Allow user to delete single entry from database

* Also display a drawable on empty database

Signed-off-by: Adam Myczkowski <mycaxd511@gmail.com>

app/src/main/java/com/luckynumbers/mycax/luckynumbers/DataB.java

@@ -62,7 +62,6 @@ public void ReadDB(Context context, ListView listView) {
         }
 
         SimpleCursorAdapter adapter = new SimpleCursorAdapter(context, R.layout.row, cursor, from, to, 0);
-        adapter.notifyDataSetChanged();
 
         listView.setAdapter(adapter);
         database.close();
@@ -74,4 +73,9 @@ public void clearDatabase() {
         String clearDBQuery = "DELETE FROM "+RESULTS_TABLE_NAME;
         sqLiteDatabase.execSQL(clearDBQuery);
     }
+
+    public void deleteEntry(long row) {
+        SQLiteDatabase sqLiteDatabase = getWritableDatabase();
+        sqLiteDatabase.delete(RESULTS_TABLE_NAME, RESULTS_COLUMN_ID + "=" + row, null);
+    }
 }

app/src/main/java/com/luckynumbers/mycax/luckynumbers/ResultsFragment.java

@@ -1,13 +1,17 @@
 package com.luckynumbers.mycax.luckynumbers;
 
+import android.app.AlertDialog;
 import android.app.Fragment;
+import android.content.DialogInterface;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
+import android.widget.AdapterView;
+import android.widget.ImageView;
 import android.widget.ListView;
 
-public class ResultsFragment extends Fragment {
+public class ResultsFragment extends Fragment implements ListView.OnItemLongClickListener {
 
     private ListView listView;
 
@@ -19,7 +23,31 @@ public View onCreateView(LayoutInflater inflater, ViewGroup container,
         listView = (ListView) view.findViewById(R.id.contentlist);
         DataB database = new DataB(getActivity());
         database.ReadDB(getActivity(), listView);
+        ImageView imageView = (ImageView) view.findViewById(R.id.imageView);
+        listView.setEmptyView(imageView);
+        listView.setOnItemLongClickListener(this);
         return view;
     }
 
+    @Override
+    public boolean onItemLongClick(AdapterView<?> adapter, View v, int position, final long id) {
+        new AlertDialog.Builder(getActivity())
+                .setIcon(R.drawable.ic_warning_black_24dp)
+                .setTitle("Delete result")
+                .setMessage("Are you sure you want delete this result?")
+                .setPositiveButton("Yes", new DialogInterface.OnClickListener()
+                {
+                    @Override
+                    public void onClick(DialogInterface dialog, int which) {
+                        DataB database = new DataB(getActivity());
+                        database.deleteEntry(id);
+                        database.ReadDB(getActivity(), listView);
+                    }
+
+                })
+                .setNegativeButton("No", null)
+                .show();
+        return true;
+    }
+
 }

app/src/main/res/drawable/ic_sort_light_grey_24dp.xml

@@ -0,0 +1,9 @@
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#bdbdbd"
+        android:pathData="M3,18h6v-2L3,16v2zM3,6v2h18L21,6L3,6zM3,13h12v-2L3,11v2z"/>
+</vector>

app/src/main/res/layout/fragment_results.xml

@@ -1,10 +1,18 @@
 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
     android:orientation="vertical"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent">
     <ListView
         android:id="@+id/contentlist"
         android:layout_width="fill_parent"
         android:layout_height="fill_parent" />
+
+    <ImageView
+        android:id="@+id/imageView"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:layout_gravity="center"
+        app:srcCompat="@drawable/ic_sort_light_grey_24dp" />
 </LinearLayout>

app/src/main/res/layout/row.xml

@@ -1,8 +1,8 @@
 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
-android:orientation="vertical"
-android:layout_width="fill_parent"
-android:layout_height="fill_parent">
+    android:orientation="vertical"
+    android:layout_width="fill_parent"
+    android:layout_height="fill_parent">
     <!-- A CardView that contains a TextView -->
     <android.support.v7.widget.CardView xmlns:card_view="http://schemas.android.com/apk/res-auto"
         android:id="@+id/card_view"