I have no idea what I'm doing wrong here. I've tried explicitly setting heights, column definitions, but I cannot get the sizing here to be correct.
I tried setting two columns with one row, with and without explicit heights and sizes.
What do I have to do?
something like this should work
<ViewCell>
<!-- need to specify an overall height -->
<Grid HeightRequest="200">
<Grid.RowDefinitions>
<!-- two rows equal height -->
<RowDefinition Height="50*" />
<RowDefinition Height="50*" />
</Grid.RowDefinitions>
<Grid.ColumnDefintions>
<!-- two cols equal width -->
<ColumnDefintions Width="50*" />
<ColumnDefintions Width="50*" />
</Grid.ColumnDefinitions>
<Label Grid.Row="0" Grid.Column="0" Text="Location" />
<Label Grid.Row="0" Grid.Column="1" Text="Amount" />
<Label Grid.Row="1" Grid.ColumnSpan="2" Text="Created" />
</Grid>
</ViewCell>
Related
I have a grid inside a CollectionView and I need to change the layout based on a certain condition, changing dynamically the size of the columns and rows and hiding/showing some specific columns.
The datasource of the collectionView is always the same.
Basically, I want to achieve something like this:
Default layout:
Alternative layout:
I saw that maybe I could use the DataTemplateSelectors, but is that the best way or is there another method?
You can use the Grid in the Collectionview and set the Grid format.
First, you can set the CollectionView ItemsLayout. Here is the example.
<CollectionView ItemsSource="{Binding Items}"
ItemsLayout="VerticalGrid, 3">
it will divide the CollectionView list into three vertical parts.
Second, you can make a Grid to preserve the data.
<Grid Padding="10">
<Grid.RowDefinitions>
<RowDefinition Height="60" />
<RowDefinition Height="35" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="70" />
</Grid.ColumnDefinitions>
<Image Grid.Row="0"
Source="{Binding ImageUrl}"
Aspect="AspectFill"
HeightRequest="60"
WidthRequest="60" />
<Label Grid.Row="1"
Text="{Binding Location}" />
</Grid>
in my XAML I have this grid:
<Grid Grid.Row="12" Grid.Column="1" ColumnSpacing="0" >
<Grid.RowDefinitions>
<RowDefinition Height="*"></RowDefinition>
<!--Label-->
<RowDefinition Height="3*" ></RowDefinition>
<!--ProfilePic-->
<RowDefinition Height="*"></RowDefinition>
<!-- Btn change-->
</Grid.RowDefinitions>
<BoxView BackgroundColor="Purple" Grid.Row="1"></BoxView>
<ImageButton
Grid.Row="2"
x:Name="row_forpic_editProfile"
HorizontalOptions="Center"
VerticalOptions="Center"
/>
<Label
Grid.Row="0"
FontSize="16"
TextColor="#272727"
VerticalOptions="End"
Text="Proilfbild"
FontFamily="arial"
/>
<Button
Grid.Row="2"
x:Name="btn_changepic_editprofile"
Text="Ändern"
HorizontalOptions="Center"
VerticalOptions="Center"
/>
</Grid>
This is the result of that:
The result
Now, I want to add an imageview into the purple row (which is Grid.Row="1") from code because I downloaded a picture from the internet.
How can I now add my new Image (ImageButton) into this exact row? (row 1)
And also have it maintain its dimensions (only the picture must full the container).
thank you:)
to add a View to a Grid
myGrid.Children.Add(view,col,row);
Say I create the following shared XAML:
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Button Grid.Row="0" Text="One" />
<Grid Grid.Row="1">
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto" />
<ColumnDefinition Width="Auto" />
</Grid.ColumnDefinitions>
<Button Grid.Column="0" Text="Two First" />
<Button Grid.Column="1" Text="Two Second" />
</Grid>
<Button Grid.Row="2" Text="Three" />
</Grid>
I then run this on an Android device and run the TalkBack screen reader. As I swipe forward through the UI, TalkBack moves from button "One", to button "Three", and then to buttons "Two First" and "Two Second". This doesn't match the order in which I've defined the UI, so is this expected? I get what I consider the expected navigation of moving through the buttons in order of "One"->"Two First"->"Two Second"->"Three", when running the same UI as a Xamarin.UWP app and using the Narrator screen reader.
I've found I can avoid the unexpected TalkBack navigation if I update the UI such that certain parts of the UI are balanced in how deep the UI is defined in the XAML hierarchy. For example, if I wrap button "Three" in a Grid, then I get the expected navigation path.
I can also avoid the unexpected TalkBack navigation if I add a TabIndex to everything that I want TalkBack to reach, but that'll need maintaining as the app UI evolves over time, and as I understand things, not all types of Xamarin.Forms control support TabIndex.
not sure if it's a problem from designs of Grid .From shared code , I think Grid maybe set the second Row as the low level of priority .Because the second Row define the Column individually .
If that is the logic about the design of Grid . You can have a try with define the Row and Column at the same level of priority .
Code as follow :
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="*" />
<RowDefinition Height="*" />
<RowDefinition Height="*" />
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Button Grid.Row="0"
Grid.ColumnSpan="2"
Text="One" />
<Button Grid.Row="1"
Grid.Column="0"
Text="Two First" />
<Button Grid.Row="1"
Grid.Column="1"
Text="Two Second" />
<Button Grid.Row="2"
Grid.Column="0"
Grid.ColumnSpan="2"
Text="Three" />
</Grid>
Xamarin layout advice
Hi given the nature of mobile devices screen sizes as a rule of thumb when building screen
would you say use "Flexlayout" all the time rather than a grid.
It is my understanding that the flexlayout is more suitable for adapting to various screens sizes without building complexity in your pages.
Still do not understand "Grow and shrink" despite reading few documentations.
How would you describe grow and shrink?
Sample one
<Grid
RowSpacing="0">
<Grid.RowDefinitions>
<RowDefinition Height="3*" />
<RowDefinition Height="6*" />
<RowDefinition Height="1*" />
</Grid.RowDefinitions>
<StackLayout Grid.Row="0" BackgroundColor="Green">
<Label Text="Header with logo"
HorizontalTextAlignment="Center"
VerticalTextAlignment="Center" />
</StackLayout>
<StackLayout Grid.Row="1" BackgroundColor="LightBlue">
<Label Text="Content"
HorizontalTextAlignment="Center"
VerticalTextAlignment="Center" />
</StackLayout>
<StackLayout Grid.Row="2" BackgroundColor="Red">
<Label Text="Footer"
HorizontalTextAlignment="Center"
VerticalTextAlignment="Center" />
</StackLayout>
</Grid>
VS
<FlexLayout Direction="Column">
<!-- Header -->
<Label Text="HEADER"
FontSize="Large"
BackgroundColor="Aqua"
HorizontalTextAlignment="Center" />
<!-- Body -->
<FlexLayout FlexLayout.Grow="1">
<!-- Content -->
<Label Text="Content"
FontSize="Large"
BackgroundColor="Gray"
HorizontalTextAlignment="Center"
VerticalTextAlignment="Center"
FlexLayout.Grow="1" />
</FlexLayout>
<!-- Footer -->
<Label Text="FOOTER"
FontSize="Large"
BackgroundColor="Pink"
HorizontalTextAlignment="Center" />
</FlexLayout>
Grow setting of 1. This means that all the extra vertical space is allocated to this blank Label like these screenshot.
I add second label called content2, if I set grow 0, content2 will not fill extra vertical space
if I set grow 1, content2 will fill extra vertical space
shrink property plays a role when the Wrap property is set to NoWrap and the aggregate width of a row of children is greater than the width of the FlexLayout, or the aggregate height of a single column of children is greater than the height of the FlexLayout. Normally the FlexLayout will display these children by constricting their sizes. The Shrink property can indicate which children are given priority in being displayed at their full sizes.
You can download this demo, and test it by yourself.
https://developer.xamarin.com/samples/xamarin-forms/UserInterface/FlexLayoutDemos/
I have loaded the views inside a grid as below,
<Grid>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="*" />
</Grid.ColumnDefinitions>
<Grid.RowDefinitions>
<RowDefinition Height="Auto" />
<RowDefinition Height="*" />
<RowDefinition Height="Auto" />
</Grid.RowDefinitions>
<Entry x:Name="SearchTextBox"
Grid.Row="0"
HorizontalOptions="Fill"
Placeholder="Search"
VerticalOptions="Fill" />
<ListView x:Name="listView"
Grid.Row="1"
HorizontalOptions="Fill"
VerticalOptions="Fill" />
<local:CustomListView x:Name="customView"
Grid.Row="0"
ItemsSource="{Binding Items}">
</local:CustomListView >
</Grid>
Out of 3 views in the above code snippet, first two views are rendered properly. But the 3rd view(custom view) not rendered. CustomViews are not rendered only if I set RowDefinition as "Auto". So, anyone please tell why the custom view is not loaded if I set "Auto".
your CustomListView probably doesn't request a minimum size correctly, and as the middle row has a height of *, it takes all of the available space minus the minimum size requests.