Develop Reference

Android: Replace sub fragment with it's parent fragment in main activity container

Imagine i have main activity that has viewpager. I have 2 fragments called (F1 & F2) that will transaction into viewpager.
Again imagine in F1 fragment i want to set a button. When clicking on button, i want to transaction other fragment call SUBF1 but not into F1 fragment.
My question is here!!! Is it possible to replace SUBF1 with it's parent means F1?My idea is that i want to replace sub fragment with it's parent fragment that has been kept on fragment's container in main activity?

final FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.replace(R.id.details, new NewFragmentToReplace(), "NewFragmentTag");
ft.commit();

You can save the instance of current fragment, when you are
navigating from one fragment to other. When user press the back
button, you can open the specific fragment with the help of tag.
#Override
public void onBackPressed() {
String currentTag = currentFragment.getTag();
if(currentTag.equals(res.getString(R.string.fragmentTagTest)))
{
currentFragment = AnotherFragment;
replaceFragment() // integrate replace current fragment with new one.
}
}

Return from activity to last visited intent

I have a main activity that exists out of three fragments. Fragment 2 is the main fragment. On fragment 3 I have a button. Once I click the button it directs the user to a ChatActivity. The ChatActivity has an onBackButtonPressed that should return the user back to fragment 3. However, it seems that it would always return the user to fragment 2 (the main fragment).
How can I bring the user to the fragment they last visited, or at least back to fragment 3?
Edit:
I added this block of code in the button onClick function:
ChatFragment fragment = new ChatFragment();
FragmentManager manager = getFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.add(R.id.main_tabPager, fragment);
transaction.addToBackStack(null);
transaction.commit();
When I click the back button in the activity it does not return me to fragment 3 but instead rebuild the fragmentpager and start back at Fragment 2.

When you are opening fragment 3 from main fragment (fragment 2), add fragment 3 into backstack like this:
Fragment3 fragment3 = new Fragment3();
getSupportFragmentManager().beginTransaction().add(R.id.content, fragment3).addToBackStack(null).commit();
You should add all fragments to backstack that you want to return to

Ideally addToBackStack() on fragment transaction should be enough as per documentation, but it seems not true at times, so we have to handle the popping up of the back stack upon Back button pressed by ourselves. I added this to my activity and it worked as expected:
#Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() > 0 ){
getFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}
Hope it helps.

Going from 3rd to 1st fragment in the backstack: Android

I have a sequence of event via which i have added three fragments to the backstack, one by one. Each of these fragments covers the full screen of the activity.
I have stored the is returned from the commit of Frag1.
Now in Frag3, based on a specific click, I want to go back to Frag1 directly and discard/pop all Fragments in between.
So, when this button is clicked i send a message to the activity which does the following:
getSupportFragmentManager().popBackStack(mFrag1Id, FragmentManager.POP_BACK_STACK_INCLUSIVE);
But i just got a blank screen, so i assume no fragment was loaded.
I even tried:
In commit - fragmentTransaction.addToBackStack("Fragment1");
and then
getSupportFragmentManager().popBackStack("Fragment1", FragmentManager.POP_BACK_STACK_INCLUSIVE);
But it doesn't work.
Could someone please help me with this?
Thanks.

OK so I found the issue.
FragmentManager.POP_BACK_STACK_INCLUSIVE pops all the fragments including the one whose id passed as argument.
SO for example:
getSupportFragmentManager().popBackStack(mFrag1Id, FragmentManager.POP_BACK_STACK_INCLUSIVE);
Here it will pop everything on the stack including fragment whose id id mFrag1Id.

from third fragment you should call popBackStack();
twice (one to remove third fragment and the second to remove second fragment )
android.support.v4.app.FragmentManager fm = getActivity().getSupportFragmentManager();
FragmentTransaction transaction = fm.beginTransaction();
transaction.remove(ThirdFragment.this);
transaction.commit();
fm.popBackStack();
fm.popBackStack();

When you opened Fragment A and you Navigated to Fragment B and then to Fragment C and then You want to close Fragment C and B and land on Fragment A
Now in some scenario, you want to close Fragment C and Fragment B and you want to land on Fragment A... then use this logic of FragmentManager to do such task.
First get the number of fragment entries in back stack (When we are adding any fragment to addToBackStack("Frag1")) at that time fragment back stack entry will increase.
so get using this
FragmentManager fmManager = activity.getSupportFragmentManager();
Log.e("Total Back stack Entry: ", fmManager.getBackStackEntryCount() + "");
Now assume, you want to close current fragment (Fragment C) and your last fragment (Fragment B) so simple logic is getBackStackEntryCount -2 and at that time your back stack entry count will be 3 (Fragment A, Fragment B and Fragment C)
Here -2 is for because we want to go 2 fragment step back (Fragment C
and Fragment B)
So simple two line of Code is:
if (fmManager.getBackStackEntryCount() > 0) {
fmManager.popBackStack(fmManager.getBackStackEntryAt(fmManager.getBackStackEntryCount()-2).getId(), FragmentMaanger.POP_BACK_STACK_INCLUSIVE);
}
You can also do it by adding two time "popBackStack()" and will also work, but it not idle way to do this
FragmentManager fmManager = activity.getSupportFragmentManager();
fmManager.popBackStack();
fmManager.popBackStack();

If you want user to back at the beginning fragment, code snippet below will help you.
public static void popBackStackInclusive(AppCompatActivity activity) {
FragmentManager fragmentManager = activity.getSupportFragmentManager();
for (int i = 1; i < fragmentManager.getBackStackEntryCount(); i++){
try {
int fragmentId = fragmentManager.getBackStackEntryAt(i).getId();
fragmentManager.popBackStack(fragmentId, FragmentManager.POP_BACK_STACK_INCLUSIVE);
} catch (Exception e) {
Timber.d("Fragment Back Stack Error: %s", e.getLocalizedMessage());
}
}
}
Also if you want to prevent user to close app when no fragments at back stack, take a look at below.
#Override
public void onBackPressed() {
FragmentManager fragmentManager = getSupportFragmentManager();
if(fragmentManager.getBackStackEntryCount() > 1) {
super.onBackPressed();
} else {
// TODO: Show dialog if user wants to exit app or;
//finish();
}
}

android fragment addToBackStack(null) :how to add the same fragment to stack just one time?

when fragment use addToBackStack(null) method and click a method many times in an activity, the fragment page will save to back stack everytime, when I press back key, it will restore the same page, how to add the same fragment to stack just one time?
mSettingBtn.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
SettingFragment settingFragment = new SettingFragment();
FragmentTransaction transaction = getFragmentManager().beginTransaction();
transaction.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_FADE);
transaction.replace(R.id.left_framelayout, settingFragment);
transaction.addToBackStack(null);
transaction.commit();
}
});

When adding your Fragment to the backstack you should also pass a TAG to be able to identify that Fragment:
.addToBackStack(SettingsFragment.TAG);
Prior to adding the Fragment you will be able to check if this Fragment is allready in the backstack using :
getFragmentMangager().findFragmentByTag(SettingsFragment.TAG);
This will return null if the Fragment is not allready added.

Android fragments navigation and backstack

I have a header bar (kinda like menu) and 4 fragments (MAIN, A, B, C) from which the MAIN should be 'main/root' fragment for backstack.
Problem i have is when user via menu goes for example MAIN > A > B > C.
If i simply use backstack it will go in reverse order which i don't want.
I need back button to go back to MAIN no matter how user navigated to one of those 3.
My current code (which is wrong, it quits app when not in MAIN and current fragment is switched from other non-MAIN fragment) looks like this:
private void SwitchFragment(Fragment pFragment)
{
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.main_fl_fragmentcontainer, pFragment);
if (_CurrentFragment == _Frag_Main)
ft.addToBackStack(null);
ft.commit();
_CurrentFragment = pFragment;
}

Your stack must contains 2 fragments at maximum
Main is visible
Main is onBackstack / AorBorC is visible.
User click on back ==> Main is visible.
User click on back ==> application end
I suppose A / B / C are displayed in the same view so in this case,
When user click on your Menu, you have to check if A/ B / C is currently displayed and replace it by the one selected by the user.
private void displayFragment(Fragment pFragment) {
Fragment fr = getSupportFragmentManager()
.findFragmentById(R.id.main_fl_fragmentcontainer);
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.main_fl_fragmentcontainer, pFragment);
if (_CurrentFragment == _Frag_Main) {
ft.addToBackStack(null);
}
ft.commit();
_CurrentFragment = pFragment;
}
can override OnBackPressed method of your activity.