We Keep Coding

Fragment is invisible but its views could be clicked

I am trying to enable user to go to a new Fragment when a list item is clicked. That's OK. I created an interface which allows me to handle click events from my FragmentA.java class. FragmentA is attached to my activity when activity started. my activity extends FragmentActivity.
In my activity class:
#Override
protected void onCreate(Bundle savedInsantaceState){
//...
getSupportFragmentManager().beginTransaction().replace(R.id.container, FragmentA.newInstance(param1, param2)).commit();
}
And then in FragmentA.java, i set that to my RecyclerView Adapter as click handler. I use add() method instead of replace() method to change the fragment, because i want to save the FragmentA's state (like RecyclerView position etc.) when FragmentB is attached.
private void setListeners(){
mAdapter.setOnItemClickListener(itemClickListener);
}
private ItemListAdapter.ItemClickListener itemClickListener = new ItemListAdapter.ItemClickListener() {
#Override
public void onItemClicked(View v, ItemModel item) {
FragmentManager manager =((FragmentActivity)mActivity).getSupportFragmentManager();
manager.beginTransaction().add(R.id.post_activity_layout_container, FragmentB.newInstance(item, param2, param3)).addToBackStack("comment").commit();
}
};
HERE IS THE ISSUE : In this case, FragmentA is running but invisible, while user sees FragmentB. User can reach views of FragmentA, and that cause problems. I wanna save the last state of FragmentA but user should not click on views of FragmentA from FragmentB. How to handle that issue? Is there a better practice to accomplish saving the last state?
EDIT
FragmentA contains some sorting, filtering. When i use replace() method, all filters that user set is invalidated, and also RecyclerView position became 0. Imagine that user is looking at (for example) 33. item in the list, clicks on it, FragmentB is attached, then go back to FragmentA. I want user to continue from 33. item, don't want user to try to find for where he was.

I'm not sure what you mean by "I wanna save the last state of FragmentA" exactly, but, AFAIK, the fact that you replace Fragments in a container doesn't mean they lose state. For example, you can still click on back button and this will revert the transaction, bringing the previous Fragment from the back-stack.
Edit: the effects that you observe are most probably caused by the destruction and re-creation of Fragment's View hierarchy. There are couple of approaches around it. The first one would be to store UIs state and restore it after re-initialization of the Fragment. Unfortunately, it might be tricky with RecyclerView position (you can google it). Another simpler approach (which is a hack) is to create the root View in onCreateView only once, keep a reference to it inside Fragment and return the same View on subsequent calls to onCreateView. If you decide to use the later approach, be careful because you'll be using Fragments not exactly the way there were intended to use.
Not directly related to your question, but I absolutely recommend avoiding manual Fragments management. It'll be too painful. You can use the official Navigation Component, or, alternatively, a simpler solution like FragNav library. I wrote this post about the later and it might help you.

Question about BottomNavigationView in Android

I have general questions about BottomNavigationView. I would like to have a BottomNavigationView in each of my Activities in an App for ordering something (e.g. food). It should have 4 buttoms:
Back
Info
Stats
My Orders
With 'Back' the app should just go back to the previous activity. The buttoms 'Stats' and 'My Orders' should switch to a persistent activity that should not be destroyed when not being displayed. 'My Orders' should display the last orders. The buttom 'Info' should only display some information about the current item or current menu (depending from which activity it is called). So basically I have 2 questions:
Should the Activities 'Info', 'Stats', and 'My Orders' be real Activities or just Fragments? Normally I think that at leat 'Stats', and 'My Orders' should be real Activities as they are persistent. But in many BottomNavigationView only Fragments are used?
How can I pass content information to the Activity/Fragment 'Info'. This Activity/Fragment should display information based on the Activity is was called from. Let's say the Activities are different dishes. Do I have to create a separate Info-Activity/Fragment for each dish? Or can I somehow define a dynamic Activity/Fragment that displayes information based on the current Activity?
I'd appreciate every comment and I'd really appreciate your help.

The recommended approach is Single Activity and Multiple fragments.
You can do this using Jetpack's Navigation Component
In case you need to pass data from an Activity/Fragment to the new calling Fragment, it can be done by setting arguments on the calling fragment and then getting it on the called fragment. If there is something which requires to be dynamic, for example- dishes fragment, make a single fragment and common layout and load the data dynamically from the backend.
For Setting Arguments, this should help
How to pass a variable from Activity to Fragment, and pass it back?
Note: You can use fragment without using Navigation Components but you have to use FragmentManager and FragmentTransaction and also have to maintain the Backstack by yourself which could be quite complicated

What are the general instructions to add a new fragment that uses a new screen and has its own layout?

I'm struggling to figure out how to create fragments that have their own layout files and take up the whole screen, as opposed to adding them to the activity's layout.
For instance, in my activity there is a button which should call a RecyclerView Fragment that takes up the whole screen, let the user pick an item, and then return to the activity. All the examples I'm finding though use transactions to add or replace on the activity's layout. How do I make fragments that are inflated from their own layout files and call them from the activity?
And sorry, I'm sure there's a better way to ask but I'm just going through docs and vids trying to learn.

A few line difference between Fragment and Activity:
An Activity is an application component that provides a screen, with which users can interact in order to do something. More details: http://developer.android.com/guide/components/activities.html
Whereas a Fragment represents a behavior or a portion of user interface in an Activity. http://developer.android.com/guide/components/fragments.html

Switch between fragments from inside one of the fragmens

Two days ago i asked the following question:
Change the fragment in a framelayout from within another fragment of said framelayout
A fellow user Krish, really helped me out in finding out what was wrong with the way i thought, but i am stil not sure how to actually get what i want done.
I want to be able to switch between three fragments in one FrameLayout.
- the first of the three is loaded at the start of the parent fragment and when back is pressed at the second fragment
- the second must be replacing the first at the click of an item in the listview of the first fragment, and when the back button is pressed from the third fragment
-the third must be loaded when a button is pressed in the second layout
I've tried achieving this by calling the following line whenever the fragment must be changed. A1_frame is the FrameLayout of the parent Fragment/Layout and A1_B0_C2 is the fragment i am replacing
getChildFragmentManager().beginTransaction().replace(R.id.A1_Frame, new A1_B0_C2()).addToBackStack(null).commit();
From what i understand the problem with my solution is that it isn't possible to replace a fragment in the FrameLayout of a parent Fragment/Layout, but if it would work, it would solve my solution. thats why i chose to put it in here.
I hope someone is able to tell me what would work!

getChildFragmentManager() returns the Fragment manager of the Fragment it's being called from, in this case whatever Fragment is in A1_Frame
The method you're looking for is getFragmentManager(), which returns the Fragment Manager of the Activity/Fragment that the Fragment is a part of. I.e. MainActivity, or whatever is creating your first fragment.

Fragments onClick method in fragment element

I read quite some articles about fragments, but I am still confused about how to do what.
I have a MainActivity, which displays two fragments side by side. In one of the fragments I have a button and defined in the fragments layout XML for the button
android:onClick="buttonClicked"
Now I want to implement that method
public void buttonClicked(View view)
I would have assumed that this has to be implemented in FragmentA.java and not in MainActivity.java. But it only works if that method is implemented in MainActivity.java. Why is that? To me that doesn't make sense. Pre Honeycomb a method belonging to one activity stayed in that activity, now on a tablet I am merging many activities to one MainActivity and all the different methods are merged? Whatever do you put for example in FragmentA.java then? What if you have to start you an own activity because this app runs on a handheld, then the onClick method has not to be in the MainActivity but in the Activity which needs to be called then. I am pretty confused at the moment...

I'm not sure what the specific problem is, but maybe this will help.
From the Android documentation on Fragments:
You should design each fragment as a modular and reusable activity component. That is, because each fragment defines its own layout and its own behavior with its own lifecycle callbacks, you can include one fragment in multiple activities, so you should design for reuse and avoid directly manipulating one fragment from another fragment.
That is, you should never manipulate a fragment from another fragment; rather, this should be done through the underlying Activity. Read the "Creating event callbacks to the activity" section in this article for more information (it's important stuff!!).
On the other hand, if you want the button to perform an action within the Fragment itself (i.e. if you wanted a Button click to change the text of a TextView within the Fragment), you should implement this in the Fragment, not the Activity (this is because the resulting behavior is contained within the Fragment and has nothing to do with the parent Activity).
Leave a comment and I can clarify if my post is confusing... I only recently began to understand Fragment's myself :).

Well,
I guess it is related to hierarchy of android context structure.
Activity is host of all child views and hence you can say fragment is actually using its host's context.And that's why when you use onClick with fragment system always searches it in Host activity of fragment.
Check it on.
Android developer onClick attribute description
I haven't checked one thing but you could put a test.
By providing implementation in host activity rather than in fragment,but use onClick on layout file of fragment.It should call parent's method.