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using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using UIKit;
using static System.String;
namespace Xamarin.Forms.Platform.iOS
{
public static class UIViewExtensions
{
public static IEnumerable<UIView> Descendants(this UIView self)
{
if (self.Subviews == null)
return Enumerable.Empty<UIView>();
return self.Subviews.Concat(self.Subviews.SelectMany(s => s.Descendants()));
}
public static SizeRequest GetSizeRequest(this UIView self, double widthConstraint, double heightConstraint, double minimumWidth = -1, double minimumHeight = -1)
{
var s = self.SizeThatFits(new SizeF((float)widthConstraint, (float)heightConstraint));
var request = new Size(s.Width == float.PositiveInfinity ? double.PositiveInfinity : s.Width, s.Height == float.PositiveInfinity ? double.PositiveInfinity : s.Height);
var minimum = new Size(minimumWidth < 0 ? request.Width : minimumWidth, minimumHeight < 0 ? request.Height : minimumHeight);
return new SizeRequest(request, minimum);
}
public static void SetBinding(this UIView view, string propertyName, BindingBase bindingBase, string updateSourceEventName = null)
{
var binding = bindingBase as Binding;
//This will allow setting bindings from Xaml by reusing the MarkupExtension
updateSourceEventName = updateSourceEventName ?? binding?.UpdateSourceEventName;
if (!IsNullOrEmpty(updateSourceEventName))
{
NativeBindingHelpers.SetBinding(view, propertyName, bindingBase, updateSourceEventName);
return;
}
NativeViewPropertyListener nativePropertyListener = null;
if (bindingBase.Mode == BindingMode.TwoWay)
{
nativePropertyListener = new NativeViewPropertyListener(propertyName);
try
{
//TODO: We need to figure a way to map the value back to the real objectiveC property.
//the X.IOS camelcase property name won't work
var key = new Foundation.NSString(propertyName.ToLower());
var valueKey = view.ValueForKey(key);
if (valueKey != null)
{
view.AddObserver(nativePropertyListener, key, Foundation.NSKeyValueObservingOptions.New, IntPtr.Zero);
}
}
catch (Foundation.MonoTouchException ex)
{
nativePropertyListener = null;
if (ex.Name == "NSUnknownKeyException")
{
System.Diagnostics.Debug.WriteLine("KVO not supported, try specify a UpdateSourceEventName instead.");
return;
}
throw ex;
}
}
NativeBindingHelpers.SetBinding(view, propertyName, bindingBase, nativePropertyListener);
}
public static void SetBinding(this UIView self, BindableProperty targetProperty, BindingBase binding)
{
NativeBindingHelpers.SetBinding(self, targetProperty, binding);
}
public static void SetValue(this UIView target, BindableProperty targetProperty, object value)
{
NativeBindingHelpers.SetValue(target, targetProperty, value);
}
public static void SetBindingContext(this UIView target, object bindingContext, Func<UIView, IEnumerable<UIView>> getChildren = null)
{
NativeBindingHelpers.SetBindingContext(target, bindingContext, getChildren);
}
internal static void TransferbindablePropertiesToWrapper(this UIView target, View wrapper)
{
NativeBindingHelpers.TransferBindablePropertiesToWrapper(target, wrapper);
}
internal static T FindDescendantView<T>(this UIView view) where T : UIView
{
var queue = new Queue<UIView>();
queue.Enqueue(view);
while (queue.Count > 0)
{
var descendantView = queue.Dequeue();
var result = descendantView as T;
if (result != null)
return result;
for (var i = 0; i < descendantView.Subviews.Length; i++)
queue.Enqueue(descendantView.Subviews[i]);
}
return null;
}
internal static UIView FindFirstResponder(this UIView view)
{
if (view.IsFirstResponder)
return view;
foreach (var subView in view.Subviews)
{
var firstResponder = subView.FindFirstResponder();
if (firstResponder != null)
return firstResponder;
}
return null;
}
}
}
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