Develop Reference

How to call NavController from fragment?

In my fragment_main.xml, I have the following code :
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.fragment.app.FragmentContainerView
android:id="#+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="#+id/bottomBar"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:navGraph='#navigation/bottom_bar_nav_graph' />
<!--custom bottom navigation ui-->
</androidx.constraintlayout.widget.ConstraintLayout>
I would like to have access to navController(***bottom_bar_nav_graph***) from fragment.
Is it possible?

If I get what you are trying to do correctly, you what to do something like
findViewbyId(R.id.bottom_bar_nav_graph)
which is not possible.
What this line of code is doing
app:navGraph='#navigation/bottom_bar_nav_graph'
is to let FragmentContainerView know about your graph bottom_bar_nav_graph which is an XML file that describes how your fragments relate, pass data and navigate between each other.
But can have access to nav_host_fragment which is the id for the host fragment.
If you want to access the navController with the id in Activity, you can use
val navController = findNavController(R.id.nav_host_fragment)

extends Fragment {
private static final String ARG_SECTION_NUMBER = "section_number";
private PageViewModel pageViewModel;
private FragmentMainBinding binding;
public static PlaceholderFragment newInstance(int index) {
PlaceholderFragment fragment = new PlaceholderFragment();
Bundle bundle = new Bundle();
bundle.putInt(ARG_SECTION_NUMBER, index);
fragment.setArguments(bundle);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
pageViewModel = new ViewModelProvider(this).get(PageViewModel.class);
int index = 1;
if (getArguments() != null) {
index = getArguments().getInt(ARG_SECTION_NUMBER);
}
pageViewModel.setIndex(index);
}
#Override
public View onCreateView(
#NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
binding = FragmentMainBinding.inflate(inflater, container, false);
View root = binding.getRoot();
final TextView textView = binding.sectionLabel;
pageViewModel.getText().observe(getViewLifecycleOwner(), new Observer<String>() {
#Override
public void onChanged(#Nullable String s) {
textView.setText(s);
}
});
return root;
}

ViewPager inside Fragment doest show content

im developing an android app which has a bottomnavigation that opens 3 different fragments without a viewpager. One fragment has a viewpager inside it which opens 2 fragments. these 2 fragments are the same fragment and each has a recyclerview inside it. my problem is that when I run the app everything except the viewpager runs as intended. I tried putting the fragment inside the viewpager instead of it and the fragment works. I even tried putting the viewpager in a empty activity which worked as well.
This is my MainActivity which holds the BottomNavigation and its functionality:
public class MainActivity extends AppCompatActivity implements BottomNavigationView.OnNavigationItemSelectedListener {
private androidx.appcompat.widget.Toolbar toolbar;
private BottomNavigationView navView;
private Fragment fragment1 = new HomeFragment();
private Fragment fragment2 = new SearchFragment();
private Fragment fragment3 = new SettingsFragment();
private FragmentManager fm = getSupportFragmentManager();
private Fragment active = fragment1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
toolbar = findViewById(R.id.action_bar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("Home");
fm.beginTransaction().add(R.id.main_container, fragment3, "settings").hide(fragment3).commit();
fm.beginTransaction().add(R.id.main_container, fragment2, "search").hide(fragment2).commit();
fm.beginTransaction().add(R.id.main_container, fragment1, "home").commit();
navView = findViewById(R.id.nav_view);
navView.setOnNavigationItemSelectedListener(this);
}
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem menuItem) {
switch (menuItem.getItemId()) {
case R.id.navigation_home:
fm.beginTransaction().hide(active).show(fragment1).addToBackStack("home").commit();
active = fragment1;
toolbar.setTitle("Home");
return true;
case R.id.navigation_search:
fm.beginTransaction().hide(active).show(fragment2).addToBackStack("search").commit();
active = fragment2;
toolbar.setTitle("Search");
return true;
case R.id.navigation_settings:
fm.beginTransaction().hide(active)
.show(fragment3).addToBackStack("settings").commit();
active = fragment3;
toolbar.setTitle("Settings");
return true;
}
return false;
}
public void setCurrentPage(Fragment fragment, int position) {
if(fm.findFragmentByTag("playlist"+position) != null){
fm.beginTransaction().remove(fragment).hide(active).add(R.id.main_container, fragment, "playlist"+position).addToBackStack(null).commit();
active = fragment;
} else {
fm.beginTransaction().hide(active).add(R.id.main_container, fragment, "playlist"+position).addToBackStack(null).commit();
active = fragment;
}
}
}
This is the MainActivityLayout:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
tools:context=".MainActivity">
<include
layout="#layout/action_bar"
android:id="#+id/action_bar"/>
<androidx.core.widget.NestedScrollView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="56dp"
android:layout_marginBottom="70dp"
android:id="#+id/main_container_parent">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
android:id="#+id/main_container"/>
</androidx.core.widget.NestedScrollView>
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/nav_view"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="?android:attr/windowBackground"
android:layout_alignParentBottom="true"
app:menu="#menu/bottom_nav_menu"
app:itemTextColor="#color/bottom_nav_color"
app:itemIconTint="#color/bottom_nav_color"
android:elevation="20dp"/>
</RelativeLayout>
This is my Fragment that implements the ViewPager:
public class HomeFragment extends Fragment {
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_home, container, false);
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
PlaylistsPagerAdapter playlistsPagerAdapter = new PlaylistsPagerAdapter(getChildFragmentManager());
playlistsPagerAdapter.addFragment(new PlaylistsFragment(),"private");
playlistsPagerAdapter.addFragment(new PlaylistsFragment(),"public");
ViewPager viewPager = view.findViewById(R.id.pager_home);
viewPager.setAdapter(playlistsPagerAdapter);
TabLayout tabLayout = view.findViewById(R.id.tab_layout_home);
tabLayout.setupWithViewPager(viewPager);
setHasOptionsMenu(false);
}
public class PlaylistsPagerAdapter extends FragmentStatePagerAdapter {
ArrayList<Fragment> mFragmentList = new ArrayList<>();
ArrayList<String> mFragmentListTitle = new ArrayList<>();
public void addFragment(Fragment playlistsFragment, String title) {
mFragmentListTitle.add(title);
mFragmentList.add(playlistsFragment);
}
public PlaylistsPagerAdapter(FragmentManager fm) {
super(fm);
}
#NonNull
#Override
public Fragment getItem(int i) {
return mFragmentList.get(i);
}
#Override
public int getCount() {
return mFragmentList.size();
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentListTitle.get(position);
}
}
}
This is the HomeFragmentLayout:
<?xml version="1.0" encoding="utf-8"?>
<androidx.viewpager.widget.ViewPager
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#+id/pager_home"
android:layout_width="match_parent"
android:layout_height="match_parent">
<com.google.android.material.tabs.TabLayout
android:id="#+id/tab_layout_home"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</androidx.viewpager.widget.ViewPager>
This is the PlaylistsFragment:
public class PlaylistsFragment extends Fragment {
private static final String TAG = "PlaylistsFragment";
private ArrayList<String> mPlaylistName = new ArrayList<>();
#Nullable
#Override
public View onCreateView(#NonNull LayoutInflater inflater, #Nullable ViewGroup container, #Nullable Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_playlists, container, false);
}
#Override
public void onViewCreated(#NonNull View view, #Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
initNameBitmap(view);
}
private void initNameBitmap(View view){
mPlaylistName.add("Playlist1");
mPlaylistName.add("Playlist2");
mPlaylistName.add("Playlist3");
mPlaylistName.add("Playlist4");
initRecyclerView(view);
}
private void initRecyclerView(View view){
RecyclerView recyclerView = view.findViewById(R.id.recycler_view_playlists);
RecyclerViewAdapterPlaylists recyclerViewAdapterPlaylists = new RecyclerViewAdapterPlaylists(mPlaylistName, view.getContext(),this);
recyclerView.setAdapter(recyclerViewAdapterPlaylists);
recyclerView.setLayoutManager(new LinearLayoutManager(getView().getContext()));
}
}
This is the PlaylistsFragments Layout:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.recyclerview.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="#+id/recycler_view_playlists"
android:layout_margin="10dp" />
</LinearLayout>
The weird thing is that it worked already. I tried around with onBackPressed and when i implemented this and pressed another View on the BottomNavigation than the back button on the phone and than the Home button it showed as intened:
fm.beginTransaction().hide(active).show(fragmentsHistory.get(fragmentsHistory.size()-1));
active = fragmentsHistory.get(fragmentsHistory.size()-1)
fragmentsHistory.remove(fragmentsHistory.size()-1);
What am I doing wrong?
Appreciate the help!

i think the problem is in your layout
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
tools:context=".ui.plans.PlansFragment">
<com.google.android.material.tabs.TabLayout
android:id="#+id/tabLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#color/colorPrimaryDark"
app:tabSelectedTextColor="#color/white"
app:tabTextColor="#DBD8D8" />
<androidx.viewpager.widget.ViewPager
android:id="#+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent" />
</LinearLayout>
your HomeFragmentLayout should be similar to this

Replace fragmentA with fragmentB issue

I have a image in the main activity and when this image is clicked i want to show the fragmentA that has a list view.
When a item of this listView is clicked i want to replace the fragmentA by the fragmentB that has a textview, and I want to show in this textview the text associated to the clicked list item.
So in main activity I have this:
public class MainActivity extends AppCompatActivity implements Listener{
private ImageView img;
private String text;
FragmentManager fragmentManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
fragmentManager = getFragmentManager();
img = (ImageView) findViewById(R.id.imageView);
}
public void AddFragmentA(View view) {
FragmentA fragmentA = new FragmentA();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.containerFragmentA, new FragmentA(), "fragA");
transaction.commit();
}
public void AddFragmentB() {
FragmentB fragment = new FragmentB();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.containerFragmentB, new FragmentA(), "fragB");
transaction.commit();
}
#Override
public void addText(String text) {
this.text = text;
Toast.makeText(this, "Text received in Activity:" +text, Toast.LENGTH_SHORT).show();
sendDataToFragmentB();
}
public void sendDataToFragmentB(){
FragmentB fragmentB = (FragmentB) fragmentManager.findFragmentByTag("fragB");
fragmentB.addText(text);
}
}
Note: The toast in addText() appears with the correct text at this point, so the text of the list view is received in Activity with success.
Question: Now how to replace fragmentA with fragmentB and show the textview with the received text in the activity instead of showing the listview of the fragmentA?
Below is all the complete example.
FragmentA class:
public class FragmentA extends Fragment{
private ListView listItems;
private String[] items = {
"item1",
"item2",
"item3",
"item4"
};
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment, container, false);
return view;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
listItems = (ListView) getView().findViewById(R.id.listviewInFragment);
ArrayAdapter<String> adapter =
new ArrayAdapter<String>(getActivity().getApplicationContext(),
android.R.layout.simple_list_item_1, android.R.id.text1, items);
listItems.setAdapter(adapter);
listItems.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
int positionCode = i;
String clickedValue = (String) adapterView.getItemAtPosition(i);
Listener listener = (Listener) getActivity();
listener.addText(clickedValue);
}
});
}
}
FramentB:
public class FragmentB extends Fragment {
private TextView tv;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_b, container, false);
tv = (TextView) getView().findViewById(R.id.textView);
return view;
}
public void addText(String text) {
String result = text;
tv.setText(result);
}
}
main activity xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:id="#+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:srcCompat="#drawable/image"
android:onClick="AddFragmentA"
tools:layout_editor_absoluteX="0dp"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginBottom="8dp" />
<FrameLayout
android:id="#+id/containerFragmentA"
android:layout_width="0dp"
android:layout_height="300dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintHorizontal_bias="0.0"
tools:layout_editor_absoluteY="1dp">
</FrameLayout>
<FrameLayout
android:id="#+id/containerFragmentB"
android:layout_width="0dp"
android:layout_height="300dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintHorizontal_bias="0.0"
tools:layout_editor_absoluteY="1dp">
</FrameLayout>
</android.support.constraint.ConstraintLayout>
fragment a xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#0ff">
<ListView
android:layout_width="368dp"
android:layout_height="495dp"
android:layout_marginLeft="8dp"
android:layout_marginStart="16dp"
android:id="#+id/listviewInFragment"/>
</android.support.constraint.ConstraintLayout>
fragment b xml:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#ff0">
<TextView
android:id="#+id/textView"
android:layout_width="wrap_content"
android:layout_height="300dp"
android:layout_marginLeft="8dp"
android:layout_marginRight="8dp"
/>
</android.support.constraint.ConstraintLayout>

This is how you will achieve the required task.
make chnages to your class accordingly below.
MainActivity.java
public class MainActivity extends AppCompatActivity implements FragmentA.ClickListener{
private Button button;
public static String EXTRA_STRING = "extraString";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
button = (Button)findViewById(R.id.button);
button.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
AddFragment(FragmentA.getInstance());
}
});
}
public void AddFragment(Fragment fragment) {
getSupportFragmentManager().beginTransaction().replace(R.id.containerFragmentA, fragment).commit();
}
#Override
public void onClick(String data) {
AddFragment(FragmentB.getInstance(data));
}
}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent">
<FrameLayout
android:id="#+id/containerFragmentA"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintHorizontal_bias="0.0"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
tools:layout_editor_absoluteY="1dp"/>
<Button
android:id="#+id/button"
style="#style/Widget.AppCompat.Button.Colored"
android:layout_margin="8dp"
android:layout_alignParentBottom="true"
android:text="Add Fragment B"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</RelativeLayout>
FragmentA.java
public class FragmentA extends Fragment {
private ListView listItems;
private String[] items = {"item1", "item2", "item3", "item4"};
private ClickListener clickListener;
public static FragmentA getInstance() {
return new FragmentA();
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
clickListener = (ClickListener)context;
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_a, container, false);
return view;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
listItems = (ListView) getView().findViewById(R.id.listviewInFragment);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(getContext(),android.R.layout.simple_list_item_1, items);
listItems.setAdapter(adapter);
listItems.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
String clickedValue = items[i];
clickListener.onClick(clickedValue);
}
});
}
public interface ClickListener{
void onClick(String data);
}
}
fragment_a.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent"
android:layout_height="match_parent">
<ListView
android:layout_width="368dp"
android:layout_height="495dp"
android:layout_marginLeft="8dp"
android:layout_marginStart="16dp"
android:id="#+id/listviewInFragment"/>
</android.support.constraint.ConstraintLayout>
FragmentB.java
public class FragmentB extends Fragment {
private TextView tv;
private String data;
public static FragmentB getInstance(String data){
Bundle bundle = new Bundle();
bundle.putString(MainActivity.EXTRA_STRING,data);
FragmentB fragmentB = new FragmentB();
fragmentB.setArguments(bundle);
return fragmentB;
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_b, container, false);
tv = view.findViewById(R.id.textView);
data = getArguments().getString(MainActivity.EXTRA_STRING);
addText(data);
return view;
}
public void addText(String text) {
String result = text;
tv.setText(result);
}
}
fragment_b.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_gravity="center"
android:gravity="center"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:gravity="center"
android:textSize="24dp"
android:textAppearance="#style/TextAppearance.AppCompat.Widget.PopupMenu.Header"
android:id="#+id/textView"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</LinearLayout>

you are placing fragment A in below function instead of fragment B
public void AddFragmentB() {
FragmentB fragment = new FragmentB();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.containerFragmentB, new FragmentA(), "fragB");
transaction.commit();
}
it should be
public void AddFragmentB() {
FragmentB fragment = new FragmentB();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.replace(R.id.containerFragmentB, new FragmentB(), "fragB");
transaction.commit();
}
if you want to replace a fragment with another just use the same container
don't create separate (R.id.containerFragmentB, R.id.containerFragmentA) container.

You need to change your
public void AddFragmentA(View view) {
FragmentA fragmentA = new FragmentA();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.containerFragmentA, new FragmentA(), "fragA");
transaction.commit();
}
public void AddFragmentB() {
FragmentB fragment = new FragmentB();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.containerFragmentB, new FragmentA(), "fragB");
transaction.commit();
}
to
public void AddFragmentA(View view) {
FragmentA fragmentA = new FragmentA();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.container, fragmentA , "fragA");
transaction.commit();
}
public void AddFragmentB() {
FragmentB fragment = new FragmentB();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.container, fragment, "fragB");
transaction.commit();
}
and activity_main.xml should be
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<ImageView
android:id="#+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:srcCompat="#drawable/image"
android:onClick="AddFragmentList"
tools:layout_editor_absoluteX="0dp"
app:layout_constraintBottom_toBottomOf="parent"
android:layout_marginBottom="8dp" />
<FrameLayout
android:id="#+id/container"
android:layout_width="0dp"
android:layout_height="300dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintHorizontal_bias="0.0"
tools:layout_editor_absoluteY="1dp">
</FrameLayout>
</android.support.constraint.ConstraintLayout>
EDIT
listItems.setAdapter(adapter);
listItems.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
int positionCode = i;
String clickedValue = (String) adapterView.getItemAtPosition(i);
Listener listener = (Listener) getActivity();
listener.addText(clickedValue);
}
});
Listener
public interface IScanner {
void addText(String Text);
}
MainActivity
public class MainActivity extends AppCompatActivity implements Listener{
private ImageView img;
private String text;
FragmentManager fragmentManager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
fragmentManager = getFragmentManager();
img = (ImageView) findViewById(R.id.imageView);
}
public void AddFragmentA(View view) {
FragmentA fragmentA = new FragmentA();
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.containerFragmentA, new FragmentA(), "fragA");
transaction.commit();
}
#Override
public void addText(String text) {
this.text = text;
Toast.makeText(this, "Text received in Activity:" +text, Toast.LENGTH_SHORT).show();
sendDataToFragmentB(text);
}
public void sendDataToFragmentB(String clickedValue){
Bundle b = new Bundle();
b.putString("clickedValue", clickedValue);
FragmentB fragment = new FragmentB();
fragment.setArguments(b);
FragmentTransaction transaction = fragmentManager.beginTransaction();
transaction.add(R.id.containerFragmentB, new FragmentA(), "fragB");
transaction.commit();
}
}
FragmentB
public class FragmentB extends Fragment {
private TextView tv;
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_b, container, false);
tv = (TextView) getView().findViewById(R.id.textView);
return view;
}
Bundle bundle = this.getArguments();
if (bundle != null) {
String text = bundle.getString("clickedValue", "");
}
}
This will solve your problem

Replace fragment in fragment itself in TabActivity

I am sorry on the duplicate question but I didn't get answer for my problem.
I create app with TabActivity and also trying to replace one fragment from fragment itself, I read in https://developer.android.com/training/basics/fragments/fragment-ui.html how to do it and i created interface in my fragment that i want to be replace with another,
I implement the interface in my MainActivity and still when running my app it show me container itself.
here is my code:
Main Activity:
public class MainActivity extends FragmentActivity implements New2.OnReplaceFragment {
private SectionsPagerAdapter mSectionsPagerAdapter;
private ViewPager mViewPager;
public static MainActivity instance = null;
public static MainActivity getInstance(){
return instance;
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.frame_container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
tabLayout.getTabAt(0).setIcon(R.drawable.icon_info);
tabLayout.getTabAt(1).setIcon(R.drawable.icon_heart_rate_sensor_jpg);
tabLayout.getTabAt(2).setIcon(R.drawable.icon_graph_jpg);
instance = this;
}
#Override
public void onReplaceFragment(Class fragmentClass) {
Fragment fragment = null;
try {
fragment = (Fragment) fragmentClass.newInstance();
} catch (Exception e) {
e.printStackTrace();
}
// Insert the fragment by replacing any existing fragment
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.frame_container,fragment);
// Replace whatever is in the fragment_container view with this fragment,
// and add the transaction to the back stack so the user can navigate back
transaction.addToBackStack(null);
// Commit the transaction
transaction.commit();
}
public static class PlaceholderFragment extends Fragment {
/**
* The fragment argument representing the section number for this
* fragment.
*/
private static final String ARG_SECTION_NUMBER = "section_number";
public PlaceholderFragment() {
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
TextView textView = (TextView) rootView.findViewById(R.id.section_label);
textView.setText(getString(R.string.section_format, getArguments().getInt(ARG_SECTION_NUMBER)));
return rootView;
}
}
public class SectionsPagerAdapter extends FragmentPagerAdapter {
public SectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
// getItem is called to instantiate the fragment for the given page.
// Return a PlaceholderFragment (defined as a static inner class below).
switch (position) {
case 0:
// New1 tab1 = new New1();
return New1.newInstance();
case 1:
return New2.newInstance();
case 2:
return New3.newInstance();
default:
return null;
}
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "SECTION 1";
case 1:
return "SECTION 2";
case 2:
return "SECTION 3";
}
return null;
}
}
}
my fragment that I want to replace
Fragment:
public class New2 extends Fragment {
TextView name;
Button change;
ImageView image1;
Animation anime;
private OnReplaceFragment dataPasser;
public static New2 newInstance(){
New2 fragment = new New2();
return fragment;
}
public New2(){
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_new2, container, false);
name = (TextView) rootView.findViewById(R.id.nameTt);
change = (Button) rootView.findViewById(R.id.changeBtn);
image1 = (ImageView) rootView.findViewById(R.id.image1);
anime = AnimationUtils.loadAnimation(getActivity().getApplicationContext(),R.anim.zoom);
change.setOnClickListener(changeName);
return rootView;
}
View.OnClickListener changeName = new View.OnClickListener() {
#Override
public void onClick(View view) {
image1.startAnimation(anime);
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
#Override
public void run(){
dataPasser.onReplaceFragment(Result.class);
}
},1000);
}
};
public interface OnReplaceFragment {
public void onReplaceFragment(Class fragmentClass);
}
#Override
public void onAttach(Activity a) {
super.onAttach(a);
try {
dataPasser = (OnReplaceFragment) a;
} catch (ClassCastException e) {
throw new ClassCastException(a.toString() + " must implement onDataPass");
}
}
}
the fragment that i want to display
public class Result extends Fragment {
TextView textView;
Button btnBack;
public static Result instance = null;
public static Result getInstance(){
return instance;
}
public Result() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View v = inflater.inflate(R.layout.fragment_result, container, false);
textView = (TextView) v.findViewById(R.id.text11);
btnBack = (Button) v.findViewById(R.id.btnBack);
textView.setText("working!!");
Toast.makeText(getActivity().getApplicationContext(),"working",Toast.LENGTH_LONG).show();
return v;
}
}
Main Activity XML:
<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="#+id/main_content"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:context="com.example.hercules.tadhosttutrial.MainActivity">
<android.support.design.widget.AppBarLayout
android:id="#+id/appbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="#dimen/appbar_padding_top"
android:background="#color/red"
android:theme="#style/AppTheme.AppBarOverlay">
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/frame_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
New2 XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.hercules.tadhosttutrial.New2"
android:background="#color/yellow">
<!-- TODO: Update blank fragment layout -->
<Button
android:id="#+id/changeBtn"
android:layout_width="80dp"
android:layout_height="40dp"
android:layout_gravity="center_horizontal"
android:text="change"/>
<ImageView
android:id="#+id/image1"
android:background="#drawable/icon_complete"
android:layout_width="200dp"
android:layout_height="200dp"
android:layout_centerHorizontal="true"
android:layout_centerVertical="true"
/>
Result XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#color/colorAccent"
tools:context="com.example.hercules.tadhosttutrial.Result">
<!-- TODO: Update blank fragment layout -->
<Button
android:id="#+id/btnBack"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="back"/>
<TextView
android:id="#+id/text11"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="WORKING"
android:layout_centerVertical="true"
android:layout_centerHorizontal="true"
android:textSize="70dp"
/>
</RelativeLayout>

What i mean, is making MainActivity as a main container for all fragments, either with tabs or just a regular fragment,
1- Main Activity XML: remove ViewPager, add a FrameLayout instead (use same id)
2- Create new fragment TabsFragment with this XML:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.example.hercules.tadhosttutrial.New2"
android:background="#color/yellow">
<android.support.v4.view.ViewPager
android:id="#+id/frame_container"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</RelativeLayout>
3- Move initializing SectionsPagerAdapter and ViewPager from main activity to TabsFragment:
this part:
private SectionsPagerAdapter mSectionsPagerAdapter;
private ViewPager mViewPager;
and this:
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
mViewPager = (ViewPager) findViewById(R.id.frame_container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(mViewPager);
tabLayout.getTabAt(0).setIcon(R.drawable.icon_info);
tabLayout.getTabAt(1).setIcon(R.drawable.icon_heart_rate_sensor_jpg);
tabLayout.getTabAt(2).setIcon(R.drawable.icon_graph_jpg);
4- I think moving SectionsPagerAdapter class in a new file is better too.
now if you want default view for app to be the tabs, then in MainActivity at onCreate() show TabsFragment by calling your method:
onReplaceFragment(TabsFragment.class);
now every thing should work fine, because the idea here is to replace the fragment displayed in main activity with another one
in this case TabsFragment, Result, and New2
not to replace viewpager fragments (because as i told you this is managed via the adapter) not by calling replace()
you may need to play around this, it's not a final code, just something to give you idea about it.

How to add dynamic fragment tab items

I want to add dynamic tab items. I have a fragment which is FragmentOne and it has a TextView. I'm trying create FragmentOne in foreach and add to tabs. I tested code which is in setupViewPager but it doesn't work. How can I edit TextView which in fragments?
if I remove this lines it works but contents of fragment always show default that = "TAB ONE". I want to edit all TextView which is in fragments that created at run time;
View view = fView.getView();
TextView txtTabItemNumber = (TextView)view.findViewById(R.id.txtTabItemNumber);
txtTabItemNumber.setText("TAB " + i);
DynamicTabsActivity.java
public class DynamicTabsActivity extends AppCompatActivity {
private Toolbar toolbar;
private TabLayout tabLayout;
private ViewPager viewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dynamic_tabs);
toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
viewPager = (ViewPager) findViewById(R.id.viewpager);
setupViewPager(viewPager);
tabLayout = (TabLayout) findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
}
private void setupViewPager(ViewPager viewPager) {
ViewPagerAdapter adapter = new ViewPagerAdapter(getSupportFragmentManager());
LayoutInflater inflator = (LayoutInflater) getSystemService(Context.LAYOUT_INFLATER_SERVICE);
int count = 10;
for (int i=0; i<count; i++){
OneFragment fView = new OneFragment();
View view = fView.getView();
TextView txtTabItemNumber = (TextView)view.findViewById(R.id.txtTabItemNumber);
txtTabItemNumber.setText("TAB " + i);
adapter.addFrag(fView,"TAB " + i);
}
viewPager.setAdapter(adapter);
}
class ViewPagerAdapter extends FragmentPagerAdapter {
private final List<Fragment> mFragmentList = new ArrayList<>();
private final List<String> mFragmentTitleList = new ArrayList<>();
public ViewPagerAdapter(FragmentManager manager) {
super(manager);
}
#Override
public Fragment getItem(int position) {
return mFragmentList.get(position);
}
#Override
public int getCount() {
return mFragmentList.size();
}
public void addFrag(Fragment fragment, String title) {
mFragmentList.add(fragment);
mFragmentTitleList.add(title);
}
#Override
public CharSequence getPageTitle(int position) {
return mFragmentTitleList.get(position);
}
}
}
activity_dynamic_tabs.xml
<android.support.design.widget.CoordinatorLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light" />
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMode="scrollable"/>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.design.widget.CoordinatorLayout>
OneFragment.java
public class OneFragment extends Fragment{
public OneFragment() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_one, container, false);
}
}
fragment_one.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="info.androidhive.materialtabs.fragments.OneFragment">
<TextView
android:id="#+id/txtTabItemNumber"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TAB ONE"
android:textSize="40dp"
android:textStyle="bold"
android:layout_centerInParent="true"/>
</RelativeLayout>

The fragment's layout hasn't been created at point that you call findViewById below:
OneFragment fView = new OneFragment();
View view = fView.getView();
TextView txtTabItemNumber = (TextView)view.findViewById(R.id.txtTabItemNumber);
Following is more typically way this is coded:
public static class OneFragment extends Fragment {
private static final String ARG_SECTION_NUMBER = "section_number";
private int sectionNumber;
public OneFragment() {
}
public static OneFragment newInstance(int sectionNumber) {
OneFragment fragment = new OneFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_one, container, false);
sectionNumber = getArguments().getInt(ARG_SECTION_NUMBER);
TextView textView = (TextView) rootView.findViewById(R.id.txtTabItemNumber);
textView.setText("TAB " + sectionNumber);
return rootView;
}
}
you might also want to move fragment creation in to adapter...for example:
public Fragment getItem(int position) {
return OneFragment.newInstance(position + 1);
}

After trying for long...I came up with the following solution:
DynamicTabsActivity is my main activity, looks like this:
public class DynamicTabsActivity extends AppCompatActivity {
private TabLayout tabLayout;
private ViewPager viewPager;
private ViewPagerAdapter viewPagerAdapter;
private int noOfTabs = 10;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_dynamic_tabs);
viewPagerAdapter = new ViewPagerAdapter(getSupportFragmentManager(), noOfTabs);
viewPager = findViewById(R.id.viewpager);
viewPager.setAdapter(viewPagerAdapter);
tabLayout = findViewById(R.id.tabs);
tabLayout.setupWithViewPager(viewPager);
}
}
My fragment looks like this:
public class DynamicFragment extends Fragment {
private static final String ARG_SECTION_NUMBER = "section_number";
private int sectionNumber;
public DynamicFragment() {
// Required empty public constructor
}
#Override
public void onCreate(#Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
sectionNumber = getArguments() != null ? getArguments().getInt(ARG_SECTION_NUMBER) : 1;
}
#Override
public View onCreateView(#NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment_dynamic, container, false);
TextView textView = view.findViewById(R.id.txtTabItemNumber);
textView.setText("TAB " + sectionNumber);
return view;
}
public static DynamicFragment newInstance(int sectionNumber) {
DynamicFragment fragment = new DynamicFragment();
Bundle args = new Bundle();
args.putInt(ARG_SECTION_NUMBER, sectionNumber);
fragment.setArguments(args);
return fragment;
}
}
My ViewPager Class looks like this:
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
private int noOfItems;
public ViewPagerAdapter(FragmentManager fm, int noOfItems) {
super(fm);
this.noOfItems = noOfItems;
}
#Override
public Fragment getItem(int position) {
return DynamicFragment.newInstance(position + 1);
}
#Override
public int getCount() {
return noOfItems;
}
#Override
public CharSequence getPageTitle(int position) {
return "TAB "+(position+1);
}
}
DynamicTabsActivity layout:
<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".DynamicTabsActivity">
<android.support.design.widget.AppBarLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:theme="#style/ThemeOverlay.AppCompat.Dark.ActionBar">
<android.support.v7.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?attr/actionBarSize"
android:background="?attr/colorPrimary"
app:layout_scrollFlags="scroll|enterAlways"
app:popupTheme="#style/ThemeOverlay.AppCompat.Light" />
<android.support.design.widget.TabLayout
android:id="#+id/tabs"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:tabMode="scrollable"/>
</android.support.design.widget.AppBarLayout>
<android.support.v4.view.ViewPager
android:id="#+id/viewpager"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_behavior="#string/appbar_scrolling_view_behavior" />
</android.support.constraint.ConstraintLayout>
Fragment layout:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".DynamicFragment">
<TextView
android:id="#+id/txtTabItemNumber"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:text="TAB ONE"
android:textSize="40dp"
android:textStyle="bold" />
</RelativeLayout>
Hope it helps...

Try this,
LinearLayout main = new LinearLayout(this);
main.setOrientation(LinearLayout.VERTICAL);
TextView textView = new TextView(this);
textView .setText("TAB " + i);
main .addView(textView );