Replacing a Fragment with another Fragment - android

I have a Fragment called MyFrag and I create two instance of this Fragment, frag1 and frag2. In frag1 I register a click listener, and in the callback of this click listener I want to perform a FragmentTransaction and replace frag1 with frag2.
I managed to replace Fragments in an Activity but Fragments don't have the getSupportFragmentManager() method. This is the code I am using:
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.fragment_container, new Flashcard_Fragment(false, 3));
transaction.commit();

Use getFragmentManager() in the Fragment instead of getSupportFragmentManager(). getSupportFragmentManager() is only used in the FragmentActivity. Try this:
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.fragment_container, new Flashcard_Fragment(false,3));
transaction.commit();
Also be sure that Flashcard_Fragment has an empty constructor as well! The OS requires Fragments to have an empty public constructor.

You can just call getFragmentManager() in your Fragment.
The FragmentManager you get from getFragmentManager() is used to replace/add Fragments to the Activity.
The FragmentManager you get from getChildFragmentManager() is used to replace/add Fragments inside of other Fragments.
So it seems that you just need to use getFragmentManager().

Related

Android Back to previous fragment by popBackStack

I have 3 fragments: Home, A and B. Home and A are in mobile navigation menu.
User goes from A to B and then press back button. The issue that if I use getFragmentManager().popBackStack(); onCreateView of fragment A is calling and I have duplicating of content.
But if I use getActivity().onBackPressed(); it goes to Home fragment instead of A.
How to display fragment A by clicking back button without refreshing the view?
Here is how I make transaction from A to B
CertificateItemFragment certificateItemFragment = new CertificateItemFragment(item);
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(R.id.nav_host_fragment, certificateItemFragment).addToBackStack(null);
fragmentTransaction.commit();
You need to know some premise before using FragmentManager.
in Activity there is FragmentManager and we should call it with getSupportFragmentManager(), getFragmentManager() is deprecated.
in Fragment there are multiple FragmentManagers called ParentFragmentManager and ChildFragmentManager, the final FragmentManager which is deprecated too. And ParentFragmentManager will be same as Activity's FragmentManager
getActivity().onBackPressed() will pull out fragment if any stack exists in Activity's FragmentManager
fragmentManager.popBackStack() will pull out fragment if any stack exists in Activity's or Fragment's FragmentManager rely on who calls
Base on above points
(1) If You want to hold fragments in Activity, you should call getSupportFragmentManager() in Activity, and call getParentManager() in Fragment, then onBackPressed() will pull out the fragment you last add to stack.
(2) If you want to hold fragments in a Fragment and Separated from Activity, you should call getChildFragmentManager() in Fragment, then activity.onBackPressed() will pull out the fragment which in Activity's fragment stack and ignore other fragments in Fragment's fragment stack.
For question will be same as case (1), and if you dont want re-create fragment, you should use add() instead of replace()
in Fragment A
CertificateItemFragment certificateItemFragment = new CertificateItemFragment(item);
FragmentManager fragmentManager = getParentFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.add(R.id.nav_host_fragment, certificateItemFragment).addToBackStack(CertificateItemFragment.TAG);
fragmentTransaction.commit();
now onBackPressed() will backstack from CertificateItemFragment to Pre-Fragment
In normal case navigation item list menu open fragment which are replace to each other but when we move inside of any item as like in your case move from fragment A to B,
In this case normally we use another activity on which create fragment.
If you do't want to use activity then, you just need to add fragment.
try below code that may help you
CertificateItemFragment certificateItemFragment = new CertificateItemFragment(item);
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.add(R.id.nav_host_fragment, certificateItemFragment).addToBackStack(CertificateItemFragment.TAG);
fragmentTransaction.commit();

Add only one instance of fragment into backstack

I have implemented fragments in my application. Here my code for swiching fragment in fragment_container.
private void switchFragment(Fragment fragment, boolean isAddToBackStack, String tag)
{
android.support.v4.app.FragmentManager fm = getSupportFragmentManager();
android.support.v4.app.FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.container, fragment, tag);
if (isAddToBackStack)
ft.addToBackStack(tag);
setCurrentTopFragment(Integer.parseInt(tag));
ft.commit();
}
I have 4 fragments A,B,C and D and for switching between this fragmnets I am using above method. I have A,C,B in my backstack. If again I switch to fragmnet A, my backstack is like A,C,B,A. What I actually want is If I swich to A again I want backstack sequence like this C,B,A. Means Remove old instance from backstack and add new to it.
First get the back-stacked Fragment by id which you need to remove:
Fragment fragment = getSupportFragmentManager().getFragment(new Bundle(), TAG_KEY)
or there are several methods getBackStackEntryCount(), getBackStackEntryAt. After getting the fragment which you need to remove. Remove it from the fragment back-stack.
FragmentManager manager = getActivity().getSupportFragmentManager();
FragmentTransaction trans = manager.beginTransaction();
trans.remove(fragment);
Then you can add a new fragment Done :)

PopBackStack is not working properly

I have coded like this:
FragA >> FragB >> FragC >> FragD
When I press onBackpress() of FragD it goes to directly on FragA but i want to keep it go FragC.
BackPress Code here :
if (getActivity().getSupportFragmentManager().getBackStackEntryCount() > 0) {
back_btn.setVisibility(View.GONE);
getActivity().getSupportFragmentManager().popBackStack();
}
Replacing Fragment Code :
FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
FragmentA fragmentA = new FragmentA();
fragmentTransaction.replace(R.id.framelayoutinner, fragmentA);
fragmentTransaction.addToBackStack("fragmentA");
fragmentTransaction.commit();
FragmentManager fragmentManager = getActivity().getSupportFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
FragmentA fragmentB = new Fragmentb();
fragmentTransaction.replace(R.id.framelayoutinner_2, fragmentB);
fragmentTransaction.addToBackStack("fragmentB");
fragmentTransaction.commit();
You are using nested fragments, if you load fragment from another fragment then it become nested structure. So try to check if any child fragment exist within your Root fragment then pop that child fragment first.
Use getChildFragmentManager() for that and make recursive calls till you get most young child fragment(Last added). Or better use Tag on your fragments.
You need to add every fragment into backstack using addToBackStack method
public void setmFragmentContainer(Fragment fragment)
{
final String tag = fragment.getClass().getName();
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.layout_content, fragment, tag);
transaction.addToBackStack(tag);
transaction.commit();
}
This method may help you

How to change the current fragment view with other fragment

How to change the whole view of a fragment with other fragment !!
Or how to close the current fragment with another fragment, please explain with layout also
Thanks in advance...
You can either add or replace fragments in your activity. Create a FrameLayout in activity's layout xml file.
Then do this in your activity to replace fragment. You can use same code each time you want to replace one fragment with other.
FragmentManager manager = getFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.add(R.id.container,YOUR_FRAGMENT_NAME,YOUR_FRAGMENT_STRING_TAG);
transaction.addToBackStack(null);
transaction.commit();
If you want to add fragment instead of replace then do this:
FragmentManager manager = getFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.container,YOUR_FRAGMENT_NAME,YOUR_FRAGMENT_STRING_TAG);
transaction.addToBackStack(null);
transaction.commit();
When you want to replace added frogment with anu other fragment then you have to remove previous fragment first (or you can hide previous fragment; depends on your requirement). See following code:
Fragment fragment = getSupportFragmentManager().findFragmentByTag(YOUR_FRAGMENT_STRING_TAG);
if(fragment != null)
getSupportFragmentManager().beginTransaction().remove(fragment).commit();
See following related questions on SO:
Difference between add(), replace(), and addToBackStack()
Basic difference between add() and replace() method of Fragment
Difference between add() & replace() with Fragment's lifecycle
Or see my answer to a similar question:
How to start Fragment from an Activity
getSupportFragmentManager().beginTransaction().replace(R.id.fragmentlayout,new fragment()).commit()
This will help you replace your existing fragment in view with id FragmentLayout with a new fragment().
ThankYou i hope this was helpful.
First you take one Framelayout in Your Activity where you add fragment.
FragmentManager manager = getFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.add(R.id.framelayout,fragment_1);
transaction.addToBackStack(null);
transaction.commit();
When you replace first fragment with second one you write, just change fragment_1 to fragment_2
FragmentManager manager = getFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.add(R.id.framelayout,fragment_2);
transaction.addToBackStack(null);
transaction.commit();

How to replace Fragment with Fragment from different class

I want to replace a Fragment from a defined class FluxListeFragment with another class FluxDetailFragment (and use addToBackStack fonctionnality of the FragmentTransaction). Thus, I add my fragments dynamically on the onCreate of my activity :
FluxListeFragment FragmentListe = new FluxListeFragment();
fragmentTransaction.add(R.id.FL_Portrait, FragmentListe, "fragment_portrait");
fragmentTransaction.commit();
Then, when I want to replace FragmentListe with FragmentDetail, I code this :
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
FluxDetailFragment FragmentDetail = new FluxDetailFragment();
fragmentTransaction.replace(R.id.FL_Portrait, FragmentDetail, "fragment_portrait");
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
But I get an InvalidClassCastException, since I want to replace a Fragment from a class with a fragment from another class.
How to make this work ?

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