Ошибка, которую я получаю при нажатии на порядок задач для добавления подзадач:
2020-04-23 14:52:48.749 12289-12289/com.example.justdoit E/AndroidRuntime: FATAL EXCEPTION: main Process: com.example.justdoit,
PID: 12289 java.lang.RuntimeException: Unable to start activity ComponentInfo {
com.example.justdoit/com.example.justdoit.ItemActivity
}
: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.material.floatingactionbutton.FloatingActionButton.setOnClickListener(android.view.View$OnClickListener)' on a null object reference at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2778) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856) at android.app.ActivityThread.-wrap11(Unknown Source:0) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loop(Looper.java:164) at android.app.ActivityThread.main(ActivityThread.java:6494) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807) Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void com.google.android.material.floatingactionbutton.FloatingActionButton.setOnClickListener(android.view.View$OnClickListener)' on a null object reference at com.example.justdoit.ItemActivity.onCreate(ItemActivity.java:61) at android.app.Activity.performCreate(Activity.java:7009) at android.app.Activity.performCreate(Activity.java:7000) at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214) at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2731) at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2856) at android.app.ActivityThread.-wrap11(Unknown Source:0) at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1589) at android.os.Handler.dispatchMessage(Handler.java:106) at android.os.Looper.loop(Looper.java:164) at android.app.ActivityThread.main(ActivityThread.java:6494) at java.lang.reflect.Method.invoke(Native Method) at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:438) at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:807)
ItemActivity Class:
public class ItemActivity extends AppCompatActivity {
Toolbar item_toolbar;
RecyclerView rv_item;
FloatingActionButton fab_item;
long todoId=-1;
ItemActivity activity;
DBHandler dbHandler;
ItemTouchHelper touchHelper;
ItemAdapter adapter;
ArrayList<ToDoItem>list;
@Override protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_item);
item_toolbar=findViewById(R.id.item_toolbar);
rv_item=findViewById(R.id.rv_item);
fab_item=findViewById(R.id.fab_item);
setSupportActionBar(item_toolbar);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
getSupportActionBar().setHomeButtonEnabled(true);
getSupportActionBar().setTitle(getIntent().getStringExtra(INTENT_TODO_NAME));
todoId=getIntent().getLongExtra(INTENT_TODO_ID, -1);
activity=this;
dbHandler=new DBHandler(activity);
rv_item.setLayoutManager(new LinearLayoutManager(activity));
fab_item.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View v) {
AlertDialog.Builder dialog=new AlertDialog.Builder(activity);
dialog.setTitle("Add ToDo item");
View view=getLayoutInflater().inflate(R.layout.dialog_dashboard, null);
final EditText toDoName=view.findViewById(R.id.ev_todo);
dialog.setView(view);
dialog.setPositiveButton("Add", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialog, int i) {
if (toDoName.getText().toString().length() > 0) {
ToDoItem item=new ToDoItem();
item.setItemName(toDoName.getText().toString());
item.setToDoId(todoId);
item.setCompleted(false);
dbHandler.addToDoItem(item);
refreshList();
}
}
}
);
dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialogInterface, int i) {}
}
);
dialog.show();
}
}
);
touchHelper=new ItemTouchHelper(new ItemTouchHelper.SimpleCallback(ItemTouchHelper.UP | ItemTouchHelper.DOWN, 0) {
@Override public boolean onMove(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder p1, @NonNull RecyclerView.ViewHolder p2) {
int sourcePosition=p1.getAdapterPosition();
int targetPosition=p2.getAdapterPosition();
Collections.swap(list, sourcePosition, targetPosition);
adapter.notifyItemMoved(sourcePosition, targetPosition);
return true;
}
@Override public void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int i) {}
}
);
touchHelper.attachToRecyclerView(rv_item);
}
@Override public boolean onOptionsItemSelected(MenuItem item) {
if (item.getItemId()==android.R.id.home) {
finish();
return true;
}
else return super.onOptionsItemSelected(item);
}
@Override protected void onResume() {
refreshList();
super.onResume();
}
void refreshList() {
list=dbHandler.getToDoItems(todoId);
adapter=new ItemAdapter(activity);
rv_item.setAdapter(adapter);
}
void updateItem(final ToDoItem item) {
AlertDialog.Builder dialog=new AlertDialog.Builder(activity);
dialog.setTitle("Update ToDo Item");
View view=getLayoutInflater().inflate(R.layout.dialog_dashboard, null);
final EditText toDoName=view.findViewById(R.id.ev_todo);
toDoName.setText(item.getItemName());
dialog.setView(view);
dialog.setPositiveButton("Update", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialogInterface, int i) {
if (toDoName.getText().toString().length() > 0) {
item.setItemName(toDoName.getText().toString());
item.setToDoId(todoId);
item.setCompleted(false);
dbHandler.updateToDoItem(item);
refreshList();
}
}
}
);
dialog.show();
}
class ItemAdapter extends RecyclerView.Adapter<ItemAdapter.ViewHolder> {
ItemActivity activity;
ItemAdapter(ItemActivity activity) {
this.activity=activity;
}
@NonNull @Override public ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int i) {
return new ViewHolder(LayoutInflater.from(activity).inflate(R.layout.rv_child_item, viewGroup, false));
}
@Override public void onBindViewHolder(@NonNull final ViewHolder holder, final int i) {
holder.itemName.setText(list.get(i).getItemName());
holder.itemName.setChecked(list.get(i).isCompleted());
holder.itemName.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View view) {
list.get(i).setCompleted(!list.get(i).isCompleted());
activity.dbHandler.updateToDoItem(list.get(i));
}
}
);
holder.delete.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View v) {
AlertDialog.Builder dialog=new AlertDialog.Builder(activity);
dialog.setTitle("Are you sure");
dialog.setMessage("Do you want to delete this item?");
dialog.setPositiveButton("Continue", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialogInterface, int pos) {
activity.dbHandler.deleteToDoItem(list.get(i).getId());
activity.refreshList();
}
}
);
dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
@Override public void onClick(DialogInterface dialogInterface, int i) {}
}
);
dialog.show();
}
}
);
holder.edit.setOnClickListener(new View.OnClickListener() {
@Override public void onClick(View view) {
activity.updateItem(list.get(i));
}
}
);
holder.move.setOnTouchListener(new View.OnTouchListener() {
@Override public boolean onTouch(View view, MotionEvent motionEvent) {
if (motionEvent.getActionMasked()==MotionEvent.ACTION_DOWN) {
activity.touchHelper.startDrag(holder);
}
return false;
}
}
);
}
@Override public int getItemCount() {
return list.size();
}
class ViewHolder extends RecyclerView.ViewHolder {
CheckBox itemName;
ImageView edit;
ImageView delete;
ImageView move;
ViewHolder(View v) {
super(v);
itemName=v.findViewById(R.id.cb_item);
edit=v.findViewById(R.id.iv_edit);
delete=v.findViewById(R.id.iv_delete);
move=v.findViewById(R.id.iv_move);
}
}
}
}
Когда я нажимаю на задачу, чтобы добавить подзадачи приложение перестает работать и сразу же закрывается, показывая следующую ошибку, которую я прикрепил.
Я хочу добавить подзадачи, нажав на главную задачу, но я не могу это сделать. Как я могу это сделать?
Я объявил FloatingActionButton как fab_item и написал:
fab_item = findViewById(R.id.fab_item);
перед onClick под onCreate.