title: Required XML attribute 'adSize' was missing
body: <p>So for some reason when I place in an adview it doesn't auto fill the ads:adSize and ads:adUnitId and I am not able to select them, and my ad is displaying text that reads Required XML attribute 'adSize' was missing. also I don't think I can fill out xmlns:ads in my layout, although I may be mistaken. Why is this?</p>
  
  <p>my gradles</p>
  
  <pre><code>    // Top-level build file where you can add configuration options common to all sub-projects/modules.
  
  buildscript {
      repositories {
          jcenter()
      }
      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()
      }
  }
  
  task clean(type: Delete) {
      delete rootProject.buildDir
  }
  </code></pre>
  
  <p>second build.gradle</p>
  
  <pre><code>    apply plugin: 'com.android.application'
  
  android {
      compileSdkVersion 25
      buildToolsVersion "25.0.0"
      defaultConfig {
          applicationId "com.example.matig.adtest"
          minSdkVersion 15
          targetSdkVersion 25
          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-v7:25.1.0'
      testCompile 'junit:junit:4.12'
      compile 'com.google.firebase:firebase-ads:9.0.2'
      compile 'com.google.android.gms:play-services-ads:9.0.2'
  }
  
  apply plugin: 'com.google.gms.google-services'
  </code></pre>
  
  <p>my layout:</p>
  
  <pre><code>    &lt;?xml version="1.0" encoding="utf-8"?&gt;
  &lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
      xmlns:tools="http://schemas.android.com/tools"
      android:id="@+id/activity_main"
      android:layout_width="match_parent"
      android:layout_height="match_parent"
      android:paddingBottom="@dimen/activity_vertical_margin"
      android:paddingLeft="@dimen/activity_horizontal_margin"
      android:paddingRight="@dimen/activity_horizontal_margin"
      android:paddingTop="@dimen/activity_vertical_margin"
      tools:context="com.example.matig.adtest.MainActivity"&gt;
  
      &lt;TextView
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:text="Hello World!" /&gt;
  
      &lt;com.google.android.gms.ads.AdView
          android:layout_width="wrap_content"
          android:layout_height="wrap_content"
          android:layout_alignParentBottom="true"
          android:layout_centerHorizontal="true"
          android:id="@+id/adView3" /&gt;
  
  
  &lt;/RelativeLayout&gt;
  </code></pre>
  
  <p>I followed firebases tutorial step by step So i'm really confused as to what I'm doing wrong</p>