Android : Activity onCreate is Called Infinitely After Screen Rotation to Landscape

I created an Android app with custom Toolbar and NavigationDrawer. When I started the app in landscape screen (and also rotate the app from portrait to landscape), the app always showed blinking infinitely. Although, I rotated to portrait, it kept blinking. I used Android API 22 and tested on Nexus 5 (Android 5.1.0).

This is my code:

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example">

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/MyTheme.NoActionBar">
        <activity
            android:name=".activity.MainActivity"
            android:label="@string/app_name">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".activity.SettingsActivity"
            android:configChanges="locale"
            android:label="@string/settings"
            android:parentActivityName=".activity.MainActivity"
            android:theme="@style/MyTheme.Light">
            <meta-data
                android:name="android.support.PARENT_ACTIVITY"
                android:value=".activity.MainActivity" />
        </activity>
    </application>

</manifest>

MainActivity.java

package com.example.activity;

import android.content.Intent;
import android.content.res.Configuration;
import android.content.res.TypedArray;
import android.net.Uri;
import android.os.Bundle;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarActivity;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.AdapterView;
import android.widget.LinearLayout;
import android.widget.ListView;

import com.example.R;
import com.example.nav.NavDrawerItem;
import com.example.nav.NavDrawerListAdapter;
import com.example.util.VersionUtil;

import java.util.ArrayList;

public class MainActivity extends ActionBarActivity {

    private Toolbar mToolbar;
    private DrawerLayout mDrawerLayout;
    private LinearLayout mDrawerRoot;
    private ListView mDrawerList;
    private ActionBarDrawerToggle mDrawerToggle;
    private NavDrawerListAdapter mDrawerAdapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mDrawerList = (ListView) findViewById(R.id.drawer_list);
        mToolbar = (Toolbar) findViewById(R.id.toolbar);
        mDrawerLayout = (DrawerLayout) findViewById(R.id.main_drawer_layout);
        mDrawerRoot = (LinearLayout) findViewById(R.id.drawer_root);

        initNavigationDrawer();
    }

    protected void initNavigationDrawer() {
        if (mToolbar != null) {
            setSupportActionBar(mToolbar);
        }

        mDrawerToggle = new ActionBarDrawerToggle(this, mDrawerLayout, mToolbar, R.string.drawer_open, R.string.drawer_close) {
            @Override
            public void onDrawerClosed(View drawerView) {
                super.onDrawerClosed(drawerView);
            }

            @Override
            public void onDrawerOpened(View drawerView) {
                super.onDrawerOpened(drawerView);
            }
        };
        mDrawerLayout.setDrawerListener(mDrawerToggle);


        String[] navMenuTitles = getResources().getStringArray(R.array.nav_drawer_items);
        TypedArray navMenuIcons = getResources().obtainTypedArray(R.array.nav_drawer_icons);
        TypedArray navMenuSelectedIcons = getResources().obtainTypedArray(R.array.nav_drawer_selected_icons);

        ArrayList<NavDrawerItem> navDrawerItems = new ArrayList<>();
        for (int i = 0, len = navMenuTitles.length; i < len; i++) {
            navDrawerItems.add(new NavDrawerItem(navMenuTitles[i], navMenuIcons.getResourceId(i, -1), navMenuSelectedIcons.getResourceId(i, -1), false));
        }

        // Recycle the typed array
        navMenuIcons.recycle();
        navMenuSelectedIcons.recycle();

        // setting the nav drawer list adapter
        mDrawerAdapter = new NavDrawerListAdapter(getApplicationContext(), navDrawerItems);
        mDrawerList.setAdapter(mDrawerAdapter);
        mDrawerList.setOnItemClickListener(new DrawerItemClickListener());
        mDrawerList.setChoiceMode(ListView.CHOICE_MODE_SINGLE);
        selectDrawerMenuItem(0);
    }

    @Override
    protected void onPostCreate(Bundle savedInstanceState) {
        super.onPostCreate(savedInstanceState);
        mDrawerToggle.syncState();
    }

    @Override
    public void onConfigurationChanged(Configuration newConfig) {
        super.onConfigurationChanged(newConfig);
        mDrawerToggle.onConfigurationChanged(newConfig);
        setContentView(R.layout.activity_main);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        if (mDrawerToggle.onOptionsItemSelected(item)) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    @Override
    public void setTitle(CharSequence title) {
        if (mToolbar != null) {
            mToolbar.setTitle(title);
        } else {
            super.setTitle(title);
        }
    }

    private class DrawerItemClickListener implements ListView.OnItemClickListener {
        @Override
        public void onItemClick(AdapterView parent, View view, int position, long id) {
            selectDrawerMenuItem(position);
        }
    }

    private void selectDrawerMenuItem(int position) {
        switch (position) {
            case 3: // Settings
                showSettings();
                break;
            case 4: // Help and Feedback
                sendHelpAndFeedbackEmail();
                break;
            default:
                setSelectedNavItemMenu(position);
                break;
        }
        mDrawerLayout.closeDrawer(mDrawerRoot);
    }

    private void setSelectedNavItemMenu(int position) {
        for (int i = 0, size = mDrawerAdapter.getCount(); i < size; i++) {
            NavDrawerItem menuItem = (NavDrawerItem) mDrawerAdapter.getItem(i);
            menuItem.setSelected(i == position);
        }
        mDrawerList.setItemChecked(position, true);
    }

    private void showSettings() {
        Intent settingsIntent = new Intent(this, SettingsActivity.class);
        startActivity(settingsIntent);
    }

    private void sendHelpAndFeedbackEmail() {
        Intent emailIntent = new Intent(Intent.ACTION_SENDTO);
        emailIntent.setType("text/plain");

        String versionName = VersionUtil.getVersionName(this);
        int versionCode = VersionUtil.getVersionCode(this);
        emailIntent.putExtra(Intent.EXTRA_SUBJECT, String.format(getString(R.string.email_help_subject), getText(R.string.app_name), versionName, versionCode));

        emailIntent.setData(Uri.parse("mailto:" + getText(R.string.email_send_to)));
        emailIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        startActivity(Intent.createChooser(emailIntent, getText(R.string.email_chooser_title)));
    }
 }

Why was the app blinking? Is there any solution to this problem? Thanks.