Develop Reference

.Net MAUI: Different result for CollectionView/DataTemplate between Android and iOS

I wrote a simple CollectionView (.Net MAUI) with a DataTemplate and get completely different results when I deploy the code to either a Android device or a iOS device.
It would be really awesome if someone has a hint - this project drives me crazy since 4 months :D
I used the same code in Xamarin before without any issues.
EDIT:
I added the WidthRequest (and a margin) and now the style is as expected - thanks so far. (I also checked the text colors which are fine and I changed the TextColor of two lables to red - just for testing)
But I still have another issue. When the iOS App is opened, the part on the right hand side does not show up and it seems that the app is hung up. If I try to scroll, then I get a completlely random list of my items (some are missing) and everything is stuck.
<RefreshView x:DataType="local:ItemsViewModel" Command="{Binding LoadItemsCommand}" IsRefreshing="{Binding IsBusy, Mode=TwoWay}">
<CollectionView x:Name="ItemsListView" ItemsSource="{Binding Items}" SelectionMode="None">
<CollectionView.ItemTemplate>
<DataTemplate>
<Grid Padding="10" x:DataType="model:Cryptocurrency">
<Grid.RowDefinitions>
<RowDefinition Height="auto" />
<RowDefinition Height="auto" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="auto" />
<ColumnDefinition Width="auto" />
<ColumnDefinition Width="*" />
<ColumnDefinition Width="auto" />
</Grid.ColumnDefinitions>
<Image Source="{Binding image}" Grid.Row="0" Grid.Column="0" Grid.RowSpan="2" HeightRequest="50" WidthRequest="50" Margin="0,0,10,0" />
<Label Text="{Binding name}" Grid.Row="0" Grid.Column="1"
LineBreakMode="NoWrap"
Style="{DynamicResource ListItemTextStyle}"
FontSize="16" />
<Label Text="Price" Grid.Row="0" Grid.Column="2"
LineBreakMode="NoWrap" HorizontalTextAlignment="End" Padding="0,0,20,0"
Style="{DynamicResource ListItemTextStyle}"
FontSize="16" />
<Label Text="x to ATH" Grid.Row="0" Grid.Column="3"
LineBreakMode="NoWrap"
Style="{DynamicResource ListItemTextStyle}"
FontSize="16" />
<Label Text="{Binding market_cap_rank}" Grid.Row="1" Grid.Column="1"
LineBreakMode="NoWrap"
Style="{DynamicResource ListItemDetailTextStyle}"
FontSize="13" />
<Label Text="{Binding current_price, StringFormat='{}{0:C}'}" Grid.Row="1" Grid.Column="2"
LineBreakMode="NoWrap" HorizontalTextAlignment="End" Padding="0,0,20,0"
Style="{DynamicResource ListItemDetailTextStyle}"
FontSize="13" />
<Label Text="{Binding RatioToATH}" Grid.Row="1" Grid.Column="3"
LineBreakMode="NoWrap"
Style="{DynamicResource ListItemDetailTextStyle}"
FontSize="13" />
<Grid.GestureRecognizers>
<TapGestureRecognizer NumberOfTapsRequired="1" Command="{Binding Source={RelativeSource AncestorType={x:Type local:ItemsViewModel}}, Path=ItemTapped}"
CommandParameter="{Binding .}">
</TapGestureRecognizer>
</Grid.GestureRecognizers>
</Grid>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
</RefreshView>
EDIT2:
It also works flawlessly on macOS (MacCatalyst)

You could set the constraint of Image(give it a width), please refer to the following code.
<Image Source="{Binding image}" Grid.Row="0" Grid.Column="0" Grid.RowSpan="2" HeightRequest="50" WidthRequest="150" />

Yes! this is how MAUI work they will call out the native controls instead of control that is written in the middle layer like Flutter
They provide you OnPlatform so you can easily adjust the UI better
IsVisible={x:OnPlatform WinUI=true, Android=false, iOS=false, Tizen=false, MacCatalyst=false}

What is this big black bar at the bottom?

I am building an app in .NET MAUI. I started building it for a previous android version (API 22). The layout is fine for that version. But when I installed it on a later version of android (API 33), the vertical stack layout wasn't aligning as I wanted it to be.
I thought the problem was with how I arranged all these elements. So, I rewrote the XAML, but still didn't achieve what I was looking for. The black bar still remains at the bottom.
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://schemas.microsoft.com/dotnet/2021/maui"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
xmlns:viewmodels="clr-namespace:WordsAssistantMAUI.ViewModels"
x:DataType="viewmodels:DefinitionViewModel"
x:Class="WordsAssistantMAUI.Views.DefinitionView"
Title="Get Definition"
BackgroundColor="#7d83cf">
<VerticalStackLayout
VerticalOptions="Start" HorizontalOptions="Center" Margin="20,20" Spacing="20">
<!--Search bar-->
<SearchBar Text="{Binding Input}" IsEnabled="{Binding IsNotBusy}"
SearchCommand="{Binding Source={RelativeSource AncestorType={x:Type viewmodels:DefinitionViewModel}}, Path=SearchDefinitionCommand}"/>
<!--Definition and Navigation buttons-->
<Grid ColumnDefinitions="*, 10*, *"
ColumnSpacing="15" VerticalOptions="Center" RowDefinitions="*,*">
<Button Text="b"
HeightRequest="50" WidthRequest="50"
Grid.Column="0" Grid.Row="0"
Command="{Binding Source={RelativeSource AncestorType={x:Type viewmodels:DefinitionViewModel}}, Path=PreviousDefinitionCommand}"/>
<ScrollView Grid.Row="0" Grid.Column="1" HeightRequest="125">
<Label Text="{Binding Definition}"
Style="{StaticResource DefintionStyle}"/>
</ScrollView>
<Button Text="n"
Grid.Row="0" Grid.Column="2"
HeightRequest="50" WidthRequest="50"
Command="{Binding Source={RelativeSource AncestorType={x:Type viewmodels:DefinitionViewModel}}, Path=NextDefinitionCommand}"/>
<ActivityIndicator
IsVisible="{Binding IsBusy}"
IsRunning="{Binding IsBusy}"
Grid.Column="1"
Grid.Row="1"/>
</Grid>
<!--Synonyms and Antonyms-->
<Grid ColumnDefinitions="*,*" Style="{StaticResource ResponsesListGrid}">
<VerticalStackLayout Grid.Column="0" HorizontalOptions="Center">
<Label Text="Synonyms"
Style="{StaticResource ResponsesLabel}"/>
<Frame HeightRequest="300"
Style="{StaticResource ResponsesFrame}">
<ScrollView HorizontalOptions="Start">
<FlexLayout BindableLayout.ItemsSource="{Binding synonyms}"
Style="{StaticResource ResponsesFlexLayout}">
<BindableLayout.ItemTemplate>
<DataTemplate>
<Frame Style="{StaticResource ResponseStyling}">
<Label Text="{Binding .}" Style="{StaticResource Responses}"/>
</Frame>
</DataTemplate>
</BindableLayout.ItemTemplate>
<BindableLayout.EmptyViewTemplate>
<DataTemplate>
<Frame HasShadow="True" BackgroundColor="LightGray"
Padding="5">
<Label Style="{StaticResource Responses}"
Text="Nothing to show right now!"/>
</Frame>
</DataTemplate>
</BindableLayout.EmptyViewTemplate>
</FlexLayout>
</ScrollView>
</Frame>
</VerticalStackLayout>
<VerticalStackLayout Grid.Column="1" HorizontalOptions="Center">
<Label Text="Antonyms"
Style="{StaticResource ResponsesLabel}"/>
<Frame HeightRequest="300"
Style="{StaticResource ResponsesFrame}">
<ScrollView HorizontalOptions="Start">
<FlexLayout BindableLayout.ItemsSource="{Binding antonyms}"
Style="{StaticResource ResponsesFlexLayout}">
<BindableLayout.ItemTemplate>
<DataTemplate>
<Frame Style="{StaticResource ResponseStyling}">
<Label Text="{Binding .}" Style="{StaticResource Responses}"/>
</Frame>
</DataTemplate>
</BindableLayout.ItemTemplate>
<BindableLayout.EmptyViewTemplate>
<DataTemplate>
<Frame HasShadow="True" BackgroundColor="LightGray"
Padding="5">
<Label Style="{StaticResource Responses}"
Text="Nothing to show right now!"/>
</Frame>
</DataTemplate>
</BindableLayout.EmptyViewTemplate>
</FlexLayout>
</ScrollView>
</Frame>
</VerticalStackLayout>
</Grid>
<Button Text="Clear all" WidthRequest="150"
IsEnabled="{Binding IsNotBusy}"
Command="{Binding Source={RelativeSource AncestorType={x:Type viewmodels:DefinitionViewModel}}, Path=ClearAllCommand}"/>
</VerticalStackLayout>
</ContentPage>

Fill the screen with a listview

i need a trick, i have in my xamarin.forms app a listview, but it don't feel my screen, and it's orrible to see it now, because it take off a quarter of screen without nothing, could you helo me?
XAML:
<ContentPage.Content>
<AbsoluteLayout VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand" BackgroundColor="WhiteSmoke">
<ListView x:Name="ItemsListView"
HeightRequest="000" <--this is the bad thing
VerticalOptions="FillAndExpand"
HasUnevenRows="true"
IsPullToRefreshEnabled="true"
Refreshing="OnRefresh"
CachingStrategy="RecycleElement"
ItemSelected="OnItemSelected"
SeparatorVisibility="Default"
BackgroundColor="Transparent">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ViewCell.ContextActions>
<MenuItem Clicked="MenuItem_Clicked" CommandParameter="{Binding .}" Text="Delete" IsDestructive="True" />
</ViewCell.ContextActions>
<ViewCell.View>
<Grid Margin="0,0,0,15">
<Grid.RowDefinitions>
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<StackLayout Orientation="Horizontal" BackgroundColor="White" Padding="10">
<controls:CircleImage Source="{Binding UserPicture}" WidthRequest="40" HeightRequest="40" Aspect="AspectFit" VerticalOptions="Start"/>
<StackLayout Orientation="Vertical" Padding="5" Spacing="20">
<StackLayout Orientation="Vertical" Spacing="2">
<Label Text="{Binding Title}" LineBreakMode="TailTruncation" Style="{DynamicResource ListItemTextStyle}"
FontSize="18" FontAttributes="Bold" TextColor="Black"/>
<Label Text="{Binding UserName}" LineBreakMode="NoWrap" Style="{DynamicResource ListItemDetailTextStyle}"
FontSize="14" />
</StackLayout>
<BoxView HeightRequest="1" WidthRequest="250" BackgroundColor="LightGray"/>
<StackLayout Orientation="Horizontal" VerticalOptions="End" >
<StackLayout Orientation="Horizontal">
<Image Source="people.png" WidthRequest="20" HeightRequest="20" />
<Label Text="{Binding Posti}" LineBreakMode="NoWrap" Style="{DynamicResource ListItemDetailTextStyle}"
FontSize="14" />
<Label Text="/" LineBreakMode="NoWrap" Style="{DynamicResource ListItemDetailTextStyle}"
FontSize="14" />
<Label Text="{Binding Participants}" LineBreakMode="NoWrap" Style="{DynamicResource ListItemDetailTextStyle}"
FontSize="14" />
</StackLayout>
</StackLayout>
</StackLayout>
</StackLayout>
</Grid>
</ViewCell.View>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
<fab:FloatingActionButtonView
ImageName="add.png"
ColorNormal="#2196F3"
ColorPressed="#2196F3"
ColorRipple="#2196F3"
x:Name="FloatingActionButtonAdd"
IsVisible="False"
AbsoluteLayout.LayoutFlags="PositionProportional"
AbsoluteLayout.LayoutBounds="1, 1, AutoSize, AutoSize"/>
</AbsoluteLayout>
</ContentPage.Content>
I want the heghtrequest will scale automatically with the device or have a standard heght for any devices

Because you are using absolutelayout around your listview you should try as below. add these on your listview VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand" AbsoluteLayout.LayoutFlags="All" AbsoluteLayout.LayoutBounds="0,0,1,1"
<AbsoluteLayout VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand" BackgroundColor="WhiteSmoke">
<ListView x:Name="ItemsListView" VerticalOptions="FillAndExpand" HorizontalOptions="FillAndExpand" AbsoluteLayout.LayoutFlags="All"
AbsoluteLayout.LayoutBounds="0,1,1,1"
HasUnevenRows="true"
IsPullToRefreshEnabled="true"
Refreshing="OnRefresh"
CachingStrategy="RecycleElement"
ItemSelected="OnItemSelected"
SeparatorVisibility="Default"
BackgroundColor="Transparent">
read more about absolutelayout here. in my code
AbsoluteLayout.LayoutBounds="0,0,1,1"
tells you to start from position vertical 0, horizontal 0 and align the UI as large as the screen. you dont need to use HeightRequest in this case as it will take the screen size dynamically.

Here is simple style and code you can change it to your own
<RelativeLayout><ListView x:Name="MessagesListView" HasUnevenRows="True" IsPullToRefreshEnabled ="true" SeparatorVisibility="None"
RelativeLayout.WidthConstraint="{ConstraintExpression Type=RelativeToParent,Property=Width,Factor=1,Constant=0}"
RelativeLayout.HeightConstraint="{ConstraintExpression Type=RelativeToParent,Property=Height,Factor=.92,Constant=0}">
</ListView></RelativeLayout>

how can i make expandable listView in Grid?

I want make ui like this image.
but I don't know how can I make expandable listview in grid.
<?xml version="1.0" encoding="utf-8" ?>
<ContentPage xmlns="http://xamarin.com/schemas/2014/forms"
xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
x:Class="ElronWebtoon_Test.myLibrary.LibTab" BackgroundColor="White">
<Grid RowSpacing="0">
<Grid.RowDefinitions>
<RowDefinition x:Name="TopGrid"/>
<RowDefinition />
<RowDefinition x:Name="menuRow"/>
</Grid.RowDefinitions>
<Grid Grid.Row="0" x:Name="GlobalLayout" >
<Grid.RowDefinitions>
<RowDefinition x:Name="TopBtn_Grid"/>
<RowDefinition x:Name="menu_Grid"/>
</Grid.RowDefinitions>
<Grid Grid.Row="0" VerticalOptions="Start" >
<Label x:Name="labelBox1" Text="LabelBox1" Font="Bold, 16" TextColor="Black" HorizontalOptions="Start" HorizontalTextAlignment="Center" VerticalTextAlignment="Center" VerticalOptions="Center" Grid.Column="0" BackgroundColor="#A8D2F1">
<Label.GestureRecognizers>
<TapGestureRecognizer/>
</Label.GestureRecognizers>
</Label>
<Label x:Name="LabelBox2" Text="LabelBox2" Font="Bold, 16" TextColor="Black" HorizontalOptions="End" HorizontalTextAlignment="Center" VerticalTextAlignment="Center" VerticalOptions="Center" Grid.Column="0" BackgroundColor="#A8D2F1">
<Label.GestureRecognizers>
<TapGestureRecognizer />
</Label.GestureRecognizers>
</Label>
</Grid>
<Grid Grid.Row="1" x:Name="libMenu" RowSpacing="0" HorizontalOptions="CenterAndExpand">
<Grid Grid.Column="0" x:Name="menuGrid_1" HorizontalOptions="Center">
<Button BorderRadius="30" BorderColor="Black" BorderWidth="2" BackgroundColor="White" VerticalOptions="Center"/>
<Label x:Name="BtnText1" Text="BtnText1" TextColor="Black" VerticalOptions="Center" HorizontalOptions="Center" VerticalTextAlignment="Center"/>
</Grid>
<Grid Grid.Column="1" x:Name="menuGrid_2" HorizontalOptions="Center">
<Button BorderRadius="30" BorderColor="Black" BorderWidth="2" BackgroundColor="White" VerticalOptions="Center"/>
<Label x:Name="BtnText2" Text="BtnText2" TextColor="Black" VerticalOptions="Center" HorizontalOptions="Center" VerticalTextAlignment="Center"/>
</Grid>
<Grid Grid.Column="2" x:Name="menuGrid_3" HorizontalOptions="Center">
<Button BorderRadius="30" BorderColor="Black" BorderWidth="2" BackgroundColor="White" VerticalOptions="Center"/>
<Label x:Name="BtnText3" Text="BtnText3" TextColor="Black" VerticalOptions="Center" HorizontalOptions="Center" VerticalTextAlignment="Center"/>
</Grid>
</Grid>
</Grid>
<Grid Grid.Row="1" VerticalOptions="Fill" x:Name="inner_Content">
</Grid>
<Grid Grid.Row="2" >
<Grid>
<Button Text="BTN1" Grid.Column="0" />
<Button Text="BTN2" Grid.Column="1"/>
<Button Text="BTN3" Grid.Column="2"/>
<Button Text="BTN4" Grid.Column="3"/>
<Button Text="BTN5" Grid.Column="4"/>
</Grid>
</Grid>
</Grid>
</ContentPage>
this is my sample code.
I want insert expandable listview in Grid, named inner_Content in this code.
but if I searching expandable listview, that only in contentPage.
not in grid.
can you help me?

I guess you are looking something like an accordion control to be used in Xamarin.
Check the URL below:
https://www.codeproject.com/Articles/1088093/Simple-Accordion-User-Control-in-Xamarin-Forms
Hope this helps, mark this as an answer if you think this meets your requirement.
Regards,
N Baua

xamarin cross platform form for buttons with image and text layout

I am looking to create a xamarin cross platform dashboard page with some buttons. Each button have an icon image and a text. I tried two approaches 1. with using inbuilt property of Icon of Button control and another with separate StackLayout
But my output needs some optimization on xaml
The xaml i tried is like this
<Grid Padding="10">
<Grid.RowDefinitions>
<RowDefinition Height="150" ></RowDefinition>
<RowDefinition Height="150"></RowDefinition>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition></ColumnDefinition>
<ColumnDefinition></ColumnDefinition>
</Grid.ColumnDefinitions>
<StackLayout Grid.Row="0" Grid.Column="0" BackgroundColor="#3094d2" >
<StackLayout VerticalOptions="Center" HorizontalOptions="Center">
<Image Source="#drawable/announcement.png" VerticalOptions="Center" HorizontalOptions="Center" />
</StackLayout>
<StackLayout VerticalOptions="Center" HorizontalOptions="Center">
<Button Text="Announcement" TextColor="White" VerticalOptions="Center" HorizontalOptions="Center" />
</StackLayout>
</StackLayout>
<Button Text="News & Events" Grid.Row="0" Grid.Column="1" BackgroundColor="#287cbe" Image="#drawable/announcement.png" TextColor="White" Clicked="Button_NewsHome_Clicked" />
<Button Text="Messages" Grid.Row="1" Grid.Column="0" BackgroundColor="#5153a9" Image="#drawable/announcement.png" TextColor="White" Clicked="Button_SMSHome_Clicked" />
<Button Text="SMS Alers" Grid.Row="1" Grid.Column="1" Image="#drawable/announcement.png" BackgroundColor="#a434a6" TextColor="White" Clicked="Button_SMSHome_Clicked" />
</Grid>
What adjustments i have to do on Vertical and Horizontal align to make my ouput looks like that on the left side

You can use XLabs Extended Button to get desired output