Xamarin forms custom renderer button

I am using Xamarin. I have positioned it before the TitleLabel and everything seems to be working ok although Im not sure that I am positioning it using the best method. My question is this, when using the button, the TitleLabel text shows a tap effect when pressed it fades out, or an overlay fades in, not surehow do I get my added UILabel to receive or participate in the out of the box pressed effect? I have literally no idea how the native effect is accomplished and Im a bit new to Xamarin in general so its been slow going.

Is this the proper place to do this? You can override those as needed to alter the appearance of your custom subclass in response to touch events. Ok, so Ive made a bit of headway. I guess Im looking to emulate what SetTitleColor color,state does. I cant seem to find the implementation of this though so I don't know how to recreate this functionality for my new UILabel.

I eventually accomplished this by casting the Control in the renderer to UIControl. I was then able to hook into the Touch events and rolled my own to change the TextColor on touch and then made a handler to animate the TextColor change back. It works pretty well but it still doesnt match the iOS out of the box button effect exactly. Xamarin Inc. Xamarin Menu About What is Xamarin? What is Xamarin. August in Xamarin. Thanks for any info.

Best Answer. August Accepted Answer. August Can someone point me to the source implementation of that method or tell me what its doing?

Supercharging Xamarin Forms with Custom Renderers, Part 1

Sign In or Register to comment. Facebook Twitter GitHub. About Xamarin Xamarin.Author: Les Brown. Creating a compelling user interface is a must when it comes to mobile development. What works for iOS may not be acceptable in Android and vice versa.

In order to accommodate the various platform expectations, we must be able to customize and create controls as needed.

Xamarin.Forms Custom Renderers

Renderers allows us this flexibility. I would like the background of a button to accommodate gradients rather than just a solid color. For those using MFractor, I will demonstrate how to do this using their toolset as well as how to navigate to existing renderers. I also intend to share my experience with file nesting and how it has helped me organize my projects. We will create a class for each platform that inherits from ButtonRenderer and attach the ExportRender attribute so that Xamarin will use it instead of the default renderer.

There are two ways to do this. We can use MFractor toolset or do this manually. As mentioned before, I would like to share a couple of tips from coding large projects. This is possible is you use shared projects. Another advantage is that your code is always compiled to the same SDK level of the deploying project.

In order to enable this is Visual Studio Mac, install the file nesting extension. I annotate the file name with the platform so that is visually easy to differentiate and as well as prevent duplicate name conflicts. The project should look like this now and visually it is easy to find the renderers without jumping around to different projects.

One last thing we need to do is allow disparate platform specific code within the same project. This is accomplished using compiler directives. Surround the entire code with the appropriate directive as shown below.

In our renderers we need to create a gradient layer that can be placed in the background of the control. The code base provided is very simple and production code should accommodate for property changes as well as give the user a visual indication that the button has been clicked.Download the sample. Forms Visual enables renderers to be created and selectively applied to VisualElement objects, without having to subclass Xamarin.

Forms views. A renderer that specifies an IVisual type, as part of its ExportRendererAttributewill be used to render opted in views, rather than the default renderer. At renderer selection time, the Visual property of the view is inspected and included in the renderer selection process. Currently the Visual property cannot be changed after the view has been rendered, but this will change in a future release. For information about creating a renderer class, see Custom Renderers.

However, note that a Xamarin. Forms Visual renderer is applied to a view without having to subclass the view. The renderer classes outlined here implement a custom Button that displays its text with a shadow. The CustomVisual type can then be registered against the renderer classes, permitting Button objects to opt into using the renderers. In this example for the iOS platform project, the ExportRendererAttribute specifies that the CustomButtonRenderer class will be used to render consuming Button objects, with the IVisual type registered as the third argument.

A Button object can opt into using the renderer classes by setting its Visual property to Custom :. However, the full type name can also be specified.

At renderer selection time, the Visual property of the Button is inspected and included in the renderer selection process. If a renderer isn't located, the Xamarin.

Forms default renderer will be used. The following screenshots show the rendered Buttonwhich displays its text with a shadow:. The VisualAttribute can be used to optionally register a different name for the IVisual type.

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This approach can be used to resolve naming conflicts between different Visual libraries, or in situations where you just want to refer to a Visual by a different name than its type name.

The VisualAttribute should be defined at the assembly level in either the cross-platform library, or in the platform project:. When consuming a Visual through its registered name, any "Visual" suffix must be included. Skip to main content.Forms user interfaces are rendered using the native controls of the target platform, allowing Xamarin.

Forms applications to retain the appropriate look and feel for each platform. Custom Renderers let developers override this process to customize the appearance and behavior of Xamarin. Forms controls on each platform. Custom renderers provide a powerful approach for customizing the appearance and behavior of Xamarin. Forms controls. They can be used for small styling changes or sophisticated platform-specific layout and behavior customization.

This article provides an introduction to custom renderers, and outlines the process for creating a custom renderer.

Every Xamarin. Forms control has an accompanying renderer for each platform that creates an instance of a native control. This article lists the renderer and native control classes that implement each Xamarin. Forms page, layout, view, and cell. The Xamarin.

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Forms Entry control allows a single line of text to be edited. This article demonstrates how to create a custom renderer for the Entry control, enabling developers to override the default native rendering with their own platform-specific customization. A ContentPage is a visual element that displays a single view and occupies most of the screen.

This article demonstrates how to create a custom renderer for the ContentPage page, enabling developers to override the default native rendering with their own platform-specific customization. Maps provides a cross-platform abstraction for displaying maps that use the native map APIs on each platform, to provide a fast and familiar map experience for users.

xamarin forms custom renderer button

This topic demonstrates how to a create custom renderer for the Map control, enabling developers to override the default native rendering with their own platform-specific customization. A Xamarin. Forms ListView is a view that displays a collection of data as a vertical list.

Xamarin.Forms Custom Button

This article demonstrates how to create a custom renderer that encapsulates platform-specific list controls and native cell layouts, allowing more control over native list control performance.

This article demonstrates how to create a custom renderer for a ViewCell that's hosted inside a Xamarin. Forms ListView control. This stops the Xamarin.

Forms layout calculations from being repeatedly called during ListView scrolling. This article explains how to create a custom renderer that extends the WebView to allow C code to be invoked from JavaScript.

Forms custom user interfaces controls should derive from the View class, which is used to place layouts and controls on the screen.Each control has a default appearance, and each control exposes properties that allow you to customize its appearance.

What if, for example, you need to round the corners on an Entry control or wrap and truncate text in a Label? The Xamarin Forms Label control supports either but not both. Knowing how to write custom renderers — and when to use them — is one of the skills that separates expert Xamarin Forms developers from the rest of the pack.

The subject of custom renderers is a multifaceted one. Some renderers require little effort to write. Others are much more difficult and require intimate knowledge of the platforms on which they run.

But not so on Windows Phone and Android.

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On Android, none of the three Border properties are honored. Xamarin Forms promises you that if you declare a Button control — or a Label, or a ListView, or whatever — a native version of that control will be rendered onto each platform. What if you need borders with rounded corners on Windows Phone and Android, too?

Are you out of luck, or can Button be customized to support these attributes on other platforms as well?

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My button renderers were built and tested with Xamarin Forms 1. Every control in Xamarin Forms is accompanied by a set of renderers. There is one renderer per control per platform.

For example, when you declare a Button control and run the app on iOS, Xamarin instantiates a class named ButtonRenderer, which is found in the Xamarin. Android namespace of the Xamarin. WinPhone namespace of the Xamarin. WP8 assembly to create a Windows Phone Button.

The following diagram illustrates the relationship between Button controls and per-platform ButtonRenderers:. But if you wish to customize the way a control is rendered, you can replace one or more of the built-in renderers with renderers of your own.

Through reflection, Xamarin discovers the attribute and instead of instantiating a ButtonRenderer for each Button you create, it instantiates a CustomButtonRenderer. Now that you have a reference to the native control, you can manipulate it as needed.

It frequently but not always needs to be overridden as well. The template is the same for each. Also remember that inside the renderer, Control refers to a native control. To do so, you have to know a bit about how controls work on Windows Phone. Each control on that platform is accompanied by a control template — basically a blueprint for the control itself in form of a collection of XAML primitives that are created when the control is created.

From this, we can discern that it is a Border element that forms the border a user sees around a Windows Phone Button. That solves the problem on Windows Phone, but what about Android?

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To tackle this problem on Android, you need to know that the appearance of Android controls is defined by drawables. When you create a button in an Android app, the system uses a set of predefined drawables to paint the button on the screen in various states focused, pressed, etc. A collection of drawables representing the button in different states is called a state list and is represented by instances of a class named StateListDrawable. Android programmers can customize the look of buttons by eschewing the built-in drawables and providing drawables of their own.

Drawables and state lists are typically defined in XML, but can also be created programmatically. It then packages them together in a DrawableStateList and assigns the state list to the button. OnElementPropertyChanged ensures that the drawables are updated if any of these properties change on the Xamarin Forms Button.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Does anyone have a complete example of a Xamarin Forms android button custom renderer? Or is that even possible? Activity is a property of type Context that I set when the app initializes.

xamarin forms custom renderer button

Learn more. Xamarin Forms android button custom renderer Ask Question. Asked 2 years, 8 months ago. Active 2 years, 6 months ago. Viewed 3k times. I am basically looking to make round corners button. Generic; using System. Shared; using Xamarin.

Forms; using Android. Drawables; using System. ComponentModel; using Xamarin. Android; using Android. Graphics; using Android. Views; using System. Contexts; using CustomRenderer. OnElementChanged e ; if Control!

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Max 1, Resources. GetMode int button. GradientDrawable ; if button. SetColor Android. SetColor button.

SetStroke int borderWidth, button. GetColor 0, Android. CenterHorizontal GravityFlags. Android' are you missing an assembly reference?He had mentioned to me some of the interesting problems he had getting a ripple effect into a custom Xamarin Forms button. The ultimate solution he found is fairly simple, but some of the obvious choices like "Use an effect" didn't work for various reasons. So I asked if he'd be interested in writing a post about it! He gives us a solution below that hard codes the "counting behavior" of the button for simplicity of demo, but should be really easy to generalize if you want to do something similar yourself!

Xamarin Forms is powerful system and allows for a lot of customization out of the box. However, sometimes you need to go beyond the default controls and build something custom. I recently ran into this when I needed to build a multi-line custom button similiar to. The Button control in Xamarin Forms only allows a single line of text and doesn't provide a way to customize the button's layout.

You could create a custom control within Forms using a StackLayout and a TapGestureRecognizer, but you would lose responsive behaviors like color changes on iOS and the ripple effect on Android.

This is where custom renderers come in. Xamarin provides documentation on how to create a custom renderer in several situations here but there isn't anything specific to custom buttons, so I thought I'd write down what I did to create this effect.

All of the code for this post is available on GitHub with tags for each step of the process. If you want to follow along, start with the tag "initial-view-model". The first thing to do is to set up our view and view model so they handle any bindable data you need.

In this case we'll create two buttons that, when clicked, increment a counter. The counter is displayed below each button. The view XAML is:. It may seem like overkill to set up the View this way even though we plan to replace the buttons and labels with our own custom content, but it serves a purpose.

This way we can verify that we have all the bindings we need in place and working before we start getting into the more interesting, and more complicated, renderer logic. The first thing we need to do is determine what data we need to bind to our custom button. For this example we need four items: the button title, the button's click count, the button's click command, and the button's background color.

We then create a custom control in the Forms project that subclasses View. It may seem like Button would be a better base class, but the Android button has similar limitations to the Xamarin Forms button and can't use a custom layout.

xamarin forms custom renderer button

To support Android, we need to use the more generic View type. Notice that there is no BackgroundColor property in the code. This is because BackgroundColor is already implemented by View and we can use that for our control. Next we need to use the new control in our View. Since our control is in the same namespace as the view, we can just use the 'local' XML namespace created by Xamarin.

If 'local' is missing or the control is in a different namespace, we would need to create a new XML namespace. Now we can use our new control just like any built-in control:.


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