Create checkboxes dropdown component

app/src/main/java/com/beemdevelopment/aegis/ui/components/DropdownCheckBoxes.java

@@ -0,0 +1,175 @@
+package com.beemdevelopment.aegis.ui.components;
+
+import android.content.Context;
+import android.content.res.TypedArray;
+import android.text.InputType;
+import android.util.AttributeSet;
+import android.view.LayoutInflater;
+import android.view.View;
+import android.view.ViewGroup;
+import android.widget.BaseAdapter;
+import android.widget.CheckBox;
+import android.widget.Filter;
+import android.widget.Filterable;
+
+import androidx.annotation.PluralsRes;
+import androidx.appcompat.widget.AppCompatAutoCompleteTextView;
+
+import com.beemdevelopment.aegis.R;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Set;
+import java.util.TreeSet;
+import java.util.stream.Collectors;
+
+public class DropdownCheckBoxes extends AppCompatAutoCompleteTextView {
+    private @PluralsRes int _selectedCountPlural = R.plurals.dropdown_checkboxes_default_count;
+
+    private boolean _allowFiltering = false;
+
+    private final List<String> _items = new ArrayList<>();
+    private List<String> _visibleItems = new ArrayList<>();
+    private final Set<String> _checkedItems = new TreeSet<>();
+
+    private CheckboxAdapter _adapter;
+
+    public DropdownCheckBoxes(Context context) {
+        super(context);
+        initialise(context, null);
+    }
+
+    public DropdownCheckBoxes(Context context, AttributeSet attrs) {
+        super(context, attrs);
+        initialise(context, attrs);
+    }
+
+    public DropdownCheckBoxes(Context context, AttributeSet attrs, int defStyleAttr) {
+        super(context, attrs, defStyleAttr);
+        initialise(context, attrs);
+    }
+
+    private void initialise(Context context, AttributeSet attrs) {
+        _adapter = new CheckboxAdapter();
+        setAdapter(_adapter);
+
+        if (attrs != null) {
+            TypedArray a = context.obtainStyledAttributes(
+                    attrs,
+                    R.styleable.DropdownCheckBoxes,
+                    0, 0);
+
+            _allowFiltering = a.getBoolean(R.styleable.DropdownCheckBoxes_allow_filtering, false);
+            a.recycle();
+        }
+
+        if (!_allowFiltering) {
+            setInputType(0);
+        } else {
+            setInputType(InputType.TYPE_CLASS_TEXT);
+        }
+    }
+
+    public void addItems(List<String> items, boolean startChecked) {
+        _items.addAll(items);
+        _visibleItems.addAll(items);
+
+        if (startChecked) {
+            _checkedItems.addAll(items);
+        }
+
+        updateCheckedItemsCountText();
+        _adapter.notifyDataSetChanged();
+    }
+
+    private void updateCheckedItemsCountText() {
+        if (_allowFiltering) {
+            return;
+        }
+
+        int count = _checkedItems.size();
+        String countString = getResources().getQuantityString(_selectedCountPlural, count, count);
+
+        setText(countString, false);
+    }
+
+    public void setCheckedItemsCountTextRes(@PluralsRes int resId) {
+        _selectedCountPlural = resId;
+    }
+
+    public Set<String> getCheckedItems() {
+        return _checkedItems;
+    }
+
+    private class CheckboxAdapter extends BaseAdapter implements Filterable {
+
+        @Override
+        public int getCount() {
+            return _visibleItems.size();
+        }
+
+        @Override
+        public String getItem(int i) {
+            return _visibleItems.get(i);
+        }
+
+        @Override
+        public long getItemId(int i) {
+            return i;
+        }
+
+        @Override
+        public View getView(int i, View convertView, ViewGroup viewGroup) {
+            if (convertView == null) {
+                convertView = LayoutInflater.from(getContext()).inflate(R.layout.dropdown_checkbox, viewGroup, false);
+            }
+
+            String item = _visibleItems.get(i);
+
+            CheckBox checkBox = convertView.findViewById(R.id.checkbox_in_dropdown);
+            checkBox.setText(item);
+            checkBox.setChecked(_checkedItems.contains(item));
+
+            checkBox.setOnCheckedChangeListener((buttonView, isChecked) -> {
+                String label = buttonView.getText().toString();
+
+                if (isChecked) {
+                    _checkedItems.add(label);
+                } else {
+                    _checkedItems.remove(label);
+                }
+
+                updateCheckedItemsCountText();
+            });
+
+            return convertView;
+        }
+
+        @Override
+        public Filter getFilter() {
+            return new Filter() {
+                @Override
+                protected FilterResults performFiltering(CharSequence query) {
+                    FilterResults results = new FilterResults();
+                    results.values = (query == null || query.toString().isEmpty())
+                                   ? _items
+                                   : _items.stream().filter(str -> {
+                                                        String q = query.toString().toLowerCase();
+                                                        String strLower = str.toLowerCase();
+
+                                                        return strLower.contains(q);
+                                                    })
+                                                    .collect(Collectors.toList());
+
+                    return results;
+                }
+
+                @Override
+                protected void publishResults(CharSequence charSequence, FilterResults filterResults) {
+                    _visibleItems = (List<String>) filterResults.values;
+                    notifyDataSetChanged();
+                }
+            };
+        }
+    }
+}

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

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.appcompat.widget.LinearLayoutCompat xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent">
+
+    <CheckBox
+        android:id="@+id/checkbox_in_dropdown"
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:buttonTint="@color/colorSecondary"/>
+
+</androidx.appcompat.widget.LinearLayoutCompat>

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

@@ -19,4 +19,8 @@
         <attr name="dot_color" format="color" />
         <attr name="dot_color_selected" format="color" />
     </declare-styleable>
+
+    <declare-styleable name="DropdownCheckBoxes">
+        <attr name="allow_filtering" format="boolean" />
+    </declare-styleable>
 </resources>

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

@@ -500,4 +500,9 @@
         <item quantity="one">%d year ago</item>
         <item quantity="other">%d years ago</item>
     </plurals>
+
+    <plurals name="dropdown_checkboxes_default_count">
+        <item quantity="one">%d item selected</item>
+        <item quantity="other">%d items selected</item>
+    </plurals>
 </resources>