我正在尝试找出一种方法使复选框出现在页面上的按钮单击上。
默认情况下它是不可见的，因为我已经checkBox.Visibility = Android.Views.ViewStates.Invisible;在我的自定义渲染器中进行了设置。
我在页面内容中有一个按钮，在模板中有一个复选框，它位于页面资源中。
从我的 ViewModel 中，我可以在 CheckBox 控件中调用 PropertyChanged，我可以在其中看到正确设置的旧值和新值。
但我需要一种在 ViewRenderer 上设置它的方法。我猜它需要处理某种类似于CheckedChanged.
视图模型
CheckBox c = new CheckBox { IsCheckBoxVisible=true,IsVisible=true };
CheckBox control
public class CheckBox : View
{
/// <summary>
/// The checked state property.
/// </summary>
public static readonly BindableProperty CheckedProperty =
BindableProperty.Create<CheckBox, bool>(
p => p.Checked, false, BindingMode.TwoWay, propertyChanged: OnCheckedPropertyChanged);
**public static readonly BindableProperty IsCheckBoxVisibleProperty =
BindableProperty.Create<CheckBox, bool>(
p => p.IsCheckBoxVisible, false, BindingMode.OneWay, propertyChanged: OnVisibilityPropertyChanged);**
/// <summary>
/// The checked text property.
/// </summary>
public static readonly BindableProperty CheckedTextProperty =
BindableProperty.Create<CheckBox, string>(
p => p.CheckedText, string.Empty, BindingMode.TwoWay);
/// <summary>
/// The unchecked text property.
/// </summary>
public static readonly BindableProperty UncheckedTextProperty =
BindableProperty.Create<CheckBox, string>(
p => p.UncheckedText, string.Empty);
/// <summary>
/// The default text property.
/// </summary>
public static readonly BindableProperty DefaultTextProperty =
BindableProperty.Create<CheckBox, string>(
p => p.Text, string.Empty);
/// <summary>
/// Identifies the TextColor bindable property.
/// </summary>
///
/// <remarks/>
public static readonly BindableProperty TextColorProperty =
BindableProperty.Create<CheckBox, Color>(
p => p.TextColor, Color.Default);
/// <summary>
/// The font size property
/// </summary>
public static readonly BindableProperty FontSizeProperty =
BindableProperty.Create<CheckBox, double>(
p => p.FontSize, -1);
/// <summary>
/// The font name property.
/// </summary>
public static readonly BindableProperty FontNameProperty =
BindableProperty.Create<CheckBox, string>(
p => p.FontName, string.Empty);
/// <summary>
/// The checked changed event.
/// </summary>
public event EventHandler<EventArgs<bool>> CheckedChanged;
**public event EventHandler<EventArgs<bool>> VisibilityChanged;**
/// <summary>
/// Gets or sets a value indicating whether the control is checked.
/// </summary>
/// <value>The checked state.</value>
public bool Checked
{
get
{
return this.GetValue<bool>(CheckedProperty);
}
set
{
if (this.Checked != value)
{
this.SetValue(CheckedProperty, value);
this.CheckedChanged.Invoke(this, value);
}
}
}
**public bool IsCheckBoxVisible
{
get
{
return this.GetValue<bool>(IsCheckBoxVisibleProperty);
}
set
{
if (this.IsCheckBoxVisible != value)
{
this.SetValue(IsCheckBoxVisibleProperty, value);
this.VisibilityChanged.Invoke(this, value);
//OnPropertyChanged("IsCheckBoxVisible");
}
}
}**
/// <summary>
/// Gets or sets a value indicating the checked text.
/// </summary>
/// <value>The checked state.</value>
/// <remarks>
/// Overwrites the default text property if set when checkbox is checked.
/// </remarks>
public string CheckedText
{
get
{
return this.GetValue<string>(CheckedTextProperty);
}
set
{
this.SetValue(CheckedTextProperty, value);
}
}
/// <summary>
/// Gets or sets a value indicating whether the control is checked.
/// </summary>
/// <value>The checked state.</value>
/// <remarks>
/// Overwrites the default text property if set when checkbox is checked.
/// </remarks>
public string UncheckedText
{
get
{
return this.GetValue<string>(UncheckedTextProperty);
}
set
{
this.SetValue(UncheckedTextProperty, value);
}
}
/// <summary>
/// Gets or sets the text.
/// </summary>
public string DefaultText
{
get
{
return this.GetValue<string>(DefaultTextProperty);
}
set
{
this.SetValue(DefaultTextProperty, value);
}
}
/// <summary>
/// Gets or sets the color of the text.
/// </summary>
/// <value>The color of the text.</value>
public Color TextColor
{
get
{
return this.GetValue<Color>(TextColorProperty);
}
set
{
this.SetValue(TextColorProperty, value);
}
}
/// <summary>
/// Gets or sets the size of the font.
/// </summary>
/// <value>The size of the font.</value>
public double FontSize
{
get
{
return (double)GetValue(FontSizeProperty);
}
set
{
SetValue(FontSizeProperty, value);
}
}
/// <summary>
/// Gets or sets the name of the font.
/// </summary>
/// <value>The name of the font.</value>
public string FontName
{
get
{
return (string)GetValue(FontNameProperty);
}
set
{
SetValue(FontNameProperty, value);
}
}
/// <summary>
/// Gets the text.
/// </summary>
/// <value>The text.</value>
public string Text
{
get
{
return this.Checked
? (string.IsNullOrEmpty(this.CheckedText) ? this.DefaultText : this.CheckedText)
: (string.IsNullOrEmpty(this.UncheckedText) ? this.DefaultText : this.UncheckedText);
}
}
/// <summary>
/// Called when [checked property changed].
/// </summary>
/// <param name="bindable">The bindable.</param>
/// <param name="oldvalue">if set to <c>true</c> [oldvalue].</param>
/// <param name="newvalue">if set to <c>true</c> [newvalue].</param>
private static void OnCheckedPropertyChanged(BindableObject bindable, bool oldvalue, bool newvalue)
{
var checkBox = (CheckBox)bindable;
checkBox.Checked = newvalue;
}
**private static void OnVisibilityPropertyChanged(BindableObject bindable, bool oldvalue, bool newvalue)
{
var checkBox = (CheckBox)bindable;
checkBox.IsCheckBoxVisible = newvalue;
}**
}
复选框渲染器
protected override void OnElementChanged(ElementChangedEventArgs e)
{
base.OnElementChanged(e);
if (this.Control == null)
{
var checkBox = new Android.Widget.CheckBox(this.Context);
checkBox.Visibility = Android.Views.ViewStates.Invisible;
checkBox.CheckedChange += CheckBoxCheckedChange;
defaultTextColor = checkBox.TextColors;
this.SetNativeControl(checkBox);
}
Control.Text = e.NewElement.Text;
Control.Checked = e.NewElement.Checked;
UpdateTextColor();
if (e.NewElement.FontSize > 0)
{
Control.TextSize = (float)e.NewElement.FontSize;
}
if (!string.IsNullOrEmpty(e.NewElement.FontName))
{
Control.Typeface = TrySetFont(e.NewElement.FontName);
}
}
protected override void OnElementPropertyChanged(object sender, PropertyChangedEventArgs e)
{
base.OnElementPropertyChanged(sender, e);
switch (e.PropertyName)
{
case "Checked":
Control.Text = Element.Text;
Control.Checked = Element.Checked;
break;
case "TextColor":
UpdateTextColor();
break;
case "FontName":
if (!string.IsNullOrEmpty(Element.FontName))
{
Control.Typeface = TrySetFont(Element.FontName);
}
break;
case "FontSize":
if (Element.FontSize > 0)
{
Control.TextSize = (float)Element.FontSize;
}
break;
case "CheckedText":
case "UncheckedText":
Control.Text = Element.Text;
break;
** case "IsCheckBoxVisible":
if(Element.IsCheckBoxVisible==true)
{
Control.Visibility = Android.Views.ViewStates.Visible;
}
else
{
Control.Visibility = Android.Views.ViewStates.Invisible;
}
break;**
default:
System.Diagnostics.Debug.WriteLine("Property change for {0} has not been implemented.", e.PropertyName);
break;
}
}