Develop Reference

How do I set onClick listener to recyclerView?

I want to add onClick to recyclerView to send data back to form Activity for update data process. How can I implement onItemClickListner when this code doesn't have adapter in it?
Show_Employees.java:
package com.example.roomdatabaseandroid;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.ItemTouchHelper;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
import com.example.roomdatabaseandroid.DataModel.EmployeeDao;
import com.example.roomdatabaseandroid.DataModel.EmployeeDatabase;
import com.google.android.material.floatingactionbutton.FloatingActionButton;
public class ShowEmployees extends AppCompatActivity {
private static final int EDIT_COURSE_REQUEST = 2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_show_employees);
RecyclerView recyclerView;
FloatingActionButton fab = findViewById(R.id.idFABAdd);
EmployeeDao employeeDao;
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//starting a new activity for adding a new course and passing a constant value in it.
Intent intent = new Intent(ShowEmployees.this, MainActivity.class);
startActivity(intent);
}
});
employeeDao = EmployeeDatabase.getDBInstance(this).employeeDao();
recyclerView = findViewById(R.id.employeeRecyclerView);
EmployeeRecycler employeeRecycler = new EmployeeRecycler(employeeDao.getAllEmployee());
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setAdapter(employeeRecycler);
//below method is use to add swipe to delete method for item of recycler view.
new ItemTouchHelper(new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT) {
#Override
public boolean onMove(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder, #NonNull RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(#NonNull RecyclerView.ViewHolder viewHolder, int direction) {
//on recycler view item swiped then we are deleting the item of our recycler view.
employeeDao.deleteEmployee(employeeRecycler.data.get(viewHolder.getAdapterPosition()));
Toast.makeText(ShowEmployees.this, "Employee deleted", Toast.LENGTH_SHORT).show();
}
}).attachToRecyclerView(recyclerView);
}
}
Employee_Recycler.java:
package com.example.roomdatabaseandroid;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import com.example.roomdatabaseandroid.DataModel.DataConverter;
import com.example.roomdatabaseandroid.DataModel.Employee;
import java.util.List;
public class EmployeeRecycler extends RecyclerView.Adapter<EmployeeViewHolder> {
List<Employee> data;
public EmployeeRecycler(List<Employee> employees){
data = employees;
}
#NonNull
#Override
public EmployeeViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(
R.layout.list_item_1,
parent,false
);
return new EmployeeViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull EmployeeViewHolder holder, int position) {
Employee employee = data.get(position);
holder.imageView.setImageBitmap(DataConverter.convertByteArraytoImage(employee.getImage()));
holder.firstName.setText(employee.getFirstName());
holder.middleName.setText(employee.getMiddleName());
holder.lastName.setText(employee.getLastName());
holder.dob.setText(employee.getDOB());
holder.gender.setText(employee.getGender());
holder.address.setText(employee.getAddress());
holder.designation.setText(employee.getDesignation());
holder.email.setText(employee.getEmail());
holder.phoneNumber.setText(employee.getPhoneNumber());
}
#Override
public int getItemCount() {
return data.size();
}
}
EmployeeViewHolder.java:
package com.example.roomdatabaseandroid;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
public class EmployeeViewHolder extends RecyclerView.ViewHolder {
ImageView imageView;
TextView firstName,middleName,lastName,email,phoneNumber,address,designation,gender,dob;
public EmployeeViewHolder(#NonNull View itemView) {
super(itemView);
firstName = itemView.findViewById(R.id.idTVFirstName);
middleName = itemView.findViewById(R.id.idTVMiddleName);
lastName = itemView.findViewById(R.id.idTVLastName);
dob = itemView.findViewById(R.id.idTVDOB);
address = itemView.findViewById(R.id.idTVAddress);
gender = itemView.findViewById(R.id.idTVGender);
designation = itemView.findViewById(R.id.idTVDesignation);
email = itemView.findViewById(R.id.idTVEmail);
phoneNumber = itemView.findViewById(R.id.idTVPhoneNumber);
imageView = itemView.findViewById(R.id.profileImageView);
}
}

add an interface
interface AdapterItemClickListener {
void onItemClickListener(Employee employee, int position)
}
your actvity must implement this interface
public class ShowEmployees extends AppCompatActivity implements AdapterItemClickListener {
private static final int EDIT_COURSE_REQUEST = 2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_show_employees);
RecyclerView recyclerView;
FloatingActionButton fab = findViewById(R.id.idFABAdd);
EmployeeDao employeeDao;
fab.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//starting a new activity for adding a new course and passing a constant value in it.
Intent intent = new Intent(ShowEmployees.this, MainActivity.class);
startActivity(intent);
}
});
employeeDao = EmployeeDatabase.getDBInstance(this).employeeDao();
recyclerView = findViewById(R.id.employeeRecyclerView);
EmployeeRecycler employeeRecycler = new EmployeeRecycler(employeeDao.getAllEmployee(), this);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setAdapter(employeeRecycler);
//below method is use to add swipe to delete method for item of recycler view.
new ItemTouchHelper(new ItemTouchHelper.SimpleCallback(0, ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT) {
#Override
public boolean onMove(#NonNull RecyclerView recyclerView, #NonNull RecyclerView.ViewHolder viewHolder, #NonNull RecyclerView.ViewHolder target) {
return false;
}
#Override
public void onSwiped(#NonNull RecyclerView.ViewHolder viewHolder, int direction) {
//on recycler view item swiped then we are deleting the item of our recycler view.
employeeDao.deleteEmployee(employeeRecycler.data.get(viewHolder.getAdapterPosition()));
Toast.makeText(ShowEmployees.this, "Employee deleted", Toast.LENGTH_SHORT).show();
}
}).attachToRecyclerView(recyclerView);
}
void onItemClickListener(Employee employee, int position) {
//update or another job
}
}
and your adapter
public class EmployeeRecycler extends RecyclerView.Adapter<EmployeeViewHolder> {
List<Employee> data;
AdapterItemClickListener itemClickListener;
public EmployeeRecycler(List<Employee> employees, AdapterItemClickListener itemClickListener){
data = employees;
this.itemClickListener = itemClickListener;
}
#NonNull
#Override
public EmployeeViewHolder onCreateViewHolder(#NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(
R.layout.list_item_1,
parent,false
);
return new EmployeeViewHolder(view);
}
#Override
public void onBindViewHolder(#NonNull EmployeeViewHolder holder, int position) {
Employee employee = data.get(position);
holder.imageView.setImageBitmap(DataConverter.convertByteArraytoImage(employee.getImage()));
holder.firstName.setText(employee.getFirstName());
holder.middleName.setText(employee.getMiddleName());
holder.lastName.setText(employee.getLastName());
holder.dob.setText(employee.getDOB());
holder.gender.setText(employee.getGender());
holder.address.setText(employee.getAddress());
holder.designation.setText(employee.getDesignation());
holder.email.setText(employee.getEmail());
holder.phoneNumber.setText(employee.getPhoneNumber());
holder.itemView.setOnClickListener (v -> {
itemClickListener.onItemClickListener(employee, position);
});
}
#Override
public int getItemCount() {
return data.size();
}
}

Android RecyclerView Showing only one item from 100

i'm new to android programming, i have a issue with a recyclerview ( i'm reading an android programming book and practice ) : it's showing only one item although i passed a list of 100 items
here's the code of the class:
package com.training.criminalintent;
import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.CheckBox;
import android.widget.TextView;
import android.widget.Toast;
import java.util.List;
public class CrimeListFragment extends Fragment {
private RecyclerView mCrimeRecyclerView;
private CrimeAdapter mAdapter;
#Override
public View onCreateView(LayoutInflater inflater,ViewGroup container,
Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.fragment_crime_list, container, false);
mCrimeRecyclerView = (RecyclerView) view
.findViewById(R.id.crime_recycler_view);
mCrimeRecyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
updateUI();
return view;
}
private class CrimeHolder extends RecyclerView.ViewHolder implements View.OnClickListener{
private Crime mCrime;
private TextView mTitleTextView;
private TextView mDateTextView;
private CheckBox mSolvedCheckBox;
public CrimeHolder(View itemView) {
super(itemView);
itemView.setOnClickListener(this);
mTitleTextView = (TextView)
itemView.findViewById(R.id.list_item_crime_title_text_view);
mDateTextView = (TextView)
itemView.findViewById(R.id.list_item_crime_date_text_view);
mSolvedCheckBox = (CheckBox)
itemView.findViewById(R.id.list_item_crime_solved_check_box);
}
public void bindCrime(Crime crime) {
mCrime = crime;
mTitleTextView.setText(mCrime.getTitle());
mDateTextView.setText(mCrime.getDate().toString());
mSolvedCheckBox.setChecked(mCrime.isSolved());
}
#Override
public void onClick(View v) {
Intent intent = new Intent(getActivity(), CrimeActivity.class);
startActivity(intent);
}
}
private class CrimeAdapter extends RecyclerView.Adapter<CrimeHolder> {
private List<Crime> mCrimes;
public CrimeAdapter(List<Crime> crimes) {
mCrimes = crimes;
}
#Override
public int getItemCount() {
return mCrimes.size();
}
#Override
public CrimeHolder onCreateViewHolder(ViewGroup parent, int viewType) {
LayoutInflater layoutInflater = LayoutInflater.from(getActivity());
View view = layoutInflater
.inflate(R.layout.list_item_crime, parent, false);
return new CrimeHolder(view);
}
#Override
public void onBindViewHolder(CrimeHolder holder, int position) {
Crime crime = mCrimes.get(position);
holder.bindCrime(crime);
}
}
private void updateUI() {
CrimeLab crimeLab = CrimeLab.get(getActivity());
List<Crime> crimes = crimeLab.getCrimes();
mAdapter = new CrimeAdapter(crimes);
mCrimeRecyclerView.setAdapter(mAdapter);
}
}
Thanks in advance for you help,

The book somehow made a mistake.
The actual input should be android:layout_height="wrap_content"

Thanks yo your answer. Indeed my mistake was the recyclerView attribute android:layout_height.
I put match_parent instead of wrap_content

view pager is swiping same image again and again

i have been working on app (Question Answer based) . I have included view pager to swipe the image but it's only swiping same image .
code of class which call a class (where view pager is included in activity)
package com.example.joshiyogesh.puzzle;
import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
public class ExerciseOneQuestionList extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_exercise_one_question_list);
}
public void questionOne(View view) {
Intent intent = new Intent(getApplicationContext(),ExerciseOneQuestions.class);
intent.putExtra("question_index",0);
startActivity(intent);
}
}
ExerciseOneQuestion.java
package com.example.joshiyogesh.puzzle;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
public class ExerciseOneQuestions extends AppCompatActivity {
ViewPager viewPager;
public int questionIndexReceive;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_exercise_one_questions);
questionIndexReceive = getIntent().getIntExtra("question_index",1);
// questionIndexReceive =Integer.parseInt(getIntent().getStringExtra("question_index"));
viewPager = (ViewPager)findViewById(R.id.pager);
PagerAdapter pagerAdapter = new PagerAdapter(getSupportFragmentManager());
viewPager.setAdapter(pagerAdapter);
}
}
pager Adapter class
package com.example.joshiyogesh.puzzle;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
public class PagerAdapter extends FragmentPagerAdapter {
public PagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
position = new ExerciseOneQuestions().questionIndexReceive;
Fragments fragments = new Fragments();
Bundle bundle = new Bundle();
bundle.putInt("question_no",position);
fragments.setArguments(bundle);
return fragments;
}
#Override
public int getCount() {
return 2;
}
}
fragments class
public class Fragments extends Fragment {
ImageView imageView;
#Override
public View onCreateView(LayoutInflater inflater , ViewGroup container ,
Bundle savedInstanceState){
int [] image_index = {R.drawable.eightypageanswer1,R.drawable.eightypageanswer8};
Bundle bundle = getArguments();
int message = bundle.getInt("question_no");
View rootView = inflater.inflate(R.layout.fragments,container,false);
imageView = (ImageView) rootView.findViewById(R.id.imageQuestions);
imageView.setImageResource(image_index[message]);
return rootView;
}
}
for testing purpose I have considered only two images in integer, But its always swiping same image i.e first image.
instead of changing "question_index" in ExerciseOneQuestionList.java
here ...
public void questionOne(View view) {
Intent intent = new Intent(getApplicationContext(),ExerciseOneQuestions.class);
intent.putExtra("question_index",0);
startActivity(intent);
}
couldn't understand why its always showing same image ?

It seems that problem is in line
position = new ExerciseOneQuestions().questionIndexReceive;
It seems that position is always set on the same number.

I really dont know what you are doing with this " new ExerciseOneQuestions().questionIndexReceive;" line. But in standard way you should have make two fragments then add these fragments to your adapter. Rest of thing will be done by adapter , following rough code may help you :
public class ViewPagerAdapter extends FragmentStatePagerAdapter {
private final List<Fragment> mFragments = new ArrayList<>();
public ViewPagerAdapter(FragmentManager fm) {
super(fm);
}
public void addFragment(Fragment fragment, String title) {
mFragments.add(fragment);
}
#Override
public Fragment getItem(int position) {
return mFragments.get(position); // Which Fragment should be dislpayed by the viewpager for the given position
}
#Override
public int getCount() {
return mFragments.size();
}
}
Make two fragments object in class add them in adapter by calling addFragment method and then setadapter.

IllegalStateException while acessing FragmentManager inside RecyclerAdapter class with the help of activity's object

I am trying to open a dialog box from my Recycler adapter onClick of a button.
For that i need to get the FragmentManager using the getFragmentManager method ,which can only be called with the help of the activity object .
Here is my code :
RecyclerAdapter2 :
package com.example.batrad.expenseassist;
import android.app.Activity;
import android.app.FragmentManager;
import android.content.Context;
import android.media.Image;
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.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import java.util.Collections;
import java.util.List;
/**
* Created by batrad on 11/18/2016.
*/
public class RecyclerAdapter2 extends RecyclerView.Adapter<RecyclerAdapter2.MyViewHolder> {
List<Information2> data = Collections.emptyList();
private LayoutInflater inflator;
Activity activity;
FragmentManager fm;
public RecyclerAdapter2(Context context, List<Information2> data) {
activity=(Activity)context;
inflator = LayoutInflater.from(context);
this.data = data;
fm=activity.getFragmentManager();
}
#Override
public RecyclerAdapter2.MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view =inflator.inflate(R.layout.recycler_row_category,parent,false);
MyViewHolder holder=new MyViewHolder(view);
return holder;
}
#Override
public void onBindViewHolder(RecyclerAdapter2.MyViewHolder holder, int position) {
Log.d("tag",data.get(0)+"");
Information2 info=data.get(position);
Log.d("testre",info.categoryName+info.amount);
holder.categoryName.setText(info.categoryName);
holder.amount.setText(info.amount+"");
holder.categoryImage.setImageResource(info.categoryImage);
}
public void onInsert(int size){
notifyItemInserted(size);
}
#Override
public int getItemCount() {
return data.size();
}
class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
TextView categoryName;
TextView amount;
ImageView categoryImage;
ImageView deleteIcon;
ImageView addIcon;
public MyViewHolder(View itemView) {
super(itemView);
categoryName=(TextView) itemView.findViewById(R.id.categoryName);
amount=(TextView) itemView.findViewById(R.id.amount);
categoryImage=(ImageView) itemView.findViewById(R.id.categoryImage);
deleteIcon=(ImageView) itemView.findViewById(R.id.deleteIcon);
addIcon=(ImageView) itemView.findViewById(R.id.addIcon);
addIcon.setOnClickListener(this);
}
#Override
public void onClick(View view) {
SubCategoryDialog subCategoryDialog=new SubCategoryDialog();
SubCategoryDialog.setValues(data.get(getAdapterPosition()).categoryName);
subCategoryDialog.show(fm, "Create Category");
}
}
}
Inside the constructor of RecyclerAdapter2 I am passing the context of the activity from my MainActivity Java file:
MainActivity.java :
categoryrecycleAdapter = new RecyclerAdapter2(this, getdata());
Inside RecyclerAdapter2 constructor i assign the context to Activity class's object .
And than i use the object to get the fragmentManager.
But i am getting IllegalStateException here :
java.lang.IllegalStateException: Activity has been destroyed
at android.app.FragmentManagerImpl.enqueueAction(FragmentManager.java:1433)
at android.app.BackStackRecord.commitInternal(BackStackRecord.java:687)
at android.app.BackStackRecord.commit(BackStackRecord.java:663)
at android.app.DialogFragment.show(DialogFragment.java:230)
at com.example.batrad.expenseassist.RecyclerAdapter2$MyViewHolder.onClick(RecyclerAdapter2.java:85)
at android.view.View.performClick(View.java:5233)
at android.view.View$PerformClick.run(View.java:21209)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:152)
Please help .

This is not the right way to attach listeners. You should set the onClickListener in the constructor of your viewholder and should send a callback to your fragment using an interface as shown below or you can also use BaseAdapter from this or this.
public interface OnItemClickListener {
void onItemClick(View v);
}
private final OnItemClickListener listener;
public RecAdapter(OnItemClickListener listener) {
this.listener = listener;
}
public ViewHolder(View itemView) {
super(itemView);
itemView.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
listener.onItemCLick(v);
}
});
}

Android fragment tabbed layout, reselecting tab 3, listview disappears

When I select tab 3 my listview appears, yet when I select tab 1 and reselect tab 3, the listview doesn't appear.
Why is this?
https://github.com/jdavey1996/News-Android-App
import android.support.design.widget.TabLayout;
import android.support.v4.view.ViewPager;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
public class MainActivity extends AppCompatActivity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
TabLayout tabLayout = (TabLayout) findViewById(R.id.tab_layout);
tabLayout.addTab(tabLayout.newTab().setText("Local"));
tabLayout.addTab(tabLayout.newTab().setText("Top rated"));
tabLayout.addTab(tabLayout.newTab().setText("All"));
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
final FragmentAdapter adapter = new FragmentAdapter(getSupportFragmentManager(),tabLayout.getTabCount());
final ViewPager viewPager = (ViewPager) findViewById(R.id.pager);
viewPager.setAdapter(adapter);
viewPager.addOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
viewPager.setCurrentItem(tab.getPosition());
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
}
});
}
}
package com.josh_davey.news_app;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentPagerAdapter;
public class FragmentAdapter extends FragmentPagerAdapter {
int count;
public FragmentAdapter(FragmentManager fm, int count) {
super(fm);
this.count = count;
}
#Override
public Fragment getItem(int position) {
switch (position){
case 0:
Fragment1 temp = new Fragment1();
return temp;
case 1:
Fragment2 temp2 = new Fragment2();
return temp2;
case 2:
Fragment3 temp3 = new Fragment3();
return temp3;
}
return null;
}
#Override
public int getCount() {
return count;
}
}
package com.josh_davey.news_app;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
public class Fragment3 extends Fragment {
public Fragment3() {
// Required empty public constructor
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
GetData getData = new GetData(getContext(),getActivity());
getData.execute("lincoln");
}
#Override
public void onResume() {
super.onResume();
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment3, container, false);
}
}
If you need link to the full code it's on my github. Thanks in advance for any help
https://github.com/jdavey1996/News-Android-App

Default ViewPager's offscreenPageLimit is 1. So the tab3 is detached when tab1 is re-selected. If fragment is detached, Fragment's views are destroyed.
see: ViewPager.setOffscreenPageLimit
So I recommend you to set offscreenPageLimit to 2.
viewPager.setOffscreenPageLimit(2);
Or you can hold the list of ArticleConstructor in Fragment3 like blew.
GetData.java:
public class GetData extends AsyncTask<String, String,ArrayList<ArticleConstructor>>{
Callback callback;
interface Callback {
void onArticleConstructorLoaded(ArrayList<ArticleConstructor> articleConstructors);
}
public GetData(Callback callback) {
this.callback = callback;
}
...
#Override
protected void onPostExecute(ArrayList<ArticleConstructor> result) {
callback.onArticleConstructorLoaded(result);
}
....
}
Fragment3.java:
public class Fragment3 extends Fragment implements GetData.Callback {
private ListView listView;
private ArrayList<ArticleConstructor> articleConstructors = new ArrayList<>();
private ArticleArrayAdapter adapter;
public Fragment3() {
// Required empty public constructor
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View view = inflater.inflate(R.layout.fragment3, container, false);
listView = (ListView) view.findViewById(R.id.listView);
adapter = new ArticleArrayAdapter(getActivity(), getContext(), articleConstructors);
listView.setAdapter(adapter);
return view;
}
#Override
public void onActivityCreated(#Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
if (articleConstructors.size() == 0) {
GetData getData = new GetData(this);
getData.execute("lincoln");
}
}
#Override
public void onArticleConstructorLoaded(ArrayList<ArticleConstructor> articleConstructors) {
this.articleConstructors = articleConstructors;
adapter.setArticleConstructors(articleConstructors);
}
}