Google Sign-in button error in Android
<p>I try to include Google sign-in button in my android app by following steps:</p>

<p>1) Including the button:</p>

<pre><code>&lt;com.google.android.gms.common.SignInButton
    android:id="@+id/sign_in_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content" /&gt;
</code></pre>

<p>2) Editing  Top-level build file </p>

<pre><code>classpath 'com.google.gms:google-services:1.5.0-beta2'
</code></pre>

<p>3) Editing App-level build file</p>

<pre><code>apply plugin: 'com.google.gms.google-services'
</code></pre>

<p>Now I am getting error in button UI as</p>

<blockquote>
  <p>Blockquote
  The following classes could not be found:
  - com.google.android.gms.common.SignInButton (Fix Build Path, Create Class)</p>
</blockquote>

<p>Please help me solve this issue!</p>