Tag Archives: Label

XFHACKS-008 Label with Border and Background!

Ever wanted to have a Xamarin.Forms.Label, with a Border, or even better with a Background, or with a Corner Radius customization? Welcome to another lightening short post of me hacking around Xamarin.Forms elements!

By default Xamarin.Forms.Label doesn’t have a Border, Background neither a Corner Radius property, the only possible way to achieve that is by resorting to custom renderers. So I thought of making use of my own crazy imagination and hack my way around to get this to work right from Xamarin.Forms itself!

No custom renderers, no platform specific code and no third party libraries! Just by using pure out of the box Xamarin.Forms! 😉

Sneak Peak!

That’s what we gonna be build yol!

A Label with a Border and a Background, none other than with Corner Radius customization, a true dream come true for Xamarin.Forms developers! lol kidding! 😉

XFHACKS Recipe!

Buckle up fellas, its recipe time! 😉 Now this hack basically has mostly to do with my previous post, XFHACKS-007 Frame with a Border Width! If you would like to read more on detail about it then please check that article and come back here, but let me explain it in short form here though. Basically we’re placing a Frame element inside another Frame element with a Margin value which will create visually a single frame with a Border as our choice of the Margin.

Now for our Label, we’re going to place it inside that custom Frame we just built, giving it a nicely rendered border around it. You have the complete control over the Border Width property as explained in my previous article.

And the best part of it is that this Frame will resize itself according to the Label inside of it, since we’re not restricting it to any static values, whatever the Height or Width property you set to the Label, the border will follow it. Talking of Alignment of the Label you can freely use the Margin, HorizontalOptions and VerticalOptions to easily align the Label inside the Border. 😉

Code!

Behold the golden XAML code!

<!--  Label with a Border  -->
<Frame
    Padding="0"
    BackgroundColor="#2196F3"
    CornerRadius="7"
    HasShadow="False">
    <Frame
        Margin="2"
        Padding="5"
        BackgroundColor="White"
        CornerRadius="5"
        HasShadow="False">
        <Label
            BackgroundColor="Transparent"
            HorizontalOptions="Center"
            Text="Border with curved corners"
            TextColor="Black" />
    </Frame>
</Frame>

 

There you have the Label with a Border in XAML! Just like I explained above the two Frames rendering the Border around it. Feel free to change the Margin value of the child Frame element to increase or decrease the Border-Width. And both Frames CornerRadius are used to give a curved corners effect to the Border. Let’s see it in actions:

If you want to have curved sides for the Label Border, then simply increase the CornerRadius=”16″ parent Frame and CornerRadius=”14″ for the child Frame.

Now Imagine if you want to Align the Label inside the Border, then simply use the HorizontalOptions property as you wish, for example HorizontalOptions=”Start” and just to avoid the Label crashing with the border use the Margin property of the Label in whichever the direction you’re aligning your Label to, as an example Margin=”5,0,0,0″

How about that Background I promised earlier, well then simply set the child Frame’s background Color as you wish, and if you prefer to have a different Color for Border and Background, just make sure to set different colors to parent Frame’s Background color and child Frame’s background color.

Now how about having a Background Image, what you need to do is simply add an Image behind the Label using a Grid Layout by laying down both the elements on top of each other.

<!--  Label with a Background  -->
<Frame
    Padding="0"
    BackgroundColor="#2196F3"
    CornerRadius="7"
    HasShadow="False">
    <Frame
        Margin="2"
        Padding="0"
        BackgroundColor="White"
        CornerRadius="5"
        IsClippedToBounds="True"
        HasShadow="False">
        <Grid HeightRequest="30" IsClippedToBounds="True">
            <Image Aspect="AspectFill" Source="{extensions:ImageResource XFHacks.Resources.abstractbackground.jpg}" />
            <Label
                BackgroundColor="Transparent"
                FontAttributes="Bold"
                HorizontalOptions="Center"
                Text="With a Cool Background!"
                TextColor="White"
                VerticalOptions="Center" />
        </Grid>
    </Frame>
</Frame>

 

There you have it, the golden XAML! So what we have done here is basically the same concept but with a bit more icing on top, by removing the padding inside the child Frame allowing the Image background to stretch to on to the edge of the border. Then inside the child Frame we have a Grid Layout, and its got a HeightRequest property which determines the Height of the Label, meanwhile cropping out using IsClippedToBounds property, the excessive rendering of the Image inside that’s acting as the Background.

Now let’s put it together and fire it up! 😉

Fire it up!

Load your cannons, fire it up!

 

There you go! 😀 Running side by side Android, iOS and UWP.

A little Trick! 😉

Just like how I’ve implemented the Border and Background for the Label element, you could follow the same pattern and use this for any UI Element in Xamarin.Forms as you wish, such as Image, Editor, Slider, ListView, etc whichever you wish! 😉 Just replace that Label with the UI element of your choice! 😀

Grab it on Github!

https://github.com/UdaraAlwis/XFHacks

Well then, that’s it for now. More awesome stuff on the way!

Cheers! 😀 share the love!

Advertisements

Awesome Xamarin Forms Label with HTML Text Formatting…

Why would you wanna use a WebView when you could use your Label to display HTML mark up text in your Xamarin Forms app? 😉

How it all started?

Well some times back I had to implement a Xamarin Forms Label which can display HTML formatted text…

The problem with Xamarin Forms Label?

Well of course you would tell me to use the FormattedText property built into Xamarin Forms Label. But before you say that do you even know how limited that property is? and you have to break up your string in to pieces and rebuild it with Span blocks, and also there’s only a few text formatting options available. Usually HTML has a ton of text formatting options, which you can even get close to with the default Xamarin Forms Span block customization.

So the default Xamarin Forms Label can not do any help at this case.

Solution?

Well we all know it’s super easy to parse HTML text to be rendererd in a Label with Android and iOS native implementation. That’s why I had to drill down to native level and come up with a Custom Label that could display HTML markup text. 😀

Without further due, let’s jump into it! 😉

Create the Custom Control…

So as usual let’s create our Custom Label by subclassing Xamarin Forms Label control.

namespace WhateverYourNamespace
{
    public class HtmlFormattedLabel : Label
    {

    }
}

 

Nothing fancy there… Next are the big stuff!

Xamarin Android implementation…

So here’s the renderer for our HtmlFormattedLabel

[assembly:ExportRenderer(typeof(HtmlFormattedLabel), typeof(HtmlFormattedLabelRenderer))]
namespace WhateverYourNamespace.Droid
{
    public class HtmlFormattedLabelRenderer : LabelRenderer
    {
        protected override void OnElementChanged(ElementChangedEventArgs<Label> e)
        {
            base.OnElementChanged(e);

            var view = (HtmlFormattedLabel)Element;
            if (view == null) return;
            
            Control.SetText(Html.FromHtml(view.Text.ToString()),TextView.BufferType.Spannable);
        }
    }
}

 

So what we basically do here is native Android TextView through the Control property of our renderer and access the SetText() method, and  directly use the Android HTML parser to set your HTML Text.

Xamarin iOS implementation…

Next is our iOS renderer for the custom control.

[assembly:ExportRenderer(typeof(HtmlFormattedLabel), typeof(HtmlFormattedLabelRenderer))]
namespace WhateverYourNamespace.iOS
{
    public class HtmlFormattedLabelRenderer : LabelRenderer
    {
        protected override void OnElementChanged(ElementChangedEventArgs<Label> e)
        {
            base.OnElementChanged(e);
            
            var view = (HtmlFormattedLabel)Element;
            if (view == null) return;

            var attr = new NSAttributedStringDocumentAttributes();
            var nsError = new NSError();
            attr.DocumentType = NSDocumentType.HTML;
            
            Control.AttributedText = new NSAttributedString(view.Text, attr, ref nsError);
        }
    }
}

 

So here what we do is, we access the native iOS UILabel through the Control property and directly set the AttributedText property with our natively parsed HTML string. 😉

Now unlike Android, I wasn’t much familiar with iOS implementation of HTML text parsing, therefore I took some help from this thread for the above implementation How to display html formatted text in a UILabel ?.

KABOOM! EASY!

Let’s consume this Awesome Label! 😉

Alright time to use the Awesome Label we just created in Xamarin Forms!

Content = new StackLayout
{
	VerticalOptions = LayoutOptions.Center,
	Padding = new Thickness(20,0,20,0),
	Spacing = 30,
	Children = {
		new Label {
			HorizontalTextAlignment = TextAlignment.Center,
			TextColor = Color.Black,
			Text = "Welcome to the awesome HTML Formatter Label" +
			"Control by ÇøŋfuzëÐ SøurcëÇødë!"
		},
		new HtmlFormattedLabel()
		{
			FontSize = 14,
			TextColor = Color.Black,
			Text = 
			   "<html><body><Center>" +
			   "<font size='6'>" +
			   "This is a html formatted text," +
			   "so this is <b>bold text</b>... " +
			   "and this is <u>underline text</u>... " +
			   "and this is <strike>strike through text</strike>... " +
			   "and finally this is <i>italic text</i>... " +
			   "<br />" +
			   "Ops this is html line break..." +
			   "<br />" +
			   "And this is <sup>superscripted</sup> html text."+
			   "</font>" +
			   "<Center></body></html>",
		}
	}
}

 

So here I’m using our HtmlFormattedLabel control and directly setting a HTML formatted text to its Text property. 😀

Now hit F5 and Run that beautiful code! 😉

screen-shot-2017-02-05-at-4-08-31-pmnexus-5-lollipop-screenshot-3

There you have it fellas! 😀

Now you may grab this code from my github: Xamarin-Playground/XFHtmlFormattedLabelControl

Enjoy!

And pass on to another Developer by sharing it! 😉