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Android. How to avoid fragment be recreated when back from another fragment?

I'm using MVP in my project. I have an activity. Inside this activity I'm showing fragment. Fragment contains some data, edit text, buttons etc. From this fragment it is possible to navigate to another fragment. Here is my code for showing another fragment:
getParentFragmentManager()
.beginTransaction()
.replace(R.id.main_container, secondFragment)
.addToBackStack(null)
.commitAllowingStateLoss();
Next, when I try to go back from fragment 2 to fragment 1, my fragment one is re-created.The method onViewCreated() is called again with saveedInstanceState = null. Also in the onViewCreated() I call presenter.onCreate(savedInstanceState) and because of this, all requests that should be called when I first enter the fragment are re-called when I back to first fragment.
As far as I understand, when calling a .replace(container, fragment), I cannot avoid recreating the fragment view, but in this case, how can I save all my data in the presenter so that I do not re-execute all requests when returning to the fragment?
P.S. With .add() fragment is not recreated. But in my activity I have toolbar with title, and I don't need it to show in my second fragment. When I open my second fragment with .replace() toolbar is not showing, but when open with .add() toolbar is showing.

Use Fragment Result API :
For implemention this method set - setFragmentResultListener - in source fragment and also set - setResult() and finish() - in destination fragment
Note 1 : for having clean code i suggest you to use FragmentTransaction class in:
https://github.com/mahditavakoli1312/FragmentTransaction---mahdi-tavakoli
Note 2 : use Navigation for navigate betwin fragments and activities Instead tranastion

communication between 2 fragments

framentA calls fragmentB via an mother activity. FragmentA is no longer in memory. FragmentB calls fragmentA(go back to previous screen). FragmentB has some data to share with FragmentA. But, how?
here is what I tried:
static variable - it worked, but a bad habit, I can not use it
viewModel - each fragment creates it's OWN instance of view model. Therefore the 2 instances of the viewModel will not work.
DB - not a good pattern. Therefore I cant use it.

I think what you need is to store the fragments in Fragment Manager, when you do that you are basically trying to maintain a back stack of your fragments:
FragmentManager fragmentManager = getSupportFragmentManager();
//or FragmentManager fragmentManager = getFragmentManager();
fragmentManager.beginTransaction()
.add(FragmentToBeAdded, "textRelatedtoFragment")
.addToBackStack(null)
.commit();
Adding to the backstack helps in saving the state of the fragment.

My suggestion would be:
For Fragment Navigation use: https://developer.android.com/guide/navigation/navigation-getting-started
It will greatly simplify your in-app navigation.
For passing parameters between Fragments/Activities:
First solution is to use ViewModel with scoping of Activity using by activityViewModels(). Read More here: https://developer.android.com/jetpack/guide This will give you an indirect way of passing arguments.
Use SafeArgs (part of Navigation component) to directly pass needed data.
More information can be found here: https://developer.android.com/guide/navigation/navigation-getting-started#ensure_type-safety_by_using_safe_args

Fragment doesn't display

The project is multiple-fragment project. Launch application to start BaseActivity, which all fragments are attached into it.
Issue:
Fragment A is the first fragment and is launched very well.
Fragment B is trigged by clicking button of Fragment A, also launched very well.
During from B back to A, the problem occurs. Nothing to display, only background, the BaseActivity.
All fragments use the api "replace" to display, although this API may produce performance problems, please ignore it firstly.
I have tried many methods, but nothing works.
The launched fragment method shows below:
public void navigateToFragment(Fragment fragment, boolean isClear){
if(isClear){
getSupportFragmentManager()
.popBackStack(null,FragmentManager.POP_BACK_STACK_INCLUSIVE);
}
getSupportFragmentManager().beginTransaction()
.addToBackStack(null)
.replace(R.id.container,fragment)
.commit()
}
As I know, popBackStack and replace, commit can lead to one fragment is launched twice, but why no display after replace whatever I replace it?

try use add instead of replace
getSupportFragmentManager().beginTransaction()
.addToBackStack(null)
.add(R.id.container,fragment)
.commit()

Android how to send data to a running fragment

is there a way to send some data from an activity to a running fragment?
In my app I'm adding a second fragment over another fragment. I intentionally use the add method instead of the replace method. So now I want to hide my second fragment with
fragmentManager.popBackStack();
and my first fragment reappears. After hiding the second fragment I want to send some data from my activity to the still running frist fragment.
Any idea how to do this? It doesn't work with bundles (put extra), because I don't rebuild the fragment, I just hide the second one!

one simple solution is:
MyFragment oldFragment = (MyFragment) fragmentManager.findFragmentById(R.id.fragment_place);
fragmentManager.popBackStackImmediate();
MyFragment newFragment = (MyFragment)fragmentManager.findFragmentById(R.id.fragment_place);
newFragment.postData(...);

You can use an EventBus library like this one, it's easy to use and very convenient.

You can use tags on the Fragments when you create them to call them when needed.
getFragmentManager().beginTransaction()
.add(R.id.content, new SomeFragment(), SomeFragment.class.getSimpleName())
.commit();
So above I use the simple name of the class to tag the fragment when I create and add it to the activity.
SomeFragment fragment = (SomeFragment) getFragmentManager().findFragmentByTag(SomeFragment.class.getSimpleName());
And I can call it back when I need it and know it is being displayed like above, now I can call send it data like normal by calling a public method in the custom fragment and passing it the data as a param.

Communicating between fragments in Android

Based on the example from http://developer.android.com/training/basics/fragments/communicating.html I tried to reproduce the communication between two fragments which are sub fragments of a larger fragment.
In the example, AB activity contains A fragment and B fragment. But I am trying to achieve the same but in my case AB Fragment contains A fragment and B fragment.
The problem is the overridden method in the AB Fragment never gets called. Does this not work because the containing component is a Fragment and not a Activity like in the example? Am I missing out something here?

If you are referring to onClick() or some other onSomething() handler, then these always get called in the Activity class, not the fragment. So in the example you linked, the onArticleSelected() must remain in the Activity, even if you have nested fragments.
To pass info on to the fragment, you have a few options. One, you can keep a reference to the fragment within the activity. This might be lost if your activity recreates (settings event for example).
The second and better way would be to tag your fragments, and then use findFragmentByTag.
When you add your fragment (notice the parameter "my_fragment" which is the tag I gave to the fragment):
getSupportFragmentManager().beginTransaction().add(R.id.fragment_container, myFragment, "my_fragment").commit();
Or when you replace one fragment with another:
getSupportFragmentManager().beginTransaction().replace(R.id.fragment_container, myFragment, "my_fragment").comit();
Then, when you want to do something in the fragment from within your onArticleSelected of the activity:
Fragment fragment = getSupportFragmentManger().findFragmentByTag("my_fragment");
if (fragment != null) {
fragment.articleSelected(articleId);
}

You can always use an Interface to communicate between fragments. It is the safest way to do so.