Questions on UI for Xamarin Forum

3 answers

274 views

Binding group headers

I have the following RadListView:

<telerik:RadListView x:Name="PhaseListView" ItemsSource="{Binding Items}">

<telerik:RadListView.GroupHeaderTemplate>

<DataTemplate>

<StackLayout>

<Label Text="{Binding}" TextColor="White" HorizontalOptions="Center"></Label>

</StackLayout>

</DataTemplate>

</telerik:RadListView.GroupHeaderTemplate>

<telerik:RadListView.ItemTemplate>

<DataTemplate>

<template:ListViewTemplateCell >

<template:ListViewTemplateCell.View>

<StackLayout>

<StackLayout Orientation="Horizontal">

<Label Text="{Binding ID}"></Label>

</StackLayout>

<Slider Value="{Binding Complete}" IsEnabled="False" HorizontalOptions="FillAndExpand"></Slider>

</StackLayout>

</template:ListViewTemplateCell.View>

</template:ListViewTemplateCell>

</DataTemplate>

</telerik:RadListView.ItemTemplate>

<telerik:RadListView.LayoutDefinition>

<template:ListViewLinearLayout Orientation="Vertical"/>

</telerik:RadListView.LayoutDefinition>

</telerik:RadListView>

The grouping is done in the code behind via:

public partial class PhaseXaml : ContentPage

{

public RadListView PhaseList { get; private set; }

public PhaseXaml()

{

InitializeComponent();

PhaseList = PhaseListView; // So it can be accessed from viewmodel

var lookup = new DelegateGroupDescriptor{KeyExtractor = new PhaseGrouping().GetKey};

PhaseListView.GroupDescriptors.Add(lookup);

BindingContext = new PhaseViewModel(new PhaseRepository(), this);

}

private class PhaseGrouping : IKeyLookup

{

public object GetKey(object item)

{

var phase = (Phase) item;

return phase.ProjectName;

}

The ProjectName property is a string, now it does group the items correctly but the header text remains empty. When I break in the GetKey method I can see that at that point the ProjectName property does have a value. I have tried other string Properties on the phase object and it appears that while it groups correctly the header stays empty. If I bind it to say an int (Project id) that will be displayed in the header.
I have attempted to group with a PropertyGroupDescriptor as well but that has the same results. I'm testing on an Android device at the moment.

So my question is is there a way to get string properties to display in the groupheader, and if not whether it's possible to bind the text of the header to another property than is used to group the item (that we can assume is same for all items in the group)

ListView

answered on 07 Apr 2016

1 answer

167 views

Use DataForm ViewModel in Xamarin.Forms and WPF

I am doing some research on porting an old WPF app in a way that we could have a common layer for the Model and ViewModel so we can have an Android app using Xamarin Forms (maybe later iOS) and a WPF app for Windows 7 users. The DataForm would be perfect. Is it possible to have data annotations that would work for both or do you have to duplicate effort here.

DataForm

answered on 05 Apr 2016

2 answers

118 views

chart is not rendering properly in ios platform

I am encountered with following errors while trying to deploy app in ios simulator

1)ErrorDuplicate symbol in: /Users/ComTec/Library/Caches/Xamarin/mtbs/builds/chartsample2iOS/48534ae52ccc8ef3258af6378e6dc16b/obj/iPhoneSimulator/Debug/mtouch-cache/TelerikUI.a(TKChartAnnotation.o) (Location related to previous error)chartsample2.iOS

2)ErrorNative linking failed, duplicate symbol: '_llvm.embedded.module'.chartsample2.iOS

Chart

answered on 31 Mar 2016

6 answers

128 views

Multiday Event - how to do it?

Hi,

I am trying to replicate the UI from your ios demo app, where an event spans over multiple days as a coloured bar. (attached)

I had a look at the source in objective c and convert it to c#:

calEvent = new TKCalendarEvent ();
calEvent.Title = “name”;
calEvent.StartDate = (NSDate)startDate;
calEvent.EndDate = (NSDate)endDate;
calEvent.AllDay = true;
calEvent.EventColor = UIColor.Red;

but what I get is an event displayed on the startDate only, not a bar from startDate to endDate.

What am I doing wrong?

Thank you,

Gelu

Calendar & Scheduling

answered on 24 Mar 2016

1 answer

109 views

Custom Labels & Grid-Lines

Hey,

I'm using the 'Custom Labels' function for a DateTimeAxis and it works.

But the vertical gridlines are not matching with the 'Custom Labels'.

What is a proper way to fix this problem?

kind regards,

Marcel

Chart - Xamarin.iOS

answered on 18 Mar 2016

1 answer

93 views

List View swipe event

How to trigger an event once the List View Item has been swipe to left or right.

ListView

answered on 17 Mar 2016

1 answer

120 views

Xamarin.Forms Chart not clickable in iOS

Hello,

I am trying to make the entire chart rendering area respond to a user's 'tap' by using a TapGestureRecognizer. This works fine when running on Android, but when I run it in iOS, the tap is never recognized.

Chart

answered on 14 Mar 2016

6 answers

908 views

Disable scroll of listview

I am using the telerik listview in our project(Xamarin.forms). I have a scenario where i want to disable the scrolling of telerik listview. I have xamarin scroll view inside that i have telerik listview also some other controls. I want the full page scroll able. But due to telerik internal scrolling the full page does not become scroll able. Could you please help with this.

Thanks In Advance.

ListView

answered on 12 Mar 2016

1 answer

221 views

Expose ScrollState event to list

Hi,

in order to improve performance, I want to pause downloading of images when user is in fling scrolling mode.

_myListView.ScrollStateChanged += (object sender, ScrollStateChangedEventArgs scrollArgs) =>

{

switch (scrollArgs.ScrollState)

{

case ScrollState.Fling:

ImageService.SetPauseWork(true); // all image loading requests will be silently canceled

break;

case ScrollState.Idle:

ImageService.SetPauseWork(false); // loading requests are allowed again

// Here you should have your custom method that forces redrawing visible list items

_myListView.ForcePdfThumbnailsRedraw();

break;

}

};

source: https://github.com/molinch/FFImageLoading/wiki/Advanced-Usage

ScrollStateChanged is came from Android.Widget.AbsListView, but RadListView isn't derived from this class.

any option to add this event ?

Thank you

ListView - Xamarin.Android

answered on 12 Mar 2016

7 answers

263 views

Xamarin.Forms Chart DateTimeContinuousAxis LabelFormat Time issue

I am using a DateTimeContinuousAxis to display various metrics over time. I have set the LabelFormat to M/dd/yy h:mm. However, even though I convert the DateTime values from UTC to local time before setting the data on the chart, the labels are displayed in UTC. How can I change this? Also, regarding the LabelFormt, how can I get AM or PM displayed? I have tried adding tt to the format string, but it does not seem to work?

Chart

answered on 07 Mar 2016