I need to go from FragmentA to FragmentB (i'm using navigationdrawer)
I create this method in FragmentB:
public void onBackPressed(){
FragmentManager fm = getActivity().getFragmentManager();
fm.popBackStackImmediate();
}
but they don't work, how can i implement this method?
When you add your fragment, you also have to add it to your fragment's backstack.
FragmentTransaction ft = getSupportFragmentManager.beginTransaction();
ft.replace(R.id.content, fragment, backStateName);
ft.addToBackStack(backStateName);
ft.commit();
(here R.id.content is your fragment container in your activity)
Then you have to override onBackPressed method in your activity that contains your fragments.
#Override
public void onBackPressed() {
if (getSupportFragmentManager().getBackStackEntryCount() > 1) {
getSupportFragmentManager().popBackStack();
}
}
if you want to customize your onBackPressed then you can check for your currently visible fragment in your activity and create a callback for performing action for that particular fragment.
example -
#Override
public void onBackPressed() {
if (getSupportFragmentManager().getBackStackEntryCount() > 1) {
Fragment fragment = getSupportFragmentManager().findFragmentById(R.id.content);
if (fragment instanceof FragmentB) {
((FragmentB) fragment).onBackPressed();
// getSupportFragmentManager().popBackStack();
}
}
now you can add getSupportFragmentManager().popBackStack(); in your Fragment's onBackPressed() method.
This code should be inside Activity holding both fragments.
Be sure, that you add (not replace) the fragment to back stack, by calling:
android.app.FragmentTransaction#add(int, android.app.Fragment, java.lang.String)
android.app.FragmentTransaction#addToBackStack
android.app.FragmentTransaction#commit
or their equivalent from support library
For going to the one fragment to another I am calling the Activity's method from Fragment so that the Activity's method has access to that view which is holding fragment and it can switch easily.
like this in my Fragment
((MainActivity) getActivity()).TransitionFromItemToCategory();
And in the fragment Like this
public void TransitionFromItemToCategory(){
FoodCategoryFragment FCM = new FoodCategoryFragment();
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.fragment_container, FCM);
ft.commit();
}
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'm adding the fragment using android.R.id.content in order to fill up Activity's space using the following code.
private void doFragmentTransaction(Fragment fragment, String tag) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.setCustomAnimations(R.anim.slide_in_bottom_y, R.anim.slide_out_bottom_y,
R.anim.slide_in_bottom_y, R.anim.slide_out_bottom_y);
transaction.add(android.R.id.content, fragment, tag);
transaction.addToBackStack(tag);
transaction.commitAllowingStateLoss();
}
And I have got a problem to catch the moment that the fragment is closed by pressing back button. The lifecycle method onStop is not called.
What I should do in order to make it working properly that all lifecycle methods are called?
Hello you can work on activity onBackPressed() like below
#Override
public void onBackPressed() {
if (getSupportFragmentManager().getBackStackEntryCount() > 1) {
val frag = getSupportFragmentManager().findFragmentById(android.R.id.container);
if (frag is HomeFragment) {
Fragment currentFragment = (HomeFragment) frag;
//do your code
return
}
}
super.onBackPressed();
}
I do the next steps:
Create and open a fragment (fr1) in my main Acitivty.
Replace the fragment for another one (and created too)(fr2)
Pressing button OnBackPressed and navigate to the fr1 (With pop back stack).
4.Trying to replace the fragment(fr1) for the same
fr2 (another time) but my onCreateView is not called.
I read some post this is for lifecycle fragments but did not know how to resolve it.
I need to initialize the view each time that I replace the fragment.
How can I solve it?
public void navigateFragment(Fragment fragment, int fm, String tagFragment) {
FragmentTransaction fragmentTransaction = getSupportFragmentManager().beginTransaction();
fragmentTransaction.setCustomAnimations(R.anim.fade_in, R.anim.fade_out);
fragmentTransaction.replace(R.id.frame_container, fragment, tagFragment).addToBackStack(tagFragment).commit();
}
public void onBackPressed() {
if (getSupportFragmentManager().getBackStackEntryCount() > 0) {
getSupportFragmentManager().popBackStack();
}
}
I am creating an application with multiple fragments. I have four fragments fragment1, fragment2, fragment3, fragment4. I am moving from different orders like f1 -> f2 -> f4 -> f3 -> f1 or any other order. But when I click the back button from each fragment I need to go to the previous fragment. How to handle this.
Edit 1:
I already tried
FragmentManager fm = ((Activity) context).getFragmentManager();
for (int i = 0; i < fm.getBackStackEntryCount(); i++) {
fm.popBackStack();
}
Which is not help me to solve my issue.
Sample code of Manage Fragment back stack
private Stack<Fragment> stack = new Stack<Fragment>();
public void pushFragments(Fragment fragment, boolean shouldAnimate,
boolean shouldAdd) {
drawerClose = false;
if (shouldAdd)
stack.push(fragment);
this.changeFragment = fragment;
invalidateOptionsMenu();
changeFragment(fragment, shouldAnimate, false);
}
public void popFragments() {
/*
* Select the second last fragment in current tab's stack.. which will
* be shown after the fragment transaction given below
*/
Fragment fragment = stack.elementAt(stack.size() - 2);
// / pop current fragment from stack.. /
stack.pop();
/*
* We have the target fragment in hand.. Just show it.. Show a standard
* navigation animation
*/
this.changeFragment = fragment;
invalidateOptionsMenu();
changeFragment(fragment, false, true);
}
private void changeFragment(Fragment fragment, boolean shouldAnimate, boolean popAnimate) {
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction ft = manager.beginTransaction();
if (shouldAnimate)
ft.setCustomAnimations(R.anim.slide_in_right,
R.anim.slide_out_left);
if (popAnimate)
ft.setCustomAnimations(R.anim.slide_in_left,
R.anim.slide_out_right);
ft.replace(R.id.content_frame, fragment);
ft.commit();
}
//On BackPress just check this thing
private void backManage() {
if (stack.size() > 1) {
popFragments();
}
}
Use addToBackStack(String tag), while committing the fragment to add the fragment into the stack of your application:
getFragmentManager().beginTransaction().replace(fragmentContainer.getID(), fragment)
.addToBackStack(null).commit();`
on Activity
#Override
public void onBackPressed() {
if(check_if_backstack_is_null)
super.onBackPressed();
else
{
popupFromBackstack();
}
}
You should override onBackPressed method:
#Override
public void onBackPressed() {
if (fragment != null && fragment.getChildFragmentManager().getBackStackEntryCount() > 0){
fragment.getChildFragmentManager().popBackStack();
}else {
super.onBackPressed();
}
}
For this you can set addToBackStack to fragment transation and then call commit.
By calling addToBackStack(), the replace transaction is saved to the back stack so the user can reverse the transaction and bring back the previous fragment by pressing the Back button.
If you add multiple changes to the transaction (such as another add() or remove()) and call addToBackStack(), then all changes applied before you call commit() are added to the back stack as a single transaction and the Back button will reverse them all together.
You just need to add addToBackStack(null) by FragmentTransaction.
when you are calling next Fragment just add this method with null parameter.
Like this.
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(..............);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
Use this lines of code for it:-
#Override
public void onBackPressed() {
if ( getSupportFragmentManager().getBackStackEntryCount() > 0){
fm.popBackStack();
}else {
super.onBackPressed();
}
}
To get the backStack functionality in your fragmentthan you should have use the .addToBackStack(null) , while performing the fragment transaction like below:-
getSupportFragmentManager()
.beginTransaction()
.replace(R.id.YOUR_CONTAINER, YOUR_FRAGMENT,"TAG")
.addToBackStack(null) /// IT IS NECESSARY TO GET THE BACK STACK PROPERTY IN YOUR FRAGMENT
.commitAllowingStateLoss();
I have an Activity and many fragments inflated in same FrameLayout
<FrameLayout
android:id="#+id/content_frame"
android:layout_width="match_parent"
android:layout_height="match_parent" />
example: mainActivity > any fragment (press back button) > activity is blank.
In onCreate:
layout = (FrameLayout)findViewById(R.id.content_frame);
layout.setVisibility(View.GONE);
When I start a fragment:
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.content_frame, profileFragment);
ft.addToBackStack(null);
ft.commit();
layout.setVisibility(View.VISIBLE);
I suppose I need to make the frameLayout's visibility GONE again on back pressed, but how do I do this?
I tried onBackPressed and set layout.setVisibility(View.GONE); but I cannot go back through fragments, as I go directly to main page.
If you have more than one fragment been used in the activity or even if you have only one fragment then the first fragment should not have addToBackStack defined. Since this allows back navigation and prior to this fragment the empty activity layout will be displayed.
// fragmentTransaction.addToBackStack() // dont include this for your first fragment.
But for the other fragment you need to have this defined otherwise the back will not navigate to earlier screen (fragment) instead the application might shutdown.
#Override
public void onBackPressed() {
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
if (drawer.isDrawerOpen(GravityCompat.START)) {
drawer.closeDrawer(GravityCompat.START);
}
else {
int fragments = getSupportFragmentManager().getBackStackEntryCount();
if (fragments == 1) {
finish();
} else if (getFragmentManager().getBackStackEntryCount() > 1) {
getFragmentManager().popBackStack();
} else {
super.onBackPressed();
}
}
}
To add a fragment
getSupportFragmentManager().beginTransaction()
.replace(R.id.layout_main, dashboardFragment, getString(R.string.title_dashboard))
.addToBackStack(getString(R.string.title_dashboard))
.commit();
Sorry for the late response.
You don't have to add ft.addToBackStack(null); while adding first fragment.
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.content_frame, profileFragment);
// ft.addToBackStack(null); --remove this line.
ft.commit();
// ... rest of code
If you want to track by the fragments you should override the onBackPressed method, like this
public void onBackPressed() {
if (getFragmentManager().getBackStackEntryCount() == 1) {
finish();
} else {
super.onBackPressed();
}
}
You can override onBackPressed and check to see if there is anything on the backstack.
#Override
public void onBackPressed() {
int fragments = getFragmentManager().getBackStackEntryCount();
if (fragments == 1) {
// make layout invisible since last fragment will be removed
}
super.onBackPressed();
}
Just don't add the first fragment to back stack
Here is the Kotlin code that worked for me.
val ft = supportFragmentManager.beginTransaction().replace(container, frag)
if (!supportFragmentManager.fragments.isEmpty()) ft.addToBackStack(null)
ft.commit()
On a recent personal project, I solved this by not calling addToBackStack if the stack is empty.
// don't add the first fragment to the backstack
// otherwise, pressing back on that fragment will result in a blank screen
if (fragmentManager.getFragments() != null) {
transaction.addToBackStack(tag);
}
Here's my full implementation:
String tag = String.valueOf(mCurrentSectionId);
FragmentManager fragmentManager = mActivity.getSupportFragmentManager();
Fragment fragment = fragmentManager.findFragmentByTag(tag);
if (fragment != null) {
// if the fragment exists then no need to create it, just pop back to it so
// that repeatedly toggling between fragments doesn't create a giant stack
fragmentManager.popBackStackImmediate(tag, 0);
} else {
// at this point, popping back to that fragment didn't happen
// So create a new one and then show it
fragment = createFragmentForSection(mCurrentSectionId);
FragmentTransaction transaction = fragmentManager.beginTransaction()
.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN)
.replace(R.id.main_content, fragment, tag);
// don't add the first fragment to the backstack
// otherwise, pressing back on that fragment will result in a blank screen
if (fragmentManager.getFragments() != null) {
transaction.addToBackStack(tag);
}
transaction.commit();
}
irscomp's solution works if you want to end activity when back button is pressed on first fragment. But if you want to track all fragments, and go back from one to another in back order, you add all fragments to stack with:
ft.addToBackStack(null);
and then, add this to the end of onCreate() to avoid blank screen in last back pressed; you can use getSupportFragmentManager() or getFragmentManager() depending on your API:
FragmentManager fm = getSupportFragmentManager();
fm.addOnBackStackChangedListener(new OnBackStackChangedListener() {
#Override
public void onBackStackChanged() {
if(getSupportFragmentManager().getBackStackEntryCount() == 0) finish();
}
});
Final words: I don't suggest you to use this solution, because if you go from fragment1 to fragment 2 and vice versa 10 times, when you press back button 10 times it will do it in back order which users will not want it.
Almost same as Goodlife's answer, but in Xamarin.Android way:
Load fragment (I wrote helper method for that, but it's not necessary):
public void LoadFragment(Activity activity, Fragment fragment, string fragmentTitle = "")
{
var fragmentManager = activity.FragmentManager;
var fragmentTransaction = fragmentManager.BeginTransaction();
fragmentTransaction.Replace(Resource.Id.mainContainer, fragment);
fragmentTransaction.AddToBackStack(fragmentTitle);
fragmentTransaction.Commit();
}
Back button (in MainActivity):
public override void OnBackPressed()
{
if (isNavDrawerOpen()) drawerLayout.CloseDrawers();
else
{
var backStackEntryCount = FragmentManager.BackStackEntryCount;
if (backStackEntryCount == 1) Finish();
else if (backStackEntryCount > 1) FragmentManager.PopBackStack();
else base.OnBackPressed();
}
}
And isNavDrawerOpen method:
bool isNavDrawerOpen()
{
return drawerLayout != null && drawerLayout.IsDrawerOpen(Android.Support.V4.View.GravityCompat.Start);
}
I still could not fix the issue through getBackStackEntryCount() and I solved my issue by making the main page a fragment too, so in the end I have an activity with a FrameLayout only; and all other fragments including the main page I inflate into that layout. This solved my issue.
I had the same problem when dealing with Firebase's Ui Login screen. When back button was pressed it left a blank screen.
To solve the problem I just called finish() in my onStop() method for said Activity. Worked like a charm.
If you have scenario like me where a list fragment opens another details fragment, and on back press you first need to show the list fragment and then get out the whole activity then, addToBackStack for all the fragment transactions.
and then on the activity, do like this (courtesy: #JRomero's answer, #MSaudi's comment)
#Override
public void onBackPressed() {
int fragments = getFragmentManager().getBackStackEntryCount();
if (fragments == 1) {
// make layout invisible since last fragment will be removed
}
super.onBackPressed();
}
Just Comment or Remove transaction.addToBackStack(null) in your code.Below is code to change fragment in kotlin.
fun ChangeFragment(activity: MainActivity, fragment: Fragment) {
val transaction: FragmentTransaction =
activity.getSupportFragmentManager().beginTransaction()
transaction.replace(R.id.tabLayoutContainer, fragment)
transaction.commit()
}