Add Swife To Delete Tutorial Android

In the 3rd video of the SQLite tutorial, we will add an ItemTouchHelper to our RecyclerView and delete entries from our SQLite database by swiping them off our list.

Links & Dependencies
MainActivity.java
GroceryAdapter.java
activity_main.xml
grocery_item.xml
GroceryContract.java
GroceryDBHelper.java

package com.example.application.grocerylist;  import android.content.ContentValues; import android.database.Cursor; import android.database.sqlite.SQLiteDatabase; import android.support.v7.app.AppCompatActivity; import android.os.Bundle; import android.support.v7.widget.LinearLayoutManager; import android.support.v7.widget.RecyclerView; import android.support.v7.widget.helper.ItemTouchHelper; import android.view.View; import android.widget.Button; import android.widget.EditText; import android.widget.TextView;  public class MainActivity extends AppCompatActivity {     private SQLiteDatabase mDatabase;     private GroceryAdapter mAdapter;     private EditText mEditTextName;     private TextView mTextViewAmount;     private int mAmount = 0;      @Override     protected void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.activity_main);          GroceryDBHelper dbHelper = new GroceryDBHelper(this);         mDatabase = dbHelper.getWritableDatabase();          RecyclerView recyclerView = findViewById(R.id.recyclerview);         recyclerView.setLayoutManager(new LinearLayoutManager(this));         mAdapter = new GroceryAdapter(this, getAllItems());         recyclerView.setAdapter(mAdapter);          new ItemTouchHelper(new ItemTouchHelper.SimpleCallback(0,                 ItemTouchHelper.LEFT | ItemTouchHelper.RIGHT) {             @Override             public boolean onMove(RecyclerView recyclerView, RecyclerView.ViewHolder viewHolder, RecyclerView.ViewHolder target) {                 return false;             }              @Override             public void onSwiped(RecyclerView.ViewHolder viewHolder, int direction) {                 removeItem((long) viewHolder.itemView.getTag());             }         }).attachToRecyclerView(recyclerView);          mEditTextName = findViewById(R.id.edittext_name);         mTextViewAmount = findViewById(R.id.textview_amount);          Button buttonIncrease = findViewById(R.id.button_increase);         Button buttonDecrease = findViewById(R.id.button_decrease);         Button buttonAdd = findViewById(R.id.button_add);          buttonIncrease.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View v) {                 increase();             }         });          buttonDecrease.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View v) {                 decrease();             }         });          buttonAdd.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View v) {                 addItem();             }         });     }      private void increase() {         mAmount++;         mTextViewAmount.setText(String.valueOf(mAmount));     }      private void decrease() {         if (mAmount > 0) {             mAmount--;             mTextViewAmount.setText(String.valueOf(mAmount));         }     }      private void addItem() {          if (mEditTextName.getText().toString().trim().length() == 0 || mAmount == 0) {             return;         }          String name = mEditTextName.getText().toString();         ContentValues cv = new ContentValues();         cv.put(GroceryContract.GroceryEntry.COLUMN_NAME, name);         cv.put(GroceryContract.GroceryEntry.COLUMN_AMOUNT, mAmount);          mDatabase.insert(GroceryContract.GroceryEntry.TABLE_NAME, null, cv);         mAdapter.swapCursor(getAllItems());          mEditTextName.getText().clear();     }      private void removeItem(long id) {         mDatabase.delete(GroceryContract.GroceryEntry.TABLE_NAME,                 GroceryContract.GroceryEntry._ID + "=" + id, null);         mAdapter.swapCursor(getAllItems());     }      private Cursor getAllItems() {         return mDatabase.query(                 GroceryContract.GroceryEntry.TABLE_NAME,                 null,                 null,                 null,                 null,                 null,                 GroceryContract.GroceryEntry.COLUMN_TIMESTAMP + " DESC"         );     } }

package com.example.application.grocerylist;  import android.content.Context; import android.database.Cursor; import android.support.v7.widget.RecyclerView; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.TextView;  public class GroceryAdapter extends RecyclerView.Adapter<GroceryAdapter.GroceryViewHolder> {     private Context mContext;     private Cursor mCursor;      public GroceryAdapter(Context context, Cursor cursor) {         mContext = context;         mCursor = cursor;     }      public class GroceryViewHolder extends RecyclerView.ViewHolder {         public TextView nameText;         public TextView countText;          public GroceryViewHolder(View itemView) {             super(itemView);              nameText = itemView.findViewById(R.id.textview_name_item);             countText = itemView.findViewById(R.id.textview_amount_item);         }     }      @Override     public GroceryViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {         LayoutInflater inflater = LayoutInflater.from(mContext);         View view = inflater.inflate(R.layout.grocery_item, parent, false);         return new GroceryViewHolder(view);     }      @Override     public void onBindViewHolder(GroceryViewHolder holder, int position) {         if (!mCursor.moveToPosition(position)) {             return;         }          String name = mCursor.getString(mCursor.getColumnIndex(GroceryContract.GroceryEntry.COLUMN_NAME));         int amount = mCursor.getInt(mCursor.getColumnIndex(GroceryContract.GroceryEntry.COLUMN_AMOUNT));         long id = mCursor.getLong(mCursor.getColumnIndex(GroceryContract.GroceryEntry._ID));          holder.nameText.setText(name);         holder.countText.setText(String.valueOf(amount));         holder.itemView.setTag(id);     }      @Override     public int getItemCount() {         return mCursor.getCount();     }      public void swapCursor(Cursor newCursor) {         if (mCursor != null) {             mCursor.close();         }          mCursor = newCursor;          if (newCursor != null) {             notifyDataSetChanged();         }     } }

<?xml version="1.0" encoding="utf-8"?> <RelativeLayout 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:padding="16dp"     tools:context="com.example.application.grocerylist.MainActivity">      <EditText         android:id="@+id/edittext_name"         android:layout_width="match_parent"         android:layout_height="wrap_content" />      <TextView         android:id="@+id/textview_amount"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_below="@+id/edittext_name"         android:layout_centerHorizontal="true"         android:layout_margin="8dp"         android:text="0"         android:textSize="50sp" />      <Button         android:id="@+id/button_decrease"         android:layout_width="50dp"         android:layout_height="wrap_content"         android:layout_alignTop="@+id/textview_amount"         android:layout_alignBottom="@+id/textview_amount"         android:layout_toStartOf="@+id/textview_amount"         android:text="-" />      <Button         android:id="@+id/button_increase"         android:layout_width="50dp"         android:layout_height="wrap_content"         android:layout_alignTop="@+id/textview_amount"         android:layout_alignBottom="@+id/textview_amount"         android:layout_toEndOf="@+id/textview_amount"         android:text="+" />      <Button         android:id="@+id/button_add"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_alignTop="@+id/button_increase"         android:layout_alignBottom="@+id/button_increase"         android:layout_marginStart="8dp"         android:layout_toEndOf="@+id/button_increase"         android:text="add" />      <android.support.v7.widget.RecyclerView         android:id="@+id/recyclerview"         android:layout_width="match_parent"         android:layout_height="match_parent"         android:layout_below="@+id/textview_amount" />  </RelativeLayout>

<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"     android:layout_width="match_parent"     android:layout_height="wrap_content"     android:layout_margin="8dp">      <TextView         android:id="@+id/textview_amount_item"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:text="0"         android:textSize="30sp" />      <TextView         android:id="@+id/textview_name_item"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:layout_marginStart="8dp"         android:text="Empty Item"         android:textSize="30sp" />  </LinearLayout>

package com.example.application.grocerylist;  import android.provider.BaseColumns;  public class GroceryContract {      private GroceryContract() {     }      public static final class GroceryEntry implements BaseColumns {         public static final String TABLE_NAME = "groceryList";         public static final String COLUMN_NAME = "name";         public static final String COLUMN_AMOUNT = "amount";         public static final String COLUMN_TIMESTAMP = "timestamp";     } }

package com.example.application.grocerylist;  import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.database.sqlite.SQLiteOpenHelper;  import com.example.application.grocerylist.GroceryContract.*;   public class GroceryDBHelper extends SQLiteOpenHelper {     public static final String DATABASE_NAME = "grocerylist.db";     public static final int DATABASE_VERSION = 1;      public GroceryDBHelper(Context context) {         super(context, DATABASE_NAME, null, DATABASE_VERSION);     }      @Override     public void onCreate(SQLiteDatabase db) {         final String SQL_CREATE_GROCERYLIST_TABLE = "CREATE TABLE " +                 GroceryEntry.TABLE_NAME + " (" +                 GroceryEntry._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +                 GroceryEntry.COLUMN_NAME + " TEXT NOT NULL, " +                 GroceryEntry.COLUMN_AMOUNT + " INTEGER Not NULL, " +                 GroceryEntry.COLUMN_TIMESTAMP + " TIMESTAMP DEFAULT CURRENT_TIMESTAMP" +                 ");";          db.execSQL(SQL_CREATE_GROCERYLIST_TABLE);     }      @Override     public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {         db.execSQL("Anjlok TABLE IF EXISTS " + GroceryEntry.TABLE_NAME);         onCreate(db);     } }

Source: https://codinginflow.com/tutorials/android/sqlite-recyclerview/part-3-swipe-to-delete