Error with branch io on android - getCurrentActivity() on a null object reference

I keep getting this error:

> java.lang.NullPointerException: Attempt to invoke virtual method
> 'android.app.Activity io.branch.referral.Branch.getCurrentActivity()'
> on a null object reference

this is the source code:

MainApp.java

public class MainApp extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
}
@Override public void onStart() {
super.onStart();
try {
Branch.sessionBuilder(this).withCallback(new Branch.BranchReferralInitListener() {
@Override
public void onInitFinished(JSONObject referringParams, BranchError error) {
if (error == null) {
// option 3: navigate to page
Intent intent = new Intent(MainApp.this, Main2Activity.class);
startActivity(intent);
} else {
Log.i("BRANCH SDK", error.getMessage());
}
}
}).withData(this.getIntent().getData()).init();
}
catch (Exception e) {
e.printStackTrace();
}
}
@Override
protected void onNewIntent(Intent intent) {
super.onNewIntent(intent);
try {
setIntent(intent);
// if activity is in foreground (or in backstack but partially visible) launching the same
// activity will skip onStart, handle this case with reInitSession
Branch.sessionBuilder(this).withCallback(branchReferralInitListener).reInit();
}
catch (Exception ignored) { }
}
private Branch.BranchReferralInitListener branchReferralInitListener = new Branch.BranchReferralInitListener() {
@Override
public void onInitFinished(JSONObject linkProperties, BranchError error) {
// do stuff with deep link data (nav to page, display content, etc)
}
};
}

Main2Activity.java

public class Main2Activity extends AppCompatActivity {

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
}
@Override public void onStart() {
super.onStart();
try{
// Branch logging for debugging
Branch.enableLogging();
// Branch object initialization
Branch.getAutoInstance(this);
}
catch (Exception e) {
e.printStackTrace();
}
}

}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.parkwaydrive.packagename">

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme"
android:usesCleartextTraffic="true">
<meta-data
android:name="com.facebook.sdk.ApplicationId"
android:value="@string/facebook_app_id" />
<activity
android:name=".MainApp">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
<!-- Branch URI Scheme -->
<intent-filter>
<data android:scheme="hello" />
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
</intent-filter>
</activity>
<!-- Branch init -->
<meta-data android:name="io.branch.sdk.BranchKey" android:value="key_live_jeVWU2AYfrIjpJmslgNxZgjeAwcUzcqK" />
<meta-data android:name="io.branch.sdk.BranchKey.test" android:value="key_test_hlxrWC5Zx16DkYmWu4AHiimdqugRYMr" />
<meta-data android:name="io.branch.sdk.TestMode" android:value="false" />     <!-- Set to true to use Branch_Test_Key (useful when simulating installs and/or switching between debug and production flavors) -->
<activity android:name=".MainActivity" />
<activity android:name=".Main2Activity" >
<!-- Branch App Links (optional) -->
<intent-filter android:autoVerify="true">
<action android:name="android.intent.action.VIEW" />
<category android:name="android.intent.category.DEFAULT" />
<category android:name="android.intent.category.BROWSABLE" />
<data android:scheme="https" android:host="2rerz.app.link" />
<!-- example-alternate domain is required for App Links when the Journeys/Web SDK and Deepviews are used inside your website.  -->
<data android:scheme="https" android:host="2rerz-alternate.app.link" />
</intent-filter>
</activity>
</application>

</manifest>

This is occurring since you have not implemented a CustomApplication class.
Please implement the same and add the Application class to your Manifest.xml file.