RecyclerView Item not showing-CodePudding

activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <RelativeLayout
        android:id="@ id/relativeLayout"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        app:layout_constraintBottom_toTopOf="@ id/addNotificationPanel"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.207">

        <androidx.recyclerview.widget.RecyclerView
            android:id="@ id/notificationPanelRecView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginTop="5dp"
            android:visibility="visible" />

    </RelativeLayout>
    
</androidx.constraintlayout.widget.ConstraintLayout>

notification_panel_cardview.xml

<?xml version="1.0" encoding="utf-8"?>
<androidx.cardview.widget.CardView xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@ id/notificationPanelParent"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_margin="5dp"
    app:cardCornerRadius="7dp"
    app:cardElevation="4dp">

    <RelativeLayout
        android:layout_width="335dp"
        android:layout_height="130dp">

        <EditText
            android:id="@ id/notificationName"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="5dp"
            android:maxLength="29"
            android:text="Notification"
            android:textSize="14sp"
            tools:ignore="TouchTargetSizeCheck" />

        <CheckBox
            android:id="@ id/enableNotificationCheckbox"
            android:layout_width="34dp"
            android:layout_height="34dp"
            android:layout_marginRight="4dp"
            android:layout_toLeftOf="@ id/deleteNotificationPanel"
            android:gravity="fill"
            tools:ignore="TouchTargetSizeCheck" />

        <ImageButton
            android:id="@ id/deleteNotificationPanel"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="true"
            android:layout_gravity="right|center_vertical"
            android:layout_marginRight="6dp"
            android:background="@null"
            android:src="@android:drawable/ic_delete"
            tools:ignore="TouchTargetSizeCheck,SpeakableTextPresentCheck" />

        <TextView
            android:id="@ id/notifyEvery"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@ id/notificationName"
            android:layout_marginLeft="6dp"
            android:layout_marginTop="1dp"
            android:text="Notify me every :"
            android:textSize="17sp" />

        <Spinner
            android:id="@ id/hoursSpinner"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@ id/notificationName"
            android:layout_toRightOf="@ id/notifyEvery"
            tools:ignore="TouchTargetSizeCheck,SpeakableTextPresentCheck" />

        <RelativeLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_below="@ id/notifyEvery"
            android:layout_marginTop="5dp">

            <CheckBox
                android:id="@ id/mondayCheckBox"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:button="@null"
                android:drawableBottom="?android:attr/listChoiceIndicatorMultiple"
                android:gravity="center"
                android:text="Mon"
                android:textSize="13sp" />

            <CheckBox
                android:id="@ id/tuesdayCheckBox"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_toRightOf="@ id/mondayCheckBox"
                android:button="@null"
                android:drawableBottom="?android:attr/listChoiceIndicatorMultiple"
                android:gravity="center"
                android:text="Tue"
                android:textSize="13sp" />

            <CheckBox
                android:id="@ id/wednesdayCheckBox"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_toRightOf="@ id/tuesdayCheckBox"
                android:button="@null"
                android:drawableBottom="?android:attr/listChoiceIndicatorMultiple"
                android:gravity="center"
                android:text="Wed"
                android:textSize="13sp" />

            <CheckBox
                android:id="@ id/thursdayCheckBox"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_toRightOf="@id/wednesdayCheckBox"
                android:button="@null"
                android:drawableBottom="?android:attr/listChoiceIndicatorMultiple"
                android:gravity="center"
                android:text="Thu"
                android:textSize="13sp" />

            <CheckBox
                android:id="@ id/fridayCheckBox"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_toRightOf="@ id/thursdayCheckBox"
                android:button="@null"
                android:drawableBottom="?android:attr/listChoiceIndicatorMultiple"
                android:gravity="center"
                android:text="Fri"
                android:textSize="13sp" />

            <CheckBox
                android:id="@ id/saturdayCheckBox"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_toRightOf="@ id/fridayCheckBox"
                android:button="@null"
                android:drawableBottom="?android:attr/listChoiceIndicatorMultiple"
                android:gravity="center"
                android:text="Sat"
                android:textSize="13sp" />

            <CheckBox
                android:id="@ id/sundayCheckBox"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_toRightOf="@id/saturdayCheckBox"
                android:button="@null"
                android:drawableBottom="?android:attr/listChoiceIndicatorMultiple"
                android:gravity="center"
                android:text="Sun"
                android:textSize="13sp"
                tools:ignore="TouchTargetSizeCheck" />
        </RelativeLayout>

    </RelativeLayout>

</androidx.cardview.widget.CardView>

NotificationPanel.java

public class NotificationPanel {
    private int id;
    private String notificationName ;

    public NotificationPanel(int id, String notificationName) {
        this.id = id;
        this.notificationName = notificationName;

    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getNotificationName() {
        return notificationName;
    }

    public void setNotificationName(String notificationName) {
        this.notificationName = notificationName;
    }

    @Override
    public String toString() {
        return "NotificationPanel{"  
                "id="   id  
                ", notificationName='"   notificationName   '\''  
                '}';
    }
}

NotificationPanelRecViewAdapter.java

public class NotificationPanelRecViewAdapter extends RecyclerView.Adapter<NotificationPanelRecViewAdapter.ViewHolder> {
    private String TAG = "NotificationPanelRecViewAdapter";

    private ArrayList<NotificationPanel> notificationPanel = new ArrayList<>();
    private Context mContext;

    public NotificationPanelRecViewAdapter(Context mContext) {
        this.mContext = mContext;
    }

    @NonNull
    @Override
    public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        LayoutInflater inflater = LayoutInflater.from(mContext);
        View view = inflater.inflate(R.layout.notification_panel_cardview,null,false);
        ViewHolder holder = new ViewHolder(view);
        return holder;
    }

    @Override
    public void onBindViewHolder(@NonNull ViewHolder holder,final int position) {
        Log.d(TAG,"onBindViewHolder: Called");
        holder.notificationName.setText(notificationPanel.get(position).getNotificationName());

    }

    @Override
    public int getItemCount() {
        return 0;
    }

    public void setNotificationPanel(ArrayList<NotificationPanel> notificationPanel) {
        this.notificationPanel = notificationPanel;
        notifyDataSetChanged();
    }

    public class ViewHolder extends RecyclerView.ViewHolder{
        private CardView parent;
        private EditText notificationName ;
        private CheckBox monCheckBox ,tueCheckBox,wedCheckBox,thuCheckBox,friCheckBox,satCheckBox,sunCheckBox,enableNotifCheckbox;
        private TextView notifyEvery;
        private Spinner hoursSpinner;
        private ImageButton deleteNotificationPanel;

        public ViewHolder(@NonNull View itemView) {
            super(itemView);
            parent = itemView.findViewById(R.id.notificationPanelParent);
            notificationName = itemView.findViewById(R.id.notificationName);
            monCheckBox = itemView.findViewById(R.id.mondayCheckBox);
            tueCheckBox = itemView.findViewById(R.id.tuesdayCheckBox);
            wedCheckBox = itemView.findViewById(R.id.wednesdayCheckBox);
            thuCheckBox = itemView.findViewById(R.id.thursdayCheckBox);
            friCheckBox = itemView.findViewById(R.id.fridayCheckBox);
            satCheckBox = itemView.findViewById(R.id.saturdayCheckBox);
            sunCheckBox = itemView.findViewById(R.id.sundayCheckBox);
            enableNotifCheckbox = itemView.findViewById(R.id.enableNotificationCheckbox);
            notifyEvery = itemView.findViewById(R.id.notifyEvery);
            hoursSpinner = (Spinner) itemView.findViewById(R.id.hoursSpinner);
            deleteNotificationPanel = itemView.findViewById(R.id.deleteNotificationPanel);

            ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(mContext,R.array.hoursSpinnerValues,R.layout.notification_panel_cardview);
        }
    }
}

MainActivity.java

public class MainActivity extends AppCompatActivity {

private RecyclerView notificationPanelRecView;
private NotificationPanelRecViewAdapter adapter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    AppCompatDelegate.setDefaultNightMode(AppCompatDelegate.MODE_NIGHT_NO);

    notificationPanelRecView = findViewById(R.id.notificationPanelRecView);

    ArrayList<NotificationPanel> notificationPanel = new ArrayList<>();
    notificationPanel.add(new NotificationPanel(1, "Pills"));

    NotificationPanelRecViewAdapter adapter = new NotificationPanelRecViewAdapter(this);
    adapter.setNotificationPanel(notificationPanel);

    notificationPanelRecView.setLayoutManager(new LinearLayoutManager(this));
    notificationPanelRecView.setAdapter(adapter);

}

I made an ArrayList with one item added in MainActivity just to test the layout and my problem is that it is not showing at all. Any hint about why is this happening would be helpful.---------------------------------------------------------------------------------------------------------------

CodePudding user response：

The adapter won't bind anything if it thinks there is nothing to bind.

@Override
public int getItemCount() {
     return 0;
}

needs to be

@Override
public int getItemCount() {
    return notificationPanel.size();
}