ability to remove a category

app/src/main/java/org/foxarmy/barcodescannerforemployees/DBStorageController.kt

@@ -62,7 +62,51 @@ class DBStorageController(context: Context) : SQLiteOpenHelper(context, DATABASE
         TODO("Not yet implemented")
     }
 
-    public fun eraseAbstractProduct(db: SQLiteDatabase, id: Int, context: Context) {
+    fun eraseCategory (db: SQLiteDatabase, id: Int, context: Context) {
+        val productsInCategory = getAllAbstractProductInCategory(db, id)
+
+        for (product in productsInCategory.iterator()) {
+            eraseAbstractProduct(db, product.id, context)
+        }
+
+        db.delete(CategoriesContract.CategoryEntry.TABLE_NAME, BaseColumns._ID + "=" + id, null)
+    }
+
+    fun getAllAbstractProductInCategory(db: SQLiteDatabase, id: Int) : List<AbstractProduct> {
+
+        var result = mutableListOf<AbstractProduct>()
+        val projection = arrayOf(
+            BaseColumns._ID,
+            ProductContract.ProductEntry.PRODUCT_NAME,
+            ProductContract.ProductEntry.IMAGE_FILENAME,
+            ProductContract.ProductEntry.PRODUCT_NET_WEIGHT,
+        )
+
+        val selection = "${ProductContract.ProductEntry.CATEGORY} = ?"
+        val selectionArgs = arrayOf(id.toString())
+
+        val cursor = db.query(ProductContract.ProductEntry.TABLE_NAME, projection, selection, selectionArgs, null, null, null)
+
+        with(cursor) {
+            while (moveToNext()) {
+                val abstractProductId = getInt(getColumnIndexOrThrow(BaseColumns._ID))
+                val abstractProductName = getString(getColumnIndexOrThrow(ProductContract.ProductEntry.PRODUCT_NAME))
+                val abstractProductNetWeight = getDouble(getColumnIndexOrThrow(ProductContract.ProductEntry.PRODUCT_NET_WEIGHT))
+                val abstractProductImageHash = getString(getColumnIndexOrThrow(ProductContract.ProductEntry.IMAGE_FILENAME))
+
+                val abstractProduct = AbstractProduct(
+                    abstractProductId, abstractProductName, abstractProductNetWeight, abstractProductImageHash,
+                    categoryName = ""
+                )
+
+                result.add(abstractProduct)
+            }
+        }
+
+        return result
+    }
+
+    fun eraseAbstractProduct(db: SQLiteDatabase, id: Int, context: Context) {
         val projection = arrayOf(
             ProductContract.ProductEntry.IMAGE_FILENAME
         )

app/src/main/java/org/foxarmy/barcodescannerforemployees/views/CategoryView.kt

@@ -1,7 +1,9 @@
 package org.foxarmy.barcodescannerforemployees.views
 
 import android.app.Activity
+import android.app.AlertDialog
 import android.content.Context
+import android.content.DialogInterface
 import android.content.Intent
 import android.os.Bundle
 import android.view.LayoutInflater
@@ -10,6 +12,7 @@ import android.widget.LinearLayout
 import android.widget.TextView
 import androidx.core.content.ContextCompat
 import org.foxarmy.barcodescannerforemployees.Category
+import org.foxarmy.barcodescannerforemployees.DBStorageController
 import org.foxarmy.barcodescannerforemployees.R
 import org.foxarmy.barcodescannerforemployees.activities.AddCategoryActivity
 
@@ -41,7 +44,16 @@ class CategoryView : LinearLayout {
         }
 
         deleteButton.setOnClickListener {
-            TODO("implement delete button")
+            val builder = AlertDialog.Builder(context)
+                .setMessage("Deleting this category will also delete ALL the products, that belong to that category. Do you want to proceed?")
+                .setPositiveButton("Yes") { _: DialogInterface, _: Int ->
+                    val db = DBStorageController(context).writableDatabase
+                    DBStorageController(context).eraseCategory(db, category.id, context)
+
+                }
+                .setNegativeButton("No") { _: DialogInterface, _: Int ->
+
+                }.show()
         }
     }
 }