ActionBar navigation tabs showing fragments on top of each other - android

I have an ActionBar with various navigation tabs on it. I am finding that in some circumstances (I do not understand them fully) fragment content is appearing on top of fragment content.
i.e. I visit one tab, then click a button that swaps the fragment for another, then click one of the other tabs, and the fragment content from the initial tab click is visible under the new fragment content. It seems I've built an app where it's possible to use the navigation to place fragment content on top of other fragment content, which is not what I want.
How can I ensure that when updating fragment content, the old content is removed correctly?

How can I ensure that when updating fragment content, the old content is removed correctly?
You are the one creating the FragmentTransaction that is being applied by the TabListener. In that FragmentTransaction, you are telling Android what fragments to add, what fragments to remove, etc. Make sure you are setting up the FragmentTransaction objects with the business rules you want.

Related

Error while calling Navigation Components while using ViewPager 2

I have a hard time with trying to learn Navigation Components.
In my app, I have 6 fragments.
Four of them are swipeable by using ViewPager 2
Fifth fragment is not implemented in ViewPager, so user can't go there by swipping
Sixth fragment is just a host for ViewPager, since the other fragments are used by Navigation Components
I can swipe fragments for now, but whenever I try to use Navigation Components, I getting error about action/destionation. It's simply about calling for example ActionFrag1ToFrag5 from my Host Fragment
It seems like I can browse through fragments, but I can't cast any Navigation Component functions, because the fragment stays the same, it doesn't change label after swipe to another one.
Is there a way to get proper NavController from specific fragment, or it's just my poor implementation?
If Frag1, Frag2, Frag3, and Frag4 are those in the ViewPager and you want to go to Frag5.
The direction needs to be from the Frag6 that is hosting the ViewPager to the Frag5.

How do I retain the state of my ViewPager in my TabLayout when I'm replacing a Fragment on top of it?

I have a single activity that uses a bunch of different Fragments. I have a TabContainer Fragment that holds a TabLayout which uses a ViewPager to handle tab navigation. Each Tab is its own Fragment.
In one of my tabs, I want to tap and place a fragment on top of my Tabbed fragment. This is meant to be a "details" sort of screen, so I don't want the tabs to be visible. I'm using this and it works as intended:
fragmentTransaction.replace(android.R.id.content, fragmentToDisplay).addToBackStack(null).commit();
Now, when I navigate back, the content in my tab is empty. The content in the tab directly next to that tab is also empty. When I navigate two tabs away, the content is recreated and the normal functionality returns. Why is content not being recreated on the tabs initially when I remove my "detail" fragment?
It turns out that I was simply not passing the correct FragmentManager to the FragmentStatePagerAdapter.
I needed to call getChildFragmentManager() on the Fragment, not getSupportFragmentManager() on the activity.
Thanks to these two posts for the answer:
Fragment in ViewPager not restored after popBackStack
and: Replacing ViewPager with Fragment - Then Navigating Back

Android - how to slide screens, inside a fragment

I've created an app, that has a main activity with a drawer menu so the user can click on some option and a fragment is open inside the activity.
What I'd like to do is to have several screens in one of the options and to navigate between them by tabs/slide the screen.
I saw an example of doing it inside one activity and with a fragment per 'sub-screen', my question is: how can I do it when I'm already 'inside' a fragment?
Thanks
Fragments can support having other Fragments inside them. The key to making this work is to remember to use getChildFragmentManager() to get the Fragment's FragmentManager instead of getFragmentManager() which gets the Activity's FragmentManager.
If you want to swipe between views, use a ViewPager inside your Fragment UI. The ViewPager will use a FragmentPagerAdapter to handle the Fragments for display.

Fragment Transaction inside a fragment with a Tabbed actionbar not working

I want to be able to replace the current fragment which is loaded via the actionbar tabs using a ViewPager with another fragment that is not connected to any tab like this
getSupportFragmentManager().beginTransaction()
.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE)
.replace(id,frag , "VideoEdit")
.commit();
however when I do this it loads the fragment all right but the tabs don't work anymore and everytime I click on a tab it just stays on this fragment. I managed to find this gist
https://gist.github.com/andreynovikov/4619215 but I'm not sure it's the same thing I'm looking for and I don't want to try it out for fear of messing up my existing code with it.
You should avoid transitions like that.
I'll recomend to use FragmentWrapper.
One more fragment that you placed inside Tab it contains only FrameLayout as a container for other fragments. In this fragment, you could use childFragmentManager to add current Fragment and replace it with VideoEdit.

Fragment doesn't refresh content after returning from back stack

I have a ZooFragment which contains a ViewPager.
This ViewPager has three children: LionFragment, LeopardFragment, and TigerFragment, each of these children can request transaction to call a new ZooFragment.
When a ZooFragment called zooA (with arguments) is initialized, all three children in ViewPager display content. From any child fragment, user touch will call a new ZooFragment called zooB (with different arguments, of course).
Based on transaction action from child fragment to ZooFragment:
1.If I use transaction.replace(), zooB will be blank, all three children in zooB display no content, empty. At zooB, pressing hardkey Back from navigation, zooA becomes empty.
2.If I use transaction.add(), zooB won't be blank, following by a Back button press, zooA gets empty.
In ZooFragment class, I do loading data in onCreateView(), so what is the reason why all the child fragments in ViewPager get empty?
Please do not replace the fragments in the ViewPager, just show (using transaction) in any other contained in the same layout as that of ViewPager and that container should be a FrameLayout. Also device a mechanism to know when and what fragment comes into view. Then request for a fresh data from a utility that responds to update your fragment. I do not think onDestroyed will be called in case of all the fragments in the ViewPager.
Fragments in the ViewPager are fixed, so should there contents will not go till the application manager wants to destroy it.Instead of trying to replace the fragments in the adapter, try to give a different set of fragments and notifyDataSet changed, or take the advantage of FrameLayout to show another fragment over the view pager tab's current fragment.
There is my solution that works:
Swipe Gesture applied at Fragment level along with ViewPager with it's default swipe disabled

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