java.lang.NullPointerException

Attempt to write to field 'android.support.v4.app.FragmentManagerImpl android.support.v4.app.Fragment.mFragmentManager' on a null object reference

Samebug tips2

Check if you imported android.support.v4.app.FragmentManager and not android.app.FragmentManager. Check for naming problems in your xml files as well, might have inconsistencies!

Also, check if you're not using android.support.v4.app.FragmentTransaction with android.app.Fragment, as they're not totally compatible.

Don't give up yet. Our experts can help. Paste your full stack trace to get a solution.

Solutions on the web21012

  • Attempt to write to field 'android.support.v4.app.FragmentManagerImpl android.support.v4.app.Fragment.mFragmentManager' on a null object reference
  • Attempt to write to field 'android.support.v4.app.FragmentManagerImpl android.support.v4.app.Fragment.mFragmentManager' on a null object reference
  • via GitHub by TIIUNDER
    , 1 year ago
    Attempt to write to field 'android.support.v4.app.FragmentManagerImpl android.support.v4.app.Fragment.mFragmentManager' on a null object reference
  • Stack trace

    • java.lang.NullPointerException: Attempt to write to field 'android.support.v4.app.FragmentManagerImpl android.support.v4.app.Fragment.mFragmentManager' on a null object reference at android.support.v4.app.BackStackRecord.doAddOp(BackStackRecord.java:414) at android.support.v4.app.BackStackRecord.add(BackStackRecord.java:409) at android.support.v4.app.FragmentPagerAdapter.instantiateItem(FragmentPagerAdapter.java:99) at android.support.v4.view.ViewPager.addNewItem(ViewPager.java:943) at android.support.v4.view.ViewPager.populate(ViewPager.java:1091) at android.support.v4.view.ViewPager.populate(ViewPager.java:1025) at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1545) at android.view.View.measure(View.java:18563) at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728) at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:464) at android.view.View.measure(View.java:18563) at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:728) at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:464) at android.view.View.measure(View.java:18563) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5827) at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135) at android.view.View.measure(View.java:18563) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5827) at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1435) at android.widget.LinearLayout.measureVertical(LinearLayout.java:721) at android.widget.LinearLayout.onMeasure(LinearLayout.java:612) at android.view.View.measure(View.java:18563) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5827) at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) at android.view.View.measure(View.java:18563) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5827) at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1435) at android.widget.LinearLayout.measureVertical(LinearLayout.java:721) at android.widget.LinearLayout.onMeasure(LinearLayout.java:612) at android.view.View.measure(View.java:18563) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5827) at android.widget.FrameLayout.onMeasure(FrameLayout.java:430) at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2888) at android.view.View.measure(View.java:18563) at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2248) at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1306) at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1548) at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1191) at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:6642) at android.view.Choreographer$CallbackRecord.run(Choreographer.java:777) at android.view.Choreographer.doCallbacks(Choreographer.java:590) at android.view.Choreographer.doFrame(Choreographer.java:560) at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:763) at android.os.Handler.handleCallback(Handler.java:739) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:145) at android.app.ActivityThread.main(ActivityThread.java:5938) 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:1400) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1195)

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