Q:

The description com.google.android.gms.play-services.4.2.42 is invalid

Android studio - googgle maps api v2 using these links:
https://developers.google.com/maps/documentation/android/start#getting_the_google_maps_android_api_v2
Google Maps in Android Studio
messages gradle tasks:
A problem occurred evaluating project ':app'.
> The description com.google.android.gms.play-services.4.2.42 is invalid

Event log:
3:29:53 PM Gradle invocation completed successfully with 1 error(s) in 6 sec
3:29:56 PM Gradle 'MyApplication2' project refresh failed:
       The description com.google.android.gms.play-services.4.2.42 is invalid
       Gradle settings

in my build.gradle file
apply plugin: 'android'

android {
compileSdkVersion 19
buildToolsVersion "19.0.0"

defaultConfig {
    minSdkVersion 13
    targetSdkVersion 19
    versionCode 1
    versionName "1.0"
}
buildTypes {
    release {
        runProguard false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-    rules.txt'
     }
 }
}

dependencies {
compile 'com.android.support:appcompat-v7:+'
compile 'com.google.android.gms.play-services.4.2.42'

I found this version number from .....sdk\extras\google\google_play_services\libproject\google-play-services_lib\AndroidManifest.xml file:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.google.android.gms"
android:versionCode="4242030"
android:versionName="4.2.42 (1018832-030)" >

<uses-sdk android:minSdkVersion="9"/>

</manifest>

and if it helps...manifest
<?xml version="1.0" encoding="utf-8"?>

<uses-sdk
    android:minSdkVersion="13"
    android:targetSdkVersion="19" />

<permission
    android:name="com.android.test.permission.MAPS_RECEIVE"
    android:protectionLevel="signature" />

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />

<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

<uses-feature
    android:glEsVersion="0x00020000"
    android:required="true" />

<meta-data
    android:name="com.google.android.gms.version"
    android:value="@integer/google_play_services_version" />

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme" >
    <activity
        android:name="com.android.myapplication2.app.MainActivity"
        android:label="@string/app_name" >
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>

    <meta-data
        android:name="com.google.android.maps.v2.API_KEY"
        android:value="my key"/>

</application>

A:

Instead of:
compile 'com.google.android.gms.play-services.4.2.42'

You need:
compile 'com.google.android.gms:play-services:4.2.42'

