title: Could not Resolve method R on Imported Project. (In App Billing Version 3) in Android Studio .4.2
body: <p>I imported the In app Billing V3 (The sample from Google). While changing the package in in android manifest or changing the target SDK of the program then rebuild, suddenly R method could not be found.</p>
  
  <p>Anyone already encounterd this? </p>
  
  <p><img src="https://i.stack.imgur.com/s4VYC.png" alt="enter image description here"></p>
  
  <p>Android Manifest</p>
  
  <pre><code>    &lt;!--
        Copyright (c) 2012 Google Inc.
  
        Licensed under the Apache License, Version 2.0 (the "License");
        you may not use this file except in compliance with the License.
        You may obtain a copy of the License at
  
        http://www.apache.org/licenses/LICENSE-2.0
  
        Unless required by applicable law or agreed to in writing, software
        distributed under the License is distributed on an "AS IS" BASIS,
        WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
        See the License for the specific language governing permissions and
        limitations under the License.
      --&gt;
  &lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
      package="com.example.android.trivialdrivesamplemotok"
      android:versionCode="3"
      android:versionName="1.3" &gt;
  
      &lt;uses-sdk
          android:minSdkVersion="8"
          android:targetSdkVersion="15" /&gt;
  
      &lt;!-- VERY IMPORTANT! Don't forget this permission, or in-app billing won't work. --&gt;
      &lt;uses-permission android:name="com.android.vending.BILLING" /&gt;
  
      &lt;application
          android:icon="@drawable/ic_launcher"
          android:label="@string/app_name"
          android:theme="@style/AppTheme" &gt;
          &lt;activity
              android:name="com.example.android.trivialdrivesample.MainActivity"
              android:label="@string/title_activity_main"
              android:screenOrientation="portrait"
               &gt;
              &lt;intent-filter&gt;
                  &lt;action android:name="android.intent.action.MAIN" /&gt;
                  &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
              &lt;/intent-filter&gt;
          &lt;/activity&gt;
      &lt;/application&gt;
  &lt;/manifest&gt;
  </code></pre>