Fragments - The specified child already has a parent. You must call removeView() on the child's parent first

Question

I am getting this error. I tried many solutions but I coudn't solve this. Help me! I need to add the surface view and the button to the activity using fragments.

CamActivity.java:

public class CamActivity extends FragmentActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_cam);
        
        FragmentManager fm = getSupportFragmentManager();
        
        Fragment fragment = fm.findFragmentById(R.id.fragmentContainer);
        
        if(fragment == null) {
            fragment = new CamFragment();
            fm.beginTransaction()
            .add(R.id.fragmentContainer, fragment)
            .commit();
        }
    }
}

CamFragment.java:

public class CamFragment extends Fragment {

    private static final String TAG = "CamFragment";
    
    private Camera mCamera;
    private SurfaceView mSurfaceView;
    
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup parent, Bundle savedInstanceState){
    View v = inflater.inflate(R.layout.camera_fragment, parent);
    
    Button capturePic = (Button)v.findViewById(R.id.img_capture);
    capturePic.setOnClickListener(new View.OnClickListener() {
        
        @Override
        public void onClick(View v) {
            getActivity().finish();
        }
    });
    
    mSurfaceView = (SurfaceView)v.findViewById(R.id.surfaceView1);
    return v;
}

}

Error:

04-18 13:24:12.735: E/AndroidRuntime(6321): FATAL EXCEPTION: main
04-18 13:24:12.735: E/AndroidRuntime(6321): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.pack.camdictionary/com.pack.camdictionary.CamActivity}: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1728)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1747)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.app.ActivityThread.access$1500(ActivityThread.java:155)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:993)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.os.Handler.dispatchMessage(Handler.java:130)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.os.Looper.loop(SourceFile:351)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.app.ActivityThread.main(ActivityThread.java:3814)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at java.lang.reflect.Method.invokeNative(Native Method)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at java.lang.reflect.Method.invoke(Method.java:538)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:901)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:659)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at dalvik.system.NativeStart.main(Native Method)
04-18 13:24:12.735: E/AndroidRuntime(6321): Caused by: java.lang.IllegalStateException: The specified child already has a parent. You must call removeView() on the child's parent first.
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.view.ViewGroup.addViewInner(ViewGroup.java:2007)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.view.ViewGroup.addView(ViewGroup.java:1902)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.view.ViewGroup.addView(ViewGroup.java:1859)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.view.ViewGroup.addView(ViewGroup.java:1839)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.support.v4.app.NoSaveStateFrameLayout.wrap(NoSaveStateFrameLayout.java:40)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:931)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:570)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1166)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.app.Activity.performStart(Activity.java:3837)
04-18 13:24:12.735: E/AndroidRuntime(6321):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1701)
04-18 13:24:12.735: E/AndroidRuntime(6321):     ... 11 more

Answer 1

Try to replace

View v = inflater.inflate(R.layout.camera_fragment, parent);

With

View v = inflater.inflate(R.layout.camera_fragment, parent, false);

or

View v = inflater.inflate(R.layout.camera_fragment, null);

Answer 2

In my case, I was doing the setTransition() during the FragmentTransaction. Below code worked for me:

override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?,
                              savedInstanceState: Bundle?): View? {

        if(this::rootView.isInitialized){
            if(rootView.getParent() != null){
                (rootView.getParent() as ViewGroup).endViewTransition(rootView)
            }
            return this.rootView

        }

        ...

}

This probably happens when you repeatedly switch between fragments, that the view does not get time to really detach from the parent due to the ongoing transition.

Answer 3

This question had already been answered but still I would like to add the reason for adding false as the third parameter.

The inflate() method takes three arguments:

• The resource ID of the layout you want to inflate.
• The ViewGroup to be the parent of the inflated layout. Passing the container is important in order for the system to apply layout parameters to the root view of the inflated layout, specified by the parent view in which it's going.
• A boolean indicating whether the inflated layout should be attached to the ViewGroup (the second parameter) during inflation. (In this case, this is false because the system is already inserting the inflated layout into the container—passing true would create a redundant view group in the final layout.)

Source: http://developer.android.com/guide/components/fragments.html

Answer 4

I am using API 26.0.2 and in my case, the crash was happening because of custom animations set for my fragments. Commenting out the call to set the custom animation, fixed the issue.

fragmentTransaction.setCustomAnimations(android.R.anim.fade_in, android.R.anim.fade_out);

Answer 5

I also met this problem, and this is my solution. it's very easy

View v;

@Nullable
@Override
public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    if (v == null) {
        v = inflater.inflate(R.layout.camera_fragment, container);
    } else {
        ViewGroup parent = (ViewGroup) v.getParent();
        if (parent != null) {
            parent.removeView(v);
        }
    }
    return v;
}

Hope to be useful to you