Xamarin Forms日期和时间选择器 [英] Xamarin Forms date and time picker

问题描述

我正在使用Xamarin Forms来制作跨平台应用程序，我需要创建一个简单的视图，用户可以选择日期和时间，类似于: 在这里找到的要创建的视图:

I am using Xamarin Forms to make Cross-platform application and I need to create simple view that user can choose date and time, similar to this: View that I want to create that i found here: Picker in Xamarin iOS. Solution for Android is ready, but I need to create solution for iOS in the same application

我不能与Xamarin Forms分开使用标准日期选择器和其他标准时间选择器.我需要创建自定义解决方案(一个视图-简单地选择日期和时间).

I can not use standard date picker and another standard time picker separately from Xamarin Forms. I need to create custom solution (one view - simple choose both date and time).

我试图在Xamarin Forms中创建视图，该视图由2个水平方向的列表组成(一个用于日期，一个用于时间)，但是当我选择一个位置时，该列表不会滚动到视图的中间，并且当我向上或向下滚动列表时，不会自动选择中间位置元素.我想创建类似Xamarin-iOS解决方案的东西:日期和时间选择器"，但使用Xamarin表单.

I have tried to create view in Xamarin Forms that consist of 2 lists in horizontal orientation (one for date, one for time) but when I select one position, the list is not scrolling to the middle of view and also there is not auto-selecting middle position element when I scroll the list up or down. I want to create something that works like Xamarin-iOS solution: "Date and time picker" but in Xamarin Forms.

我也尝试过在Xamarin-iOS中创建项目日期和时间选择器"的一部分.我有main.storyboard和视图控制器，但我不知道如何在Xamarin Forms中从Xamarin-iOS显示视图并传递选定的日期和时间.

I have tried also to create in Xamarin-iOS part of project "date and time picker". I have main.storyboard and view controller but I dont know how to display view from Xamarin-iOS inside Xamarin Forms and pass selected date and time.

可以帮我吗?

推荐答案

如果要在iOS平台上的Xamarin.Forms上实现日期时间选择器.可以使用

If you want to implement date-time picker on Xamarin.Forms in iOS platform.You can use CustomRenderer.

表格

创建Picker

public class MyPicker:Picker
{
    public MyPicker()
    {

    }
}

并将其添加到xaml

And add it in xaml

<StackLayout VerticalOptions="CenterAndExpand" HorizontalOptions="CenterAndExpand">
    <!-- Place new controls here -->

    <local:MyPicker  WidthRequest="150"  BackgroundColor="AliceBlue"/>

</StackLayout>

在iOS中

in iOS

创建Picker的渲染器.您可以设置 format 您想要的选择器.

create the renderer of Picker .And you can set the format of picker as you want.

using System;

using Foundation;
using UIKit;
using ObjCRuntime;

using Xamarin.Forms;
using Xamarin.Forms.Platform.iOS;

using xxx;
using xxx.iOS;

[assembly:ExportRenderer(typeof(MyPicker),typeof(MyPickerRenderer))]
namespace xxx.iOS
{
  public class MyPickerRenderer:PickerRenderer
  {

    string SelectedValue;

    public MyPickerRenderer()
    {

    }

    protected override void OnElementChanged(ElementChangedEventArgs<Picker> e)
    {
        base.OnElementChanged(e);

        if(Control!=null)
        {
            SetTimePicker();
        }

    }


    void  SetTimePicker()
    {
        UIDatePicker picker = new UIDatePicker
        {
            Mode = UIDatePickerMode.DateAndTime
        };

        picker.SetDate(NSDate.Now,true);

        picker.AddTarget(this,new Selector("DateChange:"),UIControlEvent.ValueChanged);

        Control.InputView = picker;


        UIToolbar toolbar = (UIToolbar)Control.InputAccessoryView;

        UIBarButtonItem done = new UIBarButtonItem("Done", UIBarButtonItemStyle.Done, (object sender, EventArgs click) =>
        {
            Control.Text = SelectedValue;
            toolbar.RemoveFromSuperview();
            picker.RemoveFromSuperview();
            Control.ResignFirstResponder();
            MessagingCenter.Send<Object, string>(this, "pickerSelected", SelectedValue);



        });

        UIBarButtonItem empty = new UIBarButtonItem(UIBarButtonSystemItem.FlexibleSpace, null);

        toolbar.Items = new UIBarButtonItem[] { empty, done };

    }

    [Export("DateChange:")]
    void DateChange(UIDatePicker picker)
    {
        NSDateFormatter formatter = new NSDateFormatter();

        formatter.DateFormat = "MM-dd HH:mm aa"; //you can set the format as you want

        Control.Text = formatter.ToString(picker.Date);

        SelectedValue= formatter.ToString(picker.Date);

        MessagingCenter.Send<Object, string>(this,"pickerSelected",SelectedValue);
    }
  }
}

并使用MessagingCenter传递所选的日期和时间.

And use MessagingCenter to pass the selected date and time.

public MainPage()
{
    InitializeComponent();

    MessagingCenter.Subscribe<Object, string>(this, "pickerSelected", (sender, arg) => {
        Console.WriteLine(arg);
        //arg is the selected date and time
    });

}

我已将演示文件上传到 github 上.您可以下载它进行测试.

I have uploaded the demo on github .You can download it for test.

效果

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