Develop Reference

App title doesn't change after returning to previous fragment

I've been developing an android app which I included the default Navigation-Drawer from Android Studio and so on. In my home fragment, I've implemented CarViews, and then set those cardview(s) OnClickListener to replace the fragment with traditional procedure.
After the fragment replacement and new page comes, I wanted to change the Actionbar title.
So in the onCreateView(...) method, I tried,
((AppCompatActivity)getActivity()).getSupportActionBar().setTitle("B");
It worked. But after pressing the hardware back button to go back to the stacked fragment, the title remains changed & it doesn't change to "Home" again. I've tried other ways. Here's my following codes. Thanks in advance.
public class HomeFragment extends Fragment implements View.OnClickListener {
public View onCreateView(#NonNull LayoutInflater inflater,
ViewGroup container, Bundle savedInstanceState) {
View root = inflater.inflate(R.layout.fragment_home, container, false);
Objects.requireNonNull(((AppCompatActivity) Objects.requireNonNull(getActivity())).getSupportActionBar()).setTitle("Home");
CardView cardView1 = root.findViewById(R.id.doctor_on);
CardView cardView2 = root.findViewById(R.id.ambulance_e);
CardView cardView3 = root.findViewById(R.id.maintainance_s);
cardView1.setOnClickListener(this);
cardView2.setOnClickListener(this);
cardView3.setOnClickListener(this);
return root;
}
#Override
public void onClick(View v) {
int id = v.getId();
switch (id) {
case R.id.doctor_on:
FragmentTransaction fragmentTransaction = Objects.requireNonNull(getActivity()).getSupportFragmentManager().beginTransaction();
Fragment fragment1 = new doctors();
fragmentTransaction.replace(R.id.container1, fragment1).addToBackStack(getString(R.string.menu_home)).commit();
return;
case R.id.ambulance_e:
//Put Actions
FragmentTransaction fragmentTransaction2 = Objects.requireNonNull(getActivity()).getSupportFragmentManager().beginTransaction();
Fragment fragment2 = new ambulance();
fragmentTransaction2.replace(R.id.container1, fragment2).addToBackStack(getString(R.string.menu_home)).commit();
return;
case R.id.maintainance_s:
//Put Actions
FragmentTransaction fragmentTransaction3 = Objects.requireNonNull(getActivity()).getSupportFragmentManager().beginTransaction();
Fragment fragment3 = new maintanance();
fragmentTransaction3.replace(R.id.container1, fragment3).addToBackStack(getString(R.string.menu_home)).commit();
return;
}
}
#Override
public void onResume() {
super.onResume();
((AppCompatActivity) getActivity()).getSupportActionBar().setTitle("Home");
}
}
To the next fragment(where I change the titlebar and pressed back button):
public class doctors extend Fragment{
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
((AppCompatActivity)getActivity()).getSupportActionBar().setTitle("B");
View root = inflater.inflate(R.layout.fragment_doctors, container, false);
return root;
}
}

And in the doctors Fragment... Should fix the title error.
#Override
public void onDestroyView() {
super.onDestroyView();
Objects.requireNonNull(((AppCompatActivity) Objects.requireNonNull(getActivity()))
.getSupportActionBar())
.setTitle(getString(R.string.your_title_here));
}

You have to override the method onBackPressed() and write the code:
#Override
public View onBackPressed(){
//Here goes the code that head back to your main fragment
FragmentTransaction fragmentTransaction3 = Objects.requireNonNull(getActivity()).getSupportFragmentManager().beginTransaction();
Fragment fragment3 = new maintanance();
fragmentTransaction3.replace(R.id.container1, fragment3).addToBackStack(getString(R.string.menu_home)).commit();
}
}`

Add below code in Home Fragment...
#Override
public void onHiddenChanged(Boolean hidden) {
super.onHiddenChanged(hidden);
((AppCompatActivity) getActivity()).getSupportActionBar().setTitle("Home");
}

Save and restore fragment state

I have a series of fragments. And I use "previous" and "next" buttons for navigation within this fragments. There are many edit texts and radio buttons in this fragments.
I want to save and and restore the user input in these edit texts and radio buttons when a previous fragment is loaded by clicking on "previous" button.
Screeshots:
Fragment 1
Fragment 2
Fragment 1:
public class Register_Page6 extends Fragment {
public Register_Page6() {}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_register_page6, container, false);
Button Previous = (Button) view.findViewById(R.id.Previous6);
Button Next = (Button) view.findViewById(R.id.Next6);
Next.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
android.support.v4.app.FragmentTransaction FT;
FT = getActivity().getSupportFragmentManager().beginTransaction();
FT.replace(R.id.main_container,new Register_Page7());
FT.commit();
}
});
Previous.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
android.support.v4.app.FragmentTransaction FT;
FT = getActivity().getSupportFragmentManager().beginTransaction();
FT.replace(R.id.main_container,new Register_Page5());
FT.commit();
}
});
return view;
}
}
Fragment 2:
public class Register_Page7 extends Fragment {
public Register_Page7(){
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_register_page7, container, false);
Button Previous = (Button) view.findViewById(R.id.Previous7);
Button Regiter = (Button) view.findViewById(R.id.Submit);
Regiter.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
android.support.v4.app.FragmentTransaction FT;
FT = getActivity().getSupportFragmentManager().beginTransaction();
FT.replace(R.id.main_container,new Register_Page6());
FT.commit();
}
});
Previous.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
android.support.v4.app.FragmentTransaction FT;
FT = getActivity().getSupportFragmentManager().beginTransaction();
FT.replace(R.id.main_container,new Register_Page6());
FT.commit();
}
});
return view;
}
}

Add Your fragment to back stack using addToBackStack("YOUTAG") like this in all your fragments :
android.support.v4.app.FragmentTransaction FT;
FT = getActivity().getSupportFragmentManager().beginTransaction();
FT.replace(R.id.main_container, new Register_Page6()).addToBackStack("FragmentName");
FT.commit();

When you have a series of fragments if you add them to the backstack it would be memory wastage.
For this kind of action android provides something called ViewPager, which will always store 2 fragments at a time and create the rest of fragments dynamically when needed.
So if you still decided you don't want to use ViewPager, you can store the Fragment's data in activity's bundle and you can retrieve data when creating the fragment again

Go back to previous fragment

Btw this is my second fragment. This will appear once i press a button in a first fragment. In this fragment, if i press the back button on my phone, it will go back to previous fragment. Need your help guys. Thanks in advance.
public class ListAllDoctorFragment extends Fragment {
Button close;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.listalldoctor, container,false);
close = (Button) view.findViewById(R.id.button);
close.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
android.app.FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
SHIT f2 = new SHIT();
ft.add(R.id.content_frame, f2);
ft.addToBackStack(null);
ft.commit();
}
});
return view;
}
}

Assuming you want to go to previous fragment, if that is the case, remove ft.addToBackStack(null); from your code.

fragments overlap each other by pressing the back

I have akivity with one button and frame:
public class MyActivity extends Activity implements View.OnClickListener {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button replaceBtn = (Button) findViewById(R.id.replaceFragment);
replaceBtn.setOnClickListener(this);
}
#Override
public void onClick(View view) {
switch (view.getId()){
case R.id.replaceFragment:
Fragment fragment1 = new Frag1();
FragmentTransaction fTrans = getFragmentManager().beginTransaction();
fTrans.replace(R.id.contentFrame, fragment1);
**fTrans.addToBackStack(null);**
fTrans.commit();
break;
}
}
}
button is pressed, etc. I create a fragment:
public class Frag1 extends Fragment implements View.OnClickListener {
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.frag1, null);
Button replaceBtn2 = (Button) v.findViewById(R.id.replaceFragment2);
replaceBtn2.setOnClickListener(this);
return v;
}
#Override
public void onClick(View view) {
switch (view.getId()){
case R.id.replaceFragment2:
Frag2 fragment2 = new Frag2();
FragmentTransaction fTrans = getFragmentManager().beginTransaction();
fTrans.replace(R.id.contentFrame,fragment2);
**fTrans.addToBackStack(null);**
fTrans.commit();
break;
}
}
}
it also has a button which when pressed I create fragment2:
public class Frag2 extends Fragment implements View.OnClickListener {
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.frag2, null);
Button replaceBtn3 = (Button) v.findViewById(R.id.replaceFragment3);
replaceBtn3.setOnClickListener(this);
return v;
}
#Override
public void onClick(View view) {
switch (view.getId()){
case R.id.replaceFragment3:
Frag3 fragment3 = new Frag3();
FragmentTransaction fTrans = getFragmentManager().beginTransaction();
fTrans.replace(R.id.contentFrame,fragment3);
**//do not add backstack**
fTrans.commit();
break;
}
}
}
fragment2 also creates a new fragment3:
public class Frag3 extends Fragment{
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.frag3, null);
return v;
}
}
then later when I press the "back" button on the screen will appear the fragments in reverse order. but I want to when I'm in fragmente3 when you press the "back" appears immediately fragment1.

that is because you don't added the fragment2 to backstack. The fragment wont be pop back or disappear when they excluded from backstack. backstack runs exactly as activity back stack or any other stack container works.
to explain better:
added first fragment to stack
[stack] topElement Fragment1 (is showing)
added 2nd but did not add to the stack [stack] topElement
Fragment1(is not showing)
added 3rd fragment to stack [stack] topElement Fragment3(is
showing)
now if you pop it will return in this order : 3rd,1st and nothing more.
EDIT
in this case you can simply override the onBackPressed() like this to achieve the behaviour you want:
onBackPressed(){
//default back pressed behaviour
if(mFragmentManager.getBackStackEntryCount()==0)//you can set it ==1 if you wish to close
finish();
mFragmentManager.popBackStackImmediate(null, FragmentManager.POP_BACK_STACK_INCLUSIVE);
}

I can not understand with the fragments and BackStack

I have aсivity with one button and frame:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="new fragment"
android:id="#+id/replaceFragment" android:layout_gravity="center_horizontal"/>
<FrameLayout
android:layout_width="match_parent"
android:layout_height="fill_parent" android:layout_gravity="center_horizontal" android:id="#+id/contentFrame">
</FrameLayout>
</LinearLayout>
code:
public class MyActivity extends Activity implements View.OnClickListener {
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button replaceBtn = (Button) findViewById(R.id.replaceFragment);
replaceBtn.setOnClickListener(this);
}
#Override
public void onClick(View view) {
switch (view.getId()){
case R.id.replaceFragment:
Fragment fragment1 = new Frag1();
FragmentTransaction fTrans = getFragmentManager().beginTransaction();
fTrans.replace(R.id.contentFrame, fragment1);
fTrans.commit();
break;
}
}
}
button is pressed, etc. I create a fragment:
public class Frag1 extends Fragment implements View.OnClickListener {
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.frag1, null);
Button replaceBtn2 = (Button) v.findViewById(R.id.replaceFragment2);
replaceBtn2.setOnClickListener(this);
return v;
}
#Override
public void onClick(View view) {
switch (view.getId()){
case R.id.replaceFragment2:
Frag2 fragment2 = new Frag2();
FragmentTransaction fTrans = getFragmentManager().beginTransaction();
fTrans.replace(R.id.contentFrame,fragment2);
fTrans.commit();
break;
}
}
}
it also has a button which when pressed I create fragment2:
public class Frag2 extends Fragment implements View.OnClickListener {
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.frag2, null);
Button replaceBtn3 = (Button) v.findViewById(R.id.replaceFragment3);
replaceBtn3.setOnClickListener(this);
return v;
}
#Override
public void onClick(View view) {
switch (view.getId()){
case R.id.replaceFragment3:
Frag3 fragment3 = new Frag3();
FragmentTransaction fTrans = getFragmentManager().beginTransaction();
fTrans.replace(R.id.contentFrame,fragment3);
fTrans.commit();
break;
}
}
}
fragment2 also creates a new fragment3:
public class Frag3 extends Fragment{
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.frag3, null);
return v;
}
}
if I do when creating each fragment will add a line:
fTrans.addToBackStack(null);
then later when I press the "back" button on the screen will appear the fragments in reverse order. but I want to when I'm in fragmente3 when you press the "back" appears immediately fragment1.
if I do not add the line fTrans.addToBackStack(null); in fragment2 they overlap.

in order to do that, you can keep the fragments backStack references in your activity or for example onBackPressed you could try something like below:
if (getSupportFragmentManager().getBackStackEntryCount() != 0) {
//back to fragment 1.
}

Here you are a function which I use for one of my projects. I implemented it in the parent of the Activity that manages the fragments. I don't know if I'm going to clarify anything about the behaviour because all you tell us in you question make sense to me.
I my case, it was a simple app (almost static), but it changes fragments and, as you want to, many times I want to go back two fragment in "history" so I think it could help.
#Override
public void replaceFragment(FRAGMENT_TYPE destinyFragmentType, int fragmentContainerID, boolean addToBackStack) {
FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
Fragment currentFragment = FragmentFactory.getFragment(destinyFragmentType);
fragmentTransaction.replace(fragmentContainerID, currentFragment);
if (addToBackStack) {
fragmentTransaction.addToBackStack(null);
}
fragmentTransaction.commit();
}
Notes:
The second parameter is the parameter that indicates if you want to
keep in history or not. For your case: frg1 -> fr2 : param true; fr2
-> fr3 : param false;
I used a Factory in order to get a cleaner code, but you can use
whatever you want, change the header, give the function your fragment
etc.
I hope this helps!!