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Bottom navigation not working. How to resolve this issue?

I have made the code to do that it loads fragment on clicking the items in the bottom navigation but when I click on it they don't work. I tried many times to check whats the problem even though Android Studio couldn't find it bu the app isn't working. I don't know whats the issue.
My main activity -
public class MainActivity extends AppCompatActivity {
BottomNavigationView btm_view;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = manager.beginTransaction();
fragmentTransaction.add(R.id.container, new Chats());
fragmentTransaction.commit();
btm_view = findViewById(R.id.bottom_view);
btm_view.setOnNavigationItemSelectedListener(new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override
public boolean onNavigationItemSelected(#NonNull MenuItem item) {
if (item.getItemId() == R.id.camera) {
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = manager.beginTransaction();
fragmentTransaction.add(R.id.container, new Camera());
fragmentTransaction.commit();
} else if (item.getItemId() == R.id.chats) {
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = manager.beginTransaction();
fragmentTransaction.add(R.id.container, new Chats());
fragmentTransaction.commit();
} else if (item.getItemId() == R.id.status) {
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = manager.beginTransaction();
fragmentTransaction.add(R.id.container, new Status());
fragmentTransaction.commit();
} else if (item.getItemId() == R.id.calls) {
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = manager.beginTransaction();
fragmentTransaction.add(R.id.container, new Calls());
fragmentTransaction.commit();
} else if (item.getItemId() == R.id.settings) {
FragmentManager manager = getSupportFragmentManager();
FragmentTransaction fragmentTransaction = manager.beginTransaction();
fragmentTransaction.add(R.id.container, new Settings());
fragmentTransaction.commit();
}
return false;
}
});
}
}
one of my fragments -
public class Chats extends Fragment {
public Chats() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
return inflater.inflate(R.layout.fragment_chats, container, false);
}
}

Try this way
BottomNavigationView.OnNavigationItemSelectedListener navigationItemSelectedListener =
new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.chats:
openFragment(Chat.newInstance());
return true;
case R.id.camera:
openFragment(Camera.newInstance());
return true;
case R.id.status:
openFragment(Status.newInstance("", ""));
return true;
}
return false;
}
};

At first use replace(R.id.container, fragment) instead of add.
Optimise Code
Utilise setOnNavigationItemSelectedListener. Try this way
Set a listener that will be notified when a bottom navigation item is
selected.
btm_view.setOnNavigationItemSelectedListener(navigationItemSelectedListener);
openFragment(Camera.newInstance());
}
public void openFragment(Fragment fragment) {
FragmentTransaction transaction = getSupportFragmentManager().beginTransaction();
transaction.replace(R.id.container, fragment);
transaction.addToBackStack(null);
transaction.commit();
}
BottomNavigationView.OnNavigationItemSelectedListener navigationItemSelectedListener =
new BottomNavigationView.OnNavigationItemSelectedListener() {
#Override public boolean onNavigationItemSelected(#NonNull MenuItem item) {
switch (item.getItemId()) {
case R.id.camera:
openFragment(Camera.newInstance());
return true;
case R.id.chats:
openFragment(Chats.newInstance());
return true;
case R.id.status:
openFragment(Status.newInstance());
return true;
case R.id.calls:
openFragment(Calls.newInstance());
return true;
case R.id.settings:
openFragment(Settings.newInstance());
return true;
}
return false;
}
};
}
Your Chats Fragment will be
public class Chats extends Fragment {
public Chats() {
// Required empty public constructor
}
public static Chats newInstance() {
Chats fragment = new Chats();
return fragment;
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_chats, container, false);
}
}

How to Save the last Fragment?

I have three Fragments and I have two buttons on main Activity b1 called next button and b2 called previous button when app is starting its show me blank Fragment , when click on b1 its show me XFragment called page 1 ,when click on b1 its show me YFragment called page 2 , I want when re-open app its show me the last Fragment has been opend ,I know should use shareprefrences but I dont know how to add it to this code
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void b1(View view) {
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
XFragment fragment = new XFragment();
ft.replace(R.id.mainfragment,fragment);
ft.commit();
}
public void b2(View view) {
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
YFragment fragment = new YFragment();
ft.replace(R.id.mainfragment,fragment);
ft.commit();
}
}

Below is your required code using SharedPreference.
public class MainActivity extends AppCompatActivity {
SharedPreference pref;
Editor editor;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
pref = getApplicationContext().getSharedPreferences("MyPref", 0);
editor = pref.edit();
int fragment_number=pref.getInt("fragment_number", -1); // getting Integer
if(int==1){
//start first fragment
}
if(int==2){
//start second fragment
}
}
public void b1(View view) {
editor.putInt("fragment_number", 1);
editor.apply();
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
XFragment fragment = new XFragment();
ft.replace(R.id.mainfragment,fragment);
ft.commit();
}
public void b2(View view) {
editor.putInt("fragment_number", 2);
editor.apply();
FragmentManager fm = getSupportFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
YFragment fragment = new YFragment();
ft.replace(R.id.mainfragment,fragment);
ft.commit();
}
}

Android: How to switch from Fragment to Main Activity?

My MainActivity is the Google Maps Activity and I have 2 fragments called "LoginForm" and "appSettings". I can switch from the MainActivity to the 2 fragments, but I can't switch back to MainActivity. I have tried fragment.addToBackStack() but it doesn't do anything. Any idea? Here is the code from the Navigation Drawer.
public void selectedDrawerItem(MenuItem menuItem){
Class fragmentClass = null;
FrameLayout frameLayoutMap = (FrameLayout) findViewById(R.id.main_container_login);
FragmentManager fragmentManager = getSupportFragmentManager();
// For every new Fragment, add in Switch statement.
switch(menuItem.getItemId()) {
case R.id.nav_geomap:
fragmentClass = MapsActivity.class;
break;
case R.id.nav_login:
Log.d(TAG, "Accessed fragment: menuItem nav_login");
//frameLayoutMap.removeAllViews();
fragmentClass = LoginForm.class;
break;
case R.id.nav_settings:
Log.d(TAG, "Accessed fragment: menuItem nav_settings");
// frameLayoutMap.removeAllViews();
fragmentClass = appSettings.class;
break;
}
try
{
fragment = (Fragment) fragmentClass.newInstance();
}
catch (Exception e){
e.printStackTrace();
}
fragmentManager.beginTransaction().replace(R.id.map, fragment).commit();
menuItem.setChecked(true);
setTitle(menuItem.getTitle());
mDrawerLayout.closeDrawers();
}

try this
public void addPage(Fragment fragment) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.add(R.id.content_main, fragment);
ft.addToBackStack(null);
ft.commit();
}
public void forwardPage(final Fragment fragment) {
FragmentTransaction ft = getSupportFragmentManager().beginTransaction();
ft.replace(R.id.content_main, fragment);
ft.addToBackStack(null);
ft.commit();
}

ListFragment called from Button

This batch of code will place a ListFragment into a LinearLayout that I have selected, and it works fine. The problem I have is that this initiates from onCreate and I would like it to trigger from a Button.
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TamInputListFragment lstfragment=(TamInputListFragment)getSupportFragmentManager().findFragmentByTag("lstfragment");
if(lstfragment==null){
lstfragment=new TamInputListFragment();
FragmentTransaction transact=getSupportFragmentManager().beginTransaction();
transact.add(R.id.fragment_container,lstfragment,"lstfragment");
transact.commit();
}
This batch of code worked for a previous tutorial that just interchanged two simple Fragment with two separate Button.
public void selectFrag(View view){
Fragment fr;
if (view == findViewById(R.id.button2)) {
fr = new FragmentTwo();
}
else {
fr = new FragmentOne();
}
FragmentManager fm = getFragmentManager();
FragmentTransaction fragmentTransaction = fm.beginTransaction();
fragmentTransaction.replace(R.id.fragment_place, fr);
fragmentTransaction.commit();
}
But when I use this same batch of code and swap out FragmentOne() and FragmentTwo() for the two new ListFragment classes that I have made, TamInputListFragment and VerbInputListFragment, I get an "Incompatible Type" error saying that is wants a android.app.Fragment and not a com.example.petakirikiri.fragmenttest.Fragments.TamInputListFragment();
public void selectFrag(View view){
Fragment fr;
if (view == findViewById(R.id.verb_button) {
fr = new TamInputListFragment();
}
else {
fr = new VerbInputListFragment();
}
FragmentManager fm = getFragmentManager();
FragmentTransaction fragmentTransaction = fm.beginTransaction();
fragmentTransaction.replace(R.id.fragment_container, fr);
fragmentTransaction.commit();
}

How to add/remove Fragment on Button click?

At present I have got a "RELATIVE_LAYOUT" container which I am using for adding my fragment.
I am using OnClickListener on a button to load the fragment XML layout into the RelativeLayout container.
What I want to achieve is that when I press the button once, the fragment should load...and when I press it again the fragment should be removed. I've already tried using integer to identify if fragment is loaded, but failed.
Any help Appreciated...
CODE:
public class MainActivity extends Activity {
Button B1,B2;
int boolb1=0, boolb2=0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
B1 = (Button)findViewById(R.id.btn1);
B2 = (Button)findViewById(R.id.btn2);
B1.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
FragmentOne f1 = new FragmentOne();
if(boolb1==0)
{ft.add(R.id.frg1, f1);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
boolb1=1;}
else
{ft.remove(f1);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_CLOSE);
boolb1=0;}
//ft.addToBackStack("f1");
ft.commit();
}
});
B2.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
FragmentTwo f2 = new FragmentTwo();
if(boolb2==0) {
ft.add(R.id.frg2, f2);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
boolb2=1;
} else {
ft.remove(f2);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_CLOSE);
boolb2=0;
}
//ft.addToBackStack("f2");
ft.commit();
}
});
}

Your issue is that you create a new Fragment everytime you click the Button. You need to get a reference to the currently added Fragment and then remove that one.
Furthermore, you no longer need to use the flag.
When adding the Fragment, you can tag it. Upon removing the Fragment, you can use the tag used for adding the Fragment to get a reference to the currently added Fragment.
Here is an example of how you should do it:
private Button B1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
B1 = (Button)findViewById(R.id.btn1);
B1.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
FragmentManager fm = getFragmentManager();
FragmentTransaction ft = fm.beginTransaction();
FragmentOne f = (FragmentOne) fm.findFragmentByTag("tag");
if(f == null) { // not added
f = new FragmentOne();
ft.add(R.id.frg1, f, "tag");
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
} else { // already added
ft.remove(f);
ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_CLOSE);
}
ft.commit();
}
});
// and so on ...
}