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トップに関する質問Xamarin.Android ListView 画像つき 高速処理

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質問編集履歴

1

Adapterクラスのコードを追記しました。

2018/07/07 14:23

投稿

dfrd
dfrd

スコア14

test CHANGED
File without changes
test CHANGED
@@ -44,6 +44,320 @@
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+ 以下に、Adapterのソースコードを記載させて頂きます。
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+
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+
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+
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+ ```ここに言語を入力
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+
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+ namespace SampleArticleMemberApp.Droid
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+
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+ {
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+
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+ public class ArticleListItemAdapter : BaseAdapter<ArticleListItem>
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+
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+ {
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+
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+ public List<ArticleListItem> items;
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+
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+ public Activity context;
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+
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+
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+
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+ /**
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+
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+ * コンストラクタ
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+
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+ */
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+
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+ public ArticleListItemAdapter(Activity context, List<ArticleListItem> items)
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+
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+ {
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_VERBOSE, "ArticleListItemAdapter", "-----START-----");
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+
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+ this.context = context;
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+
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+ this.items = items;
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_VERBOSE, "ArticleListItemAdapter", "-----END-----");
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+
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+ }
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+
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+
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+
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+ /**
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+
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+ * クリック処理
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+
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+ */
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+
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+ public override long GetItemId(int position)
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+
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+ {
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_VERBOSE, "GetItemId", "-----START-----");
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_VERBOSE, "GetItemId", "-----END-----");
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+
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+ return position;
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+
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+ }
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+
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+
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+
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+ public override ArticleListItem this[int position]
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+
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+ {
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+
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+ get { return items[position]; }
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+
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+ }
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+
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+
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+
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+ public override int Count
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+
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+ {
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+
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+ get { return items.Count; }
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+
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+ }
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+
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+
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+
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+ public override View GetView(int position, View convertView, ViewGroup parent)
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+
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+ {
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_VERBOSE, "GetView", "-----START-----");
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+
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+ var item = items[position];
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+
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+
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+
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+ View view = convertView;
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+
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+ if (view == null){
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+
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+ view = context.LayoutInflater.Inflate(Resource.Layout.ArticleListViewItem, null);
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+
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+ }
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+
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+
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+
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+ // BaseAdapter<T>の対応するプロパティを割り当て
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+
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+ view.FindViewById<TextView>(Resource.Id.articleItemDate).Text = item.date;
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+
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+ view.FindViewById<TextView>(Resource.Id.articleItemTitle).Text = item.title;
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+
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+
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_INFO, "GetView", item.title);
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_INFO, "GetView", item.url);
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_INFO, "GetView", item.thumbUrl);
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_INFO, "GetView", "readable: " +item.readable.ToString());
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+
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+
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+
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+ if(item.thumbUrl != ""){
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_INFO, "GetView", "画像を読み込みます");
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+
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+ view.FindViewById<ImageView>(Resource.Id.articleItemThumb).SetImageResource(Resource.Mipmap.def_thumb);
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+
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+ SetThumb(view, position);
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+
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+ //var image = GetImageBitmapFromUrl(item.thumbUrl);
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+
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+ //view.FindViewById<ImageView>(Resource.Id.articleItemThumb).SetImageBitmap(image);
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+
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+ }
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+
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+ else{
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+
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+ view.FindViewById<ImageView>(Resource.Id.articleItemThumb).SetImageResource(Resource.Mipmap.def_thumb);
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+
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+ }
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+
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+
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+
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+ //読み込み不可能ならば、背景色を変える
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+ if(!item.readable){
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+
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+ view.SetBackgroundColor(Color.DarkGray);
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+
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+ view.FindViewById<TextView>(Resource.Id.articleItemDate).SetTextColor(Color.GhostWhite);
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+
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+ view.FindViewById<TextView>(Resource.Id.articleItemDate).Alpha = 0.4f;
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+
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+
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+
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+ view.FindViewById<TextView>(Resource.Id.articleItemTitle).SetTextColor(Color.GhostWhite);
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+
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+ view.FindViewById<TextView>(Resource.Id.articleItemTitle).Alpha = 0.4f;
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+
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+
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+
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+ view.FindViewById<ImageView>(Resource.Id.articleItemThumb).Alpha = 0.4f;
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+
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+ }
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+
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+ else{
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+
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+ view.SetBackgroundColor(Color.GhostWhite);
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+
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+ view.FindViewById<TextView>(Resource.Id.articleItemDate).SetTextColor(Color.Black);
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+
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+ view.FindViewById<TextView>(Resource.Id.articleItemDate).Alpha = 1.0f;
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+
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+
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+
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+ view.FindViewById<TextView>(Resource.Id.articleItemTitle).SetTextColor(Color.Black);
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+
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+ view.FindViewById<TextView>(Resource.Id.articleItemTitle).Alpha = 1.0f;
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+
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+
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+
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+ view.FindViewById<ImageView>(Resource.Id.articleItemThumb).Alpha = 1.0f;
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+
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+ }
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+
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+
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+
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+
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_VERBOSE, "GetView", "-----END-----");
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+
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+ return view;
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+
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+ }
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+
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+
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+
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+ /**
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+
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+ * URLから、Bitmap生成
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+
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+ */
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+
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+ private async Task<Bitmap> GetImageBitmapFromUrl(string url)
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+
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+ {
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+
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+ Bitmap imageBitmap = null;
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+
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+
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+
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+ try{
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+
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+ using (var webClient = new WebClient())
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+
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+ {
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+
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+ var imageBytes = webClient.DownloadData(url);
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+
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+ if (imageBytes != null && imageBytes.Length > 0)
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+
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+ {
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+
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+ imageBitmap = BitmapFactory.DecodeByteArray(imageBytes, 0, imageBytes.Length);
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+
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+ }
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+
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+ }
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+
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+
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+
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+ }
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+
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+ catch(Exception e)
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+
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+ {
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_ERROR, "GetImageBitmapFromUrl", "e: " +e);
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+
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+ }
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+
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+ return imageBitmap;
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+
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+ }
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+
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+
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+
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+ private async void SetThumb(View view, int position)
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+
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+ {
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+
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+ var item = items[position];
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+
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+ if(items[position].bitmap == null)
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+
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+ {
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+
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+ ImageView imageView = view.FindViewById<ImageView>(Resource.Id.articleItemThumb);
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+
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+
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_ERROR, "GetImageBitmapFromUrl", "imgvW: " + imageView.Width);
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_ERROR, "GetImageBitmapFromUrl", "imgvH: " + imageView.Height);
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+
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+ if(0 < imageView.Width && 0 < imageView.Height){
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+
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+ Bitmap bmp = await GetImageBitmapFromUrl(item.thumbUrl);
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+
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+ int bmpH = (int)((float)imageView.Width / (float)bmp.Width *(float)bmp.Height);
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+
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+
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+
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+ int scale = Math.Max(imageView.Width, bmpH);
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+
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+
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+
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+ bmp = Bitmap.CreateScaledBitmap(bmp, imageView.Width, bmpH, false);
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+ items[position].bitmap = await GetImageBitmapFromUrl(item.thumbUrl);
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+ view.FindViewById<ImageView>(Resource.Id.articleItemThumb).SetImageBitmap(items[position].bitmap);
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+
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+ Debug.Log(Debug.DEBUG_LEVEL_ERROR, "GetImageBitmapFromUrl", "bmpW: " + bmp.Width);
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+ Debug.Log(Debug.DEBUG_LEVEL_ERROR, "GetImageBitmapFromUrl", "bmpH: " + bmp.Height);
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+
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+
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+
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+ bmp.Recycle();
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+
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+ bmp = null;
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+
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+ }
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+
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+ }
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+
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+ else
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+
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+ {
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+
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+ view.FindViewById<ImageView>(Resource.Id.articleItemThumb).SetImageBitmap(items[position].bitmap);
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+
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+ }
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+
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+ }
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+
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+ }
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+
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+ }
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+
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+ ```
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+
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+
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+
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  以上です。