So I've set up my RecyclerView with SQLite DB and it's populating the list, but every time I click on the list item it should open the new activity and pass data to it via intent extras.
The click gives me NullPointerException:
Process: com.daroioradecic.fxtodo, PID: 6762
java.lang.NullPointerException: Attempt to invoke interface method 'void data.RecAdapter$ItemClickCallback.onItemClick(int)' on a null object reference
at data.RecAdapter$RecHolder.onClick(RecAdapter.java:106)
at android.view.View.performClick(View.java:4856)
at android.view.View$PerformClick.run(View.java:19956)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:211)
at android.app.ActivityThread.main(ActivityThread.java:5389)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1020)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:815)
in my Recycler View adapter class which is:
public class RecAdapter extends RecyclerView.Adapter<RecAdapter.RecHolder> {
private int previousPosition = 0;
private List<Todo> listData;
private LayoutInflater inflater;
private ItemClickCallback itemClickCallback;
public interface ItemClickCallback {
void onItemClick(int p);
}
public void setItemClickCallback(final ItemClickCallback itemClickCallback) {
this.itemClickCallback = itemClickCallback;
}
public RecAdapter(List<Todo> listData, Context c) {
this.inflater = LayoutInflater.from(c);
this.listData = listData;
}
@Override
public RecHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = inflater.inflate(R.layout.layout_row_za_listu, parent, false);
return new RecHolder(view);
}
@Override
public void onBindViewHolder(RecHolder holder, int position) {
Todo item = listData.get(position);
holder.title.setText(item.getTitle());
if (position > previousPosition) {
AnimationUtil.animate(holder, true);
} else {
AnimationUtil.animate(holder, false);
}
previousPosition = position;
}
@Override
public int getItemCount() {
return listData.size();
}
public void setListData(ArrayList<Todo> exerciseList) {
this.listData.clear();
this.listData.addAll(exerciseList);
}
class RecHolder extends RecyclerView.ViewHolder implements View.OnClickListener {
private TextView title;
private View container;
public RecHolder(View itemView) {
super(itemView);
title = (TextView) itemView.findViewById(R.id.tekstNaListi);
container = itemView.findViewById(R.id.cont_item_root);
container.setOnClickListener(this);
}
@Override
public void onClick(View v) {
itemClickCallback.onItemClick(getAdapterPosition());
}
}
}
It gives the error on line itemClickCallback.onItemClick(getAdapterPosition()); which is the last line in the class.
I'm overriding onClick in the class where recycler view is populated like this:
@Override
public void onItemClick(int p) {
Todo item = (Todo) listData.get(p);
Intent i = new Intent(HomeScreen.this, Details.class);
Bundle extras = new Bundle();
extras.putString("naslov", item.getTitle());
extras.putString("datum", item.getRecordDate());
extras.putInt("id", item.getItemId());
startActivity(i);
}
That class implements implements RecAdapter.ItemClickCallback
Any ideas? Thanks!
MAIN ACTIVITY CLASS: (keep in mind that I just transitioned from ListView so I haven't done any cleaning)
public class HomeScreen extends AppCompatActivity implements RecAdapter.ItemClickCallback {
private RecyclerViewUtils.ShowHideToolbarOnScrollingListener showHideToolbarListener;
//SCROLL
private Toolbar tToolbar;
// REC
private RecyclerView recView;
private RecAdapter adapter;
private ArrayList listData;
// ZA SNACKBAR
private CoordinatorLayout coordinatorLayout;
private RelativeLayout relLay;
// NAVIGACIJA
private DrawerLayout mDrawer;
private ActionBarDrawerToggle drawerToggle;
private Toolbar toolbar;
NavigationView nvDrawer;
DrawerLayout dlDrawer;
//----------------------------------------------------------------------------------------------
DatabaseHandler dba;
private ArrayList<Todo> dbTodo = new ArrayList<>();
private TodoAdapter todoAdapter;
private ListView lista;
private Cursor mCursor;
LinearLayout layoutZaUnosTodoa;
EditText editTextZaNazivTodoa;
Button buttonSave;
private CheckBox checkBoxDoneOrNotNaListi;
android.support.design.widget.FloatingActionButton fab;
@TargetApi(Build.VERSION_CODES.LOLLIPOP)
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//getWindow().requestFeature(Window.FEATURE_ACTION_BAR_OVERLAY);
setContentView(R.layout.activity_home_screen);
tToolbar = (Toolbar) findViewById(R.id.tToolbar);
setSupportActionBar(tToolbar);
tToolbar.setNavigationIcon(R.drawable.ic_nav_menu);
getSupportActionBar().setTitle(R.string.app_name);
// REC
recView = (RecyclerView) findViewById(R.id.rec_list);
recView.setLayoutManager(new LinearLayoutManager(this));
adapter = new RecAdapter(listData, this);
recView.setAdapter(adapter);
adapter.setItemClickCallback(this);
recView.addOnScrollListener(showHideToolbarListener = new RecyclerViewUtils.ShowHideToolbarOnScrollingListener(tToolbar));
if (savedInstanceState != null) {
showHideToolbarListener.onRestoreInstanceState((RecyclerViewUtils.ShowHideToolbarOnScrollingListener.State) savedInstanceState
.getParcelable(RecyclerViewUtils.ShowHideToolbarOnScrollingListener.SHOW_HIDE_TOOLBAR_LISTENER_STATE));
}
layoutZaUnosTodoa = (LinearLayout) findViewById(R.id.layoutZaUnosTodoa);
editTextZaNazivTodoa = (EditText) findViewById(R.id.editTextZaNazivTodoa);
editTextZaNazivTodoa.setSelection(editTextZaNazivTodoa.getText().length());
buttonSave = (Button) findViewById(R.id.buttonSave);
//lista = (ListView) findViewById(R.id.lista);
fab = (android.support.design.widget.FloatingActionButton) findViewById(R.id.fab);
checkBoxDoneOrNotNaListi = (CheckBox) findViewById(R.id.checkBoxDoneOrNotNaListi);
coordinatorLayout = (CoordinatorLayout) findViewById(R.id.coordiantorLayout);
relLay = (RelativeLayout) findViewById(R.id.relLay);
refreshData();
layoutZaUnosTodoa.setVisibility(View.GONE);
fab.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
layoutZaUnosTodoa.setVisibility(View.VISIBLE);
}
});
buttonSave.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
saveToDB();
layoutZaUnosTodoa.setVisibility(View.GONE);
}
});
relLay.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
layoutZaUnosTodoa.setVisibility(View.GONE);
}
});
dlDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);
drawerToggle = setupDrawerToggle();
dlDrawer.setDrawerListener((DrawerLayout.DrawerListener) drawerToggle);
mDrawer = (DrawerLayout) findViewById(R.id.drawer_layout);
nvDrawer = (NavigationView) findViewById(R.id.nvView);
setupDrawerContent(nvDrawer);
drawerToggle.syncState();
}
@Override
public void onSaveInstanceState(Bundle outState) {
outState.putParcelable(RecyclerViewUtils.ShowHideToolbarOnScrollingListener.SHOW_HIDE_TOOLBAR_LISTENER_STATE,
showHideToolbarListener.onSaveInstanceState());
super.onSaveInstanceState(outState);
}
private void saveToDB() {
Todo todo = new Todo();
todo.setTitle(editTextZaNazivTodoa.getText().toString());
dba.addTodo(todo);
adapter.notifyDataSetChanged();
dba.close();
editTextZaNazivTodoa.setText("");
}
public void refreshData() {
dbTodo.clear();
dba = new DatabaseHandler(HomeScreen.this);
ArrayList<Todo> todoFromDB = dba.getTodo();
for (int i = 0; i < todoFromDB.size(); i++) {
String title = todoFromDB.get(i).getTitle();
String dateText = todoFromDB.get(i).getRecordDate();
int mid = todoFromDB.get(i).getItemId();
Todo myTodo = new Todo();
myTodo.setTitle(title);
myTodo.setItemId(mid);
myTodo.setRecordDate(dateText);
dbTodo.add(myTodo);
}
dba.close();
adapter = new RecAdapter(dbTodo, this);
recView.setAdapter(adapter);
// todoAdapter = new TodoAdapter(HomeScreen.this, R.layout.layout_row_za_listu, dbTodo);
//Animation collapseList = AnimationUtils.loadAnimation(HomeScreen.this, R.anim.collapse_search_results);
//lista.startAnimation(collapseList);
//lista.setAdapter(todoAdapter);
// todoAdapter.notifyDataSetChanged();
}
@Override
public void onItemClick(int p) {
Todo item = (Todo) listData.get(p);
Intent i = new Intent(HomeScreen.this, Details.class);
Bundle extras = new Bundle();
extras.putString("naslov", item.getTitle());
extras.putString("datum", item.getRecordDate());
extras.putInt("id", item.getItemId());
startActivity(i);
}
/* @Override
public void onSecondaryItemClick(int p) {
}*/
public class TodoAdapter extends ArrayAdapter<Todo> {
Activity activity;
int layoutResource;
Todo todo;
ArrayList<Todo> mData = new ArrayList<>();
public TodoAdapter(Activity act, int resource, ArrayList<Todo> data) {
super(act, resource, data);
activity = act;
layoutResource = resource;
mData = data;
notifyDataSetChanged();
}
@Override
public int getCount() {
return mData.size();
}
@Override
public Todo getItem(int position) {
return mData.get(position);
}
@Override
public int getPosition(Todo item) {
return super.getPosition(item);
}
@Override
public long getItemId(int position) {
return super.getItemId(position);
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
ViewHolder holder = null;
if (row == null || (row.getTag() == null)) {
LayoutInflater inflater = LayoutInflater.from(activity);
row = inflater.inflate(layoutResource, null);
holder = new ViewHolder();
holder.mTitle = (TextView) row.findViewById(R.id.tekstNaListi);
holder.checkBox = (CheckBox) row.findViewById(R.id.checkBoxDoneOrNotNaListi);
row.setTag(holder);
} else {
holder = (ViewHolder) row.getTag();
}
holder.myTodo = getItem(position);
holder.mTitle.setText(holder.myTodo.getTitle());
final ViewHolder finalHolder = holder;
holder.mTitle.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
int mid = finalHolder.myTodo.getItemId();
DatabaseHandler dba = new DatabaseHandler(HomeScreen.this);
dba.deleteTodo(mid);
Snackbar snackbar = Snackbar.make(coordinatorLayout, getResources().getString(R.string.snack_bar_tekst), Snackbar.LENGTH_SHORT);
snackbar.show();
todoAdapter.notifyDataSetChanged();
return true;
}
});
/*holder.mTitle.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String title = finalHolder.myTodo.getTitle().toString();
String dateText = finalHolder.myTodo.getRecordDate().toString();
int mid = finalHolder.myTodo.getItemId();
Intent i = new Intent(HomeScreen.this, Details.class);
i.putExtra("naslov", title);
i.putExtra("datum", dateText);
i.putExtra("id", mid);
startActivity(i);
}
});*/
final View finalRow = row;
holder.checkBox.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
finalHolder.mTitle = (TextView) finalRow.findViewById(R.id.tekstNaListi);
if (finalHolder.checkBox.isChecked()) {
finalHolder.mTitle.setPaintFlags(finalHolder.mTitle.getPaintFlags() | Paint.STRIKE_THRU_TEXT_FLAG);
finalHolder.mTitle.setAlpha(0.5f);
} else if (!finalHolder.checkBox.isChecked()) {
finalHolder.mTitle.setPaintFlags(0);
finalHolder.mTitle.setAlpha(0.8f);
}
}
});
return row;
}
}
class ViewHolder {
Todo myTodo;
TextView mTitle, mContent, mDate;
int mId;
CheckBox checkBox;
}
EDIT:
This error shows up:
java.lang.NullPointerException: Attempt to invoke interface method 'void data.RecAdapter$ItemClickCallback.onItemClick(int)' on a null object reference
at data.RecAdapter$1.onClick(RecAdapter.java:67)
and it refeers to this line in adapter class:
itemClickCallback.onItemClick(position);
