onNavigationItemSelected not getting called

I solved my question , just simply change the order in my activity_main.xml .I have a LinearLayout viewgroup and NavigationView in my DrawerLayout viewgroup , at first the NavigationView is the first in my viewgroup and now I change the order , the first one is the LinearLayout and the second is NavigationView , and it work as it suppose to be . Dear!!!

But can someone tell me why it happend ? Does it matter the view order in a viewgroup regardless the display sequence .

I too had this issue and I finally figured out what was wrong, I initially created a sample project with navigation drawer and the main activity xml was as below,

<include    layout="@layout/app_bar_main"    android:layout_width="match_parent"    android:layout_height="match_parent" /><android.support.design.widget.NavigationView    android:id="@+id/nav_view"    android:layout_width="wrap_content"    android:layout_height="match_parent"    android:layout_gravity="start"    android:fitsSystemWindows="true"    app:headerLayout="@layout/nav_header_main"    app:menu="@menu/activity_main_drawer" />

But in the actual app I made I did a mistake like this,

<?xml version="1.0" encoding="utf-8"?><android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:id="@+id/drawer_layout"android:layout_width="match_parent"android:layout_height="match_parent"android:fitsSystemWindows="true"tools:openDrawer="start"><android.support.design.widget.NavigationView    android:id="@+id/nav_view"    android:layout_width="wrap_content"    android:layout_height="match_parent"    android:layout_gravity="start"    android:fitsSystemWindows="true"    app:headerLayout="@layout/nav_header_main"    app:menu="@menu/activity_main_drawer" /><LinearLayout...../></android.support.v4.widget.DrawerLayout>

I had a LinearLayout below the NavigationView which was the issue.

Then I did this, everything started to work fine.

<?xml version="1.0" encoding="utf-8"?><android.support.v4.widget.DrawerLayout xmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:id="@+id/drawer_layout"android:layout_width="match_parent"android:layout_height="match_parent"android:fitsSystemWindows="true"tools:openDrawer="start"><LinearLayout...../><android.support.design.widget.NavigationView    android:id="@+id/nav_view"    android:layout_width="wrap_content"    android:layout_height="match_parent"    android:layout_gravity="start"    android:fitsSystemWindows="true"    app:headerLayout="@layout/nav_header_main"    app:menu="@menu/activity_main_drawer" /></android.support.v4.widget.DrawerLayout>

Key was to put the NavigationView at last. Weird that UI was not disturbed but callback was.

The Navigation Drawer help say this:

The main content view (the FrameLayout above) must be the first child in the DrawerLayout because the XML order implies z-ordering and the drawer must be on top of the content.

regards to this example:

<android.support.v4.widget.DrawerLayout    xmlns:android="http://schemas.android.com/apk/res/android"    android:id="@+id/drawer_layout"    android:layout_width="match_parent"    android:layout_height="match_parent">    <!-- The main content view -->    <FrameLayout        android:id="@+id/content_frame"        android:layout_width="match_parent"        android:layout_height="match_parent" />    <!-- The navigation drawer -->    <ListView android:id="@+id/left_drawer"        android:layout_width="240dp"        android:layout_height="match_parent"        android:layout_gravity="start"        android:choiceMode="singleChoice"        android:divider="@android:color/transparent"        android:dividerHeight="0dp"        android:background="#111"/></android.support.v4.widget.DrawerLayout>

So this is the explanation, what is kind of annoying is if you have the wrong layout order as a result of an auto-generated template. I have faced this kind of "problems" with Android Studio a few times and is so fustrating.