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How to send a value from TextView to RecyclerView in another Activity

I'm trying to send a value from TextView to RecyclerView (in an another Activity).
MainActivity.class
There is i want to use a method onClickYes for send each of word to my recyclerView in an another activity.
public class MainActivity extends AppCompatActivity {
TextView display, progress;
private List<String> worldList;
private ArrayList<RecyclerItems> recyclerItems;
private WordDataBase wordDatabaseForYes;
int counter = 1;
int i = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
display = findViewById(R.id.dispalay);
progress = findViewById(R.id.progress);
recyclerItems = new ArrayList<>();
worldList = new ArrayList<>();
worldList.add("cat");//i want to display this word firstly
worldList.add("dog");//it after click
worldList.add("monkey");//after it
worldList.add("bird");//after it
worldList.add("fish");//etc
worldList.add("home");//etc
worldList.add("car");//etc
}
public void onClickYes(View view) {
if (i >= worldList.size()) return;
display.setText(worldList.get(i));
progress.setText(counter + "");
//заполняем наш recyclerView
//Intent intent = new Intent(MainActivity.this, YesActivity.class);
//intent.putExtra("word", user + ", вам передали: " + gift);
//startActivity(intent);
i++;
counter++;
}
public void onClickNo(View view) {
Toast.makeText(this, "Size is " + worldList.size(), Toast.LENGTH_SHORT).show();
//recyclerItems.add(new RecyclerItems(worldList.get(i)));
i = 0;
counter = 0;
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
MenuInflater inflater = getMenuInflater();
inflater.inflate(R.menu.menu, menu);
return true;
}
#Override
public boolean onOptionsItemSelected(#NonNull MenuItem item) {
Intent intent;
switch (item.getItemId()) {
case R.id.yes:
recyclerItems.add(new RecyclerItems(worldList.get(i)));
intent = new Intent(MainActivity.this, YesActivity.class);
startActivity(intent);
break;
case R.id.no:
intent = new Intent(MainActivity.this, NoActivity.class);
startActivity(intent);
break;
case R.id.about:
Toast.makeText(this, "By SaturnPRO", Toast.LENGTH_SHORT).show();
//openDialogAbout
break;
}
return true;
}
}
My Second Activity
public class YesActivity extends AppCompatActivity {
private RecyclerView recyclerView;
private RecyclerView.Adapter adapter;
private RecyclerView.LayoutManager layoutManager;
ArrayList<RecyclerItems> yesWordList;
private WordDataBase wordDatabaseForYes;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
yesWordList = new ArrayList<>();
recyclerView = findViewById(R.id.rvYes);
recyclerView.setHasFixedSize(true);
adapter = new RecyclerViewAdapter(yesWordList);
layoutManager = new LinearLayoutManager(this);
recyclerView.setAdapter(adapter);
recyclerView.setLayoutManager(layoutManager);
}
}
Also i have an Adapter but i couldn't show it here.
How can i do it? enter code here Please help.

Send the word in intent extras:
case R.id.yes:
recyclerItems.add(new RecyclerItems(worldList.get(i)));
intent = new Intent(MainActivity.this, YesActivity.class);
intent.putExtra("key", worldList.get(i));
startActivity(intent);
break;
In your second activity:
String name = intent.getStringExtra("key");

You can make the wordList a static member. Then you can access it in your adapter.

ViewPager doesn't update added fragments

I got a problem with updating ViewPager fragments. We need to show fragments with data to registered user, when he doesn't registered we need to show fragments with message to register. I use this method to check it in MainActivity:
#Override
public void setAdapter(boolean isUserExist) {
Log.d("RegDebug", "In setAdapter");
mainPagerAdapter.clearData();
mainPagerAdapter.addFragment(searchFragment, getString(R.string.search_title));
if (isUserExist) {
Log.d("RegDebug", "In setAdapter reg");
mainPagerAdapter.addFragment(new ChatsFragment(), getString(R.string.chats_title));
mainPagerAdapter.addFragment(new ActionsFragment(), getString(R.string.actions_title));
Toast.makeText(getApplicationContext(), "Registered!", Toast.LENGTH_SHORT).show();
} else {
Log.d("RegDebug", "In setAdapter unreg");
mainPagerAdapter.addFragment(RegisterFragment.newInstance(Consts.CHATS_TAB_NAME), getString(R.string.chats_title));
mainPagerAdapter.addFragment(RegisterFragment.newInstance(Consts.ACTIONS_TAB_NAME), getString(R.string.actions_title));
Toast.makeText(getApplicationContext(), "Unregistered!!!", Toast.LENGTH_SHORT).show();
}
mainPagerAdapter.notifyDataSetChanged();
viewPager.setAdapter(mainPagerAdapter);
}
I call this method in presenter with setting value from firebase auth, checking if user exists:
public void checkForUserExist() {
if (mainInteractor.isUserExist()) {
getViewState().setRegAdapter();
} else getViewState().setUnregAdapter();
}
And then call presenter method in onCreate of MainActivity:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
dialogFragment = new FilterDialogFragment();
searchFragment = new SearchFragment();
//UI
toolbar = findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
viewPager = findViewById(R.id.main_view_pager);
tabLayout = findViewById(R.id.main_tabs);
//mainPagerAdapter = new MainPagerAdapter(getSupportFragmentManager());
mainPresenter.checkForUserExist();
tabLayout.setupWithViewPager(viewPager);
}
I try to log the boolean result and it returns exactly value that must be, but pager adapter can't update its content.Code of MainPagerAdapter:
public class MainPagerAdapter extends FragmentPagerAdapter{
private final List<Fragment> fragmentList = new ArrayList<>();
private final List<String> fragmentTitleList = new ArrayList<>();
public MainPagerAdapter(FragmentManager fm) {
super(fm);
}
#Override
public Fragment getItem(int position) {
return fragmentList.get(position);
}
#Override
public int getCount() {
return fragmentTitleList.size();
}
#Nullable
#Override
public CharSequence getPageTitle(int position) {
return fragmentTitleList.get(position);
}
public void addFragment(Fragment fragment, String title){
fragmentList.add(fragment);
fragmentTitleList.add(title);
}
public void clearData(){
fragmentList.clear();
fragmentTitleList.clear();
notifyDataSetChanged();
Log.d("RegDebug", " fragmentList size is " + fragmentList.size()
+ " fragmentTitleList size is " + fragmentTitleList.size());
}
}

Use OnPageChangeListener of ViewPager class & notify to your current fragment from there using interface.

Why do I get a Nullpointer Exception?

I am trying to refresh a RecyclerView by assigning a new adapter to the RecyclerView but it is throwing a NullPointerException.
I have created a TabLayout which has three tabs and when you reselect the first tab the method is called to refresh the RecyclerView. But, I am getting a NullPointerException on recyclerViewAdapter.notifyDataSetChanged();. I have initialized recyclerViewAdapter in the onCreateView(); but I still get an Exception.
EDIT :
This is a fragment not an Activity, I cannot setContentView();. Please read the question before down voting or doing anything not helpful.
Please suggest a proper way if I am doing it wrong.
Fragment which has the RecyclerView :
Tab1.class :
public class Tab1 extends Fragment {
private RecyclerView recyclerView;
private RecyclerViewAdapter recyclerViewAdapter;
private List<World> worldList;
private OnFragmentInteractionListener mListener;
private DBHelper helper;
private Context myContext;
private View view;
#Override
public void onStart() {
this.helper = new DBHelper(getContext());
recyclerViewAdapter = new RecyclerViewAdapter(getContext(), helper.getList());
super.onStart();
}
public Tab1() {
}
public void update() {
recyclerViewAdapter.notifyDataSetChanged();
}
#Override
public void onCreate(Bundle savedInstanceState) {
this.helper = new DBHelper(getContext());
this.worldList = new ArrayList<>();
this.worldList = helper.getList();
this.recyclerViewAdapter = new RecyclerViewAdapter(getContext(), this.worldList);
super.onCreate(savedInstanceState);
}
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
view = inflater.inflate(R.layout.fragment_tab1, container, false);
recyclerView = (RecyclerView) view.findViewById(R.id.recyclerView);
recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
recyclerViewAdapter = new RecyclerViewAdapter(getContext(), worldList);
recyclerView.setAdapter(recyclerViewAdapter);
return view;
}
#Override
public void onAttach(Context context) {
super.onAttach(context);
if (context instanceof OnFragmentInteractionListener) {
mListener = (OnFragmentInteractionListener) context;
} else {
throw new RuntimeException(context.toString()
+ " must implement OnFragmentInteractionListener");
}
}
#Override
public void onDetach() {
super.onDetach();
mListener = null;
}
public interface OnFragmentInteractionListener {
void onFragmentInteraction(Uri uri);
}
}
The method is called from the MainActivity.class(When the Tab is re selected).
MainActivty.class :
public class MainActivity extends AppCompatActivity implements Tab1.OnFragmentInteractionListener, Tab2.OnFragmentInteractionListener, Tab3.OnFragmentInteractionListener {
DBHelper helper;
World world;
Location location;
GPSTracker tracker;
RecyclerViewAdapter adapter;
public static Context CONTEXT = null;
RecyclerView recyclerView;
public Tab1 tab1;
public static final String BROADCAST_ACTION = "e.wolverine2.thewalkingapp";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ActivityCompat.requestPermissions(MainActivity.this, new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 123);
CONTEXT = getApplicationContext();
MessageReciever reciever = new MessageReciever(new Message());
Intent intent = new Intent(this, MyService.class);
intent.putExtra("reciever", reciever);
startService(intent);
tracker = new GPSTracker(getApplicationContext());
location = tracker.getLocation();
helper = new DBHelper(getApplicationContext());
tab1 = new Tab1();
recyclerView = (RecyclerView) findViewById(R.id.recyclerView);
adapter = new RecyclerViewAdapter(getApplicationContext(), helper.getList());
final TabLayout tabLayout = (TabLayout) findViewById(R.id.myTabLayout);
tabLayout.addTab(tabLayout.newTab().setText("LOCATIONS"));
tabLayout.addTab(tabLayout.newTab().setText("TOTAL DISTANCE"));
tabLayout.addTab(tabLayout.newTab().setText("CALS"));
tabLayout.getTabAt(0).setIcon(R.drawable.ic_list);
tabLayout.getTabAt(1).setIcon(R.drawable.ic_person_pin);
tabLayout.getTabAt(2).setIcon(R.drawable.ic_fitness_excercise);
tabLayout.setTabGravity(TabLayout.GRAVITY_FILL);
//onError();
final ViewPager viewPager = (ViewPager) findViewById(R.id.myViewPager);
final PagerAdapter pagerAdapter = new PagerAdapter(getSupportFragmentManager(), tabLayout.getTabCount());
viewPager.setAdapter(pagerAdapter);
viewPager.setOnPageChangeListener(new TabLayout.TabLayoutOnPageChangeListener(tabLayout));
tabLayout.setOnTabSelectedListener(new TabLayout.OnTabSelectedListener() {
#Override
public void onTabSelected(TabLayout.Tab tab) {
}
#Override
public void onTabUnselected(TabLayout.Tab tab) {
}
#Override
public void onTabReselected(TabLayout.Tab tab) {
if (tab.getPosition() == 0) {
Tab1 tab1 = new Tab1();
tab1.update();
}
}
});
}
public void locationChanged(double longi, double lati) {
final Location location = new Location("");
location.setLatitude(lati);
location.setLongitude(longi);
world = new World();
String timeStamp = new SimpleDateFormat("dd-MM-yyyy HH:mm:ss").format(new Date());
world.setLongitude(location.getLongitude());
world.setLatitiude(location.getLatitude());
world.setDate(timeStamp);
world.setTime(timeStamp);
world.setLocation("Anonymous");
helper.addRow(world);
//tab1.update(getApplicationContext());
}
#Override
public void onFragmentInteraction(Uri uri) {
}
public class Message {
public void displayMessage(int resultCode, Bundle resultData) throws NullPointerException {
double longi = resultData.getDouble("longitude");
double lati = resultData.getDouble("latitude");
locationChanged(longi, lati);
//Toast.makeText(MainActivity.this, "TOASTY X : " + e.getMessage(), Toast.LENGTH_SHORT).show();
//Log.v("TOASTY X : ","" + e.getMessage());
}
}
public void onError() {
helper.onDropTable();
Toast.makeText(this, "TABLE DROPED!", Toast.LENGTH_SHORT).show();
}
}
Logcat :
java.lang.NullPointerException: Attempt to invoke virtual method 'void e.wolverine2.thewalkingapp.RecyclerViewAdapter.notifyDataSetChanged()' on a null object reference
at e.wolverine2.thewalkingapp.Tab1.update(Tab1.java:57)
at e.wolverine2.thewalkingapp.MainActivity$1.onTabReselected(MainActivity.java:101)
at android.support.design.widget.TabLayout.dispatchTabReselected(TabLayout.java:1177)
at android.support.design.widget.TabLayout.selectTab(TabLayout.java:1136)
at android.support.design.widget.TabLayout.selectTab(TabLayout.java:1128)
at android.support.design.widget.TabLayout$Tab.select(TabLayout.java:1427)
at android.support.design.widget.TabLayout$TabView.performClick(TabLayout.java:1537)
at android.view.View$PerformClick.run(View.java:23985)
at android.os.Handler.handleCallback(Handler.java:751)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:154)
at android.app.ActivityThread.main(ActivityThread.java:6816)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1563)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1451)

Java Tip: When it gets here:
Tab1 tab1 = new Tab1();
tab1.update();
A new Tab is instantiated using the cunstructor:
public Tab1() {
}
in your Tab class. as you see the recyclerView is not initialized up to this point.So the recyclerView is actually Null!
Answer: To correctly implement fragment take a look at this:
https://stackoverflow.com/a/5161143/6094503
What you looking for is the following lines:
Fragment newFragment = new DebugExampleTwoFragment();
FragmentTransaction ft = getFragmentManager().beginTransaction();
ft.add(CONTENT_VIEW_ID, newFragment).commit();
but I think you need more study about fragments and how they're added to (or removed from) an activity

json items are not displayed in listview

I'm trying to bookmark my app but I have some charges in my code, below I'll explain my problems.
Let's start with my adapter memes.class
public class memes{
private String nome;
private int resID;
private Boolean mIsFavourite;
public memes(String nome, int resID){
this.nome = nome;
this.resID = resID;
}
public Boolean getmIsFavourite() {
return mIsFavourite;
}
public void setmIsFavourite(Boolean mIsFavouriteResource) {
this.mIsFavourite = mIsFavouriteResource;
}
public String getNome(){
return nome;
}
public int getResId(){
return resID;
}
#Override
public String toString(){
return nome;
}
}
Main activity
public class MainActivity extends AppCompatActivity {
ListView lv;
MediaPlayer mp;
ArrayList<memes> item;
ArrayAdapter<memes> arrayAdapter;
String[] Nomes = new String[]{"Compartilhar", "Add Favoritos"};
List<memes> favoriteMemes = new ArrayList<>();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(activity_main);
lv = findViewById(R.id.lv);
mp = new MediaPlayer();
item = new ArrayList<>();
//itens
item.add(new memes("item 1", R.raw.audio1));
item.add(new memes("item 2", R.raw.audio2));
arrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, item);
lv.setAdapter(arrayAdapter);
lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
#Override
public boolean onItemLongClick(AdapterView<?> adapterView, View view, final int position, long l) {
AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);
builder.setTitle("Menu");
builder.setItems(MainActivity.this.Nomes, new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
switch (which) {
case 0:
sendWhatsAppAudio(position);
return;
case 1:
//set item true
item.get(position).setmIsFavourite(true);
return;
default:
}
}
});
builder.show();
return true;
}
});
}
This is where I send the items to the other activity
//Here is the mess.
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case R.id.abreFavoritos:
for(int i=0;i<lv.getAdapter().getCount();i++){
memes fMeme = (memes)lv.getAdapter().getItem(i);
//mIsFavourite in my code it turns red
//what should I put after the item. to work?
if (item.mIsFavourite()) {
favoriteMemes.add(fMeme);
}
}
intent = new Intent(this, Favoritos.class);
intent.putExtra("favoritos", new Gson().toJson(favoriteMemes));
startActivity(intent);
return true;
default:
return super.onOptionsItemSelected(item);
}
}
}
Now finally activity in which we place the Favoritos.class
public class Favoritos extends AppCompatActivity {
ListView lv;
ArrayAdapter<memes> arrayAdapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(activity_main);
lv = findViewById(R.id.lv);
String memesString = getIntent().getStringExtra("favoritos");
memes[] fMemes = new Gson().fromJson(memesString,memes[].class);
arrayAdapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1, fMemes);
lv.setAdapter(arrayAdapter);
}
}
Items are not displayed with this code.
I think my problem is in if (item.mIsFavorite ()) but I have no idea what to put here.
one more thing, on the second activity how would I remove the items?
and tbm could I recommend a good tutorial from SharedPreferences so I can use that case.
Thank you

OrmLite get value from listView with Adapter

When I want to get a name of list which I pressed, I get "com.example.oleksandr.dream.DB.DreamDetails#528f8a90". How can I get a String value from my list? The problem is in "the onItemClick" methode.
public class MainActivity extends AppCompatActivity implements AdapterView.OnItemClickListener {
private DBHelper mDbHelper = null;
private DreamDetails dreamDetails;
private ListView mListView;
private DrawerLayout drawerLayout;
private Toolbar mToolbar;
private Dao<DreamDetails, Integer> dreamDetailsDao;
private List<DreamDetails> dreamList;
private int selectedRecordPosition = -1;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mListView = (ListView) findViewById(R.id.listViewAllDreams);
try {
//Getting all Data from DB
dreamDetailsDao = getHelper().getDreamDetailsesDao();
dreamList = dreamDetailsDao.queryForAll();
// Set the header of the ListView
final LayoutInflater inflater = (LayoutInflater) this.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
final View view = inflater.inflate(R.layout.list_view, mListView, false);
mListView.addHeaderView(view);
// my own adapter!
mListView.setAdapter(new AdapterArrayDream(this,R.layout.list_view,dreamList,dreamDetailsDao));
mListView.setOnItemClickListener(this);
} catch (SQLException e) {
e.printStackTrace();
}
initToolbar();
initNavigationView();
FloatingActionButton myFab = (FloatingActionButton)findViewById(R.id.fab);
myFab.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, NewDream.class);
startActivity(intent);
}
});
}
#Override
public void onItemClick(AdapterView<?> adapterView, View view, int i, long l) {
if(i > 0)
{
selectedRecordPosition = i - 1;
// final Intent intent = new Intent(this, ViewDream.class);
Log.i("TAAAAAAG", "onClick " + adapterView.getItemAtPosition(selectedRecordPosition));
// intent.putExtra("D", String.valueOf(adapterView.getItemAtPosition(selectedRecordPosition)));
// startActivity(intent);
}
}
private void initNavigationView() {
drawerLayout = (DrawerLayout) findViewById(R.id.drawlerLayout);
}
private void initToolbar() {
mToolbar = (Toolbar) findViewById(R.id.toolbar);
mToolbar.setTitle(R.string.app_name);
mToolbar.setOnMenuItemClickListener(new Toolbar.OnMenuItemClickListener() {
#Override
public boolean onMenuItemClick(MenuItem item) {
return false;
}
});
// mToolbar.inflateMenu(R.menu.menu);
}
// This is how, DatabaseHelper can be initialized for future use
#Override
public boolean onCreateOptionsMenu(Menu menu) {
getMenuInflater().inflate(R.menu.menu_list_dreams, menu);
return true;
}
private DBHelper getHelper() {
if (mDbHelper == null) {
mDbHelper = OpenHelperManager.getHelper(this, DBHelper.class);
}
return mDbHelper;
}
}

To create a query which looks up an account by name and password you would do the following:
QueryBuilder<Account, String> qb = accountDao.queryBuilder();
Where where = qb.where();
// the name field must be equal to "foo"
where.eq(Account.NAME_FIELD_NAME, "foo");
// and
where.and();
// the password field must be equal to "_secret"
where.eq(Account.PASSWORD_FIELD_NAME, "_secret");
PreparedQuery<Account, String> preparedQuery = qb.prepareQuery();