not assignable to 'android.app.activity' extends application
<p>I am implementing Adobe Creative SDK. I am getting the following error in in my my manifest file:  </p>

<pre><code>'com.example.nick.avierytest2.MainActivity is not assignable to android.app.activity' 
</code></pre>

<p>This is my XML file:</p>

<pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
</code></pre>

<p></p>

<pre><code>&lt;application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme" &gt;
    &lt;activity
        android:name=".MainActivity"
        android:label="@string/app_name"
        android:theme="@style/AppTheme.NoActionBar" &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;
</code></pre>

<p></p>

<p>This is my main activity class:</p>

<pre><code>public class MainActivity extends Application implements IAdobeAuthClientCredentials {

/* Be sure to fill in the two strings below. */
private static final String CREATIVE_SDK_CLIENT_ID = "";
private static final String CREATIVE_SDK_CLIENT_SECRET = "";

@Override
public void onCreate() {
    super.onCreate();
    AdobeCSDKFoundation.initializeCSDKFoundation(
            getApplicationContext(),
            AdobeAuthIMSEnvironment.AdobeAuthIMSEnvironmentProductionUS
    );
}

@Override
public String getClientID() {
    return CREATIVE_SDK_CLIENT_ID;
}

@Override
public String getClientSecret() {
    return CREATIVE_SDK_CLIENT_SECRET;
}
</code></pre>

<p>}</p>

<p>Every other time I have seen this question on stackoverflow it was someone trying to declare a fragment in the manifest but that is not the problem here and I have not been able to find the solution.</p>

<p>Thank you for your help.</p>