Android dependency error compile 'com.android.support:appcompat-v7:26.+'

问题

This was working before I added firebaseui dependency. Now I'm getting this: log

Its red lining compile 'com.android.support:appcompat-v7:26.+' and when I hover over it, it says "all libraries must be exact same specification version". That version was what was there when the project was created.

app/build.gradle:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 26
    buildToolsVersion "26.0.1"
    defaultConfig {
        applicationId "com.android.adarak"
        minSdkVersion 21
        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'
        }
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:26.+'
    compile 'com.android.support:support-v4:26.+'
    compile 'com.android.support.constraint:constraint-layout:1.0.2'
    compile 'com.google.firebase:firebase-auth:10.0.1'
    //compile 'com.firebaseui:firebase-ui-auth:2.3.0'
    compile 'com.firebaseui:firebase-ui:2.3.0'
    testCompile 'junit:junit:4.12'
}


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

回答1:

The firebaseui internally has a dependency on a specific version of Android support library. The firebase ui configuration contains 26.0.1 as the required support library version.

However your gradle file has a dependency on 26.+ which tells gradle to use the latest in the 26.x.x series and this could be different from 26.0.1. You can solve the issue by using the specific version required by firebase-ui (26.0.1)

Change the gradle file as shown below,

compile 'com.android.support:appcompat-v7:26.0.1'
compile 'com.android.support:support-v4:26.0.1'

来源：https://stackoverflow.com/questions/46312558/android-dependency-error-compile-com-android-supportappcompat-v726