ITブログ時々なんでもブログ

２．派生コントロールの実装

using Xamarin.Forms;
namespace AppName.Controls
{
    public class BaseImageCell : ImageCell
    {
        public BaseImageCell() : base()
        {
        }

        public static readonly BindableProperty FontFamilyProperty =
        BindableProperty.Create("FontFamily",
                                typeof(string),
                                typeof(BaseImageCell),
                                Font.Default.FontFamily);

        public string FontFamily
        {
            get { return (string)GetValue(FontFamilyProperty); }
            set { SetValue(FontFamilyProperty, value); }
        }
    }
}

３．Androidの実装方法

using System;
using Android.Content;
using Android.Views;
using Android.Widget;
using Android.Graphics;
using Xamarin.Forms.Platform.Android;
using Xamarin.Forms;
using AppName.Droid.Renderer;
using AppName.Controls;
[assembly: ExportRenderer(typeof(BaseImageCell), typeof(CustomImageCellRenderer))]
namespace AppName.Droid.Renderer
{
    public class CustomImageCellRenderer : ImageCellRenderer
    {
        //Fontを使いまわす為
        private static Typeface _font = null;

        protected override global::Android.Views.View GetCellCore(Cell item, global::Android.Views.View convertView, ViewGroup parent, Context context)
        {
            var cell = (BaseCellView)base.GetCellCore(item, convertView, parent, context);
            if (cell != null)
            {
                //ImageCellの内部のTextViewを取得する
                var linear = (LinearLayout)cell.GetChildAt(1);
                var label = (TextView)linear.GetChildAt(0);

                //BaseImageCellのカスタムプロパティに設定されたフォント名を取得する
                var imageCell = (BaseImageCell)item;
                string fontName = imageCell.FontFamily;

                //フォントを設定する
                if (_font == null)
                {
                    _font = Typeface.CreateFromAsset(Android.App.Application.Context.Assets, fontName);
                }
                label.SetText(imageCell.Text, TextView.BufferType.Normal);
                label.SetTypeface(_font, TypefaceStyle.Normal);
            }
            return cell;
        }
    }
}

４．iOSの実装方法

using System;
using UIKit;
using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;
using AppName.iOS.Renderer;
using AppName.Library.Utility;
using AppName.Controls;
[assembly: ExportRenderer(typeof(BaseImageCell), typeof(CustomImageCellRenderer))]
namespace AppName.iOS.Renderer
{
    public class CustomImageCellRenderer : ImageCellRenderer
    {
        public override UITableViewCell GetCell(Cell item, UITableViewCell reusableCell, UITableView tv)
        {
            var cell = base.GetCell(item, reusableCell, tv);
            if (cell != null)
            {
                //BaseImageCellのカスタムプロパティに設定されたフォント名を取得する
                BaseImageCell imageCell = (BaseImageCell)item;
                string fontName = imageCell.FontFamily;

                //フォントを設定する
                UILabel label1 = cell.DetailTextLabel;
                label1.Font = UIFont.FromName(fontName, label1.Font.PointSize);
                UILabel label2 = cell.TextLabel;
                label2.Font = UIFont.FromName(fontName, label2.Font.PointSize);                    

                UpdateBackground(cell, item);
            }
            return cell;
        }
    }
}

using AppName.Controls;
using Xamarin.Forms;
namespace AppName.Controls
{
    public class MenuListView : ListView
    {
        public MenuListView()
        {
            this.Initialize();
        }
        public MenuListView(ListViewCachingStrategy strategy) : base(strategy)
        {
            this.Initialize();
        }
        public void Initialize()
        {
            // ListView の設定
            List<MenuItem> data = new MenuListData(); 
            ItemsSource = data; 
            VerticalOptions = LayoutOptions.FillAndExpand;
            BackgroundColor = Color.Transparent;

            // ImageCellをバインド
            var cell = new DataTemplate(typeof(BaseImageCell));
            cell.SetBinding(TextCell.TextProperty, "Title");
            cell.SetBinding(ImageCell.ImageSourceProperty, "IconSource");
            cell.SetBinding(BaseImageCell.FontFamilyProperty, "FontFamily");  //今回作成した派生コントロールのプロパティです。
            ItemTemplate = cell;
        }
    }

    /// <summary>
    /// ListView のデータ用のクラスです。
    /// </summary>
    public class MenuItem
    {
        public string Title { get; set; }

        public string IconSource { get; set; }

        public string FontFamily
        {
            get
            {
                switch (Device.RuntimePlatform)
                {
                    case Device.iOS:
                        return "Georgia-BoldItalic"; //PostScript名

                    case Device.Android:
                        return "Fonts/Georgia-BoldItalic.ttf";  //ファイル名

                    default:
                        throw new NotImplementedException("想定していないプラットフォームです。");
                }
            }
        }
    }
}