Questions on UI for Xamarin Forum

6 answers

1.5K+ views

Could not load assembly 'Telerik.XamarinForms.SkiaSharp,

Hi All,

I have installed a licensed version of Telerik.XamarinFroms.UI and can`t build my project.

SeverityCodeDescriptionProjectFileLineSourceSuppression State
ErrorException while loading assemblies: System.IO.FileNotFoundException: Could not load assembly 'Telerik.XamarinForms.SkiaSharp, Version=2017.1.10118.233, Culture=neutral, PublicKeyToken='. Perhaps it doesn't exist in the Mono for Android profile?
File name: 'Telerik.XamarinForms.SkiaSharp.dll'
at Java.Interop.Tools.Cecil.DirectoryAssemblyResolver.Resolve(AssemblyNameReference reference, ReaderParameters parameters)
at Xamarin.Android.Tasks.ResolveAssemblies.AddAssemblyReferences(ICollection`1 assemblies, AssemblyDefinition assembly, Boolean topLevel)
at Xamarin.Android.Tasks.ResolveAssemblies.Execute()IsoPanelApp.DroidC:\Program Files (x86)\MSBuild\Xamarin\Android\Xamarin.Android.Common.targets1410Build

I have already increased the HEAP size up to 1G.
I have been trying to remove the reference, but it gives me no result.

Could you please manage this?

Best regards,
Maryan

General Discussions

answered on 06 Feb 2017

9 answers

460 views

RadListView group, sort, filter descriptors

Hi,

I'm having a hard time wrapping my head around how to handle list view group, sort and filter descriptors in an MVVM fashion.

My scenario is pretty simple: change the grouping, sorting or filtering rules of a list view by clicking a button.

Like so: Button => click => issue View Model command => affect change to the grouping, sorting, filtering rules owned by the view model that are supposedly bound to the list view

But here are some problems:

- The descriptors cannot be bound.

- The descriptors are read-only properties of type ObservableCollection, which means that they are owned by the RadListView instance. The caller cannot set an ObservableCollection owned by the view model.

So here are a couple of ideas I have been playing around with, both pretty bad:

- So one can write descriptors with bound properties to the view model (e.g. the sorting order), and force the list view to reload from the view model (by setting the ItemsSource to a new collection instance of the same items via a binding, which is ugly and causes flickering if the item count is high but couldn't find any other way).

- Or, I'll say presumably because I haven't tested that assumption, modify the descriptors' ObservableCollection on the list view (e.g. remove an alphabetical ascending sort descriptor from the collection and add a descending sort descriptor). This means having a reference to the list around when such change is needed. To avoid coupling the view and the view model, this could happen in the parent view, or page, and be isolated from the view model. Which is not great for reusing those features in different views with the same view model...

Does anyone have real life experience on that matter and could enlighten us on how to approach this?

And question for the Telerik staff: Why aren't the descriptor properties bindable and/or settable? Are they planned to be bindable and/or settable at some point?

Thanks in advance,

Jonathan

ListView

answered on 03 Feb 2017

6 answers

136 views

IValueConverter on iOS called to often

Hey guys,

I am currently implementing the Telerik Listview into my Xamarin Forms application.

But I am running into a strange behaviour on iOS. Am using the following IValueConverter

public class ByteArrayToImageConverter : IValueConverter

{

public object Convert(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)

{

if (value != null)

{

return ImageSource.FromStream(() => new MemoryStream((byte[])value));

}

return null;

}

public object ConvertBack(object value, Type targetType, object parameter, System.Globalization.CultureInfo culture)

{

throw new NotImplementedException();

}

My Listview looks like this:

<telerikDataControls:RadListView

x:Name="LVUser "

Grid.Column="0" Grid.Row="0">

<telerikDataControls:RadListView.LayoutDefinition>

<telerikListView:ListViewLinearLayout ItemLength="60" />

</telerikDataControls:RadListView.LayoutDefinition>

<telerikDataControls:RadListView.GroupHeaderTemplate>

<DataTemplate>

<ContentView Style="{StaticResource GroupingHeaderBar}">

<Label

Text="{Binding }"

Style="{StaticResource GroupingHeaderLabel}" />

</ContentView>

</DataTemplate>

</telerikDataControls:RadListView.GroupHeaderTemplate>

<telerikDataControls:RadListView.ItemTemplate>

<DataTemplate>

<telerikListView:ListViewTemplateCell>

<telerikListView:ListViewTemplateCell.View>

<Grid Padding="5,1,0,1">

<Grid.ColumnDefinitions>

<ColumnDefinition Width="48"/>

<ColumnDefinition Width="*"/>

<ColumnDefinition Width="10"/>

</Grid.ColumnDefinitions>

<ffimageloading:CachedImage

Grid.Column="0"

HeightRequest="48" WidthRequest="48"

x:Name="Picture"

Source="{Binding Picture, Converter={StaticResource ByteToImage}}"

HorizontalOptions="Start"

/>

<Label

Text="{Binding Id, Converter={StaticResource NameConverter}}"

Style="{StaticResource MainLabel}"

Grid.Column="1"

VerticalOptions="CenterAndExpand"/>

<FontAwesome:FontAwesomeIcon

x:Name="LblMore"

Text=""

Grid.Column="2"

Style="{StaticResource MainLabel}"

VerticalOptions="CenterAndExpand"

HorizontalOptions="EndAndExpand"

/>

</Grid>

</telerikListView:ListViewTemplateCell.View>

</telerikListView:ListViewTemplateCell>

</DataTemplate>

</telerikDataControls:RadListView.ItemTemplate>

</telerikDataControls:RadListView>

This runs perfectly on Android but on iOS the value converter get's called unlimited times. I am using the current stable nuget package.

The "NameConverter" get's called as often as the other one.

Can't I use IValueConverter's?

Best regards

Julian

ListView

answered on 02 Feb 2017

6 answers

342 views

Not able to bind data to RadListView

Hello guys,

I am facing issue with binding the contents to the RadListView.

I am doing it as follows,

<telerikDataControls:RadListView Grid.Row="1" Grid.Column="0" Grid.ColumnSpan="2" x:Name="uiListView" ItemsSource="{Binding Assets}">

<telerikDataControls:RadListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ViewCell.View>
<StackLayout>
<Grid Padding="10,10,10,0">

<Label Grid.Row="0" Grid.Column="0" Text="{Binding AssetNumber}" FontSize="14" FontAttributes="Bold" LineBreakMode="NoWrap"/>

</Grid>
</StackLayout>
</ViewCell.View>
</ViewCell>
</DataTemplate>
</telerikDataControls:RadListView.ItemTemplate>

<telerikDataControls:RadListView.SelectedItemStyle>
<telerikListView:ListViewItemStyle BackgroundColor="#88888888"/>
</telerikDataControls:RadListView.SelectedItemStyle>
</telerikDataControls:RadListView>

ListView

answered on 01 Feb 2017

1 answer

242 views

Radar Chart in Xamarin Forms

I need to implement a radar chart in Xamarin Forms. This is easily available and implementable using Syncfusion as shown here: https://help.syncfusion.com/xamarin/sfchart/charttypes#radar-chart Although I have seen no documentation in Telerik for Xamarin Forms.

Chart

answered on 25 Jan 2017

20 answers

140 views

Bug at Area Chart when stack the series

Hi,

I'm not sure, but I think I have found a bug in the Area Chart component.

The problem is the displaying order of the different series, when you try to stack one them. I successfully achieved it in Android, but I can't find the correct order in iOS.

I have attached two captures. The correct order is the Android version. The add order is the same, but the result is different.

And here is the two code versions.

IOS Code

dailyGraphChart.BeginUpdates();

//Modo stack

var stackInfo = new TKChartStackInfo(new NSNumber(0), TKChartStackMode.Stack);

//PHOTOVOLTAICS - Yellow

var serieFVE = new TKChartAreaSeries(pointsFVE.ToArray());

serieFVE.StackInfo = stackInfo;

serieFVE.Style.Palette = new TKChartPalette();

var paletteItemFVE = new TKChartPaletteItem();

paletteItemFVE.Fill = new TKSolidFill(StyleUtil.GetChartYellow());

serieFVE.Style.Palette.AddPaletteItem(paletteItemFVE);

dailyGraphChart.AddSeries(serieFVE);

//CHARGE - Orange

var serieBatUp = new TKChartAreaSeries(pointsBatUp.ToArray());

serieBatUp.StackInfo = stackInfo;

serieBatUp.Style.Palette = new TKChartPalette();

var paletteItemBatUp = new TKChartPaletteItem();

paletteItemBatUp.Fill = new TKSolidFill(StyleUtil.GetChartOrange());

serieBatUp.Style.Palette.AddPaletteItem(paletteItemBatUp);

dailyGraphChart.AddSeries(serieBatUp);

//DISCHARGE - Green

var serieBatDown = new TKChartAreaSeries(pointsBatDown.ToArray());

serieBatDown.StackInfo = stackInfo;

serieBatDown.Style.Palette = new TKChartPalette();

var paletteItemBatDown = new TKChartPaletteItem();

paletteItemBatDown.Fill = new TKSolidFill(StyleUtil.GetChartGreen());

serieBatDown.Style.Palette.AddPaletteItem(paletteItemBatDown);

dailyGraphChart.AddSeries(serieBatDown);

//GRID - Blue

var serieGrid = new TKChartAreaSeries(pointsGrid.ToArray());

serieGrid.StackInfo = stackInfo;

serieGrid.Style.Palette = new TKChartPalette();

var paletteItemGrid = new TKChartPaletteItem();

paletteItemGrid.Fill = new TKSolidFill(StyleUtil.GetChartBlue());

serieGrid.Style.Palette.AddPaletteItem(paletteItemGrid);

dailyGraphChart.AddSeries(serieGrid);

Android Code

//Initialization

RadCartesianChartView chartView = new RadCartesianChartView(v.Context);

ChartPalette customPalette = new ChartPalette(chartView.Palette);

AreaSeries EFVAreaSeries = new AreaSeries();

EFVAreaSeries.CombineMode = ChartSeriesCombineMode.Stack;

EFVAreaSeries.StackGroupKey = 0;

EFVAreaSeries.CategoryBinding = new PowerResultDataBinding ("PowerType");

EFVAreaSeries.ValueBinding = new PowerResultDataBinding ("hour");

EFVAreaSeries.Data = (Java.Lang.IIterable)this.EFVresults;

CustomizarPaleta (customPalette,ChartPalette.AreaFamily, GetChartYellow (), 0);

EFVAreaSeries.StrokeColor = Color.Black.ToArgb ();

EFVAreaSeries.StrokeThickness = 0.5f;

chartView.Series.Add(EFVAreaSeries);

AreaSeries CargaBAreaSeries = new AreaSeries();

CargaBAreaSeries.CombineMode = ChartSeriesCombineMode.Stack;

CargaBAreaSeries.StackGroupKey = 0;

CargaBAreaSeries.CategoryBinding = new PowerResultDataBinding ("PowerType");

CargaBAreaSeries.ValueBinding = new PowerResultDataBinding ("hour");

CargaBAreaSeries.Data = (Java.Lang.IIterable)this.CargaBresults;

CustomizarPaleta (customPalette,ChartPalette.AreaFamily, GetChartOrange (), 1);

CargaBAreaSeries.StrokeColor = Color.Black.ToArgb ();

CargaBAreaSeries.StrokeThickness = 0.5f;

chartView.Series.Add(CargaBAreaSeries);

AreaSeries DescargaAreaSeries = new AreaSeries();

DescargaAreaSeries.CombineMode = ChartSeriesCombineMode.Stack;

DescargaAreaSeries.StackGroupKey =0;

DescargaAreaSeries.CategoryBinding = new PowerResultDataBinding ("PowerType");

DescargaAreaSeries.ValueBinding = new PowerResultDataBinding ("hour");

DescargaAreaSeries.Data = (Java.Lang.IIterable)this.DescargaResults;

CustomizarPaleta (customPalette,ChartPalette.AreaFamily, GetChartGreen (), 2);

DescargaAreaSeries.StrokeColor = Color.Black.ToArgb ();

DescargaAreaSeries.StrokeThickness = 0.5f;

chartView.Series.Add(DescargaAreaSeries);

AreaSeries RedAreaSeries = new AreaSeries();

RedAreaSeries.CombineMode = ChartSeriesCombineMode.Stack;

RedAreaSeries.StackGroupKey = 0;

RedAreaSeries.CategoryBinding = new PowerResultDataBinding ("PowerType");

RedAreaSeries.ValueBinding = new PowerResultDataBinding ("hour");

RedAreaSeries.Data = (Java.Lang.IIterable)this.RedResults;

CustomizarPaleta (customPalette,ChartPalette.AreaFamily, GetChartBlue (), 3);

RedAreaSeries.StrokeColor = Color.Black.ToArgb ();

RedAreaSeries.StrokeThickness = 0.5f;

chartView.Series.Add(RedAreaSeries);

AreaSeries InyecAreaSeries = new AreaSeries();

InyecAreaSeries.CombineMode = ChartSeriesCombineMode.Stack;

InyecAreaSeries.StackGroupKey = 0;

InyecAreaSeries.CategoryBinding = new PowerResultDataBinding ("PowerType");

InyecAreaSeries.ValueBinding = new PowerResultDataBinding ("hour");

InyecAreaSeries.Data = (Java.Lang.IIterable)this.Inyecresults;

CustomizarPaleta (customPalette,ChartPalette.AreaFamily, GetChartRed(), 4);

InyecAreaSeries.StrokeColor = Color.Black.ToArgb ();

InyecAreaSeries.StrokeThickness = 0.5f;

chartView.Series.Add(InyecAreaSeries);

Chart - Xamarin.iOS

answered on 24 Jan 2017

15 answers

186 views

Nuget

Hi,

The Xamarin Forms controls no longer appear in nuget packages to install, even when you select pre-release.

Is there a new server or something? I'm using https://nuget.telerik.com/nuget

Thanks,

Norman.

General Discussions

answered on 13 Jan 2017

7 answers

116 views

Chart DateTimeCategoricalAxis

Hello, I need to set the horizontal date axis

to display either 6 hours ticks or date ticks.

The label format should change like in the attached file.

We want to set the zoom behavior to zoom-in to 15 days

Appreciate Help

Chart - Xamarin.Android

answered on 12 Jan 2017

3 answers

119 views

Zoom Is Reset

Hello

We use ChartPanAndZoomBehavior

After we Add Annotation or Series the Zoom Is Reset

How can we avoid this?

Thanks

Chart - Xamarin.Android

answered on 11 Jan 2017

1 answer

129 views

Master Detail Page under Side Drawer MainContent

Hi,

Is it possible to have a master detail page under the side drawer main content?

SideDrawer

answered on 10 Jan 2017