Fragment showing nullpointerexception

Question

I am working on SlidingPaneLayout for android 2.3.3. I have assigned an id to the fragment that I used to identify the fragment. But while identifying fragment by id it is showing "null pointerexecption". I don't know why it is showing so. The code is as shown below.

Mainactivity.java

package com.example.slidpanelayout;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.widget.SlidingPaneLayout;
import android.view.Menu;
import android.view.View;

@SuppressLint("NewApi")
public class MainActivity extends FragmentActivity {

    SlidingPaneLayout Pane;
    View v;

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

        Pane = (SlidingPaneLayout) findViewById(R.id.sp);

        Pane.setPanelSlideListener(new PaneListener()); 
            getFragmentManager().findFragmentById(R.id.leftpane).setHasOptionsMenu(false);
            getFragmentManager().findFragmentById(R.id.rightpane).setHasOptionsMenu(true);  
    }

    private class PaneListener implements SlidingPaneLayout.PanelSlideListener{

        @Override
        public void onPanelClosed(View arg0) {
            // TODO Auto-generated method stub
            System.out.println("Panel closed");

            getFragmentManager().findFragmentById(R.id.leftpane).setHasOptionsMenu(false);
            getFragmentManager().findFragmentById(R.id.rightpane).setHasOptionsMenu(true);
        }

        @Override
        public void onPanelOpened(View arg0) {
            // TODO Auto-generated method stub
            System.out.println("Panel Opened");
            getFragmentManager().findFragmentById(R.id.leftpane).setHasOptionsMenu(true);
            getFragmentManager().findFragmentById(R.id.rightpane).setHasOptionsMenu(false);
        }

        @Override
        public void onPanelSlide(View arg0, float arg1) {
            // TODO Auto-generated method stub
            System.out.println("Sliding");
        }

    }

    @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;
    }
}

activity_main.xml

<android.support.v4.widget.SlidingPaneLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/sp">

    <fragment 
        android:name="com.example.slidpanelayout.ListFragment"
        android:id="@+id/leftpane"
        android:layout_width="190dp"
        android:layout_height="match_parent"
        android:layout_gravity="left"/>
    <fragment 
        android:name="com.example.slidpanelayout.ViewFragment"
        android:id="@+id/rightpane"
        android:layout_width="350dp"
        android:layout_height="match_parent"
        android:layout_gravity="right"
        />
</android.support.v4.widget.SlidingPaneLayout>

and logcat error as shown below.

11-13 06:24:05.479: E/AndroidRuntime(2375): FATAL EXCEPTION: main
11-13 06:24:05.479: E/AndroidRuntime(2375): Process: com.example.slidpanelayout, PID: 2375
11-13 06:24:05.479: E/AndroidRuntime(2375): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.slidpanelayout/com.example.slidpanelayout.MainActivity}: java.lang.NullPointerException
11-13 06:24:05.479: E/AndroidRuntime(2375):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2176)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2226)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at android.app.ActivityThread.access$700(ActivityThread.java:135)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1397)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at android.os.Handler.dispatchMessage(Handler.java:102)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at android.os.Looper.loop(Looper.java:137)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at android.app.ActivityThread.main(ActivityThread.java:4998)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at java.lang.reflect.Method.invokeNative(Native Method)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at java.lang.reflect.Method.invoke(Method.java:515)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:777)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:593)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at dalvik.system.NativeStart.main(Native Method)
11-13 06:24:05.479: E/AndroidRuntime(2375): Caused by: java.lang.NullPointerException
11-13 06:24:05.479: E/AndroidRuntime(2375):     at com.example.slidpanelayout.MainActivity.onCreate(MainActivity.java:25)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at android.app.Activity.performCreate(Activity.java:5243)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
11-13 06:24:05.479: E/AndroidRuntime(2375):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2140)
11-13 06:24:05.479: E/AndroidRuntime(2375):     ... 11 more

Please help me on this.

Answer 1

You are calling getFragmentManager. As it appears you are using the support package, you should be calling getSupportFragmentManager