FragmentManager IllegalStateException: No host

22
votes

UPDATE: Crashes gone when i put nullcheks (fragment != null, getActivity() != null) whereever i could.

My app is using ViewPager (offscreen limit 5) with FragmentStatePagerAdapter initialized with getSupportFragmentManager(). Each page has it's own fragments and backstack.

App crashes on startup. Problem occurs only on preLollipop devices and emulator. Using latest support lbrary (tried 24.0.0 also - same result) Stacktrace:

java.lang.IllegalStateException: No host at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1273) at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1268) at android.support.v4.app.FragmentManagerImpl.dispatchCreate(FragmentManager.java:2138) at android.support.v4.app.Fragment.onCreate(Fragment.java:1254) at android.support.v4.app.Fragment.performCreate(Fragment.java:2062) at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1051) at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1286) at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:758) at android.support.v4.app.FragmentManagerImpl.execSingleAction(FragmentManager.java:1632) at android.support.v4.app.BackStackRecord.commitNowAllowingStateLoss(BackStackRecord.java:637) at android.support.v4.app.FragmentStatePagerAdapter.finishUpdate(FragmentStatePagerAdapter.java:166) at android.support.v4.view.ViewPager.populate(ViewPager.java:1237) at android.support.v4.view.ViewPager.populate(ViewPager.java:1085) at android.support.v4.view.ViewPager.onMeasure(ViewPager.java:1611) at android.view.View.measure(View.java:16497) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404) at android.widget.LinearLayout.measureVertical(LinearLayout.java:695) at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) at android.view.View.measure(View.java:16497) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) at android.view.View.measure(View.java:16497) at android.widget.RelativeLayout.measureChildHorizontal(RelativeLayout.java:719) at android.widget.RelativeLayout.onMeasure(RelativeLayout.java:455) at android.view.View.measure(View.java:16497) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:135) at android.view.View.measure(View.java:16497) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) at android.view.View.measure(View.java:16497) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) at android.view.View.measure(View.java:16497) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1404) at android.widget.LinearLayout.measureVertical(LinearLayout.java:695) at android.widget.LinearLayout.onMeasure(LinearLayout.java:588) at android.view.View.measure(View.java:16497) at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:5125) at android.widget.FrameLayout.onMeasure(FrameLayout.java:310) at com.android.internal.policy.impl.PhoneWindow$DecorView.onMeasure(PhoneWindow.java:2291) at android.view.View.measure(View.java:16497) at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:1912) at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1109) at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1291) at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:996) at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:5600) at android.view.Choreographer$CallbackRecord.run(Choreographer.java:761) at android.view.Choreographer.doCallbacks(Choreographer.java:574) at android.view.Choreographer.doFrame(Choreographer.java:544) at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:747) at android.os.Handler.handleCallback(Handler.java:733) at android.os.Handler.dispatchMessage(Handler.java:95) at android.os.Looper.loop(Looper.java:136)

3
androidandroid-layoutandroid-fragmentsandroid-viewpager
can you show us some codes? – Ahad
@AbdulAhad there's so much code regarding transactions and Fragments in total - so i have no idea what code to post (and it's not clear from the stacktrace from where problem is). – localhost
you can take a look at this stackoverflow.com/questions/33210617/… – Ahad
before calling setCurrentItem(() check if getActivity() is null – Elltz
Where do you call setCurrentItem? Can u add this code block? – Tin Tran

3 Answers

1
votes

If you have nested Fragment (extends FragmentActivity), then use getChildFragmentManager() instead of getFragmentManager().

may be it will help you ..

1
votes

In my case, I am using viewpager inside fragment and was using getChildFragmentManager() while setting viewpager adapter. It is also recommended to use this I guess.

There is also an issue, java.lang.IllegalStateException: No host exception was not showing everytime but it was showing too often when I called a method of viewpager containing Activity or coming back from another Activity class before setting viewpager.setCurrentItem(POSITION);

I tried in many ways and finally I changed getChildFragmentManager() to getActivity().getSupportFragmentManager();

After changing this java.lang.IllegalStateException: No host exception is not showing any more.

I think its related to Activity state issue which contains viewpager.

0
votes

When you are using viewPager , make sure you are following these practices

  1. call super(fragmentManager) in your constructor
  2. if you are using Viewpager inside a Fragment, pass getChildFragmentManager in to Adapter