CODEWITHSUNDEEP
androidandroid-fragments
sebap123
sebap123

Reputation: 2685

NullPointerException error while adding fragment

I am having problem with implementing barcodefragmentlibv2 into my project. As a name says and from previous experience I know that I can add it into fragment. However, I am still getting NullPointerException error when I am trying to get this fragment to work with my app.

This is a part of a code responsible for barcode fragment:

import android.support.v4.app.Fragment;
//...

public class CameraFragment extends Fragment implements IScanResultHandler {
    BarcodeFragment fragment;

    public static CameraFragment newInstance() {
        CameraFragment fragment = new CameraFragment();
        return fragment;
    }

    public CameraFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.include_qrfragment, container, false);
        fragment = (BarcodeFragment)getActivity().getSupportFragmentManager().findFragmentById(R.id.sample);
        fragment.setScanResultHandler(this);
        return view;
    }
//...
}

Error appears in line:

fragment.setScanResultHandler(this);

I've also tried replacing

getActivity().getSupportFragmentManager().findFragmentById(R.id.sample);

to

getFragmentManager().findFragmentById(R.id.sample);

but the result is this same.

Below are layout files: fragment_camera

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" tools:context=".CameraFragment">

    <include
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        layout="@layout/include_qrfragment" />

    <TextView
        android:id="@+id/status_view"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="bottom|center_horizontal"
        android:layout_margin="15dp"
        android:background="#99FFFFFF"
        android:gravity="center"
        android:padding="10dp"
        android:text="@string/msg_default_status"
        android:textAppearance="?android:attr/textAppearanceMedium" />

    <View
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</FrameLayout>

include_qrfragment

<?xml version="1.0" encoding="utf-8"?>
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    android:id="@+id/sample"
    android:name="com.abhi.barcode.frag.libv2.BarcodeFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_alignParentTop="true"
    android:layout_centerHorizontal="true" />

At the beginning I've mentioned that from my own experience that this is possible. The truth is that I've built app utilizing this feature some time ago using eclipse and now I am using Android Studio - maybe there is a problem?

EDIT 1:

This is the whole error's stack trace:

06-22 23:05:56.804  30578-30578/myapp.com.test E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.NullPointerException
            at myapp.com.test.CameraFragment.onCreateView(CameraFragment.java:34)
            at android.support.v4.app.Fragment.performCreateView(Fragment.java:1789)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:955)
            at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1138)
            at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:740)
            at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1501)
            at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:458)
            at android.os.Handler.handleCallback(Handler.java:587)
            at android.os.Handler.dispatchMessage(Handler.java:92)
            at android.os.Looper.loop(Looper.java:130)
            at android.app.ActivityThread.main(ActivityThread.java:3683)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:507)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
            at dalvik.system.NativeStart.main(Native Method)

Upvotes: 1

Views: 197

Answers (3)

The Original Android
The Original Android

Reputation: 6215

I have read your responses, and now I am assuming you have tried or moved code of getActivity().getSupportFragmentManager().findFragmentById into onActivityCreated.

The only suspect I see without loading up your project is the GUI ID itself. You named it sample or R.id.sample, which is a suspect in some projects. It is possible that you have another UI element having the same name/ID. If so, that UI cannot be converted to a fragment. My suggestion is to change the name of the ID (with unique name), and use it with findFragmentById().

Upvotes: 0

Carlos
Carlos

Reputation: 386

You should only inflate the layout at the CreateView, like this: 

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

    return inflater.inflate(R.layout.your_layout, null);

}

The rest of your code, you should put it in the onActivityCreated as @waqaslam said.

You are getting a null pointer because there is no layout inflated yet.

Upvotes: 0

waqaslam
waqaslam

Reputation: 68177

The problem seems to lie in this line:

fragment = (BarcodeFragment)getActivity().getSupportFragmentManager().findFragmentById(R.id.sample);

Your fragment is not yet appended to the activity as getActivity() is null at this point.

Perhaps you should move that particular code to onActivityCreated

Upvotes: 1

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