Why would my FragmentTransacton() or FragmentManager.beginTransaction() run into a null pointer exception

11,843

Put this in your code:

FragmentManager manager = getActivity().getSupportFragmentManager()
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Updated on June 04, 2022

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  • Admin
    Admin almost 2 years

    I am recieving a nullPointerException:

    java.lang.RuntimeException: Unable to start activity ComponentInfo{---private---}: 
          java.lang.NullPointerException: Attempt to invoke virtual method 'android.support.v4.app.FragmentTransaction 
          android.support.v4.app.FragmentManager.beginTransaction()' on a null object reference
                at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
                at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
                at android.app.ActivityThread.access$800(ActivityThread.java:144)
                at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
                at android.os.Handler.dispatchMessage(Handler.java:102)
                at android.os.Looper.loop(Looper.java:135)
                at android.app.ActivityThread.main(ActivityThread.java:5221)
                at java.lang.reflect.Method.invoke(Native Method)
                at java.lang.reflect.Method.invoke(Method.java:372)
                at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
                at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
         Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'android.support.v4.app.FragmentTransaction 
          android.support.v4.app.FragmentManager.beginTransaction()' on a null object reference
                at com.zero. ??? .BoxFragment.newInstance(BoxFragment.java:59)
                at com.zero. ??? .MainActivity$SectionPagerAdapter.getItem(MainActivity.java:111)
                at com.zero. ??? .MainActivity.onCreate(MainActivity.java:58)
                at android.app.Activity.performCreate(Activity.java:5937)
                at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1105)
                at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2251)
                at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
                at android.app.ActivityThread.access$800(ActivityThread.java:144)
                at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
                at android.os.Handler.dispatchMessage(Handler.java:102)
                at android.os.Looper.loop(Looper.java:135)
                at android.app.ActivityThread.main(ActivityThread.java:5221)
                at java.lang.reflect.Method.invoke(Native Method)
                at java.lang.reflect.Method.invoke(Method.java:372)
                at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
                at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
    05-02 17:52:00.093    2227-2227/com.zero.mytoolroom I/Process﹕ Sending signal. PID: 2227 SIG: 9
    

    within this method

    /* returns a new instance of this fragment for the given section number */
    public BoxFragment newInstance(int sectionNumber) {
        Log.v(LOG_TAG, "inside newInstance()");
        manage = getFragmentManager();
        BoxFragment fragment = new BoxFragment();
        Log.v(LOG_TAG, "box fragment created");
        Bundle args = new Bundle();
        args.putInt(ARG_SECTION_NUMBER, sectionNumber);
        fragment.setArguments(args);
        transaction = manage.beginTransaction();
        transaction.add(R.id.box_layout,fragment).addToBackStack(null);
        transaction.commit();
        return fragment;
    }//end newInstance() 
    
  • Admin
    Admin almost 9 years
    Thanks alot. I completed the project already, it works. I removed the transaction alltogether. But now the display is displaying the text bunched up together on top of eachother.
  • Admin
    Admin almost 9 years
    I tried using the getSupport..... but it reacted the same way. So i removed and was able to work around it. Getting it to display properly is the problem now....