NullPointerException When starting new Activity in Navigation Drawer

Question

I am using a template navigation drawer that was provided by android studio. I am very new to android development so i'm wondering if i'm missing something simple here. I want to start a new activity by clicking on an item in my navigation menu I followed several tutorials on how to do this but i keep getting this error in my logcat:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.bsmyth.sidemenu/com.example.bsmyth.sidemenu.second_activity}: java.lang.NullPointerException

Here is the code I tried to start a new activity:

@SuppressWarnings("StatementWithEmptyBody")
@Override
public boolean onNavigationItemSelected(MenuItem item) {
    // Handle navigation view item clicks here.
    int id = item.getItemId();

    if (id == R.id.nav_camera) {
        // Handle the camera action
    } 

    else if (id == R.id.nav_gallery) {
        Intent intent = new Intent(MainActivity.this, second_activity.class);
        startActivity(intent);
    } 

      else if (id == R.id.nav_slideshow) {

    } else if (id == R.id.nav_manage) {

    } else if (id == R.id.nav_share) {

    } else if (id == R.id.nav_send) {

    }

    DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
    drawer.closeDrawer(GravityCompat.START);
    return true;
}
}

I referred to my second activity in my manifest file like this:

<application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme">
    <activity
        android:name=".MainActivity"
        android:label="@string/app_name"
        android:theme="@style/AppTheme.NoActionBar">
        <intent-filter>
            <action android:name="android.intent.action.MAIN" />

            <category android:name="android.intent.category.LAUNCHER" />
        </intent-filter>
    </activity>
    <activity android:name=".second_activity">
        <intent-filter>
            <action android:name="com.example.bsmyth.sidemenu.second_activity" />

            <category android:name="android.intent.category.DEFAULT" />
        </intent-filter>
    </activity>
</application>

Here is the drawer layout:

<group android:checkableBehavior="single">
    <item
        android:id="@+id/nav_camera"
        android:icon="@drawable/ic_menu_camera"
        android:title="Adfeed"
        android:checked="true"/>
    <item
        android:id="@+id/nav_gallery"
        android:icon="@drawable/ic_menu_gallery"
        android:title="Post" />
    <item
        android:id="@+id/nav_slideshow"
        android:icon="@drawable/ic_menu_slideshow"
        android:title="Notification" />
    <item
        android:id="@+id/nav_manage"
        android:icon="@drawable/ic_menu_send"
        android:title="Messages" />
</group>

Here is the second activity:

package com.example.bsmyth.sidemenu;

import android.app.ActionBar;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.view.View;
import android.support.design.widget.NavigationView;
import android.support.v4.view.GravityCompat;
import android.support.v4.widget.DrawerLayout;
import android.support.v7.app.ActionBarDrawerToggle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;

public class second_activity extends AppCompatActivity
            implements NavigationView.OnNavigationItemSelectedListener {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.second_activity);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        ActionBarDrawerToggle toggle = new ActionBarDrawerToggle(
                this, drawer, toolbar, R.string.navigation_drawer_open, R.string.navigation_drawer_close);
        drawer.setDrawerListener(toggle);
        toggle.syncState();

        NavigationView navigationView = (NavigationView) findViewById(R.id.nav_view);
        navigationView.setNavigationItemSelectedListener(this);
    }

    @Override
    public void onBackPressed() {
        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        if (drawer.isDrawerOpen(GravityCompat.START)) {
            drawer.closeDrawer(GravityCompat.START);
        } else {
            super.onBackPressed();
        }
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @SuppressWarnings("StatementWithEmptyBody")
    @Override
    public boolean onNavigationItemSelected(MenuItem item) {
        // Handle navigation view item clicks here.
        int id = item.getItemId();

        if (id == R.id.nav_camera) {
            // Handle the camera action
        } else if (id == R.id.nav_gallery) {

        } else if (id == R.id.nav_slideshow) {

        } else if (id == R.id.nav_manage) {

        } else if (id == R.id.nav_share) {

        } else if (id == R.id.nav_send) {

        }

        DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
        drawer.closeDrawer(GravityCompat.START);
        return true;
    }
}

Here is second_activity layout:

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Your in the second activity"
    android:textSize="20sp"/>

</android.support.v4.widget.DrawerLayout>

And here are the error messages in logcat:

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.bsmyth.sidemenu/com.example.bsmyth.sidemenu.second_activity}: java.lang.NullPointerException
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
    at android.app.ActivityThread.access$600(ActivityThread.java:130)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:137)
    at android.app.ActivityThread.main(ActivityThread.java:4745)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
    at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
    at com.example.bsmyth.sidemenu.second_activity.onCreate(second_activity.java:30)
    at android.app.Activity.performCreate(Activity.java:5008)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084) 
    at android.app.ActivityThread.access$600(ActivityThread.java:130) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195) 
    at android.os.Handler.dispatchMessage(Handler.java:99) 
    at android.os.Looper.loop(Looper.java:137) 
    at android.app.ActivityThread.main(ActivityThread.java:4745) 
    at java.lang.reflect.Method.invokeNative(Native Method) 
    at java.lang.reflect.Method.invoke(Method.java:511) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
    at dalvik.system.NativeStart.main(Native Method)

There is my second activity it is a copy of main activity apart for setContentView so that I could have the drawer nav on that page too — Brian Smith, Apr 01 '16 at 10:05
Are you sure there is `toolbar` in layout `second_activity` ? — Shree Krishna, Apr 01 '16 at 10:08
not `toolbar`, make sure you have `drawer_layout` in `second_activity.xml` it is throwing `java.lang.NullPointerException` at `drawer.setDrawerListener(toggle);` — Omkar, Apr 01 '16 at 10:09
There is no toolbar I will post my second activity layout now see what you think — Brian Smith, Apr 01 '16 at 10:11
if you dont have widget with id drawer_layout in second_layout.xml how come you are accessing — virendrao, Apr 01 '16 at 10:18

score 1 · Accepted Answer · answered Apr 01 '16 at 10:25

1

Your second activity layout has only a DrawerLayout and one TextView it does not have the views that you are calling in onCreate method. Try running it again after removing this views from your onCreate:

   Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
   setSupportActionBar(toolbar);
   NavigationView navigationView = (NavigationView)    findViewById(R.id.nav_view);
   navigationView.setNavigationItemSelectedListener(this);

answered Apr 01 '16 at 10:25

stevyhacker

1,847
2
23
31

Thank you for that instead of removing them i added the elements from activity_main.xml (Used as layout for MainActivity) to second_activity.xml so that the second_activity.java which is a copy of MainActivity would find the same elements. – Brian Smith Apr 01 '16 at 10:39

score 0 · Answer 2 · answered Apr 01 '16 at 10:19

add this:

android:id="@+id/drawer_layout"

to your DrawerLayout.

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/drawer_layout"
>

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Your in the second activity"
    android:textSize="20sp"/>

</android.support.v4.widget.DrawerLayout>

score 0 · Answer 3 · answered Apr 01 '16 at 10:22

0

Use a little common sense on these, you are using findViewById for drawer_layout, toolbar as well as nav_view and other extras too.

But there is nothing in second_activity layout except one TextView even that is without any id. Then how can these codes work ?

Create these elements like shown in new android project in android studio then follow the same pattern and see how the next layout is included there.

answered Apr 01 '16 at 10:22

Shree Krishna

8,474
6
40
68

Thank you I am very new to java and android development an was not fully aware of that id relationship between the java file and xml layout file – Brian Smith Apr 01 '16 at 10:41

score 0 · Answer 4 · answered Apr 01 '16 at 10:45

Your will get multiple NullPointerException in your code. You only copied the code of MainActivity.java to second_activity.java but not in the layout file from activity_main to second_activity.

You can create your second activity in project explorer and selecting the activity you want from the template. It is the easiest way and also very good way. After that you can simply call the second activity from first activity like you are doing now

score 0 · Answer 5 · answered Apr 01 '16 at 10:53

You are doing many things wrong in second activity code.... In layout XML..you don't give any id for drawer layout which you are using (drawer_layout). So Add this...

<?xml version="1.0" encoding="utf-8"?>
<android.support.v4.widget.DrawerLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/drawer_layout">

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Your in the second activity"
android:textSize="20sp"/>

</android.support.v4.widget.DrawerLayout>

Also create this view toolbar and nav_view in this XML file like you have create Textview in second_activity XML .

And create Drawer object only once with same drwaer id(drawer_layout). Like...

//declare this globally(means out of any method)
DrawerLayout drawer;

and then initialize this in onCreate method...

drawer = (DrawerLayout) findViewById(R.id.drawer_layout);

and at last remove this line DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout); from onBackPressed() and onNavigationItemSelected method.

Hope this will help you...

NullPointerException When starting new Activity in Navigation Drawer

5 Answers5