Xamarin.Forms: Custom Context Actions For Android - xamarin

Hi i have a list view in which i added ContextActions.
i need to change Text Size, color and alignment of menu item in context actions,
also i want to increase width of context action on which menu item is appearing?
Thanks in advance.
<ListView.ItemTemplate>
<DataTemplate>
<customControls:ExtendedViewCell SelectedBackgroundColor="Transparent" >
<ViewCell.ContextActions>
<MenuItem Text="Call" />
<MenuItem Text="Delete" IsDestructive="True" />
</ViewCell.ContextActions>
<ViewCell.View>
<StackLayout HorizontalOptions="FillAndExpand"
VerticalOptions="FillAndExpand" Orientation="Vertical"
Padding="4" Spacing="8">
<Label TextColor="OrangeRed" Text="{Binding Title}" />
<Label TextColor="Blue" Text="{Binding Subtitle} "/>
</StackLayout>
</ViewCell.View>
</customControls:ExtendedViewCell>
</DataTemplate>
</ListView.ItemTemplate>

After you change the content of the cell, call ForceUpdateSize()
https://learn.microsoft.com/en-us/dotnet/api/Xamarin.Forms.Cell.ForceUpdateSize?view=xamarin-forms

Related

Xamarin Forms Shell Flyout with multiple columns

I have a business requirement to build a flyout menu with multiple columns. The menu will have all the basic flyout behaviors bit it has to have a narrow static column on the left side with 3 buttons in it and then have the regular scrollable flyout menu next to it. Is it possible at this time to do a completely custom layout within xamarin forms shell for the flyout?
You could use the FlyoutContentTemplate to do that.
<Shell.FlyoutContentTemplate>
<DataTemplate>
<StackLayout Orientation="Horizontal">
<StackLayout BackgroundColor="Purple">
<Button Text="home" />
<Button Text="dash" />
<Button Text="chat" />
</StackLayout>
<CollectionView
BindingContext="{x:Reference shell}"
IsGrouped="True"
ItemsSource="{Binding FlyoutItems}">
<CollectionView.ItemTemplate>
<DataTemplate>
<Label
FontSize="Large"
Text="{Binding Title}"
TextColor="Black" />
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
</StackLayout>
</DataTemplate>
</Shell.FlyoutContentTemplate>

CollectionView disabling scrolling in Xamarin forms

I am trying to disable scrolling in my collection view. The reason why I want to do that is there is a scroll view already in my XAML code. When I try to scroll all page elements on the page, collection view elements are also scrolled themselves but I don't want that.
<ScrollView>
<StackLayout Padding="20" Spacing="20" >
<Frame CornerRadius="15"
BackgroundColor="#A6EDB3"
VerticalOptions="StartAndExpand"
HeightRequest="200"
IsClippedToBounds="True"
Padding="0" >
<StackLayout Padding="10,5,10,5"
Orientation="Horizontal" >
<Image Source="settingsIcon"
HeightRequest="25"
WidthRequest="25"
Aspect="Fill" />
<Label Text="Filter"
FontSize="Medium"
VerticalTextAlignment="Center"
VerticalOptions="Center"/>
</StackLayout>
</Frame>
<Label Text="Vocabulary topics" TextColor="black" FontSize="20" FontAttributes="Bold" ></Label>
<CollectionView x:Name="topics" Scrolled="topics_Scrolled" VerticalScrollBarVisibility="Never" >
<CollectionView.ItemTemplate>
<DataTemplate>
<StackLayout Padding="0,10,0,10">
<Frame HasShadow="False"
HeightRequest="60"
CornerRadius="15"
BackgroundColor="{Binding BackgroundColor}"
HorizontalOptions="Fill" >
<StackLayout Orientation="Horizontal">
<Frame BackgroundColor="{Binding BoxColor}" WidthRequest="40" ></Frame>
<StackLayout>
<Label Text="{Binding Name}"></Label>
</StackLayout>
</StackLayout>
</Frame>
</StackLayout>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
</StackLayout>
</ScrollView>
Having two scrolls on the same page is not the correct way.
Also if you just want to place items above/below your collectionView use the Header/Footer properties then!!
For instance, for the current design, your CollectionView could look something like below and work as you want it to.
<CollectionView Padding="20" x:Name="topics" Scrolled="topics_Scrolled" VerticalScrollBarVisibility="Never" >
<CollectionView.Header>
<StackLayout Spacing="20" >
<Frame CornerRadius="15"
BackgroundColor="#A6EDB3"
VerticalOptions="StartAndExpand"
HeightRequest="200"
IsClippedToBounds="True"
Padding="0" >
<StackLayout Padding="10,5,10,5"
Orientation="Horizontal" >
<Image Source="settingsIcon"
HeightRequest="25"
WidthRequest="25"
Aspect="Fill" />
<Label Text="Filter"
FontSize="Medium"
VerticalTextAlignment="Center"
VerticalOptions="Center"/>
</StackLayout>
</Frame>
<Label Text="Vocabulary topics" TextColor="black" FontSize="20" FontAttributes="Bold" ></Label>
</StackLayout>
</CollectionView.Header>
<CollectionView.ItemTemplate>
<DataTemplate>
<StackLayout Padding="0,10,0,10">
<Frame HasShadow="False"
HeightRequest="60"
CornerRadius="15"
BackgroundColor="{Binding BackgroundColor}"
HorizontalOptions="Fill" >
<StackLayout Orientation="Horizontal">
<Frame BackgroundColor="{Binding BoxColor}" WidthRequest="40" ></Frame>
<StackLayout>
<Label Text="{Binding Name}"></Label>
</StackLayout>
</StackLayout>
</Frame>
</StackLayout>
</DataTemplate>
</CollectionView.ItemTemplate>
</CollectionView>
Note: you might have to adjust the margin and padding properties for it to look the exact same. My code is just an example.
For more information on CollectionView check: https://learn.microsoft.com/en-us/xamarin/xamarin-forms/user-interface/collectionview/
You can use InputTransparent.
In your case what I would do would be to wrap the CollectionView in a <ContentView> as:
<ContentView InputTransparent="True"
x:Name="content">
<CollectionView ItemsSource="{Binding Items}"...>
...
</CollectionView>
</ContentView>
Create a scroll event to your scroll view:
<ScrollView Scrolled="ScrollView_Scrolled">
...
</ScrollView>
Then, with this event, make sure that the InputTransparent switches depending on the scroll position:
private void ScrollView_Scrolled(object sender, ScrolledEventArgs e)
{
var scrollView = sender as ScrollView;
// Get the height of your scroll view
var contentSize = scrollView.ContentSize.Height;
// Get the max position of the scrollview
var maxPos = contentSize - scrollView.Height;
// Compare it to the current position
if (Convert.ToInt16(e.ScrollY) >= Convert.ToInt16(maxPos))
{
// Switch input transparent value
content.InputTransparent = false;
}
else if (Convert.ToInt16(e.ScrollY) == 0)
{
content.InputTransparent = true;
}
}
This is perfectly fine to use two scrollable controls on the same page for what you want to do. And I don't think <CollectionView.Header> would give you the result you want.
I hope it was helpful! 🙂

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.

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>

Cross platform listview swipe in xamarin forms

I am looking for a cross platform swipe on ListView to perform an action such as opening a menu or deleting an item.
Has anyone implemented such a scenario? I would like to for instance delete an item when swiping on item to left.
I need to support all platforms: ios/droid/win
The easiest way would be to use the built-in Context Actions, this allows you to show menu items when your list item is swiped on iOS or long pressed on Android
<ListView x:Name="ContextDemoList">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<ViewCell.ContextActions>
<MenuItem Clicked="OnMore" CommandParameter="{Binding .}"
Text="More" />
<MenuItem Clicked="OnDelete" CommandParameter="{Binding .}"
Text="Delete" IsDestructive="True" />
</ViewCell.ContextActions>
<StackLayout Padding="15,0">
<Label Text="{Binding title}" />
</StackLayout>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
</ListView>
https://developer.xamarin.com/guides/xamarin-forms/user-interface/listview/interactivity/#Context_Actions
If swiping is a requirement for both platforms, or you need to do an action when the item is swiped (Instead of showing menu items) then i'd recommend SyncFucion's listview control, it is available with a Community licence and it offers more flexibility
<syncfusion:SfListView x:Name="listView" AllowSwiping="True">
<syncfusion:SfListView.LeftSwipeTemplate>
<DataTemplate x:Name="LeftSwipeTemplate">
<Grid>
<Grid BackgroundColor="#009EDA" HorizontalOptions="Fill" VerticalOptions="Fill" Grid.Column="0">
<Grid VerticalOptions="Center" HorizontalOptions="Center">
<Image Grid.Column="0"
Grid.Row="0"
BackgroundColor="Transparent"
HeightRequest="35"
WidthRequest="35"
Source="Favorites.png" />
</Grid>
</Grid>
</Grid>
</DataTemplate>
</syncfusion:SfListView.LeftSwipeTemplate>
</syncfusion:SfListView>
https://help.syncfusion.com/xamarin/sflistview/swiping
You can use SwipeView and wrap it in a ListView.
<ListView
ItemsSource="{Binding Items}"
SelectionMode="None"
CachingStrategy="RecycleElement"
RowHeight="110"
HeightRequest="1000"
BackgroundColor="White"
IsPullToRefreshEnabled="True"
Refreshing="OnRefresh">
<ListView.ItemTemplate>
<DataTemplate>
<ViewCell>
<SwipeView>
<SwipeView.GestureRecognizers>
<TapGestureRecognizer
Tapped="OnTapped"
NumberOfTapsRequired="1" />
</SwipeView.GestureRecognizers>
<SwipeView.RightItems>
<SwipeItems>
<SwipeItem
Text="Edit"
IconImageSource="edit_icon.png"
BackgroundColor="Green"
Invoked="OnEdit" />
<SwipeItem
Text="Delete"
IconImageSource="delete_icon.png"
BackgroundColor="Red"
Invoked="OnDelete" />
</SwipeItems>
</SwipeView.RightItems>
<SwipeView.Content>
:
</SwipeView.Content>
</SwipeView>
</ViewCell>
</DataTemplate>
</ListView.ItemTemplate>
From: https://github.com/xamarin/Xamarin.Forms/issues/9089

Resources