Simple way to show menu items on list item get selected

Here is the most easier way to showing menu items on list items get selected. Your Activity will look like this

public class MainActivity extends AppCompatActivity {

    private RecyclerView myList;
    private int selectedCount;
    private ArrayList list;
    private MyListAdapter adapter;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        myList = (RecyclerView) findViewById(R.id.myList);
        myList.setHasFixedSize(true);
        myList.setLayoutManager(new LinearLayoutManager(this));

        list = new ArrayList<>();
        for (int i = 0; i < 20; i++) {
            list.add(new Item("Row " + (i + 1)));
        }

        adapter = new MyListAdapter(list, this);
        myList.setAdapter(adapter);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return selectedCount > 0;
    }

    public void onLongClicked(int adapterPosition) {
        list.get(adapterPosition).isSelected = true;
        selectedCount++;
        adapter.notifyDataSetChanged();
        invalidateOptionsMenu();
    }

    public void onClicked(int adapterPosition) {
        if (selectedCount > 0) {
            Item item = list.get(adapterPosition);
            if (item.isSelected) {
                selectedCount--;
            } else {
                selectedCount++;
            }
            item.setSelected(!item.isSelected);
            adapter.notifyDataSetChanged();
            invalidateOptionsMenu();
        }
    }
}

And your adapter will look like,

public class MyListAdapter extends RecyclerView.Adapter {
    private ArrayList myList;
    private MainActivity activity;

    public MyListAdapter(ArrayList myList, MainActivity mainActivity) {
        this.myList = myList;
        activity = mainActivity;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        return new ViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.my_list_item, parent, false));
    }

    @Override
    public void onBindViewHolder(final ViewHolder holder, int position) {
        holder.textView.setText(myList.get(position).text);

        if (myList.get(position).isSelected) {
            holder.view.setBackgroundColor(ContextCompat.getColor(activity, R.color.colorAccent));
        }else {
            holder.view.setBackgroundColor(Color.WHITE);
        }
        holder.view.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View view) {
                activity.onLongClicked(holder.getAdapterPosition());
                return true;
            }
        });

        holder.view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                activity.onClicked(holder.getAdapterPosition());
            }
        });
    }

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

    public class ViewHolder extends RecyclerView.ViewHolder {
        View view;
        TextView textView;

        public ViewHolder(View itemView) {
            super(itemView);
            view = itemView;
            textView = itemView.findViewById(R.id.text);
        }
    }
}

And your Item class will look like,

public class Item {
    boolean isSelected;
    String text;

    public Item(String text) {
        this.text = text;
    }

    public boolean isSelected() {
        return isSelected;
    }

    public void setSelected(boolean selected) {
        isSelected = selected;
    }
}

And your activity_main layout will look like,

<?xml version="1.0" encoding="utf-8"?>
<android.support.design.widget.CoordinatorLayout 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="com.guna.testapplication.MainActivity">

    <android.support.design.widget.AppBarLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:theme="@style/AppTheme.AppBarOverlay">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            android:background="?attr/colorPrimary"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

    </android.support.design.widget.AppBarLayout>

    <include layout="@layout/content_main" />

</android.support.design.widget.CoordinatorLayout>

And your content_main layout will look like,

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context="com.guna.testapplication.MainActivity"
    tools:showIn="@layout/activity_main">

    <android.support.v7.widget.RecyclerView
        android:id="@+id/myList"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
</android.support.constraint.ConstraintLayout>

And your menu_main will look like,

<menu 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"
    tools:context="com.guna.testapplication.MainActivity">
    <item
        android:id="@+id/action_share"
        android:title="@string/share"
        app:showAsAction="ifRoom" />

    <item
        android:id="@+id/action_delete"
        android:orderInCategory="100"
        android:title="@string/delete"
        app:showAsAction="never" />
</menu>

And your my_list_item layout will look like

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:layout_marginBottom="1dp"
    android:background="#fff"
    android:orientation="vertical">

    <TextView
        android:id="@+id/text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:padding="10dp" />
</LinearLayout>

Here is the full video tutorial

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