I have a MainActivity and two fragments in this activity like SignupFragment and MenuFragment.First i add SignupFragment in MainActivity:
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.content_frame, new SignupFragment());
ft.commit();
Important: i don't need to store this fragment in backstack
Now from SignupFragment i replace MenuFragment
FragmentManager fm = getActivity().getSupportFragmentManager();
fm.beginTransaction()
.replace(R.id.content_frame, new MenuFragment(), FRAGMENT_TAG)
.addToBackStack(null)
.commit();
Important: i need to add this fragment to backstack.For example i have another framgent like AnotherFragment and i replace it in MenuFragment and add that to backstack too and when user in AnotherFragment pressed back button i want to return him to MenuFragment
I override OnBackPressed in MainActivity and also add a listener for OnBackStackChangeListener:
FragmentManager fm = getSupportFragmentManager();
fm.addOnBackStackChangedListener(new FragmentManager.OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
if (getSupportFragmentManager().getBackStackEntryCount() == 0)
finish();
}
});
Problem When i'm in MenuFragment and press back button then i go back to SignupFragment andOnCreateView called for a little moment and then finish() called.( when i press back button , SignupFragmen's view shows for a moment and then destroyed )
Questions
1- How can i prevent to returning back to SignupFragment ?
2- Why OncreateView called in SignupFragment when back button pressed?
Thanks in advance.
I found my problem.
when i pressed back button, OnBackPressed called and also MenuFragment is visible yet then onCreateView of SignupFragment called and then onBackStackChanged called , So i check this in OnBackPressed:
if(getSupportFragmentManager().findFragmentByTag(FRAGMENT_TAG).isVisible()){
finish();
}
Related
I am having trouble going back to previous fragment on backpress from current fragment.
I have Two fragments and i navigate to second fragment on click and when i try to click back from the second fragment, i want to go back to the previous fragment but instead the app exits on backpress. below is the code i am using..
Fragment1 calling second fragment
UserFragment frag = new UserFragment()
FragmentTransaction transaction = getFragmentManager().beginTransaction();
frag.setArguments(bundle);
transaction.addToBackStack("UserActivity");
transaction.replace(android.R.id.content, frag, "UserActivity").addToBackStack(null);
transaction.commit();
In second Fragment i have implemented an interface OnBackpress and over riding the below method
#Override
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() != 0) {
if(getFragmentManager().findFragmentByTag("UserActivity") != null){
Log.e("UserActivity",getFragmentManager().findFragmentByTag("UserActivity").toString());
getFragmentManager().popBackStack();
};
}
}
But on back press the app exits. Instead i want to go back to previous fragment. What mistake am i doing? please help. thanks
You need to add you first fragment to back stack properly, you are doing it wrong in your first part of the code.
Use the following code instead.
UserFragment frag = new UserFragment()
FragmentTransaction transaction = getFragmentManager().beginTransaction();
frag.setArguments(bundle);
transaction.addToBackStack("UserActivity");
transaction.replace(android.R.id.content, frag, "UserActivity");
transaction.commit();
Also there is no need to add any code in your onBackPressed after above change.
First, you need to add your fragments to the backstack:
public static void addFragment(FragmentManager fragmentManager, Fragment fragment, int id){
fragmentManager.beginTransaction().add(id, fragment).addToBackStack(null).commit();
}
Then you need to override the onBackPressed, which is a method gets called whenever a user clicks the back button:
#Override
public void onBackPressed() {
super.onBackPressed();
if(getSupportFragmentManager().getBackStackEntryCount() == 0){
button.setVisibility(View.VISIBLE);
}
}
please change to add() instead of replace() in your code..
UserFragment frag = new UserFragment()
FragmentTransaction transaction = getFragmentManager().beginTransaction();
frag.setArguments(bundle);
transaction.addToBackStack("UserActivity");
transaction.add(android.R.id.content, frag, "UserActivity").addToBackStack(null);
transaction.commit();
This will solve your problem.
I have 2 Activites A & B, In Activity A I managed fragment back stack but in one case as like below:
I have 4 fragments in Activity going from fragment 1 to 2 to 3 to 4 then from 4th fragment I'm going to Activity B now what i want is on press of back button fragment 4 of Activity should be opened and then on back fragment 3 and so on.
I'm using following function to replace the fragment and manage back stack
private void changeFragment(Fragment fragment) {
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.popBackStack(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
fragmentManager.beginTransaction().replace(R.id.act_home_fl_container, fragment).commit();
}
On back press
boolean isPopFragment = getSupportFragmentManager().getBackStackEntryCount() > 0 ? true : false;
if (isPopFragment) {
getSupportFragmentManager().popBackStack();
}
I got success upto here but when I'm going to Activity B from 4th fragment and coming back to Activity A, I'm not able to manage back stack of fragments of Activity A.
I'm not having any how to start with it.
you can override onBackPressed inside your activities, check which fragment is on top and decide what to do as you wish:
#Override
public void onBackPressed()
{
// code here
super.onBackPressed(); // check if you need this, depends on your needs
}
Use this code to change fragment
public static void addFragment( final Fragment newFragment, final Fragment hideFragment) {
final FragmentManager fragmentManager = getFragmentManager();
final FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.hide(hideFragment);
fragmentTransaction.add(R.id.activity_home_container, newFragment, newFragment.getClass().getSimpleName());
fragmentTransaction.addToBackStack(hideFragment.getClass().getSimpleName());
fragmentTransaction.commitAllowingStateLoss();
}
newFragment "Fragment you want to add"
hideFragment "Fragment which is on container"
just use addToBackStack(tag_name) before commit
You can add en extension function in kotlin
fun AppCompatActivity.replaceFragment(containerId: Int, fragment: Fragment) =
supportFragmentManager.beginTransaction()
.replace(containerId, fragment, fragment.javaClass.name)
.addToBackStack(fragment.javaClass.name).commit()
How is it possible to go back to the last Activity one has been in from a Fragment? Let's assume we've Activity A and Fragment A. I launch Fragment A from Activity A, and now I want to go back to Fragment A. When I press on the back button on my phone it closes the app.
I launch the fragment by using the FragmentManager:
Fragment fragment = new Kontakt();
getFragmentManager().beginTransaction()
.add(R.id.kontaktfrag, fragment)
.commit();
Is the solution; popBackStackImmediate() or addToBackStack() ?
Firstly try addToBackStack when adding your fragment.
then you need to override your onBackPressed function of your activity, for example:
#Override
public void onBackPressed() {
if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
getSupportFragmentManager().popBackStackImmediate();
} else {
super.onBackPressed();
}
}
I tried myself and it worked.
try adding
getFragmentManager()
.beginTransaction()
.addToBackStack("")
.commit();
or just add .addToBackStack("") before .commit();
here is the code in your case,
Fragment fragment = new Kontakt();
getFragmentManager().beginTransaction()
.add(R.id.kontaktfrag, fragment)
.addToBackStack("")
.commit();
My activity consists of navigation drawer and currently have 5 options in the left menu. Which all opens in fragment.
I am looking for a way to keep a stack of all the fragments so when the user presses back button he moves to previous fragment.
Like- Activity consists of drawer menu which have 5 options menu1, menu2, menu3, menu4, menu5 having corresponding fragments F1, F2, F3, F4, F5.
User presses menu1 he is forwarded to F1
Then presses menu2, and then menu4.
When the user is at F4 and he presses back he should be moved to F2 rather than exiting the activity or app.
How can it implemented and example or sample code preferred.
I currently use this code but it does not help me out
FragmentManager fragmentManager = getSupportFragmentManager();
fragmentManager.beginTransaction()
.replace(R.id.frame_container, fragment)
.addToBackStack(null)
.commit();
I found some workaround for your query :
Override onBackPressed() in code
Use methods related to backstack maintained which contains your all fragment transactions
public void onBackPressed(){
FragmentManager fm = getFragmentManager();
if (fm.getBackStackEntryCount() > 0) {
Log.i("MainActivity", "popping backstack");
fm.popBackStack(); // this will display last visible fragment
getActinBar().setTitle(mTitle); // save your title in some variable and restore here
} else {
Log.i("MainActivity", "nothing on backstack, calling super");
super.onBackPressed(); // system will handle back key itself
}
}
Reference answer : this
I used to replace Fragment like as below :
public void replaceFragment(Fragment fragment, boolean addToBackStack, int transition) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.activity_main_relative_container, fragment, fragment.getClass().getName());
ft.setTransition(transition);
if (addToBackStack) {
ft.addToBackStack(fragment.getClass().getName());
}
ft.commitAllowingStateLoss();
}
// While to replace Fragment
replaceFragment(mFragment, true, FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
// False for not adding Fragment in back stack and true to add.
Hope this helps.
You need to add fragment to backstack
private FragmentTransaction m_fragmentTransaction;
FragmentOne m_fragOne = new FragmentOne();
m_fragmentTransaction = m_fragmentManager.beginTransaction();
m_fragmentTransaction.replace(R.id.dl_flContainer, m_fragOne , FragmentOne.class.getSimpleName());
m_fragmentTransaction.addToBackStack(FragmentOne.class.getSimpleName());
m_fragmentTransaction.commit();
I am working fragment, I replaced FragmentA by fragment B.it's working perfect,but when I press back button I can't back Fragment A.
I tried to override onKeyDown method,but I can't override this method in fragment
this is a my source
CategoryViewPager fragment1 = new CategoryViewPager();
FragmentTransaction ft = getSupportFragmentManager()
.beginTransaction().addToBackStack("method");
ft.setCustomAnimations(R.anim.trans_left_in, R.anim.trans_left_out);
ft.replace(R.id.content_frame, fragment1, "fragment2");
ft.commit();
when I use CategoryViewPager and click back button I can't go back(fragment wich i replaced this fragment)
how can I solve my problem?
Call addToBackStack() before you commit the transaction:
getSupportFragmentManager().beginTransaction()
// Add this transaction to the back stack
.addToBackStack()
.commit();
No need to use tag in your case. just use like this
/*
* Add this transaction to the back stack.
* This means that the transaction will be remembered after it is
* committed, and will reverse its operation when later popped off
* the stack.
*/
fragmentTransaction.addToBackStack(null);
It is better to handle back button press through your activity unless your actvity host large number of fragments.When you press back button inside your fragment onBackPressed() method of your activity will be called which can be overridden and handled..So handling back button for fragments can be done in this way..
MainActvity
public static boolean isMainActivityShown ;
public static boolean isFragment1Shown=false ;
public static boolean isFragment2Shown=false ;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
isMainActivityShown=true //inside onCreate method put isMainActivityShown true
.
.
.
}
.
.
Fragment currentFragment = new Fragment1();
isMainActivityShown=false; //when moving to fragment1
isFragment1Shown=true;
frgManager = getFragmentManager();
frgManager.beginTransaction().replace(R.id.content_frame, currentFragment)
.commit();
#Override
public void onBackPressed() {
if(isMainActivityShown)
{
finish();
}
else if(isFragment1Shown)
{
//write the code to handle back button when you are in Fragment1
}
else if(isFragment2Shown)
{ //When you are in Fragment 2 pressing back button will move to fragment1
Fragment currentFragment = new Fragment1();
isFragment2Shown=false;
isFragment1Shown=true;
FragmentManager frgManager;
frgManager = getFragmentManager();
frgManager.beginTransaction().replace(R.id.content_frame, currentFragment)
.commit();
}
}
Fragment1
Fragment currentFragment = new Fragment2();
MainActivity.isFragment1Shown=false;
MainActivity.isFragment2Shown=true;
frgManager = getFragmentManager();
frgManager.beginTransaction().replace(R.id.content_frame, currentFragment)
.commit();
Check this link
Check the addToBackStack(String name) method. This should solve your problem.