工具栏在使用 Xamarin.Forms 的 Android 上不起作用

Question

I have used the following code to create a searchbar using Xamarin.Forms.

But it breaks at this point.

protected void Search(StackLayout layout)
{
    SearchBar searchBar = new SearchBar
    {
        Placeholder = "Xamarin.Forms Property",
    };
    layout.Children.Add(searchBar);
}

protected override void BuildView(StackLayout layout)
{

    Search(layout);

    CallDataFromDB(layout);

    Device.OnPlatform(
        //broken in Xamarin 1.2. Awaiting a fix
        Android: () =>
        {
            var tbi = new ToolbarItem("Refresh", "", () =>
            {
                BuildView(layout);
            }, 0, 0);
            tbi.Order = ToolbarItemOrder.Secondary;  // forces it to appear in menu on Android
            if (ToolbarItems.Count == 0)
                ToolbarItems.Add(tbi);
        }
    );

}

It breaks when I make a gesture (touch) on the screen it breaks.

This is the exact error which I am facing now:

Missing method Android.Widget.SearchView::get_InputType() in assembly Mono.Android.dll, referenced in assembly Xamarin.Forms.Platform.Android.dll

Can anybody help me with this?

Answer 1

This code works for me :

public class ItemsPage : ContentPage
{
ItemListView list;
SearchBar searchbar;

public ItemsPage ()
{
    Title = "Items";

    list = new ItemListView ();

    searchbar = new SearchBar () {
        Placeholder = "Search",
    };

    searchbar.TextChanged += (sender, e) => {
        /*Work to be done at time text change*/
    };
    searchbar.SearchButtonPressed += (sender, e) => {
        /*Work to be done at time of Search button click*/
    };

    var stack = new StackLayout () {
        Children = {
            searchbar,
            list
        }
    };

    Content = stack;
}
}

Note :

• Minimum Android version: Override - Android 4.0.3 (API Level 15)

• Target framework: Use latest installed platform (API Level 21)

• Target Android version: Automatic - API Level 19

Answer 2

I used this and its working. I set: Build > General > Target framework: Use latest installed platform (4.4) Build > Android Application > Minimum Android version: Override - Android 4.0.3 (API Level 15) Build > Android Application > Target Android version: Automatic - use target framework version.

Answer 3

Have you tried doing the same in Xaml? I'm using a SearchBar in my app and it's working just fine. Here's some sample code below:

<ContentPage xmlns="http://xamarin.com/schemas/2014/forms" 
             xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
             Title="Results"
             x:Class="MyApp.ResultPage">
<StackLayout Orientation="Vertical" 
                 Spacing="0">
<SearchBar x:Name="SearchBar"
                   Placeholder="Search by name"
                   SearchButtonPressed="OnSearchButtonTapped"
                   CancelButtonColor="Gray"
                   TextChanged="OnSearchBarTextChanged" />
        <ListView x:Name="ListView"
                  HasUnevenRows="true"
                  IsGroupingEnabled="true"
                  GroupDisplayBinding="{Binding Title}"
                  ItemTapped="DirectoryListOnItemTapped"
                  VerticalOptions="FillAndExpand"
                  SeparatorColor="Silver"
                  BackgroundColor="White"
                  IsPullToRefreshEnabled="true"
                  Refreshing="OnRefresButtonTapped">
            <ListView.ItemTemplate>
                <DataTemplate>
                    <TextCell Text="{Binding Name}"
                              TextColor="Black" />
                </DataTemplate>
            </ListView.ItemTemplate>
        </ListView>
</StackLayout>
<ContentPage>

Answer 4

I am using following code,I am following MVVM design pattern write bellow code in Veiw Page :-

 internal class NotificationsPage :  ContentPage
    {
        #region Variables and Controlls declaration 
        private NotificationsViewModel _viewModel; 
        private SearchBar _notificationSearchBar; 
        #endregion Variables and Controlls declaration

        #region Constructor

        public NotificationsPage()  
        {
                BindingContext = App.Locator.Notification;
                _viewModel = BindingContext as NotificationsViewModel;

                _notificationSearchBar = new SearchBar()
                { 
                };
                _notificationSearchBar.SetBinding(SearchBar.TextProperty,"TEXT");
                _notificationSearchBar.SetBinding(SearchBar.SearchCommandProperty,"SearchCommand" );
        }

In the viewModel can

#region Search Functionality


    #region Commands
    private RelayCommand _searchCommand;
    public RelayCommand SearchCommand
    { get { return _searchCommand ?? (_searchCommand = new RelayCommand(async () => 
    {
        if (SearchedList.Count > 0)
        {

            if (!string.IsNullOrEmpty(Text))
            {

                List<Notification> entities = SearchedList.Where(e =>

                 Convert.ToString(e.NotificationSubject).ToLower().Trim().Contains(Text.ToLower().Trim())
                 || Convert.ToString(e.LinkedRecordName).ToLower().Trim().Contains(Text.ToLower().Trim())
                 || Convert.ToString(e.NotificationDateSent).ToLower().Trim().Contains(Text.ToLower().Trim())
                 || Convert.ToString(e.NotificationContent).ToLower().Trim().Contains(Text.ToLower().Trim())).ToList();

                NotificationsList = new ObservableCollection<Notification>(entities);
            }
            else
            {

                NotificationsList = SearchedList;

            }
        }

    }
    )); } }


    private string _searchText = string.Empty;

    public string Text          // This is the text property we bind on page   _notificationSearchBar.SetBinding(SearchBar.TextProperty,"TEXT"); 
    {
        get { return _searchText; }
        set
        {
            if (_searchText != value)
            {
                _searchText = value;
                Set(() => Text, ref _searchText, value);

                if (SearchCommand.CanExecute(null))
                {
                    SearchCommand.Execute(null);

                }
            }
        }
    }
    #endregion

    #endregion

Where SearchedList and NotificationList is the observable collection binded to list you can take it as list of class as well

private ObservableCollection<Notification> _notificationsList;

        public ObservableCollection<Notification> NotificationsList
        {
            get { return _notificationsList; }
            set
            {
                Set(() => NotificationsList, ref _notificationsList, value);
            }
        }



        /// <summary>
        /// Holds Searched notifications
        /// </summary>
        private ObservableCollection<Notification> _searchedList;

        public ObservableCollection<Notification> SearchedList
        {
            get { return _searchedList; }
            set
            {
                Set(() => SearchedList, ref _searchedList, value);
            }
        }

Answer 5

I did this a lot of time. I prefer using MVVM pattern. i am using event to Command Behaviours for binding search command to ViewModel basically you search on some text or quantity and operate on some collection that you already have. as simple as that. I have written a blog about this, see if that helps you in any way. Thanks :) please Ref: https://adityadeshpandeadi.wordpress.com/2018/01/14/search-through-listview-items-in-xamarin-forms/