I have an scrollabe layout with an Editor inside that I'd like to make scrollable or auto resizable to fit the contents.
I can't find how to do it.
I tried a custom renderer but I can't find how to set InputMethods to the Control.
Any ideas?
With the help of this post: https://forums.xamarin.com/discussion/80360/editor-inside-scrollview-not-scrolling
That fixed the scrolling on Android (iOS works by default). It avoids the parent scroll event when touching inside the Editor, triggering only the Editor scroll.
First a class on Android project:
using Android.Views;
namespace MyApp.Droid
{
public class DroidTouchListener : Java.Lang.Object, View.IOnTouchListener
{
public bool OnTouch(View v, MotionEvent e)
{
v.Parent?.RequestDisallowInterceptTouchEvent(true);
if ((e.Action & MotionEventActions.Up) != 0 && (e.ActionMasked & MotionEventActions.Up) != 0)
{
v.Parent?.RequestDisallowInterceptTouchEvent(false);
}
return false;
}
}
}
And then use it on the Android Custom EditorRenderer:
protected override void OnElementChanged(ElementChangedEventArgs<Editor> e)
{
base.OnElementChanged(e);
if (e.OldElement == null)
{
var nativeEditText = (global::Android.Widget.EditText)Control;
//While scrolling inside Editor stop scrolling parent view.
nativeEditText.OverScrollMode = OverScrollMode.Always;
nativeEditText.ScrollBarStyle = ScrollbarStyles.InsideInset;
nativeEditText.SetOnTouchListener(new DroidTouchListener());
//For Scrolling in Editor innner area
Control.VerticalScrollBarEnabled = true;
Control.MovementMethod = ScrollingMovementMethod.Instance;
Control.ScrollBarStyle = Android.Views.ScrollbarStyles.InsideInset;
//Force scrollbars to be displayed
Android.Content.Res.TypedArray a = Control.Context.Theme.ObtainStyledAttributes(new int[0]);
InitializeScrollbars(a);
a.Recycle();
}
}
Related
I am working on an App that requires one list view having text labels with NSUnderlineStyle on user deletion.
As per the requirement user have Delete/restore option in detail screen. On delete confirmation the text label should be underline style for that particular cell.
I am using LabelRenderer for NSUnderlineStyle in Xamarin iOS.
But currently ListView displays text Labels with underline style which is not deleted by user on list view scroll. The underline style are swapping from one cell label to another on list view scroll.
Below my sample code.
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if (this.Control == null)
{
return;
}
if (this.Element is ExtendedLabel extended)
{
var strikethroughStyle = extended.IsStrikeThrough ? NSUnderlineStyle.Single : NSUnderlineStyle.None;
this.Control.AttributedText = new NSMutableAttributedString(
extended.Text ?? string.Empty,
this.Control.Font,
strikethroughStyle: strikethroughStyle);
}
}
This is the common issue of TableView Cell Resue , tableView will reuse the cell for the visible(inside screen shot) ones , so it would show the previous style .
To solve this we can forcedly set the style each time when the cell is going to display .
Create custom renderer for ListView , and do this in WillDisplay method ,before it we need to override TableView's Delegate.
[assembly: ExportRenderer(typeof(ListView), typeof(MyRenderer))]
namespace FormsApp.iOS
{
public class MyDelegate : UITableViewDelegate
{
List<Model> data;
public MyDelegate(List<Model> _data)
{
data = _data;
}
public override void WillDisplay(UITableView tableView, UITableViewCell cell, NSIndexPath indexPath)
{
var views = cell.ContentView.Subviews;
foreach (var view in views)
{
if(view is LabelRenderer renderer)
{
UILabel label = renderer.Control;
var strikethroughStyle = data[indexPath.Row].YourProperty?NSUnderlineStyle.Single : NSUnderlineStyle.None;
label.AttributedText = new NSMutableAttributedString(
label.Text ?? string.Empty,
label.Font,
strikethroughStyle: strikethroughStyle);
}
}
}
}
public class MyRenderer : ListViewRenderer
{
protected override void OnElementChanged(ElementChangedEventArgs<ListView> e)
{
base.OnElementChanged(e);
if (e.OldElement != null)
{
// Unsubscribe
}
if (e.NewElement != null)
{
IEnumerable<Model> data = (IEnumerable<Model>)Element.ItemsSource;
Control.Delegate = new MyDelegate(data.ToList());
}
}
}
}
I am having some difficulty figuring out how to properly update my existing custom renderer I have for my DatePicker on iOS to display the DatePicker with a different preferred style as is mentioned in this article here (albeit it is for swift) https://medium.com/better-programming/introducing-swifts-new-modern-date-picker-37bb5e0a106
My renderer is as follows:
public class BorderlessDatePickerRenderer : DatePickerRenderer
{
public override void LayoutSubviews()
{
base.LayoutSubviews();
var element = Element as BorderlessDatePicker;
Control.BorderStyle = UITextBorderStyle.None;
if (element.Date.Year == 1900) {
Control.Text = "";
}
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
var element = Element as BorderlessDatePicker;
if (Control != null && element.Date.Year == 1900) {
Control.Text = "";
}
}
The BorderlessDatePicker itself is just an empty class that extends the DatePicker Xamarin.Forms control. The root of my woes is that I am not sure how to properly set a PreferredDatePickerStyle on my Control object given that Control is a UITextField under the hood instead of a UIDatePicker. In essence what I would like to do is instead of displaying the Date picker using the compact style that seems to be default for iOS 14, I would like for it to be displayed as wheels instead by being to do something like:
PreferredDatePickerStyle = UIDatePickerStyle.Wheels;
After some more researching, and browsing the xamarin github, I've come across this solution:
protected override void OnElementChanged(ElementChangedEventArgs<DatePicker> e)
{
base.OnElementChanged(e);
if(e.NewElement != null && this.Control != null)
{
try
{
if (UIDevice.CurrentDevice.CheckSystemVersion(14, 0))
{
UIDatePicker picker = (UIDatePicker)Control.InputView;
picker.PreferredDatePickerStyle = UIDatePickerStyle.Wheels;
}
} catch (Exception ex)
{
Log.Error(ex, "Failed to set PreferredDatePickerStyle to be UIDatePickerStyle.Wheels for iOS 14.0+");
}
}
}
I am facing problem when using a ListView inside a Scrollview in Android (via Xamarin Forms).
I am calculating the height of the listview based on item source and a row height but i can still scroll inside the listview :
The listview is the white area contained in the scrollview, with few labels below, so we can scroll :
But in Android we can also scroll inside the listview itself :
I tried to catch the move event in a custom renderer :
public class CustomListViewRenderer : ListViewRenderer
{
public CustomListViewRenderer(Context context) : base(context)
{
}
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.ListView> e)
{
base.OnElementChanged(e);
var customListView = Element as CustomListView;
if (customListView == null)
{
return;
}
if (customListView.IsScrollingEnable == false)
{
Control.Touch += ListView_Touch;
}
}
private void ListView_Touch(object sender, TouchEventArgs e)
{
if (e.Event.Action == MotionEventActions.Move)
{
e.Handled = true;
}
else
{
e.Handled = false;
}
}
}
This can solve the space issue but if the user scroll from listview area with touch, the global scrollview doesn't work (you can only scroll with touch from Aqua Blue area).
Is there a way to disable the scroll in the listview without affect the parent scrollview ? The link to the sample project to reproduce the issue : https://1drv.ms/u/s!An8JKHwJo47up2ss_6pdzlXOhtDz?e=GdXrbf
Like Jason said, you could use the Listview directly.
With your code, you could set setScrollContainer to false in custom renderer.
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.ListView> e)
{
base.OnElementChanged(e);
if (e.NewElement == null)
return;
if (Control != null)
{
Control.SetScrollContainer(false);
}
}
I would like to extend all the contentpages in my xamarin.forms app with a native view in UWP. I can basically go to each and every page and embed a native view but i dont want this. I want to know if there is a way to do it using a pagerenderer. I tried doing like below.
my idea was to get current page rendering and extend the content with native view and stacklayout and define app.content again with this change. It works in general. If you run the small test project below, you can see that native UWP FontIcons are displayed for each page but there is a problem, if i navigate same page 2 times in MasterDetail in the attached project, page becomes blank. Why is this happening?
and is the approach below best for my case? I am open for alternative solutions.
[assembly: ExportRenderer(typeof(ContentPage), typeof(App3.UWP.ContentPageRenderer))]
namespace App3.UWP
{
public class ContentPageRenderer : PageRenderer
{
bool isDisposing = false;
protected override void OnElementChanged(ElementChangedEventArgs<Xamarin.Forms.Page> e)
{
base.OnElementChanged(e);
if (isDisposing)
return;
if (e.OldElement != null || Element == null)
{
return;
}
ContentPage page = ((ContentPage)Element);
if (page.Content == null)
return;
var XboxControls = new MyUserControl1();
StackLayout stackLayout = new StackLayout() { Orientation = StackOrientation.Vertical };
stackLayout.Children.Add(page.Content);
stackLayout.Children.Add(XboxControls.ToView());
page.Content = stackLayout;
}
protected override Windows.Foundation.Size ArrangeOverride(Windows.Foundation.Size finalSize)
{
return base.ArrangeOverride(finalSize);
}
protected override void Dispose(bool disposing)
{
isDisposing = disposing;
base.Dispose(disposing);
}
}
Test Project
I'm trying to insert a UWP specific child in the custom renderer of a StackLayout.
However, in the sample code below, Control is always null whereas my StackLayout has Children. Maybe StackPanel is not what StackLayout is rendered into in UWP.
public class MyRenderer : ViewRenderer<StackLayout, StackPanel>
{
private bool _childAdded;
protected override void OnElementPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
if (!_childAdded && Control?.Children != null)
{
_childAdded = true;
Control.Children.Insert(0, new Windows.UI.Xaml.Shapes.Rectangle());
}
base.OnElementPropertyChanged(sender, e);
}
}
Some modification in you are cade because you are calling base.OnElementPropertyChanged(sender,e) after code implementation. Just try to use below code.
public class MyRenderer : ViewRenderer<StackLayout, StackPanel>
{
private bool _childAdded;
protected override void OnElementPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
if(Control==null)
return;
if (!_childAdded && Control.Children != null)
{
_childAdded = true;
Control.Children.Insert(0, new Windows.UI.Xaml.Shapes.Rectangle());
}
}
}
The StackLayout (Layout) renderer is ViewRenderer and implemented on UWP by FrameworkElement; Renderer Base Classes and Native Controls.
Theoretical renderer:
public class MyRenderer : ViewRenderer<StackLayout, FrameworkElement>
...
Control is always null whereas my StackLayout has Children. Maybe StackPanel.
Derive from official document,
In Xamarin.Forms, all layout classes derive from the Layout<T> class and constrain the generic type to View and its derived types. But the layout of children element is incorrect.
And the match Native control within UWP platform is LayoutRenderer. So it is not inherit StackPanel directly. You could also custom a customrederer like the follow.
[assembly: ExportRenderer(typeof(StackLayout), typeof(ICustomStackLayoutRenderer))]
namespace CustomStackLayoutRenderer.UWP
{
public class ICustomStackLayoutRenderer : ViewRenderer<StackLayout, StackPanel>
{
private bool _childAdded;
protected override void OnElementChanged(ElementChangedEventArgs<StackLayout> e)
{
base.OnElementChanged(e);
if (Control == null)
{
var stacklayout = new StackPanel();
SetNativeControl(stacklayout);
}
if (e.OldElement != null)
{
}
if (e.NewElement != null)
{
if (!_childAdded && Control.Children != null)
{
_childAdded = true;
Control.Children.Insert(0, new Windows.UI.Xaml.Shapes.Rectangle() { Width = 100, Height = 100, Fill = new SolidColorBrush(Colors.Red) });
}
}
}
}
}
For your requirement, the better way is that create a CustomStackLayout inherit StackLayout in Xamarin.Forms, and re-layout your children element in your LayoutChildren override method. For more detail you could refer Creating a Custom Layout.