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();
Related
I have three fragments A、B、C , my process is A to B to C .
I want that when i change to C and call back to B , B can switch to A immediately.
So i set the switch fragment function on onResume on B .
But the result is that i always land up on A fragment , because when i change to B the function onResume be called
I know i can remove transaction.addToBackStack(null); then i can C to A
, but it will cause some bug in my project , so i try to keep it.
Is any function only start when C call back to B ?
Thanks in advance.
Below is my switch function:
private void switchFragment(Fragment fragment) {
FragmentManager manager = getActivity().getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.mainFrame, fragment, null);
transaction.addToBackStack(null);
transaction.commit();
}
I try to add onResume on fragment B , but it will be A to B , and then B go back to A immediately.
#Override
public void onResume() {
super.onResume();
//go back to fragment A
switchFragment(NewHomepage.newInstance());
}
your fragment transition code should be:
private void switchFragment(Fragment fragment) {
FragmentManager manager = getActivity().getSupportFragmentManager();
FragmentTransaction transaction = manager.beginTransaction();
transaction.replace(R.id.mainFrame, fragment, null);
transaction.addToBackStack("fragment_name_tagX");
transaction.commit();
}
above, X is your fragment. After you navigate from fragment A to C using above function, your stack will have every fragment with name 'fragment_name_tag' that you assign.
#Override
public void onBackPressed() {
FragmentManager fm = getActivity().getSupportFragmentManager();
int count = fm.getBackStackEntryCount();
if (count != 0) {
fm.popBackStack ("fragment_name_tagB",FragmentManager.POP_BACK_STACK_INCLUSIVE);
} else {
super.onBackPressed();
}
}
So when you now press back button from fragment C, it will go on fragment A.
Hi I am using a Stack variable for storing the sequence of fragments clicked by the user
For example : [A,B,C,A,D]
Now I need to check if a fragment exits in the stack I need to reuse it.
From the above example I need to reuse the first element i.e, A when user clicks on the fourth time.
The problem is I have a custom keyboard opening in fragment A, now if the same fragment is in the stack as forth element the keyboard is not opening .but when I backpress and go to first element keyboard is opened in the first instance of A
Code for storing in the Stack
public void switchContent(Fragment fragment) {
if(mContent !=null && (fragment.getClass().toString().equals(mContent.getClass().toString()))){
getSlidingMenu().showContent();
return;
}
mContent = fragment;
FragmentManager fragmentManager = getSupportFragmentManager();
FragmentTransaction ft = fragmentManager.beginTransaction();
ft.add(R.id.content_frame, mContent);
FragmentChangeActivity.fragmentStack.lastElement().onPause();
FragmentChangeActivity.fragmentStack.push(mContent);
ft.commit();
getSlidingMenu().showContent();
}
Code for backpress
#Override
public void onBackPressed() {
if (fragmentStack.size() >= 2) {
FragmentTransaction ft = fragmentManager.beginTransaction();
fragmentStack.lastElement().onPause();
ft.remove(fragmentStack.pop());
fragmentStack.lastElement().onResume();
ft.show(fragmentStack.lastElement());
ft.commit();
} else {
super.onBackPressed();
}
}
Any help is appreciated.
The following code check's if Fragment named SearchFragment exists or not in backstack and processes accordingly. You can use this logic to determine if a specific Fragment exists or not
FragmentManager fragmentManager=getSupportFragmentManager();
Fragment currentFragment = (Fragment)fragmentManager.findFragmentById(R.id.mainContent);
if(currentFragment!=null && currentFragment instanceof SearchFragment){
//SearchFragment exists in backstack , process accordingly
}else{
//SearchFragment not present in backstack
}
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.
Im trying to load an new fragment when a method is called. This method creates a new fragment and "replaces" the other fragment:
private void showTestFragment(Fragment oldFragment, boolean addBackStack, BaseAdapter adapter, int position) {
Cursor cursor = (Cursor)adapter.getItem(position);
if(cursor != null){
int idx = cursor.getColumnIndexOrThrow(Episode._ID);
long rowId = cursor.getLong(idx);
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
if(oldFragment != null){
Log.i(TAG, "Removing the old fragment");
fragmentTransaction.remove(oldFragment);
}
TestFragment testFragment = new TestFragment();
testFragment.setId(rowId);
fragmentTransaction.add(android.R.id.content, testFragment);
if(addBackStack){
Log.i(TAG, "Added to the backstack");
fragmentTransaction.addToBackStack(TAG);
}
fragmentTransaction.commit();
Fragment f = getFragmentManager()
.findFragmentById(R.id.index);
Log.i(TAG, "after commit, frag is "+ f);
}
}
This works fine, until i go back. The last fragment, should be removed when i go back. Before i'm going to implement methods on the activities
public void onBackPressed(){}
to remove the last fragment, i want to know if i handle the fragment change correctly. It looks like i'm missing something here..
If you really want to replace the fragment then use replace() methode instead of doing a remove() and an add().
FragmentManager fragmentManager = getFragmentManager();
FragmentTransaction fragmentTransaction = fragmentManager.beginTransaction();
fragmentTransaction.replace(..............);
fragmentTransaction.addToBackStack(null);
fragmentTransaction.commit();
Don't forget to do the addToBackStack(null) so your previous state will be added to the backstack allowing you to go back with the back button.
See also https://developer.android.com/reference/android/app/FragmentTransaction.html#replace(int, android.app.Fragment, java.lang.String) .
Another good source is http://developer.android.com/guide/components/fragments.html (search for replace() function).
Just remove first and the call super.onBackPressed
public void onBackPressed(){
// here remove code for your last fragment
super.onBackPressed();
}
//lets wait for systems back to finish
super.onBackPressed();
//here we believe a fragment was popped, so we need to remove the fragment from ourbackstack
if(fragmentBackStack.size()>0)
{
Log.d("custombackstack","before back: "+fragmentBackStack.size()+" current:"+fragmentBackStack.peek());
fragmentBackStack.pop();
}
//after popping is the size > 0, if so we set current fragment from the top of stack, otherwise we default to home fragment.
if(fragmentBackStack.size()>0)
{
Log.d("custombackstack","after back: "+fragmentBackStack.peek());
currentFragment = fragmentBackStack.peek();
}
else
{
//back stack empty
currentFragment = HOME_FRAGMENT;
}