NativeScript ScrollView bug on Android with runtime version 5.0.0 - nativescript

The ScrollView isUserInteractionEnabled parameter doesn't behave the same on NativeScript runtime version 5.0.0 as it did on 4.2.0 for Android.
No script files required. All you need is this XML to observe this problem:
<Page class="page" xmlns="http://www.nativescript.org/tns.xsd">
<ActionBar title="Horizontal Scroll Bug" class="action-bar">
</ActionBar>
<StackLayout>
<Label text="ScrollView's isUserInteractionEnabled property is false."
padding="10" textWrap="true" fontSize="20" />
<ScrollView id="horizontalScroll" orientation="horizontal" isUserInteractionEnabled="false">
<StackLayout orientation="horizontal">
<StackLayout backgroundColor="yellow">
<Label text="Box 1" padding="70" />
</StackLayout>
<StackLayout backgroundColor="red">
<Label text="Box 2" padding="70" />
</StackLayout>
<StackLayout backgroundColor="blue">
<Label text="Box 3" padding="70" />
</StackLayout>
<StackLayout backgroundColor="green">
<Label text="Box 4" padding="70" />
</StackLayout>
<StackLayout backgroundColor="purple">
<Label text="Box 5" padding="70" />
</StackLayout>
<StackLayout backgroundColor="orange">
<Label text="Box 6" padding="70" />
</StackLayout>
</StackLayout>
</ScrollView>
<Label text="Try to scroll the colored boxes above to the right and left to reveal more boxes. You shouldn't be able to."
padding="10" textWrap="true" fontSize="20" />
<Label text="On Android with run time version 4.2.0 you can't, but on run time version 5.0.0 you can."
padding="10" textWrap="true" fontSize="20" />
</StackLayout>
</Page>
I posted the app on NativeScript playground here if you want to scan the QR code:
https://play.nativescript.org/?template=play-js&id=hKrNlK

Disable scroll when isUserInteractionEnabled is set to false - This seems to be a behavioural change introduced in {N} 5.x. At same time I'm unsure whether this was intentional, you might want to report this at Github.
Meanwhile you may use this workaround.

Related

Cross-platform pager with xamarin.form

In Xamarin.Android it has a class named ViewPager to support "Gestural navigation allows the user to swipe left and right to step through pages of data." (https://learn.microsoft.com/en-us/xamarin/android/user-interface/controls/view-pager/)
But my task is write cross-platform codes for both Android & iOS (without rewrite new code for this gesture). With Xamarin.Form does any library support this ? I have read about Xamarin.Form carousel, but it seem used for slideshow, not appropriate for news list.
I think TabbedPage is more suitable for you. tabbedPage support the Gestural navigation allows the user to swipe left and right to step through pages of data, just set the different pages of data in different tabs.
Here is running GIF.
You can add this Tabbedpage like following code.
<TabbedPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="clr-namespace:TabbedPageDemo;assembly=TabbedPageDemo"
x:Class="TabbedPageDemo.TabbedPageDemoPage">
<TabbedPage.Resources>
<ResourceDictionary>
<local:NonNullToBooleanConverter x:Key="booleanConverter" />
</ResourceDictionary>
</TabbedPage.Resources>
<TabbedPage.ItemTemplate>
<DataTemplate>
<ContentPage Title="{Binding Name}" Icon="monkeyicon.png">
<StackLayout Padding="5, 25">
<Label Text="{Binding Name}"
Font="Bold,Large"
HorizontalOptions="Center" />
<Image Source="{Binding PhotoUrl}"
WidthRequest="200"
HeightRequest="200" />
<StackLayout Padding="50, 10">
<StackLayout Orientation="Horizontal">
<Label Text="Family:"
HorizontalOptions="FillAndExpand" />
<Label Text="{Binding Family}"
Font="Bold,Medium" />
</StackLayout>
<StackLayout Orientation="Horizontal"
IsVisible="{Binding Subfamily,
Converter={StaticResource booleanConverter}}">
<Label Text="Subfamily:"
HorizontalOptions="FillAndExpand" />
<Label Text="{Binding Subfamily}"
Font="Bold,Medium" />
</StackLayout>
<StackLayout Orientation="Horizontal"
IsVisible="{Binding Tribe,
Converter={StaticResource booleanConverter}}">
<Label Text="Tribe:"
HorizontalOptions="FillAndExpand" />
<Label Text="{Binding Tribe}"
Font="Bold,Medium" />
</StackLayout>
<StackLayout Orientation="Horizontal">
<Label Text="Genus:"
HorizontalOptions="FillAndExpand" />
<Label Text="{Binding Genus}"
Font="Bold,Medium" />
</StackLayout>
</StackLayout>
</StackLayout>
</ContentPage>
</DataTemplate>
</TabbedPage.ItemTemplate>
</TabbedPage>
You can add different ItemTemplate in the Tabbedpage.
Here is a related link.
https://learn.microsoft.com/en-us/xamarin/xamarin-forms/app-fundamentals/navigation/tabbed-page
Update: you can add the listview in the tabbpage like following GIF.

How to set FlexLayout height automatically according to its children height

I'm trying to create a FlexLayout without specifying its height as I am supposing it will get it from its children height. When I'm doing so, the FlexLayout is not displayed at all. Here is a simple code:
<FlexLayout Direction="Column">
<Button Text="Test Button" />
<!-- Here I'm trying to create FlexLayout without specifying its height -->
<FlexLayout JustifyContent="Start" AlignItems="Start" AlignContent="Start" BackgroundColor="Blue" Direction="RowReverse" Wrap="Wrap">
<Label Text="Test Label" HeightRequest="50" WidthRequest="50" BackgroundColor="Yellow" />
</FlexLayout>
</FlexLayout>
I tried everything but nothing works unless I specify HeightRequest or FlexLayout.Basis for the (inner) FlexLayout.
Any Suggestions will be appreciated.
If I changed the first FlexLayout to StackLayout as follows, it will work. This is so weird as I assume it should work without changing it to StackLayout :
<StackLayout Orientation="Vertical" Spacing="0">
<Button Text="Test Button" />
<FlexLayout JustifyContent="Start" AlignItems="Start" AlignContent="Start" BackgroundColor="Blue" Direction="RowReverse" Wrap="Wrap">
<Label Text="Test Label" HeightRequest="50" WidthRequest="50" BackgroundColor="Yellow" />
</FlexLayout>
</StackLayout>

Change Orientation to Vertical when use of Repeater

I am creating a Horizontal scroll in NS. When using below code it's working as expected.
<Page xmlns="http://schemas.nativescript.org/tns.xsd" navigatingTo="onPageLoad" class="page">
<StackLayout>
<!-- This is where the magic happens -->
<ScrollView orientation="horizontal">
<StackLayout orientation="horizontal" class="scroll-menu">
<StackLayout class="scroll-pane">
<Button text="Button" />
</StackLayout>
<StackLayout class="scroll-pane">
<Button text="Button" />
</StackLayout>
<StackLayout class="scroll-pane">
<Button text="Button" />
</StackLayout>
<StackLayout class="scroll-pane">
<Button text="Button" />
</StackLayout>
</StackLayout>
</ScrollView>
</StackLayout>
Horizontal Scroll:
But, Once I am using the Repeater it's changing to orientation with Vertical and not scrolling.
<Page xmlns="http://schemas.nativescript.org/tns.xsd" navigatingTo="onPageLoad" class="page">
<StackLayout>
<!-- This is where the magic happens -->
<ScrollView orientation="horizontal">
<StackLayout orientation="horizontal" class="scroll-menu">
<Repeater items="{{ categories }}" >
<Repeater.itemTemplate>
<StackLayout class="scroll-pane" >
<Label text="{{name}}" />
</StackLayout>
</Repeater.itemTemplate>
</Repeater>
</StackLayout>
</ScrollView>
</StackLayout>
Change to Vertical when use of Repeater:
What's wrong with the code?

StackLayout ignoring EndAndExpand on iOS

It seems that there is a confirmed Bug in Xamarin.Forms in iOS, when you have a content/label with a text too large that needs 2 lines to display it in a StackLayout (lets say layoutA), the others siblings and parent elements takes the width of the layoutA.
Kent Boogaart filled a Bug with the following example to reproduce the error.
<StackLayout Margin="0,20,0,0">
<!-- works (by virtue of no wrapping) -->
<StackLayout Orientation="Horizontal">
<Switch/>
<Label Text="Some text"/>
<Button Text="A Button" HorizontalOptions="EndAndExpand"/>
</StackLayout>
<!-- works (by virtue of no switch) -->
<StackLayout Orientation="Horizontal">
<Label Text="Some longer text that wraps over two lines"/>
<Button Text="A Button" HorizontalOptions="EndAndExpand"/>
</StackLayout>
<!-- does not work -->
<StackLayout Orientation="Horizontal">
<Switch/>
<Label Text="Some longer text that wraps over two lines"/>
<Button Text="A Button" HorizontalOptions="EndAndExpand"/>
</StackLayout>
</StackLayout>
Is there a solution/fix/workaround for this problem?
EDIT
Here is the code used:
<ListView HasUnevenRows="True" SeparatorVisibility="None" HorizontalOptions="StartAndExpand" CachingStrategy="RecycleElement">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<StackLayout Orientation="Horizontal" HorizontalOptions="FillAndExpand" VerticalOptions="FillAndExpand" BackgroundColor="#eee" Padding="5" Margin="5" >
<ffimageloading:CachedImage HorizontalOptions="Start" VerticalOptions="Start" HeightRequest="75" Source="{Binding ID, StringFormat='https://example/api/{0}'}" CacheDuration="15">
<ffimageloading:CachedImage.Transformations>
<fftransformations:CircleTransformation/>
</ffimageloading:CachedImage.Transformations>
</ffimageloading:CachedImage>
<StackLayout Orientation="Vertical" HorizontalOptions="FillAndExpand">
<Label Text="{Binding Name}" TextColor="#f35e20" HorizontalOptions="FillAndExpand"/>
<Label Text="{Binding Description}" HorizontalOptions="FillAndExpand" TextColor="#503026" />
<Label Text="{Binding ID}" x:Name="ID" IsVisible="False"></Label>
<Button Text="Ver productos" TextColor="#FF5F6D" HorizontalOptions="End" BackgroundColor="Transparent"></Button>
</StackLayout>
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
These are actual screenshots of the app in iOS, in Android it just work great.
As you can see, in the Image1 the first card is OK, the button ("Agregar al carrito" or "Ver Productos") is at the end.
But in the second card as the text is too large, the button gets down out of the card.
And in the second image, the text in the middle needs 2 lines, and the StackLayout that wraps the content (the 2 labels and the button) gets just as wide as the label with the large text.
I draw a red square in the large text, and a red line so you can see that because of that large text, the StackLayout gets narrow.
This is a known issue that when setting the padding on stacklayout inside Cell , the row height displays incorrectly.
Solution: Use StackLayout to wrap the content under the Cell.
<ViewCell>
<StackLayout > //add this
<StackLayout Orientation="Horizontal" Padding="5" Margin="5" >
</ffimageloading:CachedImage>
<StackLayout BackgroundColor="Brown" Orientation="Vertical">
<Label TextColor="#f35e20" HorizontalOptions="FillAndExpand"/>
<Label/>
<Label Text="fff" x:Name="ID" IsVisible="False"></Label>
<Button Text="Ver productos" TextColor="#FF5F6D" BackgroundColor="Yellow"></Button>
</StackLayout>
</StackLayout>
</StackLayout>
</ViewCell>

TextWrapped Label breaks Layout Option FillAndExpand in StackLayout

I'm having a cell view with nested StackLayouts, there's one label that will be wrapped if the text is long, which is the desired behaviour. However, the wrap breaks the LayoutOptions set to (basically) all parent views resulting in a gray gap on the right hand side.
<StackLayout Orientation="Horizontal" BackgroundColor="Gray" Margin="0,30,0,0">
<BoxView
HorizontalOptions="Start"
BackgroundColor="#EEBB00"
WidthRequest="100"
/>
<StackLayout
BackgroundColor="#CC4400"
HorizontalOptions="FillAndExpand"
>
<BoxView
BackgroundColor="Green"
HeightRequest="10"
HorizontalOptions="FillAndExpand"
/>
<Label
FontSize="16"
HorizontalOptions="FillAndExpand"
Text="Name that is toolongandwillbewrapped"
/>
<StackLayout
Orientation="Horizontal"
HorizontalOptions="FillAndExpand"
BackgroundColor="Blue"
>
<Label
FontSize="13"
Text="Left"
TextColor="White"
HorizontalOptions="StartAndExpand"
VerticalTextAlignment="End"
/>
<Label
FontSize="13"
Text="Right"
TextColor="White"
HorizontalOptions="EndAndExpand"
VerticalTextAlignment="End"
/>
</StackLayout>
</StackLayout>
</StackLayout>
The resulting views are:
So I can tell why this is happening, but well, of course I don't like it. The expected behaviour is for the right-hand-side stacklayout to expand all the way to the right. I've tried various ways to circumvent this and would not be here if I had succeeded. Does anybody have an idea?
Unfortunately, it's a bug in Xamarin.Forms (probably, iOS-only).
Bugzilla #28650
Bugzilla #31128
Bugzilla #33841
The workaround in that case is using Grid instead of StackLayout : http://forums.xamarin.com/discussion/comment/152969/#Comment_152969

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