অ্যান্ড্রয়েড RecyclerView-এ সিলেক্টেড আইটেম সঠিকভাবে হাইলাইট করবেন কীভাবে?

RecyclerView-এ সিলেকশন স্টেট ম্যানেজমেন্ট (SparseBooleanArray ব্যবহার)

এই টিউটোরিয়ালটি দেখায় কীভাবে RecyclerView-এ আইটেম সিলেকশন স্টেট ম্যানেজ করা যায় background selector এবং SparseBooleanArray ব্যবহার করে।

ধাপ ১: Dependencies

dependencies {
    implementation "androidx.recyclerview:recyclerview:1.3.2"
    implementation "androidx.cardview:cardview:1.0.0"
}

ধাপ ২: লেআউট (activity_main.xml)

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="https://schemas.android.com/apk/res/android"
    xmlns:tools="https://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="4dp"
    tools:context=".MainActivity">
    <androidx.recyclerview.widget.RecyclerView
        android:id="@+id/recyclerView"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:paddingBottom="8dp" />
</RelativeLayout>

ধাপ ৩: আইটেম লেআউট (res/layout/list_layout.xml)

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="https://schemas.android.com/apk/res/android"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:background="@drawable/background_selector"
    android:padding="16dp">
    
    <TextView
        android:id="@+id/awardTitle"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="10dp"
        android:text="Award Title"
        android:textSize="18sp"
        android:textStyle="bold" />
    
    <TextView
        android:id="@+id/awardYear"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/awardTitle"
        android:layout_alignStart="@id/awardTitle"
        android:layout_marginTop="20dp"
        android:text="Year"
        android:textColor="#000" />
    
    <TextView
        android:id="@+id/playerName"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentEnd="true"
        android:text="Player Name" />
        
</RelativeLayout>

ধাপ ৪: ড্রয়েবল রিসোর্সেস

res/drawable/background_selector.xml - স্টেট-ভিত্তিক ব্যাকগ্রাউন্ড

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="https://schemas.android.com/apk/res/android">
    <!-- সিলেক্টেড স্টেট -->
    <item android:drawable="@color/colorAccent" 
          android:state_pressed="false" 
          android:state_selected="true" />
    <!-- ডিফল্ট স্টেট -->
    <item android:drawable="@android:color/white" 
          android:state_selected="false" />
    <!-- প্রেসড স্টেট (ঐচ্ছিক) -->
    <item android:drawable="@color/colorPrimary" 
          android:state_pressed="true" />
</selector>

res/drawable/line_divider.xml - আইটেম বিভাজক

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="https://schemas.android.com/apk/res/android" 
    android:shape="rectangle">
    <size android:width="2dp" android:height="2dp" />
    <solid android:color="@color/colorPrimaryDark" />
</shape>

ধাপ ৫: মডেল ক্লাস (ItemObject.java)

package com.app.sample;

public class ItemObject {
    private String awardTitle;
    private String awardYear;
    private String player;

    public ItemObject(String awardTitle, String awardYear, String player) {
        this.awardTitle = awardTitle;
        this.awardYear = awardYear;
        this.player = player;
    }

    public String getAwardTitle() { return awardTitle; }
    public String getAwardYear() { return awardYear; }
    public String getPlayer() { return player; }
}

ধাপ ৬: ViewHolder (RecyclerViewHolders.java) - ক্লিক হ্যান্ডলিং

package com.app.sample;

import android.util.SparseBooleanArray;
import android.view.View;
import android.widget.TextView;
import androidx.recyclerview.widget.RecyclerView;

class RecyclerViewHolders extends RecyclerView.ViewHolder implements View.OnClickListener {
    TextView awardTitle;
    TextView awardYear;
    TextView player;
    
    // সিলেকশন স্টেট স্টোর
    private SparseBooleanArray selectedItems = new SparseBooleanArray();

    RecyclerViewHolders(View itemView) {
        super(itemView);
        itemView.setOnClickListener(this);
        awardTitle = itemView.findViewById(R.id.awardTitle);
        awardYear = itemView.findViewById(R.id.awardYear);
        player = itemView.findViewById(R.id.playerName);
    }

    @Override
    public void onClick(View view) {
        int position = getAdapterPosition();
        
        if (selectedItems.get(position, false)) {
            // অ-সিলেক্ট
            selectedItems.delete(position);
            view.setSelected(false);
        } else {
            // সিলেক্ট
            selectedItems.put(position, true);
            view.setSelected(true);
        }
    }
    
    // বাহ্যিক অ্যাক্সেসের জন্য
    public boolean isSelected(int position) {
        return selectedItems.get(position, false);
    }
    
    public void setSelected(int position, boolean selected) {
        if (selected) selectedItems.put(position, true);
        else selectedItems.delete(position);
    }
}

ধাপ ৭: Adapter (RecyclerViewAdapter.java)

package com.app.sample;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;
import java.util.List;

public class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerViewHolders> {
    private List<ItemObject> itemList;
    private Context context;

    RecyclerViewAdapter(Context context, List<ItemObject> itemList) {
        this.context = context;
        this.itemList = itemList;
    }

    @NonNull
    @Override
    public RecyclerViewHolders onCreateViewHolder(ViewGroup parent, int viewType) {
        View layoutView = LayoutInflater.from(parent.getContext())
            .inflate(R.layout.list_layout, parent, false);
        return new RecyclerViewHolders(layoutView);
    }

    @Override
    public void onBindViewHolder(RecyclerViewHolders holder, int position) {
        ItemObject item = itemList.get(position);
        holder.awardTitle.setText("Award Title: " + item.getAwardTitle());
        holder.awardYear.setText("Award Year: " + item.getAwardYear());
        holder.player.setText("Player Name: " + item.getPlayer());
        
        // সিলেকশন স্টেট রিস্টোর (গুরুত্বপূর্ণ!)
        holder.itemView.setSelected(holder.isSelected(position));
    }

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

ধাপ ৮: ItemDecoration (SimpleItemDecoration.java)

package com.app.sample;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.view.View;
import androidx.annotation.NonNull;
import androidx.core.content.ContextCompat;
import androidx.recyclerview.widget.RecyclerView;

class SimpleItemDecoration extends RecyclerView.ItemDecoration {
    private Drawable drawable;

    SimpleItemDecoration(Context context) {
        drawable = ContextCompat.getDrawable(context, R.drawable.line_divider);
    }

    @Override
    public void onDrawOver(@NonNull Canvas canvas, RecyclerView parent, @NonNull RecyclerView.State state) {
        int left = parent.getPaddingLeft();
        int right = parent.getWidth() - parent.getPaddingRight();
        int childCount = parent.getChildCount();
        
        for (int i = 0; i < childCount; i++) {
            View child = parent.getChildAt(i);
            RecyclerView.LayoutParams params = (RecyclerView.LayoutParams) child.getLayoutParams();
            int top = child.getBottom() + params.bottomMargin;
            int bottom = top + drawable.getIntrinsicHeight();
            drawable.setBounds(left, top, right, bottom);
            drawable.draw(canvas);
        }
    }
}

ধাপ ৯: MainActivity.java

package com.app.sample;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import android.os.Bundle;
import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        RecyclerView recyclerView = findViewById(R.id.recyclerView);
        recyclerView.addItemDecoration(new SimpleItemDecoration(this));
        
        LinearLayoutManager layoutManager = new LinearLayoutManager(this);
        recyclerView.setLayoutManager(layoutManager);
        
        List<ItemObject> posts = returnListItems();
        RecyclerViewAdapter adapter = new RecyclerViewAdapter(this, posts);
        recyclerView.setAdapter(adapter);
    }

    private List<ItemObject> returnListItems() {
        List<ItemObject> items = new ArrayList<>();
        items.add(new ItemObject("Ballon d'or", "2007", "Ricardo KaKa"));
        items.add(new ItemObject("Ballon d'or", "2008", "Cristiano Ronaldo"));
        items.add(new ItemObject("Ballon d'or", "2009-2012, 2015", "Lionel Messi"));
        items.add(new ItemObject("Ballon d'or", "2013, 2014, 2016, 2017", "Cristiano Ronaldo"));
        items.add(new ItemObject("Ballon d'or", "2018", "Luka Modric"));
        items.add(new ItemObject("Ballon d'or", "2019", "Not decided yet"));
        return items;
    }
}

ধাপ ১০: ম্যানিফেস্ট

সাধারণ কনফিগারেশন।

উন্নত ফিচার: Multi-Selection (ActionMode)

// Adapter-এ যোগ করুন
private ActionMode actionMode;
private ActionMode.Callback actionModeCallback = new ActionMode.Callback() {
    @Override public boolean onCreateActionMode(ActionMode mode, Menu menu) {
        mode.getMenuInflater().inflate(R.menu.selection_menu, menu);
        return true;
    }
    @Override public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
        if (item.getItemId() == R.id.action_delete) {
            deleteSelectedItems();
            mode.finish();
            return true;
        }
        return false;
    }
    @Override public void onDestroyActionMode(ActionMode mode) {
        clearSelections();
        actionMode = null;
    }
    @Override public boolean onPrepareActionMode(ActionMode mode, Menu menu) { return false; }
};

// ViewHolder-এ লং ক্লিক
itemView.setOnLongClickListener(v -> {
    if (actionMode == null) {
        actionMode = ((AppCompatActivity)context).startSupportActionMode(actionModeCallback);
    }
    toggleSelection(getAdapterPosition());
    return true;
});