从单独的布局文件将视图添加到水平滚动视图

Question

我正在尝试将卡片列表添加到滚动视图中，使用单独的 xml 文件作为我的布局。

但是在按下按钮时出现以下错误：

System.NullReferenceException: Object reference not set to an instance of an object

我可以在不使用 Card.xml 布局的情况下很好地添加文本，当我使用它作为我的布局时，我得到了错误。

protected override void OnCreate(Bundle bundle)
{
    base.OnCreate(bundle);

    // Set our view from the "main" layout resource
    SetContentView(Resource.Layout.Main);



    Button buttonWhite = FindViewById<Button>(Resource.Id.button2);



    //On button click, loop though dealt hand of cards and add each to Scrollveiw using Card layout file
    buttonWhite.Click += delegate
    {

        HorizontalScrollView ScrollView = (HorizontalScrollView)FindViewById(Resource.Id.horizontalScrollView1);

        //create layout from Cardlayout file
        LinearLayout Test_card = (LinearLayout)FindViewById(Resource.Layout.Card);

        //loopthough Players hand and use text to add to card layout then add layout with text to scrollview
        foreach (Card Test in p.hand)
        {


            //create new textview
            TextView Test_Text = new TextView(this);


            //set new textviews text value to card text
            Test_Text.Text = Test.text;

            //addview to layout
            Test_card.AddView(Test_Text);

        }

        //add layout to scrollview
        ScrollView.AddView(Test_card);


    };
}

Answer 1

您应该扩充卡片资源布局，它不在您当前的上下文中。所以你应该替换：

 LinearLayout Test_card = (LinearLayout)FindViewById(Resource.Layout.Card);

使用（Java）：

LinearLayout Test_card = (LinearLayout) getLayoutInflater().inflate(Resource.Layout.Card);

C#（也许）：

LinearLayout Test_card = (LinearLayout) this.LayoutInflater.Inflate(
                Resource.Layout.Card ...);