Swipe to Delete RecyclerView items with UNDO in Android Studio

Here we will create an example to delete an item of RecyclerView by swiping the item with undo functionality. For this purpose, we will use the ItemTouchHelper class which is added in Android Support Library V7 in order to achieve swipe to delete Recycler view items with UNDO.

This class is used to create a swipe to delete the items of RecyclerView. It has a SimpleCallback class that configures the events which are performed to swipe or move the item of the RecyclerView.

ItemTouchHelper class

It is a utility class that provides the facility to add swipe to dismiss and drag & drops the items of RecyclerView. It overrides the callback methods onMove() or onSwipe() depending upon the functionality we implement. So lets try to implement Swipe to Delete RecyclerView items with UNDO

Must Read: Google Login And Registration For Android Using Firebase Authentication

Android Swipe to Delete RecyclerView items with UNDO Example

Create a MainActivity.java class with the following code.

activity_main.xml

activity_main.xml  
<?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"  
    android:fitsSystemWindows="true"  
    tools:context="example.androidhire.com.recyclerviewswipedeleteundo.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>  


content_main.xml

<fragment 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/fragment"      android:name="example.androidhire.com.recyclerviewswipedeleteundo.MainActivityFragment"
android:layout_width="match_parent"    android:layout_height="match_parent" app:layout_behavior="@string/appbar_scrolling_view_behavior"    tools:layout="@layout/fragment_main" />

MainActivity.java

package example.androidhire.com.recyclerviewswipedeleteundo; 
import android.os.Bundle; 
import android.support.v7.app.AppCompatActivity; 
import android.support.v7.widget.Toolbar; 
public class MainActivity extends AppCompatActivity { 
   @Override protected void onCreate(Bundle savedInstanceState) { 
super.onCreate(savedInstanceState); 
setContentView(R.layout.activity_main); 
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar); 
setSupportActionBar(toolbar); 
}
} 

Create a layout regular_item.xml which appears at normal mode

regular_item.xml

<?xml version="1.0" encoding="utf-8"?>  
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
 android:id="@+id/regularLayout"  
     android:layout_width="match_parent"  
     android:layout_height="wrap_content"  
     android:orientation="vertical"  
     android:padding="@dimen/activity_horizontal_margin">  
   
     <TextView  
         android:id="@+id/list_item"  
         android:layout_width="match_parent"  
         android:layout_height="wrap_content"  
         android:text="Regular Layout"  
         android:textSize="28sp" />  
</LinearLayout>  

Create a layout swipe_item.xml which appears at the period of swipe item

swipe_item.xml

<?xml version="1.0" encoding="utf-8"?>  
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  
     android:id="@+id/swipeLayout"  
     android:layout_width="match_parent"  
     android:layout_height="wrap_content"  
     android:background="@color/swipebackground"  
     android:orientation="horizontal"  
     android:padding="@dimen/activity_horizontal_margin"  
     android:visibility="visible"  
     android:weightSum="3">  
   
     <TextView  
         android:layout_width="match_parent"  
         android:layout_height="wrap_content"  
         android:layout_weight="1"  
         android:text="@string/archived_label"  
         android:textColor="@android:color/white"  
         android:textSize="24sp" />  
   
   
     <TextView  
         android:id="@+id/undo"  
         android:layout_width="match_parent"  
         android:layout_height="wrap_content"  
         android:layout_weight="2"  
         android:gravity="end"  
         android:paddingBottom="5dp"  
         android:paddingLeft="16dp"  
         android:paddingRight="16dp"  
         android:paddingTop="5dp"  
         android:text="@string/undo_label"  
         android:textColor="@android:color/white"  
         android:textSize="22sp"  
         android:textStyle="bold" />     
 </LinearLayout>


customlayout.xml

<?xml version="1.0" encoding="utf-8"?>  
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"  
     android:layout_width="match_parent"  
     android:layout_height="wrap_content">  
     <!-- Swipe Layout-->  
     <include layout="@layout/swipe_item" />  
     <!-- Regular Layout-->  
     <include layout="@layout/regular_item" />  
</FrameLayout>  

Create a utility class SwipeUtil.java which extends the ItemTouchHelper.SimpleCallback class and overrides its onMove(), onSwiped(), onChildDraw() methods. The onSwiped() method is called when we perform swipe operation on an item, and the onChildDraw() methods contain the implementation logic of drawing canvas while swiping the items of RecyclerView.

SwipeUtil.java

1. package example.androidhire.com.recyclerviewswipedeleteundo;  
2.   
3. import android.content.Context;  
4. import android.graphics.Canvas;  
5. import android.graphics.Color;  
6. import android.graphics.Paint;  
7. import android.graphics.PorterDuff;  
8. import android.graphics.drawable.ColorDrawable;  
9. import android.graphics.drawable.Drawable;  
10. import android.support.v4.content.ContextCompat;  
11. import android.support.v7.widget.RecyclerView;  
12. import android.support.v7.widget.helper.ItemTouchHelper;  
13. import android.view.View;  
14.   
15. public abstract class SwipeUtil extends ItemTouchHelper.SimpleCallback {  
16.   
17.     private Drawable background;  
18.     private Drawable deleteIcon;  
19.     private int xMarkMargin;  
20.     private boolean initiated;  
21.     private Context context;  
22.     private int leftcolorCode;  
23.     private String leftSwipeLable;  
24.   
25.     public SwipeUtil(int dragDirs, int swipeDirs, Context context) {  
26.         super(dragDirs, swipeDirs);  
27.         this.context = context;  
28.     }  
29.   
30.     private void init() {  
31.         background = new ColorDrawable();  
32.         xMarkMargin = (int) context.getResources().getDimension(R.dimen.ic_clear_margin);  
33.         deleteIcon = ContextCompat.getDrawable(context, android.R.drawable.ic_menu_delete);  
34.         deleteIcon.setColorFilter(Color.WHITE, PorterDuff.Mode.SRC_ATOP);  
35.         initiated = true;  
36.     }  
37.   
38.     @Override  
39.     public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {  
40.         return false;  
41.     }  
42.   
43.     @Override  
44.     public abstract void onSwiped(RecyclerView.ViewHolder viewHolder, int direction);  
45.   
46.     @Override  
47.     public int getSwipeDirs(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {  
48.   
49.         return super.getSwipeDirs(recyclerView, viewHolder);  
50.     }  
51.   
52.     @Override  
53.     public void onChildDraw(Canvas c, RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder,  
54.                             float dX, float dY, int actionState, boolean isCurrentlyActive) {  
  
         View itemView = viewHolder.itemView;  
         if (!initiated) {  
             init();  
         }  
   
         int itemHeight = itemView.getBottom() - itemView.getTop();  
         //Setting Swipe Background  
        ((ColorDrawable) background).setColor(getLeftcolorCode());  
        background.setBounds(itemView.getRight() + (int) dX, itemView.getTop(), itemView.getRight(), itemView.getBottom());  
         background.draw(c);  
   
         int intrinsicWidth = deleteIcon.getIntrinsicWidth();  
        int intrinsicHeight = deleteIcon.getIntrinsicWidth();  
   
         int xMarkLeft = itemView.getRight() - xMarkMargin - intrinsicWidth;  
        int xMarkRight = itemView.getRight() - xMarkMargin;  
         int xMarkTop = itemView.getTop() + (itemHeight - intrinsicHeight) / 2;  
         int xMarkBottom = xMarkTop + intrinsicHeight;  
  
        //Setting Swipe Icon  
         deleteIcon.setBounds(xMarkLeft, xMarkTop + 16, xMarkRight, xMarkBottom);   
         deleteIcon.draw(c);  
   
         //Setting Swipe Text  
         Paint paint = new Paint();  
         paint.setColor(Color.WHITE);  
        paint.setTextSize(48);  
         paint.setTextAlign(Paint.Align.CENTER);  
         c.drawText(getLeftSwipeLable(), xMarkLeft + 40, xMarkTop + 10, paint);  
  
        super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);  
     }  
   
     public String getLeftSwipeLable() {  
         return leftSwipeLable;  
     }  
   
     public void setLeftSwipeLable(String leftSwipeLable) {  
        this.leftSwipeLable = leftSwipeLable;  
    }  
     public int getLeftcolorCode() {  
         return leftcolorCode;  
     }  
   
     public void setLeftcolorCode(int leftcolorCode) {  
         this.leftcolorCode = leftcolorCode;  
     }  
 }  

Create an ItemViewHolder.java class and extends RecyclerView.ViewHolder.

ItemViewHolder.java

1. package example.androidhire.com.recyclerviewswipedeleteundo;  
2.   
3. import android.support.v7.widget.RecyclerView;  
4. import android.view.View;  
5. import android.widget.LinearLayout;  
6. import android.widget.TextView;  
7.   
8. public class ItemViewHolder extends RecyclerView.ViewHolder {  
9.   
10.     public LinearLayout regularLayout;  
11.     public LinearLayout swipeLayout;  
12.     public TextView listItem;  
13.     public TextView undo;  
14.   
15.     public ItemViewHolder(View view) {  
16.         super(view);  
17.   
18.         regularLayout = view.findViewById(R.id.regularLayout);  
19.         listItem =  view.findViewById(R.id.list_item);  
20.         swipeLayout = view.findViewById(R.id.swipeLayout);  
21.         undo =  view.findViewById(R.id.undo);  
22.     }  
23. } 


Create an adapter class MyAdapter.java which extends the RecyclerView.Adapter class and overrides its onCreateViewHolder(), onBindViewHolder() methods.

MyAdapter.java

1. package example.androidhire.com.recyclerviewswipedeleteundo;  
2.   
3. import android.os.Handler;  
4. import android.support.v7.widget.RecyclerView;  
5. import android.view.LayoutInflater;  
6. import android.view.View;  
7. import android.view.ViewGroup;  
8. import java.util.ArrayList;  
9. import java.util.HashMap;  
10. import java.util.List;  
11.   
12. public class MyAdapter extends RecyclerView.Adapter<ItemViewHolder> {  
13.   
14.     private List<String> dataList;  
15.     private List<String> itemsPendingRemoval;  
16.   
17.     private static final int PENDING_REMOVAL_TIMEOUT = 3000; // 3sec  
18.     private Handler handler = new Handler(); // hanlder for running delayed runnables  
19.     HashMap<String, Runnable> pendingRunnables = new HashMap<>(); // map of items to pending runnable, to cancel the removal  
20.   
21.   
22.     public MyAdapter(List<String> dataList) {  
23.         this.dataList = dataList;  
24.         itemsPendingRemoval = new ArrayList<>();  
25.     }  
26.   
27.     @Override  
28.     public ItemViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {  
29.         View itemView = LayoutInflater.from(parent.getContext()).inflate(R.layout.customlayout, parent, false);  
30.         return new ItemViewHolder(itemView);  
31.     }  
32.   
33.     @Override  
34.     public void onBindViewHolder(ItemViewHolder itemViewHolder, int position) {  
35.   
36.         final String data = dataList.get(position);  
37.   
38.         if (itemsPendingRemoval.contains(data)) {  
39.             /** show swipe layout and hide regular layout */  
40.             itemViewHolder.regularLayout.setVisibility(View.GONE);  
41.             itemViewHolder.swipeLayout.setVisibility(View.VISIBLE);  
42.             itemViewHolder.undo.setOnClickListener(new View.OnClickListener() {  
43.                 @Override  
44.                 public void onClick(View v) {  
45.                     undoOpt(data);  
46.                 }  
47.             });  
48.         } else {  
49.             /** show regular layout and hide swipe layout*/  
50.             itemViewHolder.regularLayout.setVisibility(View.VISIBLE);  
51.             itemViewHolder.swipeLayout.setVisibility(View.GONE);  
52.             itemViewHolder.listItem.setText(data);  
53.         }  
54.     }  
55.   
56.     private void undoOpt(String customer) {  
57.         Runnable pendingRemovalRunnable = pendingRunnables.get(customer);  
58.         pendingRunnables.remove(customer);  
59.         if (pendingRemovalRunnable != null)  
60.             handler.removeCallbacks(pendingRemovalRunnable);  
61.         itemsPendingRemoval.remove(customer);  
62.         // this will rebind the row in "normal" state  
63.         notifyItemChanged(dataList.indexOf(customer));  
64.     }  
65.   
66.     @Override  
67.     public int getItemCount() {  
68.         return dataList.size();  
69.     }  
70.   
71.     public void pendingRemoval(int position) {  
72.   
73.         final String data = dataList.get(position);  
74.         if (!itemsPendingRemoval.contains(data)) {  
75.             itemsPendingRemoval.add(data);  
76.             // this will redraw row in "undo" state  
77.             notifyItemChanged(position);  
78.             //create, store and post a runnable to remove the data  
79.             Runnable pendingRemovalRunnable = new Runnable() {  
80.                 @Override  
81.                 public void run() {  
82.                     remove(dataList.indexOf(data));  
83.                 }  
84.             };  
85.             handler.postDelayed(pendingRemovalRunnable, PENDING_REMOVAL_TIMEOUT);  
86.             pendingRunnables.put(data, pendingRemovalRunnable);  
87.         }  
88.     }  
89.   
90.     public void remove(int position) {  
91.         String data = dataList.get(position);  
92.         if (itemsPendingRemoval.contains(data)) {  
93.             itemsPendingRemoval.remove(data);  
94.         }  
95.         if (dataList.contains(data)) {  
96.             dataList.remove(position);  
97.             notifyItemRemoved(position);  
98.         }  
99.     }  
100.   
101.     public boolean isPendingRemoval(int position) {  
102.         String data = dataList.get(position);  
103.         return itemsPendingRemoval.contains(data);  
104.     }  
105. }  


Create a MainActivityFragment.java class and extends the Fragment class. In this class, set the adapter MyAdapter.java class and utility SwipeUtil.java class.

fragment_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"  
     xmlns:tools="http://schemas.android.com/tools"  
     android:layout_width="match_parent"  
     android:layout_height="match_parent"  
     android:paddingBottom="@dimen/activity_vertical_margin"  
     android:paddingLeft="@dimen/activity_horizontal_margin"  
     android:paddingRight="@dimen/activity_horizontal_margin"  
     android:paddingTop="@dimen/activity_vertical_margin"  
     tools:context="example.androidhire.com.recyclerviewswipedeleteundo.MainActivityFragment"  
     tools:showIn="@layout/activity_main">  
   
     <android.support.v7.widget.RecyclerView  
         android:id="@+id/recyclerView"  
         android:layout_width="match_parent"  
         android:layout_height="match_parent"/>  
 </RelativeLayout> 

MainActivityFragment.java

	package example.androidhire.com.recyclerviewswipedeleteundo;  
	  
	import android.support.v4.app.Fragment;  
	import android.os.Bundle;  
	import android.support.v4.content.ContextCompat;  
	import android.support.v7.widget.LinearLayoutManager;  
	import android.support.v7.widget.RecyclerView;  
	import android.support.v7.widget.helper.ItemTouchHelper;  
	import android.view.LayoutInflater;  
	import android.view.View;  
	import android.view.ViewGroup;  
	import java.util.ArrayList;  
	import java.util.List;  
	  
	public class MainActivityFragment extends Fragment {  
	  
	    private RecyclerView mRecyclerView;  
	    private MyAdapter myAdapter;  
	    String[] listValue = {"C Tutorial","C++ Tutorial","Data Structure","Java Tutorial","Android Example","Kotlin Programing","Python language","Ruby Tutorial",".Net Tutorial","MySQL Database"};  
	    public MainActivityFragment() {  
	    }  
	  
	    @Override  
	    public View onCreateView(LayoutInflater inflater, ViewGroup container,  
	                             Bundle savedInstanceState) {  
	        View mView = inflater.inflate(R.layout.fragment_main, container, false);  
	        mRecyclerView = mView.findViewById(R.id.recyclerView);  
	        return mView;  
	    }  
	  
	    @Override  
	    public void onResume() {  
	        super.onResume();  
	        LinearLayoutManager linearLayoutManager = new LinearLayoutManager(getActivity());  
	        linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);  
	        mRecyclerView.setLayoutManager(linearLayoutManager);  
	        myAdapter = new MyAdapter(getData());  
	        mRecyclerView.setAdapter(myAdapter);  
	  
	        setSwipeForRecyclerView();  
	    }  
	  
	    private List&lt;String&gt; getData() {  
	        List&lt;String&gt; modelList = new ArrayList&lt;&gt;();  
	        for (int i = 0; i &lt; listValue.length; i++) {  
	            modelList.add(listValue[i]);  
	        }  
	        return modelList;  
	    }  
	  
	    private void setSwipeForRecyclerView() {  
	  
	        SwipeUtil swipeHelper = new SwipeUtil(0, ItemTouchHelper.LEFT, getActivity()) {  
	            @Override  
	            public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {  
	                int swipedPosition = viewHolder.getAdapterPosition();  
	                myAdapter = (MyAdapter)mRecyclerView.getAdapter();  
	                myAdapter.pendingRemoval(swipedPosition);  
	            }  
	  
	            @Override  
	            public int getSwipeDirs(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder) {  
	                int position = viewHolder.getAdapterPosition();  
	                myAdapter = (MyAdapter) mRecyclerView.getAdapter();  
	               if (myAdapter.isPendingRemoval(position)) {  
	                     return 0;  
	                }  
	                return super.getSwipeDirs(recyclerView, viewHolder);  
	            }  
	        }; 	  
	        ItemTouchHelper mItemTouchHelper = new ItemTouchHelper(swipeHelper);  
	        mItemTouchHelper.attachToRecyclerView(mRecyclerView);  
	        //set swipe label  
	        swipeHelper.setLeftSwipeLable("Archive");  
	        //set swipe background-Color  
	        swipeHelper.setLeftcolorCode(ContextCompat.getColor(getActivity(), R.color.swipebackground));  
	    }  
}

strings.xml

<resources>  
     <string name="app_name">RecyclerView SwipeDeleteUndo</string>  
     <string name="action_settings">Settings</string>  
     <string name="hello_blank_fragment">Hello blank fragment</string>  
     <string name="undo_label"><u>Undo</u></string>  
     <string name="archived_label">Archive</string>  
</resources>

dimens.xml

<resources>  
<dimen name="fab_margin">16dp</dimen>  
     <dimen name="activity_horizontal_margin">16dp</dimen>  
     <dimen name="activity_vertical_margin">16dp</dimen>  
     <dimen name="ic_clear_margin">56dp</dimen>  
     <dimen name="text_size_medium">20sp</dimen>  
</resources> 

colors.xml

<?xml version="1.0" encoding="utf-8"?>  
<resources>  
<color name="colorPrimary">#3F51B5</color>  
<color name="colorPrimaryDark">#303F9F</color>  
<color name="colorAccent">#FF4081</color>  
<color name="swipebackground">#cf0b4e</color>  
</resources>  

Outputs:

Final Words

So from the above code you would be able to implement the feature of Swipe to Delete RecyclerView items with UNDO in your android application

Ritesh Rai

Ritesh Rai

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