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

Question

I followed google documentation to integrate my app to Google Analytics. But when adding

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

and building my app, I encountered this error:

Error:(49, 0) For input string: "+"

These are the settings I used in the build.gradle of my application:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 22
    buildToolsVersion "22.0.1"
    defaultConfig {
        applicationId "com.myapp.xyz"
        manifestPlaceholders = [
            manifestApplicationId : "${applicationId}",
            onesignal_app_id : "ccd48c54-2069-41f9-8ff7-54c7a12f2d18a",
            onesignal_google_project_number: "306632981237"
        ]
        minSdkVersion 15
        targetSdkVersion 22
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'),
            'proguard-rules.pro'
        }
    }
}

repositories {
    mavenCentral()
}

dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    // compile 'com.android.support:appcompat-v7:22.2.1'
    compile project(':facebook')
    compile 'com.android.support:design:22.2.1'
    compile 'com.android.support:palette-v7:22.2.1'
    compile 'com.astuetz:pagerslidingtabstrip:1.0.1'
    compile 'com.android.support:appcompat-v7:22.2.1'
    compile 'com.android.support:support-v4:22.2.1'
    compile 'com.onesignal:OneSignal:1.+@aar'
    compile 'com.google.android.gms:play-services-gcm:+'
    compile 'com.google.android.gms:play-services:8.4.0'
    compile 'com.google.android.gms:play-services-analytics:8.4.0'
}
apply plugin: 'com.google.gms.google-services'

These are the setting in build.gradle application:

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.2.3'
        classpath 'com.google.gms:google-services:2.0.0-alpha6'
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}
allprojects {
    repositories {
        jcenter()
    }
}

Answer 1

At first you should call

    dependencies {
    classpath 'com.android.tools.build:gradle:1.5.0'
    classpath 'com.google.gms:google-services:2.0.0-alpha2'
}

Don't (Avoid calling +)

compile 'com.google.android.gms:play-services-gcm:+'
     compile 'com.google.android.gms:play-services:8.4.0'

Do

     compile 'com.google.android.gms:play-services:8.4.0'