Android Studio Suddenly started to display unable to resolve com.android.support...25.0.0 error messages and all of my java files are erroneous now?

Question

My project was working very fine, but until one day, when I uploaded my project to github. I don't know if this issue is related to that but today when I compiled my android studio project, it started showing me these 4 horrible errors. I have tried most of the google results but no help!

Error:Failed to resolve: com.android.support:cardview-v7:25.0.0
Error:Failed to resolve: com.android.support:customtabs:25.0.0
Error:Failed to resolve: com.android.support:appcompat-v7:25.0.0
Error:Failed to resolve: com.android.support:support-v4:25.0.0

This is the screenshot of android studio screen if it helps!

This is my app level build.gradle file:

apply plugin: 'com.android.application'

repositories {
    mavenLocal()
    mavenCentral()
    flatDir {
        dirs 'libs'
    }
}

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.3"
    defaultConfig {
        applicationId "com.google.firebase.codelab.friendlychat"
        minSdkVersion 22
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    packagingOptions {
        exclude 'META-INF/LICENSE'
        exclude 'META-INF/LICENSE-FIREBASE.txt'
        exclude 'META-INF/NOTICE'
    }
    productFlavors {
    }
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:design:23.1.1'
    compile 'com.firebase:firebase-client-android:2.5.0'

    compile 'com.github.bumptech.glide:glide:3.6.1'
    compile 'de.hdodenhof:circleimageview:1.3.0'
    compile 'com.android.support:appcompat-v7:23.1.1'
    // Google
    compile 'com.google.android.gms:play-services-auth:9.4.0'
    // Firebase
    compile 'com.google.firebase:firebase-database:9.4.0'
    compile 'com.google.firebase:firebase-auth:9.4.0'
    compile 'com.google.firebase:firebase-config:9.4.0'
    compile 'com.google.android.gms:play-services-appinvite:9.4.0'
    compile 'com.google.firebase:firebase-messaging:9.4.0'
    compile 'com.google.android.gms:play-services-ads:9.4.0'
    compile 'com.google.firebase:firebase-database:9.2.1'
    compile 'com.google.firebase:firebase-messaging:9.2.1'
    compile 'com.google.firebase:firebase-crash:9.4.0'
    // Firebase UI
    compile 'com.firebaseui:firebase-ui-database:0.4.0'
    // Testing dependencies
    androidTestCompile 'junit:junit:4.12'
    androidTestCompile 'com.android.support.test.espresso:espresso-core:2.2.1'
    androidTestCompile 'com.android.support.test:runner:0.4.1'
    androidTestCompile 'com.android.support:support-annotations:23.4.0'


    compile 'com.facebook.android:facebook-android-sdk:[4,5)'
    //facebook
}

apply plugin: 'com.google.gms.google-services'

And this is my project level build.gradle file:

buildscript {
    repositories {
        jcenter()
        mavenLocal()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.2'
        classpath 'com.google.gms:google-services:3.0.0'


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

allprojects {
    repositories {
        jcenter()
        mavenLocal()
    }
}

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

Why I am starting to get these errors suddenly.
Thanks in advance!

Answer 1

Open your android SDK manager (from C:\Users\youruseraccount\AppData\Local\Android\sdk) and update following to latest versions in,

Tools section section

1. Android SDK Tool

2. Android SDK Platform-Tools

3. Android SDK Build tool

Android 7.1.1 (API 25) section

1. SDK Platform

Extras Section

1. Android Support Repository
2. Android Support Library

Then update your gradle file accordingly.