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incompatible types: FragmentDark cannot be converted to Fragment in Android [closed]

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I'm getting an error in this part of code:
package com.example.myapplication;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.view.MenuItem;
import android.view.View;
import android.view.Menu;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentPagerAdapter;
import com.example.myapplication.Fragments.FragmentDark;
import com.example.myapplication.ui.home.HomeFragment;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.android.material.snackbar.Snackbar;
import com.google.android.material.navigation.NavigationView;
import androidx.core.view.GravityCompat;
import androidx.navigation.NavController;
import androidx.navigation.Navigation;
import androidx.navigation.ui.AppBarConfiguration;
import androidx.navigation.ui.NavigationUI;
import androidx.drawerlayout.widget.DrawerLayout;
import androidx.appcompat.app.AppCompatActivity;
import androidx.appcompat.widget.Toolbar;
public class MainActivity extends AppCompatActivity implements NavigationView.OnNavigationItemSelectedListener {
FragmentDark fragmentDark;
private AppBarConfiguration mAppBarConfiguration;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
getSupportActionBar().setTitle("TEMA");
FloatingActionButton fab = findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
DrawerLayout drawer = findViewById(R.id.drawer_layout);
NavigationView navigationView = findViewById(R.id.nav_view);
fragmentDark = new FragmentDark();
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public boolean onSupportNavigateUp() {
NavController navController = Navigation.findNavController(this, R.id.nav_host_fragment);
return NavigationUI.navigateUp(navController, mAppBarConfiguration)
|| super.onSupportNavigateUp();
}
public boolean onNavigationItemSelected(MenuItem item) {
int id = item.getItemId();
FragmentTransaction fragmentTransaction = getFragmentManager().beginTransaction();
// Handle navigation view item clicks here.
if (id == R.id.nav_home) {
// Handle the camera action
} else if (id == R.id.nav_gallery) {
} else if (id == R.id.nav_slideshow) {
} else if (id == R.id.tema) {
fragmentTransaction.replace(R.id.container, fragmentDark);
} else if (id == R.id.calls) {
} else if (id == R.id.invite) {
} else if (id == R.id.settings) {
} else if (id == R.id.contacts) {
}
DrawerLayout drawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawer.closeDrawer(GravityCompat.START);
return true;
}
}
It is class Dark
package com.example.myapplication.Fragments;
import android.os.Bundle;
import androidx.fragment.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentPagerAdapter;
import com.example.myapplication.R;
public class FragmentDark extends Fragment {
// TODO: Rename parameter arguments, choose names that match
// the fragment initialization parameters, e.g. ARG_ITEM_NUMBER
private static final String ARG_PARAM1 = "param1";
private static final String ARG_PARAM2 = "param2";
// TODO: Rename and change types of parameters
private String mParam1;
private String mParam2;
public FragmentDark() {
// Required empty public constructor
}
/**
* Use this factory method to create a new instance of
* this fragment using the provided parameters.
*
* #param param1 Parameter 1.
* #param param2 Parameter 2.
* #return A new instance of fragment FragmentDark.
*/
// TODO: Rename and change types and number of parameters
public static FragmentDark newInstance(String param1, String param2) {
FragmentDark fragment = new FragmentDark();
Bundle args = new Bundle();
args.putString(ARG_PARAM1, param1);
args.putString(ARG_PARAM2, param2);
fragment.setArguments(args);
return fragment;
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
if (getArguments() != null) {
mParam1 = getArguments().getString(ARG_PARAM1);
mParam2 = getArguments().getString(ARG_PARAM2);
}
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_dark, container, false);
}
}

Firstly, please format your code when asking a question.
Your problem is, that you use androidx fragments, but you try to run a platform-specific fragment transaction.
Simply replace getFragmentManager() with getSupportFragmentManager() and import the androidx FragmentTransaction class respectively.

FragmentPagerAdapter always starts from the first page

I have a Fragment pager adapter with five fragments and inside the third fragment I want to call an other activity which sends a selected picture to the container. It works fine but, every time the picture is selected from the other activity and the pager adapter starts from the first fragment in the fragment-activity instead of third fragment-activity. Do I have to force the pager adapter from the other activity or should I change something in the fragment-activity?
Code:
Fragment-activity:
package com.example.android.womb_the_game;
import android.content.pm.ActivityInfo;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import androidx.fragment.app.FragmentActivity;
import androidx.fragment.app.FragmentPagerAdapter;
import androidx.viewpager.widget.ViewPager;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
import com.google.android.material.snackbar.Snackbar;
import com.google.android.material.tabs.TabLayout;
public class Circulation extends FragmentActivity {
ViewPager vp;
public static FragmentPagerAdapter adapterViewPager;
#Override
protected void onCreate(Bundle onSavedInstanceState) {
super.onCreate(onSavedInstanceState);
this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_circulation);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
vp = findViewById(R.id.view_pager);
adapterViewPager=new Adapter_Circulation(getSupportFragmentManager(), this);
vp.setAdapter(adapterViewPager);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
tabLayout.setupWithViewPager(vp);
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
}
FragmentPagerAdapter:
package com.example.android.womb_the_game;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentPagerAdapter;
import android.content.Context;
public class Adapter_Circulation extends FragmentPagerAdapter {
private static int NUM_ITEMS = 5;
Context context;
public Adapter_Circulation(FragmentManager fm, Context c) {
super(fm);
this.context = c;
}
#Override
public Fragment getItem(int position) {
switch (position)
{
case 0:
return Frg0.newInstance ();
case 1:
return Frg1.newInstance();
case 2:
return Frg2.newInstance();
case 3:
return Frg3.newInstance();
case 4:
return Frg4.newInstance();
}
return null; //does not happen
}
#Override
public int getCount() {
return NUM_ITEMS; //three fragments
}
#Override
public CharSequence getPageTitle(int position) {
switch (position) {
case 0:
return "RULES";
case 1:
return "EVENTS";
case 2:
return "PLAN";
case 3:
return "SHOOT";
case 4:
return "JUMP";
}
return null;
}
}
Fragment3:
package com.example.android.womb_the_game;
import android.os.Bundle;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.fragment.app.FragmentManager;
import androidx.fragment.app.FragmentTransaction;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageButton;
public class Frg3 extends Fragment{
private ImageButton shoot;
private ImageButton snipe;
private ImageButton aim;
public static Frg3 newInstance() {
Bundle args = new Bundle();
Frg3 fragment = new Frg3();
fragment.setArguments(args);
return fragment;
}
#Nullable
#Override
public View onCreateView(LayoutInflater inflater, #Nullable ViewGroup container, #Nullable final Bundle savedInstanceState) {
super.onCreateView(inflater, container, savedInstanceState);
View rootView = inflater.inflate(R.layout.fragment_frg3, container, false);
shoot = (ImageButton) rootView.findViewById(R.id.shoot);
snipe = (ImageButton) rootView.findViewById(R.id.snipe);
aim = (ImageButton) rootView.findViewById(R.id.aim);
final View.OnClickListener mListener = new View.OnClickListener() {
#Override
public void onClick(View view) {
switch (view.getId()) {
case R.id.shoot:
FragmentManager FM0 = getFragmentManager();
FragmentTransaction FT0 = FM0.beginTransaction();
frg_shoot F10 = new frg_shoot();
FT0.add(R.id.fragment_container1, F10);
FT0.replace(R.id.fragment_container1, F10);
FT0.commit();
break;
case R.id.snipe:
FragmentManager FM = getFragmentManager();
FragmentTransaction FT = FM.beginTransaction();
frg_snipe F1 = new frg_snipe();
FT.add(R.id.fragment_container1, F1);
FT.replace(R.id.fragment_container1, F1);
FT.commit();
break;
case R.id.aim:
FragmentManager FM1 = getFragmentManager();
FragmentTransaction FT1 = FM1.beginTransaction();
frg_aim F11 = new frg_aim();
FT1.add(R.id.fragment_container1, F11);
FT1.replace(R.id.fragment_container1, F11);
FT1.commit();
break;
}
}
};
rootView.findViewById(R.id.shoot).setOnClickListener(mListener);
rootView.findViewById(R.id.snipe).setOnClickListener(mListener);
rootView.findViewById(R.id.aim).setOnClickListener(mListener);
return rootView;
}
}
Other Activity:
package com.example.android.womb_the_game;
import androidx.fragment.app.FragmentActivity;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.ImageButton;
import android.widget.ImageView;
public class choose_dice_column extends FragmentActivity {
private ImageButton b1;
private ImageView im1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.activity_choose_dice_column);
this.setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
b1 = (ImageButton) findViewById(R.id.b1);
im1 = findViewById(R.id.im1);
b1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Intent i = new Intent(choose_dice_column.this, Circulation.class);
i.putExtra("resid1",R.drawable.n1);
startActivity(i);
}
});
}
}

The problem is, whenever you get back to your activity, you are creating a new adapter. So add the following to your Circulation-Activity to keep the state of the adapter:
if(adapterViewPager == null)
{
adapterViewPager = new Adapter_Circulation(getSupportFragmentManager(), this);
}

Android: E/RecyclerView: No adapter attached; skipping layout

so i have a tabbed activity that contains 3 tabs as fragments, each tab has a RecyclerView.
I checked all the answered questions on here and on other sites, everything seems fine, yet it doesn't work!
here's my Code:
MainActivity.java:
package esprit.tn.mywaterproject;
import android.support.design.widget.TabLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;
import java.time.Duration;
import java.util.zip.Inflater;
public class MainActivity extends AppCompatActivity {
/**
* The {#link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {#link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {#link android.support.v4.app.FragmentStatePagerAdapter}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {#link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.e("test","test log");
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new
SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
mViewPager.addOnPageChangeListener(new
TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.addOnTabSelectedListener(new
TabLayout.ViewPagerOnTabSelectedListener(mViewPager));
FloatingActionButton fab = findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Toast.makeText(getApplicationContext(), "Chat avec un
résponsable", Toast.LENGTH_SHORT).show();
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
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() {
}
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
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) {
Log.e("frag number", "frag test number
:"+getArguments().getInt(ARG_SECTION_NUMBER));
if (getArguments().getInt(ARG_SECTION_NUMBER)==1){
Log.e("frag test1", "frag test TEST1");
new Eaux_Fragment();
return inflater.inflate(R.layout.fragment_eaux,
container,false);
}
if (getArguments().getInt(ARG_SECTION_NUMBER)==2){
Log.e("frag test2", "frag test TEST2");
return inflater.inflate(R.layout.fragment_piscine,
container,false);
}
if (getArguments().getInt(ARG_SECTION_NUMBER)==3){
Log.e("frag test3", "frag test TEST3");
return inflater.inflate(R.layout.fragment_electricite, container,false);
}
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;
}
}
/**
* A {#link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
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).
return PlaceholderFragment.newInstance(position + 1);
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
}
}
Here's my Adapter
ProduitAdapter.java :
package esprit.tn.mywaterproject;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import java.util.ArrayList;
import java.util.List;
import esprit.tn.mywaterproject.Entities.Produit_Eau;
public class ProduitAdapter extends
RecyclerView.Adapter<ProduitAdapter.ViewHolder> {
private Context context;
private List<Produit_Eau> list;
public ProduitAdapter( Context context, ArrayList<Produit_Eau> list) {
this.context=context;
this.list = list;
}
#Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
Log.e("LOG IN ADAPTER","TEST ADAPTER");
View v =
LayoutInflater.from(context).inflate(R.layout.single_produit_eau, parent,
false);
return new ViewHolder(v);
}
#Override
public void onBindViewHolder(ViewHolder holder, int position) {
Produit_Eau prod_eau = list.get(position);
holder.text_single_prod_nom.setText(prod_eau.getNom());
holder.text_single_prod_description.setText(prod_eau.getDescription());
}
#Override
public int getItemCount() {
return list.size();
}
public class ViewHolder extends RecyclerView.ViewHolder {
public TextView text_single_prod_nom, text_single_prod_description;
public ViewHolder(View itemView) {
super(itemView);
text_single_prod_nom = itemView.findViewById(R.id.single_prod_nom);
text_single_prod_description =
itemView.findViewById(R.id.single_prod_description);
}
}
}
And Here's one of the fragments
Eau_Fragment.java
package esprit.tn.mywaterproject.Fragments;
import android.app.ProgressDialog;
import android.content.Context;
import android.net.ConnectivityManager;
import android.net.NetworkInfo;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.DividerItemDecoration;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;
import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonArrayRequest;
import com.android.volley.toolbox.StringRequest;
import com.android.volley.toolbox.Volley;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.List;
import esprit.tn.mywaterproject.Entities.Produit_Eau;
import esprit.tn.mywaterproject.ProduitAdapter;
import esprit.tn.mywaterproject.R;
/**
* A simple {#link Fragment} subclass.
*/
public class Eaux_Fragment extends Fragment {
private RecyclerView recyclerList;
private LinearLayoutManager linearLayoutManager;
private ArrayList<Produit_Eau> produit_eauList;
private ProduitAdapter adapter;
private String UrlShowProducts = "http://192.168.1.7:3003/prodeau";
private LinearLayout linearLayout;
public Eaux_Fragment() {
Log.e("Test Eau Fragment","EAU FRAG TEST");
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragmentd
View view = inflater.inflate(R.layout.fragment_eaux, container, false);
linearLayoutManager = new
LinearLayoutManager(getActivity().getApplicationContext());
linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
DividerItemDecoration(recyclerList.getContext(),
linearLayoutManager.getOrientation());
adapter = new ProduitAdapter(getActivity().getApplicationContext(),
produit_eauList);
recyclerList = getActivity().findViewById(R.id.eau_prod_list);
recyclerList.setHasFixedSize(true);
recyclerList.setLayoutManager(linearLayoutManager);
produit_eauList = new ArrayList<>();
getData();
recyclerList.setAdapter(adapter);
adapter.notifyDataSetChanged();
return view;
}
private void getData() {
JsonArrayRequest jsonArrayRequest = new
JsonArrayRequest(UrlShowProducts, new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
for (int i = 0; i < response.length(); i++) {
try {
JSONObject jsonObject = response.getJSONObject(i);
Produit_Eau produit_eau = new Produit_Eau();
produit_eau.setNom(jsonObject.getString("name"));
produit_eau.setDescription(jsonObject.getString("description"));
produit_eauList.add(produit_eau);
} catch (JSONException e) {
e.printStackTrace();
}
}
adapter.notifyDataSetChanged();
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e("Volley", error.toString());
}
});
RequestQueue requestQueue =
Volley.newRequestQueue(getActivity().getApplicationContext());
requestQueue.add(jsonArrayRequest);
}
}
Edit:
The problem i'm facing here is that Eau_Fragment is not showing in the application. i've deleted every other fragment and kept only this one to test it, the fragment is displayed empty, and the only error i got is the one mentionned above.

It's only a warning but if you're concerned about it, then set the adapter before the layout manager:
recyclerList = getActivity().findViewById(R.id.eau_prod_list);
recyclerList.setAdapter(adapter);
recyclerList.setHasFixedSize(true);
recyclerList.setLayoutManager(linearLayoutManager);
Because it triggers layout update immediately when you set layout manager, which looks for the adapter eventually.

I am not sure what is the problem you are facing, but one thing I noticed, is that you are not using Eaux_Fragment in your SectionsPagerAdapter so you need change :
return PlaceholderFragment.newInstance(position + 1);
to
return Eaux_Fragment(position + 1);
and do not forget to add the newInstance method to Eaux_Fragment
public static Eaux_Fragment newInstance(int position) {
Eaux_Fragment fragment = new Eaux_Fragment();
Bundle args = new Bundle();
args.putString(ARG_POSITION, position);
fragment.setArguments(args);
return fragment;
}

Add existing activity to a TabActivity Android

Hi guys I'm adding a tab activity to an existing android app! In particular, I should add HomeActivity to TabActivity, how can I do? I read on the net that you should implement in HomeActivity fragment and then add it to the TabActivity! But if I implement Fragment in HomeActivity I have a series of errors!
Tab Activity
package xx.myapp;
import android.support.design.widget.TabLayout;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
public class TabActivity extends AppCompatActivity {
/**
* The {#link android.support.v4.view.PagerAdapter} that will provide
* fragments for each of the sections. We use a
* {#link FragmentPagerAdapter} derivative, which will keep every
* loaded fragment in memory. If this becomes too memory intensive, it
* may be best to switch to a
* {#link android.support.v4.app.FragmentStatePagerAdapter}.
*/
private SectionsPagerAdapter mSectionsPagerAdapter;
/**
* The {#link ViewPager} that will host the section contents.
*/
private ViewPager mViewPager;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_tab);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
// Create the adapter that will return a fragment for each of the three
// primary sections of the activity.
mSectionsPagerAdapter = new SectionsPagerAdapter(getSupportFragmentManager());
// Set up the ViewPager with the sections adapter.
mViewPager = (ViewPager) findViewById(R.id.container);
mViewPager.setAdapter(mSectionsPagerAdapter);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tabs);
mViewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.addOnTabSelectedListener(new TabLayout.ViewPagerOnTabSelectedListener(mViewPager));
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_tab, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
/**
* A placeholder fragment containing a simple view.
*/
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() {
}
/**
* Returns a new instance of this fragment for the given section
* number.
*/
public static PlaceholderFragment newInstance(int sectionNumber) {
PlaceholderFragment fragment = new PlaceholderFragment();
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_tab, 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;
}
}
/**
* A {#link FragmentPagerAdapter} that returns a fragment corresponding to
* one of the sections/tabs/pages.
*/
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).
return PlaceholderFragment.newInstance(position + 1);
}
#Override
public int getCount() {
// Show 3 total pages.
return 3;
}
}
}
Home Activity:
package xx.myapp;
import android.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.ListView;
import android.widget.TextView;
import java.util.ArrayList;
import xx.*;
public class HomeActivity extends AppCompatActivity {
int[] images = {R.drawable.accettato, R.drawable.fatturato, R.drawable.incorso, R.drawable.rifiutato};
ArrayList CantieriRicerca = new ArrayList();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_home);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
setTitle("Home");
/* Deserializzo l'oggetto */
Intent i = getIntent();
User u = (User) i.getSerializableExtra("User");
Cantiere c = new Cantiere();
CantieriRicerca = c.RicercaCantiere("a", u);
//Listview che visulizza in cantieri con il customadapter
ListView cantieriListView = (ListView) findViewById(R.id.ListViewCantieri);
CustomAdapter cm = new CustomAdapter();
cantieriListView.setAdapter(cm);
try {
FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
.setAction("Action", null).show();
}
});
} catch (Exception ex) {
System.out.println("\n Errore HomeActivity.java : " + ex);
}
}
class CustomAdapter extends BaseAdapter {
#Override
public int getCount() {
return CantieriRicerca.size();
}
#Override
public Object getItem(int position) {
return null;
}
#Override
public long getItemId(int position) {
return 0;
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
convertView = getLayoutInflater().inflate(R.layout.row, null);
ImageView imageView = (ImageView) convertView.findViewById(R.id.imageview_stato);
TextView textview_nomecantiere = (TextView) convertView.findViewById(R.id.textView_NomeCantiere);
TextView textview_cliente = (TextView) convertView.findViewById(R.id.textView_Cliente);
Cantiere c = (Cantiere) CantieriRicerca.get(position);
String statoCantiere = c.GetStatoCantiere();
if (statoCantiere.equals("Chiuso")==true) {
imageView.setImageResource(images[0]);
} else if (statoCantiere.equals("InCorso")==true) {
imageView.setImageResource(images[2]);
} else if (c.GetStatoFatturazione() > 0) {
imageView.setImageResource(images[1]);
}
else{
imageView.setImageResource(images[3]);
}
textview_cliente.setText(c.c.GetRagioneSociale());
textview_nomecantiere.setText(c.GetNomeCantiere());
return convertView;
}
}
}

You should consider converting you HomeActivity to Fragment and put it inside of your TabActivity. Fragments are extremely powerful as much as their API, so there should be no problems for you.

Destroy activity containing two fragments after clicking Andorid Back Button

Problem SOLVED!
ISSUE:
I have problem, and I can't find any solution. I have Maps_Activity, which contains two fragments. Both fragments show google maps v2 and I display them on screen thanks to two ActionBar tabs.
The problem is appearing when I want to return to previous activity. When I click Android back button, my whole application turns down, shows pupup, that my application was stopped.
What I should add to my code to remove this error?
Solution:
Maps_Activity.java
import android.app.ActionBar;
import android.app.Activity;
import android.app.Fragment;
import android.app.FragmentManager;
import android.app.FragmentTransaction;
import android.os.Bundle;
import android.util.Log;
import android.widget.Button;
import com.google.android.gms.maps.MapFragment;
public class Maps_Activity extends Activity {
public static FragmentManager manager;
Fragment fragmentTab1 = new Medical_Shops_Map();
Fragment fragmentTab2 = new Medical_Clicnics_Map();
Button Medical_Shops_Button, Medical_Clinics_Button;
ActionBar actionBar ;
#Override
public void onCreate(Bundle arg0) {
super.onCreate(arg0);
setContentView(R.layout.activity_maps_);
manager = getFragmentManager();
actionBar=getActionBar();
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
ActionBar.Tab tab1=actionBar.newTab();
tab1.setText("Apteki 24H/7");
tab1.setTabListener(new MyTabsListener(fragmentTab1));
ActionBar.Tab tab2=actionBar.newTab();
tab2.setText("Przychodnie Lekarskie");
tab2.setTabListener(new MyTabsListener(fragmentTab2));
actionBar.addTab(tab1);
actionBar.addTab(tab2);
}
protected class MyTabsListener implements ActionBar.TabListener {
private Fragment fragment;
public MyTabsListener(Fragment fragment) {
this.fragment = fragment;
}
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction ft) {
}
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction ft) {
ft = manager.beginTransaction();
ft.replace(R.id.map_container, fragment);
ft.commit();
Log.e("Activity", "Fragment replace");
}
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction ft) {
// some people needed this line as well to make it work:
MapFragment mMap2 = ((MapFragment) Maps_Activity.manager.findFragmentById(R.id.map));
ft = manager.beginTransaction();
if(mMap2!=null)
{
ft.remove(mMap2);
ft.commit();
Log.e("Activity", "Mapa_fragment destroy");
}
else
{
MapFragment mMap1 = ((MapFragment) Maps_Activity.manager.findFragmentById(R.id.map1));
ft.remove(mMap1);
ft.commit();
Log.e("Activity", "Mapa_fragment2 destroy");
}
}
}
}
One of the fragments:
import android.os.Bundle;
import android.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.Toast;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.GoogleMapOptions;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
public class Medical_Clicnics_Map extends Fragment implements OnMapReadyCallback {
private static View view;
private static GoogleMap mMap2;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
view = inflater.inflate(R.layout.medical__clicnics__map, container, false);
setUpMapIfNeeded();
return view;
}
public void setUpMapIfNeeded() {
MapFragment mMap2 = ((MapFragment) Maps_Activity.manager
.findFragmentById(R.id.map1));
mMap2.getMapAsync(Medical_Clicnics_Map.this);
}
#Override
public void onMapReady(GoogleMap googleMap) {
Log.d("Activity", "Map ready");
googleMap.setMyLocationEnabled(true);
LatLng sydney = new LatLng(-33.867, 151.206);
googleMap.addMarker(new MarkerOptions()
.title("Sydney")
.snippet("The most populous city in Australia.")
.position(sydney));
}
}
Maybe for someone this code will be helpful ;)