Adds swipe to delete monsters on the library screen.

app/src/main/java/com/majinnaibu/monstercards/ui/MonsterListRecyclerViewAdapter.java

@@ -110,4 +110,10 @@ public class MonsterListRecyclerViewAdapter extends RecyclerView.Adapter<Monster
         }
     }
 
+    public void deleteItem(int position) {
+        if (mOnDelete != null) {
+            Monster monster = mValues.get(position);
+            mOnDelete.onItem(monster);
+        }
+    }
 }

app/src/main/java/com/majinnaibu/monstercards/ui/library/LibraryFragment.java

@@ -1,13 +1,22 @@
 package com.majinnaibu.monstercards.ui.library;
 
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.Paint;
+import android.graphics.PorterDuff;
+import android.graphics.PorterDuffXfermode;
+import android.graphics.drawable.ColorDrawable;
+import android.graphics.drawable.Drawable;
 import android.os.Bundle;
 import android.view.LayoutInflater;
 import android.view.View;
 import android.view.ViewGroup;
 
 import androidx.annotation.NonNull;
+import androidx.core.content.ContextCompat;
 import androidx.navigation.NavDirections;
 import androidx.navigation.Navigation;
+import androidx.recyclerview.widget.ItemTouchHelper;
 import androidx.recyclerview.widget.LinearLayoutManager;
 import androidx.recyclerview.widget.RecyclerView;
 
@@ -71,10 +80,19 @@ public class LibraryFragment extends MCFragment {
                 this,
                 repository.getMonsters(),
                 (monster) -> {
+                    repository
+                            .deleteMonster(monster)
+                            .subscribeOn(Schedulers.io())
+                            .observeOn(AndroidSchedulers.mainThread())
+                            .subscribe(() -> {
+                                Logger.logDebug("deleted");
+                            }, Logger::logError);
                 },
                 mTwoPane);
         recyclerView.setAdapter(adapter);
         recyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
+        ItemTouchHelper itemTouchHelper = new ItemTouchHelper(new SwipeToDeleteMonsterCallback(adapter));
+        itemTouchHelper.attachToRecyclerView(recyclerView);
     }
 
     protected void navigateToMonsterDetail(UUID monsterId) {
@@ -82,5 +100,60 @@ public class LibraryFragment extends MCFragment {
         Navigation.findNavController(getView()).navigate(action);
     }
 
+    public static class SwipeToDeleteMonsterCallback extends ItemTouchHelper.SimpleCallback {
+        private final MonsterListRecyclerViewAdapter mAdapter;
+        private final Drawable icon;
+        private final ColorDrawable background;
+        private final Paint clearPaint;
+
+        public SwipeToDeleteMonsterCallback(MonsterListRecyclerViewAdapter adapter) {
+            super(0, ItemTouchHelper.LEFT);
+            mAdapter = adapter;
+            icon = ContextCompat.getDrawable(mAdapter.getContext(), R.drawable.ic_delete_white_36);
+            background = new ColorDrawable(Color.RED);
+            clearPaint = new Paint();
+            clearPaint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.CLEAR));
+        }
+
+        @Override
+        public boolean onMove(@NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, @NonNull RecyclerView.ViewHolder target) {
+            return false;
+        }
+
+        @Override
+        public void onSwiped(@NonNull RecyclerView.ViewHolder viewHolder, int direction) {
+            int position = viewHolder.getAdapterPosition();
+            mAdapter.deleteItem(position);
+        }
+
+        @Override
+        public void onChildDraw(@NonNull Canvas c, @NonNull RecyclerView recyclerView, @NonNull RecyclerView.ViewHolder viewHolder, float dX, float dY, int actionState, boolean isCurrentlyActive) {
+            View itemView = viewHolder.itemView;
+            int itemHeight = itemView.getBottom() - itemView.getTop();
+            boolean isCancelled = dX == 0 && !isCurrentlyActive;
+
+            if (isCancelled) {
+                c.drawRect(itemView.getRight() + dX, itemView.getTop(), itemView.getRight(), itemView.getBottom(), clearPaint);
+                return;
+            }
+            // Draw the red delete background
+            background.setBounds(itemView.getRight() + (int) dX, itemView.getTop(), itemView.getRight(), itemView.getBottom());
+            background.draw(c);
+
+            // Calculate position of delete icon
+            int iconHeight = icon.getIntrinsicHeight();
+            int iconWidth = icon.getIntrinsicWidth();
+            int iconTop = itemView.getTop() + (itemHeight - iconHeight) / 2;
+            int iconMargin = (itemHeight - iconHeight) / 2;
+            int iconLeft = itemView.getRight() - iconMargin - iconWidth;
+            int iconRight = itemView.getRight() - iconMargin;
+            int iconBottom = iconTop + iconHeight;
+
+            // Draw the icon
+            icon.setBounds(iconLeft, iconTop, iconRight, iconBottom);
+            icon.draw(c);
+
+            super.onChildDraw(c, recyclerView, viewHolder, dX, dY, actionState, isCurrentlyActive);
+        }
     }
 }

app/src/main/res/drawable/ic_delete_white_36.xml

@@ -0,0 +1,5 @@
+<vector android:height="24dp" android:tint="#FFFFFF"
+    android:viewportHeight="24" android:viewportWidth="24"
+    android:width="24dp" xmlns:android="http://schemas.android.com/apk/res/android">
+    <path android:fillColor="@android:color/white" android:pathData="M6,19c0,1.1 0.9,2 2,2h8c1.1,0 2,-0.9 2,-2V7H6v12zM19,4h-3.5l-1,-1h-5l-1,1H5v2h14V4z"/>
+</vector>

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

@@ -0,0 +1,20 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="wrap_content"
+    android:layout_height="wrap_content"
+    android:orientation="horizontal">
+
+    <TextView
+        android:id="@+id/id_text"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_margin="@dimen/text_margin"
+        android:textAppearance="?attr/textAppearanceListItem" />
+
+    <TextView
+        android:id="@+id/content"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_margin="@dimen/text_margin"
+        android:textAppearance="?attr/textAppearanceListItem" />
+</LinearLayout>

app/src/main/res/values/colors.xml

@@ -2,5 +2,6 @@
 <resources>
     <color name="colorPrimary">#9B2818</color>
     <color name="colorPrimaryDark">#661A10</color>
-    <color name="colorAccent">#188B9B</color>
+    <!--    <color name="colorAccent">#188B9B</color>-->
+    <color name="colorAccent">#995500</color>
 </resources>

app/src/main/res/values/dimens.xml

@@ -2,4 +2,7 @@
     <!-- Default screen margins, per the Android Design guidelines. -->
     <dimen name="activity_horizontal_margin">16dp</dimen>
     <dimen name="activity_vertical_margin">16dp</dimen>
+    <dimen name="text_margin">16dp</dimen>
+    <dimen name="fab_margin">16dp</dimen>
+
 </resources>