Question

我是Xamarin.Forms平台的新手。我希望你能帮我前进。我希望在xamarin.forms中有像自动完成这样的控件，如下所示

请指导一下如何才能在Xamarin.Forms中实现？我想通过Entry Control实现它

TIA

Answer 1

您还没有包含您想要的内容，只是某种自动填充功能。

我将通过手动方式指出一般项目清单：

使用TextBox允许用户输入文本。
使用List将所有对象与其可搜索属性（如对象名称）一起收集。
当用户在TextBox中输入内容时，应用程序应在List中搜索TextBox中输入的字符串。
建议应根据键入的字符串值显示在TextBox下的ListView中。
用户点击ListView项目，这是一个建议，然后通过将点击项目中的对象名称自动填充到TextBox。

在没有上述粗略程序的情况下执行自动完成的一般方法是使用Android AutoCompleteTextView。

您仍然可以使用基本逻辑在Xamarin Forms中执行此操作。

查看here以获取适用于Android的AutoCompleteTextView。查看here，here和here以获取有关Xamarin表单中的自动完成功能的帮助。

Answer 2

我在项目中实现了AutocompleteView。你可以参考一下。

public class AutoCompleteView : ContentView
{
    public static readonly BindableProperty SuggestionsProperty = BindableProperty.Create(nameof(Suggestions), typeof(IEnumerable), typeof(AutoCompleteView), null, BindingMode.OneWay, null, OnSuggestionsChanged);
    public static readonly BindableProperty SearchTextProperty = BindableProperty.Create(nameof(SearchText), typeof(string), typeof(AutoCompleteView), null, BindingMode.TwoWay, null, OnSearchTextChanged);
    public static readonly BindableProperty PlaceholderProperty = BindableProperty.Create(nameof(Placeholder), typeof(string), typeof(AutoCompleteView), null, BindingMode.OneWay, null, OnPlaceholderChanged);
    public static readonly BindableProperty MaximumVisibleSuggestionItemsProperty = BindableProperty.Create(nameof(MaximumVisibleSuggestionItems), typeof(int), typeof(AutoCompleteView), 4);
    public static readonly BindableProperty SuggestionItemTemplateProperty = BindableProperty.Create(nameof(SuggestionItemTemplate), typeof(DataTemplate), typeof(AutoCompleteView), null, BindingMode.OneWay, null, OnSuggestionItemTemplateChanged);
    public static readonly BindableProperty DisplayPropertyNameProperty = BindableProperty.Create(nameof(DisplayPropertyName), typeof(string), typeof(AutoCompleteView));

    public IEnumerable Suggestions
    {
        get { return (IEnumerable)GetValue(SuggestionsProperty); }
        set { SetValue(SuggestionsProperty, value); }
    }

    public string SearchText
    {
        get { return (string)GetValue(SearchTextProperty); }
        set { SetValue(SearchTextProperty, value); }
    }

    public string Placeholder
    {
        get { return (string)GetValue(PlaceholderProperty); }
        set { SetValue(PlaceholderProperty, value); }
    }

    public int MaximumVisibleSuggestionItems
    {
        get { return (int)GetValue(MaximumVisibleSuggestionItemsProperty); }
        set { SetValue(MaximumVisibleSuggestionItemsProperty, value); }
    }

    public DataTemplate SuggestionItemTemplate
    {
        get { return (DataTemplate)GetValue(SuggestionItemTemplateProperty); }
        set { SetValue(SuggestionItemTemplateProperty, value); }
    }

    public string DisplayPropertyName
    {
        get { return (string)GetValue(DisplayPropertyNameProperty); }
        set { SetValue(DisplayPropertyNameProperty, value); }
    }

    public ItemsStack SuggestionsListView { get; private set; }
    public Entry SearchEntry { get; private set; }
    public IEnumerable OriginSuggestions { get; private set; }
    public NestedScrollView SuggestionWrapper { get; private set; }
    public Grid Container { get; private set; }

    public bool IsSelected { get; private set; }
    public int TotalNumberOfTypings { get; private set; }

    private static void OnSuggestionsChanged(object bindable, object oldValue, object newValue)
    {
        var autoCompleteView = bindable as AutoCompleteView;

        var suggestions = (IEnumerable)newValue;
        autoCompleteView.OriginSuggestions = suggestions;

        suggestions = autoCompleteView.FilterSuggestions(suggestions, autoCompleteView.SearchText);
        autoCompleteView.SuggestionsListView.ItemsSource = suggestions;
    }

    private static void OnSearchTextChanged(object bindable, object oldValue, object newValue)
    {
        var autoCompleteView = bindable as AutoCompleteView;

        var suggestions = autoCompleteView.OriginSuggestions;
        if (newValue != null)
        {
            suggestions = autoCompleteView.FilterSuggestions(suggestions, autoCompleteView.SearchText);
            // assign when initializing with data
            if (autoCompleteView.SearchEntry.Text != autoCompleteView.SearchText)
            {
                autoCompleteView.SearchEntry.Text = autoCompleteView.SearchText;
            }
        }
        autoCompleteView.SuggestionsListView.ItemsSource = suggestions;

        if (Device.OS == TargetPlatform.Android)
        {
            // update the layout -> only do this when user is typing instead of selection an item from suggestions list 
            // -> prevent duplicated update layout
            if (!autoCompleteView.IsSelected)
            {
                autoCompleteView.UpdateLayout();
            }
            else
            {
                autoCompleteView.IsSelected = false;
            }
        }
    }

    private static void OnSuggestionItemTemplateChanged(object bindable, object oldValue, object newValue)
    {
        var autoCompleteView = bindable as AutoCompleteView;

        if (autoCompleteView.SuggestionsListView != null)
        {
            autoCompleteView.SuggestionsListView.ItemTemplate = autoCompleteView.SuggestionItemTemplate;
        }
    }

    public IEnumerable FilterSuggestions(IEnumerable suggestions, string keyword)
    {
        if (string.IsNullOrEmpty(keyword) || suggestions == null) return suggestions;

        var searchWords = keyword.ConvertToNonMark().ToLower().Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries);
        var result = suggestions.Cast<object>();
        foreach (var item in searchWords)
        {
            if (!string.IsNullOrEmpty(DisplayPropertyName))
            {
                result = result.Where(x => x.GetType().GetRuntimeProperty(DisplayPropertyName).GetValue(x).ToString().ConvertToNonMark().ToLower().Contains(item)).ToList();
            }
            else
            {
                result = result.Where(x => x.ToString().ConvertToNonMark().ToLower().Contains(item)).ToList();
            }
        }

        return result;
    }

    private static void OnPlaceholderChanged(object bindable, object oldValue, object newValue)
    {
        var autoCompleteView = bindable as AutoCompleteView;
        autoCompleteView.SearchEntry.Placeholder = newValue?.ToString();
    }

    public void UpdateLayout()
    {
        var expectedHeight = this.getExpectedHeight();
        Container.HeightRequest = expectedHeight;
        Container.ForceLayout();
    }

    private void SearchEntry_TextChanged(object sender, TextChangedEventArgs e)
    {
        TotalNumberOfTypings++;
        Device.StartTimer(TimeSpan.FromMilliseconds(1000), () => {
            TotalNumberOfTypings--;
            if (TotalNumberOfTypings == 0)
            {
                SearchText = e.NewTextValue;
            }
            return false;
        });
    }

    private void SearchEntry_Focused(object sender, FocusEventArgs e)
    {
        UpdateLayout();
        IsSelected = false;
    }

    private void SearchEntry_Unfocused(object sender, FocusEventArgs e)
    {
        Container.HeightRequest = 50;
        Container.ForceLayout();
    }

    private void SuggestionsListView_ItemSelected(object sender, ItemTappedEventArgs e)
    {
        IsSelected = true;
        SearchEntry.Text = !string.IsNullOrEmpty(DisplayPropertyName) ? e.Item?.GetType()?.GetRuntimeProperty(DisplayPropertyName)?.GetValue(e.Item)?.ToString() : e.Item?.ToString();
        Container.HeightRequest = 50;
        Container.ForceLayout();
    }

    private void OverlapContentView_Tapped(object sender, TappedEventArgs e)
    {
        UpdateLayout();
        IsSelected = false;

     }

    private int getExpectedHeight()
    {
        var items = SuggestionsListView.ItemsSource as IList;
        int wrapperHeightRequest = items != null ?
            (items.Count >= MaximumVisibleSuggestionItems ? MaximumVisibleSuggestionItems * 40 : items.Count * 40) : 0;
        if (Device.OS == TargetPlatform.Android)
        {
            return wrapperHeightRequest + 50;
        }
        return MaximumVisibleSuggestionItems * 40 + 50;
    }

    public AutoCompleteView()
    {
        Container = new Grid();
        SearchEntry = new Entry();
        SuggestionsListView = new ItemsStack();
        SuggestionWrapper = new NestedScrollView();

        // init Grid Layout
        Container.RowSpacing = 0;
        Container.ColumnDefinitions.Add(new ColumnDefinition() { Width = GridLength.Star });
        Container.RowDefinitions.Add(new RowDefinition() { Height = GridLength.Star });
        Container.RowDefinitions.Add(new RowDefinition() { Height = 50 });
        Container.HeightRequest = 50;

        // init Search Entry
        SearchEntry.HorizontalOptions = LayoutOptions.Fill;
        SearchEntry.VerticalOptions = LayoutOptions.Fill;
        SearchEntry.TextChanged += SearchEntry_TextChanged;
        SearchEntry.Unfocused += SearchEntry_Unfocused;
        SearchEntry.Focused += SearchEntry_Focused;

        // init Suggestions ListView
        SuggestionsListView.BackgroundColor = Color.White;
        SuggestionsListView.ItemTapped += SuggestionsListView_ItemSelected;
        SuggestionsListView.VerticalOptions = LayoutOptions.End;
        SuggestionsListView.Spacing = 1;

        // suggestions Listview's wrapper
        SuggestionWrapper.VerticalOptions = LayoutOptions.Fill;
        SuggestionWrapper.Orientation = ScrollOrientation.Vertical;
        SuggestionWrapper.BackgroundColor = Color.White;
        SuggestionWrapper.Content = SuggestionsListView;

        Container.Children.Add(SuggestionWrapper);
        Container.Children.Add(SearchEntry, 0, 1);

        this.Content = Container;
    }
}

用法示例：

<customControls:AutoCompleteView SearchText="{Binding User.UniversitySchool}" Suggestions="{Binding Schools}" DisplayPropertyName="Name" Placeholder="Please choose your school">
                    <customControls:AutoCompleteView.SuggestionItemTemplate>
                        <DataTemplate>
                            <ContentView Padding="10">
                                <Label Text="{Binding Name}" HeightRequest="20" LineBreakMode="HeadTruncation" Style="{StaticResource MainContentLabel}" />
                            </ContentView>
                        </DataTemplate>
                    </customControls:AutoCompleteView.SuggestionItemTemplate>
                </customControls:AutoCompleteView>

在这个视图中，我使用了ItemStack控件。您可以参考：https://gist.github.com/NVentimiglia/2723411428cdbb72fac6

Answer 3

请阅读这些文章并尝试使用自定义渲染器在Xamarin.Forms上实现解决方案。

Google Place API with Autocomplete in Xamarin Android

Xamarin.iOS Location Autocomplete by using Google Place API

Answer 4

我有一个Xamarin.Forms自定义控件，可以在iOS，Android和UWP上使用。它使用自定义渲染器在幕后提供本机UI。我之所以建立它，是因为我没有找到任何提供良好原生体验的控件，并且在下拉列表打开时没有更改控件的高度。有关NuGet软件包的所有doc +参考，请参见： https://github.com/dotMorten/XamarinFormsControls/tree/master/AutoSuggestBox

Answer 5

您可以使用SyncFusion AutoComplete插件轻松实现此目的。这为您提供了多种选择，而不是执行自定义渲染。

参考：https://help.syncfusion.com/xamarin/sfautocomplete/getting-started

Answer 6

我尝试按照Imdad的回答建立自己的建议/自动完成功能。我的标准阻碍了我的工作，当建议填充列表视图时，必须将其显示在顶部或将其扩展。没有永久占据空间的列表视图。

您可以尝试https://github.com/XamFormsExtended/Xfx.Controls 但是我遇到了一些问题。它显示在顶部

我遇到了一个问题，即自动完成视图中的文本不会从源绑定中更新，也不会使用https://github.com/XLabs/Xamarin-Forms-Labs自动完成视图从后面的代码中进行设置。这会暂时阻止显示建议的方式

我亲自使用了此解决方案https://github.com/dotMorten/XamarinFormsControls/tree/master/AutoSuggestBox

Answer 7

我正在使用这个图书馆SupportWidgetXF

这是跨平台的。

Xamarin.Forms自动完成CrossPlatform

7 个答案: