I have one fragment and that have some view element like textview buttons.
Now My problem is I have some service running background and it is checking data from server(Mysql) when these are some data it tells to Mainactivity.
Now on the basis of result I have to update fragment texeviews buttos.
In fact the fragment is a section of activity.
In the activity,you will get the fragment which involve.
You get the fragment ,so you can do you want to do .
Related
I would like to change dynamically my List of Fragment which will be sent to an adapter in Parent Activity.
I have tried to send it by a Bundle but the RecyclerView is not refreshed.
I also have tried to implement a method in my Fragment to be called from my Activity.
What's the best way the do that?
Search for observer pattern
https://www.baeldung.com/java-observer-pattern
The idea is making your fragment like an observer for any updates
I have an activity with fragment A. Fragment A hosts a list in recyclerview which requires an adapter. When an item from the list is clicked I want to open another fragment, say B, showing additional details about the item.
I can open fragment B in three ways:
From the recyclerview adapter itself where I will have the item position etc.
From fragment A using callback from the adapter, since the adapter has all the required info like position, object etc.
From the activity, again using callback. If i do from the activity, i will have to add callback interface from adapter to fragment A, and finally to the activity. Looks too much.
I want to know what is the best way to open fragment B.
Hey its not good practice to start the fragment from adaptor. because it will be very complex to find the container of fragment. so please always try to start the fragment from main activity which will be parent of all fragment.I hope its help you.
Option 2 is always good approach->
2. From fragment, A using callback from the adapter, since the adapter has all the required info like position, object etc.
"According to MVC pattern adapter is always used for binding view with lists. So adapter should always independent from the fragment so the Single Responsibility Principle will always be handled. So, there should be no dependency from the adapter to fragment but fragment to the adapter. When you call fragment or activity from adapter it will create a cyclic dependency with one another so memory will not clear until you finish the apps. You can call any callback method of the fragment from the adapter which method will call the desired fragment you want."
I have a fragment and an activity.there are some fields and an button in fragment.When i click an button in fragment then i want to go to an activity.In that activity i have another button.when i click on that button i want to return from the present activity to the previous fragment.Every thing works fine.what i need is i want to recreate the fragment when i return to the fragment from the activity..i.e,for example in the fragment if i enter anything in the edit_text before passing to the activity, which is also presented when i returned from the activity.(the fragment is same as how i left from fragment) which is i don't want .i want a fresh page.i want to recreate a fragment when i returned from activity ..i need to select fields newly..can any one suggest any help..thanks in advance..
Try to use main FragmentActivity and Fragments and organize transactions between fragments. I didn't meet examples with Activity and Fragment in one Addlication.
So I currently have an app that has 4 tabs (fragments). They are fragments A,B,C,D, in that order.
Fragment A is the first view opened (along with B because viewPager loads the view before and after the current view).
When I click a button in Fragment A, it sends Data back to MainActivity and then sends that data out to Fragments B and C.
However, this is where the issue comes into play. Since Fragment B was already called, the View isn't updated once I click the button and send the data over, but Fragment C is because the view wasn't called before.
Is there any way that I can remedy this?
You can do it a few ways right.
Just set the data to the fragment and have it update its views
Have all the fragments like B and C register themselves to recieve data from the MainActivity and when MainActivity gets it's data set you tell all the registered receivers of the new data
Recreate the fragment
Use an event bus and tell all subsribers of the new data and MainActivity, Fragment B would get notified of new data. Fragment C would get its data when created by MainActivity
I think this list is pretty endless tbh
The key here is the fragments need to fetch the data from the actvitiy aswell as be updated by the activity. In which case you need to break your UI update behaviour out of onCreateView and into its own updateUI() function. updateUI(MyData) can then be called from onCreateView and also called in a setMyData() on the fragment. Just make sure you check the isAdded flag in setMyData.
This pretty much says it all:
http://developer.android.com/training/basics/fragments/communicating.html
I used a simple fragment communicator that allows the activity to call the fragment, and the same for a fragment to talk to the activity.
You can change the views with the new data based on calling the method from within the activity. The way I do it is set the fragments in the activity then pass them into the page adapter this way I can call the methods within the fragment and implement the fragmentcommunicator interface on the fragments.
You can honestly even avoid the interface if you want, but if you are going to include the same method in all the fragments to talk to them it is easiest.
If you show code, I can show you a quick example.
I have 2 fragments which are called from the action bar of an activity. Both are gridviews, the first one displays applications with a dedicated adapter, and the second one displays a file list with another adapter. My problem is that when I launch a file then when I back to my activity I switch from one fragment to another, when I come back to the previous one, its content disappears. And when I rotate tablet I have the some problem, because my Fragment restart so for this I think that removing fragment give the possibility to create a new Fragment up to date. How can I save and reload data in my fragment.
How can I manage to update the content of the first fragment while coming back from the second one ? And how to remove fragment after the rotation in order to recreate the Action with new Fragment? I asked this questions but I don't have any responses. the code is given below
If your data is just strings or integers, you can make use of shared preferences to store and retrieve data.
Solution to your first problem -how to save fragment state
Use setRetainInstance(true) in you fragments onCreate() *it prevents your fragment from destroying and hence recreating.
Add your fragment to back stack
declare your adapter globally in fragment and resuse it when you get back.
when, you get back to fragment its onCreateView() method will be called directly. hence initialize your adapter in onCreate() method and use it in onCreateView().
Solution to your second problem -how to update fragment content
For this you can use interface. create interface in your second fragment and implement it in your first fragment. prefer this doc for this,
http://www.vogella.com/tutorials/AndroidFragments/article.html#fragments_activitycommunication