Null Pointer near the actionbar. setnavigaton mode

Question

I was trying to implement view pager .Encountering a null pointer exception.

I am Quit new to this concept.

Cannot figure out the issue.

please help

logcat

03-10 12:26:39.323: E/AndroidRuntime(10593): FATAL EXCEPTION: main
03-10 12:26:39.323: E/AndroidRuntime(10593): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.ib.qezyplay/com.ib.qezyplay.pagerMainActivity}: java.lang.NullPointerException
03-10 12:26:39.323: E/AndroidRuntime(10593):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2097)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2122)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at android.app.ActivityThread.access$600(ActivityThread.java:140)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1228)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at android.os.Handler.dispatchMessage(Handler.java:99)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at android.os.Looper.loop(Looper.java:137)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at android.app.ActivityThread.main(ActivityThread.java:4895)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at java.lang.reflect.Method.invokeNative(Native Method)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at java.lang.reflect.Method.invoke(Method.java:511)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:994)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:761)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at dalvik.system.NativeStart.main(Native Method)
03-10 12:26:39.323: E/AndroidRuntime(10593): Caused by: java.lang.NullPointerException
03-10 12:26:39.323: E/AndroidRuntime(10593):    at com.ib.qezyplay.pagerMainActivity.onCreate(pagerMainActivity.java:42)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at android.app.Activity.performCreate(Activity.java:5163)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
03-10 12:26:39.323: E/AndroidRuntime(10593):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2061)
03-10 12:26:39.323: E/AndroidRuntime(10593):    ... 11 more

pagerMainActivity

package com.ib.qezyplay;

import android.app.ActionBar;
import android.app.ActionBar.Tab;
import android.app.ActionBar.TabListener;
import android.app.FragmentTransaction;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter; 
import android.support.v4.view.ViewPager;
import android.util.Log;
import android.view.Window;


@SuppressWarnings("deprecation")
public class pagerMainActivity extends FragmentActivity  implements  TabListener{
    private static final String TAG = null;
    private MyAdapter myAdapter;
    private ActionBar actionBar;
    private ViewPager viewPager;


    @SuppressWarnings("deprecation")
    @Override
    protected void onCreate(Bundle arg0)
    {
        super.onCreate(arg0);
        getWindow().requestFeature(Window.FEATURE_ACTION_BAR);
        setContentView(R.layout.pager_main_activity);
        Intent  InfoFromSignScreen = getIntent();


        Log.e(TAG,"ENTERED **************** 1 ");
        viewPager =(ViewPager)findViewById(R.id.pager);
        myAdapter = new MyAdapter(getSupportFragmentManager());
        viewPager.setAdapter(myAdapter);

        actionBar = getActionBar();
        actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);        
        actionBar.setDisplayOptions(0, ActionBar.DISPLAY_SHOW_TITLE);



        ActionBar.Tab  tab1=actionBar.newTab();
        tab1.setText("Countries");
        tab1.setTabListener(this);


        ActionBar.Tab  tab2=actionBar.newTab();
        tab2.setText("Channels");
        tab2.setTabListener(this);


        ActionBar.Tab  tab3=actionBar.newTab();
        tab3.setText("Genres");
        tab3.setTabListener(this);


    }


    @SuppressWarnings("deprecation")
    @Override
    public void onTabReselected(Tab tab, FragmentTransaction ft) {
        // TODO Auto-generated method stub
        Log.e(TAG, " *****************TAB SELECTED  POSTION *******************" +tab.getPosition());
    }

    @Override
    public void onTabSelected(Tab tab, FragmentTransaction ft) {
        // TODO Auto-generated method stub
        Log.e(TAG, " *****************TAB SELECTED  POSTION *******************" +tab.getPosition());

    }


@Override
public void onTabUnselected(Tab tab, FragmentTransaction ft) {
    // TODO Auto-generated method stub
    Log.e(TAG, " *****************TAB SELECTED  POSTION *******************" +tab.getPosition());
}



public class MyAdapter extends FragmentPagerAdapter
{
    private String[] titles = { "Countries", "Channels", "Genres" };

    public MyAdapter(FragmentManager fm) {
        super(fm);
        // TODO Auto-generated constructor stub
    }

    @Override
    public Fragment getItem(int arg0) {
        // TODO Auto-generated method stub

        Fragment fragment =null;

        if(arg0 == 0)
        {
            fragment = new Countries();
        } 
        if(arg0 == 1)
        {
            fragment = new Genres();
        }
        if(arg0 == 2)
        {
            fragment = new UserMainScreen();
        }
        return null;
    }

    @Override
    public int getCount() {
        // TODO Auto-generated method stub
        return 3;
    }


}

}

pagerMainActivity.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.view.ViewPager xmlns:android="http://schemas.android.com/apk/res/android"  
    android:id="@+id/pager"
    android:minHeight="20dp"
    android:background="#ffffff"
    android:layout_width="match_parent"
    android:layout_height="wrap_content">

 </android.support.v4.view.ViewPager>

androidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.ib.qezyplay"
    android:versionCode="1"
    android:versionName="1.0" >    
         <uses-sdk
        android:minSdkVersion="11"
        android:targetSdkVersion="21" />


    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.READ_PHONE_STATE" />
    <uses-permission android:name="android.permission.ACCESS_WIFI_STATE" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <uses-permission android:name="android.permission.CLEAR_APP_CACHE" />
    <uses-permission android:name="android.permission.WAKE_LOCK" />
    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />

    <application
        android:name="com.ib.coverflow.StudyCenterApplication"
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/myAppTheme" >
        <activity
            android:name=".MainActivity"
            android:label="@string/app_name"
            android:screenOrientation="portrait"
            android:theme="@style/myAppTheme"
            android:windowSoftInputMode="stateHidden|adjustResize" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name=".pagerMainActivity"
            android:configChanges="orientation|keyboardHidden"
            android:label="@string/app_name" 
             android:screenOrientation="landscape">
        </activity>


        <service
            android:name="com.octoshape.android.service.StreamService"
            android:process=":OctoProc" />
    </application>

</manifest>

countries.java

package com.ib.qezyplay;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;



public class Countries extends Fragment {


         @Override
            public View onCreateView(LayoutInflater inflater, ViewGroup container,
                    Bundle savedInstanceState) {

                View rootView = inflater.inflate(R.layout.countries_layout, container, false);

                return rootView;
            }

    }

there are other two fragments same as above

you should paste the NullPointerException stacktrace so we can see where the problem is. It's impossible like this. — Gubatron, Mar 10 '15 at 07:19
debug and check `actionBar = getActionBar();` It would be `null`. — Maveňツ, Mar 10 '15 at 07:20
possible duplicate of [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) — Jens, Mar 10 '15 at 07:21
i have provided the logcat as well in the edited version of it — ludo, Mar 10 '15 at 07:30

Gubatron · Answer 1 · 2015-03-12T02:36:30.147

0

you should probably not be returning a null on your getItem method.

You go through all the trouble of instantiating a Fragment, only to return null.

public Fragment getItem(int arg0) {
        // TODO Auto-generated method stub

        Fragment fragment =null;

        if(arg0 == 0)
        {
            fragment = new Countries();
        } 
        if(arg0 == 1)
        {
            fragment = new Genres();
        }
        if(arg0 == 2)
        {
            fragment = new UserMainScreen();
        }
        return null; //here! maybe you want to return `fragment`
    }

EDIT After Logcat was provided

Your getActionBar() method is returning null.

Try calling getSupportActionBar() instead.

edited Mar 12 '15 at 02:36

answered Mar 10 '15 at 07:21

Gubatron

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but app is failed at `actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);` in `Activity` – M D Mar 10 '15 at 07:22
so it looks like `getActionBar()` is returning `null`. Try calling `getSupportActionBar()` instead. – Gubatron Mar 12 '15 at 02:35

score 0 · Answer 2 · answered Mar 10 '15 at 07:54

Since you are targeting the 21 and

getActionBar().setNavigationMode();//IS DEPRECATED

And the Navigation Mode is deprecated, You should add a if condition and check if the device api version id less than L.

NOTE: You should use the view pager with sliding tab layout what you want to achieve , The actionbar tabs are also deprecated on L.

Null Pointer near the actionbar. setnavigaton mode

2 Answers2