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创建顶部有固定视图的ContentPage模板

xamarin.ios xamarin.forms xamarin

1

Tobe · 技术社区 · 7 年前

我尝试的是:创建一个从ContentPage继承的类“SyncInfoContentPage”。我已经编写的所有ContentPage现在将不再从ContentPage继承,而是从SyncInfoContentPage继承。 SyncInfoContentPage会自动获取其内容,并将其替换为包含SyncInfo和原始内容的新Stacklayout。通过这样做,我不必重写我们已有的77页内容。

这段代码在Android上运行良好,但在iOS上SyncInfo不可见,而且(更糟糕的是)从SyncInfoContentPage继承的我的contentpage不再对任何内容做出反应。

public class SyncInfoContentPage : ContentPage
    {
        private readonly Frame SyncInfo;

        public SyncInfoContentPage()
        {
            SyncInfo = BuildSyncInfo(); //Creates the frame with the sync Information
            PropertyChanged += SyncInfoContentPage_PropertyChanged;
        }

        private void SyncInfoContentPage_PropertyChanged(object sender, PropertyChangedEventArgs e)
        {
          // Add the SyncInfo Frame on top of the Content when the Content gets changed
            if (e.PropertyName.Equals("Content"))
            {
                bool change = false;
          // If the content already is a StackLayout, check if the SyncInfo already got added, so that theres no infinite loop.
                if (Content is StackLayout)
                {
                    var check = Content as StackLayout;
                    if (!check.Children.Contains(SyncInfo))
                    {
                        change = true;
                    }
                }
                else  // if the Content is no StackLayout, the SyncInfo Frame can't be inside the Content yet
                {
                    change = true;
                }

                if (change)
                {
                    var layout = Content;       // This is a reference, probably the error?
                    Device.BeginInvokeOnMainThread(() =>
                    {
                        Content = new StackLayout
                        {
                            Children = { SyncInfo, layout }
                        };
                    });
                }
            }
        }
    }

问题可能是iOS不喜欢这一部分:

var layout = Content;
Content = new StackLayout { Children = { SyncInfo, layout } };

1 回复 | 直到 7 年前

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Tobe 7 年前

我让它工作了。解决办法很简单,但很奇怪。在添加SyncInfo状态栏之后,必须添加原始内容。

                    var layoutOld = Content; 
                    var layoutNew = new StackLayout
                    {
                        Children = { SyncInfo }
                    };
                    Content = layoutNew;
                    layoutNeu.Children.Add(layoutOld);