at Migrate to Android Plugin for Gradle 3.0.0):

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

UPDATE:

From Google's Maven repository:

The most recent versions of the following Android libraries are available from Google's Maven repository:

• Android Support Library
• Architecture Components Library
• Constraint Layout Library
• Android Test Support Library
• Databinding Library
• Android Instant App Library
• Google Play services
• Firebase

To add them to your build, you need to first include Google's Maven repository in your top-level / root build.gradle file:

allprojects {
    repositories {
        google()

        // If you're using a version of Gradle lower than 4.1, you must instead use:
        // maven {
        //     url 'https://maven.google.com'
        // }
        // An alternative URL is 'https://dl.google.com/dl/android/maven2/'
    }
}

Then add the desired library to your module's dependencies block. For example, the appcompat library looks like this:

dependencies {
    compile 'com.android.support:appcompat-v7:26.1.0'
}

However, if you're trying to use an older version of the above libraries and your dependency fails, then it's not available in the Maven repository and you must instead get the library from the offline repository.