I was using PageRenderer for native UWP (Universal Windows Platform) but it behaved weird which I didn't expect. I used following class to render a native page MyUWP to load in place of a Xamarin.Forms page
class MyUWPRenderer : PageRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<Page> e)
{
base.OnElementChanged(e);
if (e.OldElement != null || Element == null)
{
return;
}
try
{
// **** Element.Content = null;
SetNativeControl(new MyUWP());
}
catch (Exception ex)
{
}
}
}
If I don't use Element.Content = null; in above code, both pages (Native and Xamarin.Forms) will be render on top of one another. So, I had to first set the Content to null to make native page visible.
Is there any reason behind it or am I understanding wrong?
The above similar code works in Xamarin.Android project very well.
Related
I want to hide listview scrollbar in my xamarin andorid and xamarin ios application's. I have searched many post's but only few post's are having the helpful that to not clear. Please suggest any idea of hide scrollbar in listview.
Here is what I did:
Android custom renderer:
[assembly: ExportRenderer(typeof(CustomListView),typeof(CustomListViewRenderer))]
namespace ImageList.Droid
{
public class CustomListViewRenderer : ListViewRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<ListView> e)
{
base.OnElementChanged(e);
if(Control != null)
{
Control.VerticalScrollBarEnabled = false;
}
}
}
}
iOS custom renderer:
[assembly: ExportRenderer(typeof(CustomListView), typeof(CustomListViewRenderer))]
namespace ImageList.iOS
{
public class CustomListViewRenderer : ListViewRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<ListView> e)
{
base.OnElementChanged(e);
if (Control != null)
{
Control.ShowsVerticalScrollIndicator = false;
}
}
}
}
Remember: We need to use the Custom ListView instead of the native ListView in the PCL Forms
Update: Now from Xamarin.Forms version 3.5.0, we can use VerticalScrollBarVisibility, HorizontalScrollBarVisibility properties to handle ListView ScrollBarVisibility.
You can also find full source code and document from http://bsubramanyamraju.blogspot.com/2019/03/hide-listview-scrollbar-in-xamarinforms.html
Custom renders for the solution here, check official documents for that
https://developer.xamarin.com/guides/xamarin-forms/application-fundamentals/custom-renderer/listview/
Android:
ListView.VericalScrollbarEnabled = false;
iOS:
UIScrollView.ShowsVerticalScrollIndicator = false;
Is there a custom circular activity indicator for UWP/ Win10 apps using Xamarin?
Is there a custom circular activity indicator for UWP/ Win10 apps using Xamarin?
You need to create your own View for UWP's ProgressRing:
Shared Project\MyProgressRing.cs:
public class MyProgressRing:View
{
}
UWP Project\MyProgressRingRenderer.cs:
[assembly:ExportRenderer(typeof(MyProgressRing),typeof(MyProgressRingRenderer))]
namespace CircularActivityDemo.UWP
{
public class MyProgressRingRenderer:ViewRenderer<MyProgressRing,ProgressRing>
{
ProgressRing ring;
protected override void OnElementChanged(ElementChangedEventArgs<MyProgressRing> e)
{
base.OnElementChanged(e);
if (Control == null)
{
ring = new ProgressRing();
ring.IsActive = true;
ring.Visibility = Windows.UI.Xaml.Visibility.Visible;
ring.IsEnabled = true;
SetNativeControl(ring);
}
}
}
}
Notes: I hardcoded the properties of ProgressRing Control. You can create DependencyProperties for your custom ProgressRing control.
I tried to add my own image to switch Control in xamarin forms using rendering concept but i am unable to override the existing image.Below is my code.
In shared project i added code like this
Switch switcher = new ExtendedSwitchnew();
and in ios
[assembly: ExportRenderer(typeof(ExtendedSwitchnew),typeof(SwitchRenderernew))]
namespace test.iOS
{
public class SwitchRenderernew :SwitchRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<Switch> e)
{
base.OnElementChanged(e);
if (Control != null)
{
UIImage imgon = UIImage.FromFile("Images/switchon.png");
UIImage imgoff = UIImage.FromFile("Images/switchoff.png");
Control.OnImage = imgon;
Control.OffImage = imgoff;
}
}
}
}
Help me.Thanks in advace.
I'm working on a Xamarin.forms project but i need to use Android.Widget.AutoCompleteTextView how can i apply that?
When i am trying to add AutoCompleteTextView UserNameAutoComplete; to ContentPage i get the following error:
Content = new StackLayout
{
VerticalOptions = LayoutOptions.Center,
Padding = new Thickness(25),
Children =
{
UserNameAutoComplete,
passwordEditor,
}
};
cannot convert from 'Android.Widget.AutoCompleteTextView' to
'Xamarin.Forms.View'
Android.Widget.AutoCompleteTextView is a View from Android.
Solution for PCL:
You can't use platform specific View's on Xamarin Forms (PCL) ContentPage.
To use platform specific View you should use a custom render.
There is a blog post from #JamesMontemagno that shows how to do what you need.
This code is draft exemple please use it as such.
1 - Create your own custom Xamarin.Forms control that will be renderered in Android as an AutoCompleteTextView:
public class AutoCompleteView : View
{
// Place need properties here.
}
2 - In Android project add a renderer for AutoCompleteView:
[assembly: ExportRenderer(typeof(AutoCompleteView), typeof(AutoCompleteViewRenderer))]
namespace App.Droid
{
public class AutoCompleteViewRenderer : ViewRenderer<AutoCompleteView, AutoCompleteTextView>
{
// Initialize the AutoCompleteTextView
protected override void OnElementChanged (ElementChangedEventArgs<AutoComplete> e)
{
base.OnElementChanged (e);
if (e.OldElement != null || this.Element == null)
return;
var autoComplete = new AutoCompleteTextView(Forms.Context);
SetNativeControl (autoComplete);
}
// Use the control here.
protected override void OnElementPropertyChanged (object sender, PropertyChangedEventArgs e) {
base.OnElementPropertyChanged (sender, e);
if (this.Element == null || this.Control == null)
return;
// variable this.Control is the AutoCompleteTextView, so you an manipulate it.
}
}
}
Solution for Shared Project:
When using Shared Project there is a possibility to use Native Embedding, like:
...
var textView = new TextView (Forms.Context) { Text = originalText };
stackLayout.Children.Add (textView);
contentView.Content = textView.ToView();
...
I am trying to have make the Entry select all text when it is focused. I have a custom renderer for doing so on Android, but would like it to work on Windows 8 as well. How can I create a custom render for Windows in Xamarin Forms? Here is what I have:
[assembly: ExportRenderer(typeof(Xamarin.Forms.Entry), typeof(DrivingLog.Windows.MyEntryRenderer))]
namespace DrivingLog.Windows{
public class MyEntryRenderer : EntryRenderer {
protected override void OnElementChanged(ElementChangedEventArgs e) {
base.OnElementChanged(e);
if (e.OldElement == null) {
var nativeEditText = (global::Windows.UI.Xaml.Controls.TextBox)Control;
nativeEditText.ManipulationStarted += (object sender, ManipulationStartedRoutedEventArgs args) => {
nativeEditText.SelectAll();
};
}
}
}
}
I found the issue, the renderer class was in the Main Page.xaml.cs file. It needed to be in a file that did not have xaml associated with it for the assembly tag to be recognized be Xamarin Forms 2.0