我有这个所有者绘制元素：
using System;
using Tracktion.Service.WCF.Entities;
using MonoTouch.Dialog;
using MonoTouch.UIKit;
using MonoTouch.CoreGraphics;
using System.Drawing;
using MonoTouch.Foundation;
namespace Tracktion.iOS
{
public class EventListingElement : OwnerDrawnElement
{
public static UIFont EventTitleFont = UIFont.BoldSystemFontOfSize (18f);
public static UIFont EventTypeFont = UIFont.SystemFontOfSize (14f);
public static UIFont CountsFont = UIFont.ItalicSystemFontOfSize (14f);
public static UIFont DatesFont = UIFont.SystemFontOfSize (14f);
public static UIColor DefaultBackgroundColor = UIColor.White;
public EventListingElement (EventListingItem item) : base(UITableViewCellStyle.Default, "EventListingElement")
{
ev = item;
}
public EventListingElement (EventListingItem item, Action<EventListingItem> tapped) : this(item)
{
whenTapped = tapped;
}
EventListingItem ev;
Action<EventListingItem> whenTapped = null;
public override void Draw (RectangleF bounds, CGContext context, UIView view)
{
//view.BackgroundColor = EventListingElement.DefaultBackgroundColor;
//CGContext currentContext = UIGraphics.GetCurrentContext ();
SizeF sizeF;
float num = 0f;
UIColor.FromRGB (36, 112, 216).SetColor ();
string dateStr;
if (ev.StartTime.HasValue)
{
TimeSpan t = DateTime.Now - ev.StartTime.Value;
if (DateTime.Now.Day == ev.StartTime.Value.Day)
{
dateStr = ev.StartTime.Value.ToShortTimeString ();
}
else
{
if (t <= TimeSpan.FromHours (24.0))
{
dateStr = "Yesterday"; //.GetText ();
}
else
{
if (t < TimeSpan.FromDays (6.0))
{
dateStr = ev.StartTime.Value.ToString ("dddd");
}
else
{
dateStr = ev.StartTime.Value.ToShortDateString ();
}
}
}
}
else
{
dateStr = "Date TBA";
}
// Setup counts
string counts = "Staff & Volunteers: {0} reg, {1} in, {2} out\n";
counts += "Students & Visitors: {3} reg, {4} in, {5} out";
counts = string.Format (counts, ev.CountOfStaffAndVolunteersRegistered, ev.CountOfStaffAndVolunteersCheckedIn, ev.CountOfStaffAndVolunteersCheckedOut, ev.CountOfStudentsAndVisitorsRegistered, ev.CountOfStudentsAndVisitorsCheckedIn, ev.CountOfStudentsAndVisitorsCheckedOut);
float left = 13f;
// Draw
sizeF = view.StringSize (dateStr, EventListingElement.EventTitleFont);
float num2 = sizeF.Width + 21f + 5f;
RectangleF dateFrame = new RectangleF (view.Bounds.Width - num2, 6f, num2, 14f);
/*if (ev.StartTime != null && ev.StartTime.Value.Date == DateTime.Today)
{
currentContext.SaveState ();
currentContext.AddEllipseInRect (dateFrame);
currentContext.Clip ();
currentContext.DrawLinearGradient (EventListingElement.EventIsTodayGradient, new PointF (10f, 32f), new PointF (22f, 44f), CGGradientDrawingOptions.DrawsAfterEndLocation);
currentContext.RestoreState ();
}*/
view.DrawString (dateStr, dateFrame, EventListingElement.DatesFont, UILineBreakMode.Clip, UITextAlignment.Left);
float num3 = view.Bounds.Width - left;
UIColor.Black.SetColor ();
if (!string.IsNullOrWhiteSpace (ev.EventType))
{
view.DrawString (ev.EventType, new PointF (left, 2f), num3 - num2, EventListingElement.EventTypeFont, UILineBreakMode.TailTruncation);
}
view.DrawString (ev.Name, new PointF (left, 23f), num3 - left - num, EventListingElement.EventTitleFont, UILineBreakMode.TailTruncation);
UIColor.Gray.SetColor ();
view.DrawString (counts, new RectangleF (left, 40f, num3 - num, 34f), EventListingElement.CountsFont, UILineBreakMode.TailTruncation, UITextAlignment.Left);
/*if (this.NewFlag)
{
currentContext.SaveState ();
currentContext.AddEllipseInRect (new RectangleF (10f, 32f, 12f, 12f));
currentContext.Clip ();
currentContext.DrawLinearGradient (MessageSummaryView.gradient, new PointF (10f, 32f), new PointF (22f, 44f), CGGradientDrawingOptions.DrawsAfterEndLocation);
currentContext.RestoreState ();
}
*/
UIColor.Clear.SetFill();
UIColor.Black.SetColor ();
}
public override UITableViewCell GetCell (UITableView tv)
{
var cell = base.GetCell (tv);
cell.BackgroundColor = UIColor.Clear;
cell.BackgroundView = new UIView(RectangleF.Empty) { BackgroundColor = UIColor.Clear };
cell.SetNeedsDisplay();
return cell;
}
public override float Height (RectangleF bounds)
{
return 90f;
}
public override void Selected (DialogViewController dvc, UITableView tableView, NSIndexPath path)
{
base.Selected (dvc, tableView, path);
if (whenTapped != null)
whenTapped(this.ev);
}
}
}
我还没有完全正确地铺设所有东西，因为我遇到了一个主要问题 - 它总是最初渲染背景为黑色，没有圆角。然而，在选择单元格之后，在释放选择之后，单元格看起来很细，圆角等等。关于我需要做什么的任何建议？我开始使用带有2个内部类的UIView，一个用于单元格，一个用于视图，并且运气相同，并且认为切换到OwnerDrawnElement会修复此问题。
答案 0 :(得分：1)
我删除了OwnerDrawnElement作为基类，只是扩展了Element。我发现Miguel的一个旧blog entry对解决这个问题非常有帮助。
一些重点是扩展Element并实现IElementSizing。 GetCell返回一个MyDataCell实例，该实例具有一个覆盖draw方法的自定义UIView。同样非常重要的是自定义UIView将其BackgroundColor设置为清除。
public class EventListingElement2 : Element , IElementSizing
{
EventListingItem _ev;
public EventListingElement2 (EventListingItem item) : base ("")
{
_ev = item;
}
public override MonoTouch.UIKit.UITableViewCell GetCell (MonoTouch.UIKit.UITableView tv)
{
MyDataCell ret = tv.DequeueReusableCell ("xcx") as MyDataCell;
if (ret == null) {
ret = new MyDataCell (_ev, "xcx");
}
else {
ret.UpdateCell (_ev);
}
return ret;
}
public override void Selected (DialogViewController dvc, UITableView tableView, MonoTouch.Foundation.NSIndexPath path)
{
base.Selected (dvc, tableView, path);
}
#region IElementSizing implementation
public float GetHeight (UITableView tableView, MonoTouch.Foundation.NSIndexPath indexPath)
{
return 90;
}
#endregion
}
public class MyDataView : UIView
{
public MyDataView (EventListingItem myData)
{
Update (myData);
this.BackgroundColor = UIColor.Clear;
}
public void Update (EventListingItem myData)
{
this._ev = myData;
SetNeedsDisplay ();
}
EventListingItem _ev = new EventListingItem ();
public override void Draw (RectangleF rect)
{
SizeF sizeF;
float num = 0f;
UIColor.FromRGB (36, 112, 216).SetColor ();
string dateStr;
if (_ev.StartTime.HasValue) {
TimeSpan t = DateTime.Now - _ev.StartTime.Value;
if (DateTime.Now.Day == _ev.StartTime.Value.Day) {
dateStr = _ev.StartTime.Value.ToShortTimeString ();
} else {
if (t <= TimeSpan.FromHours (24.0)) {
dateStr = "Yesterday"; //.GetText ();
} else {
if (t < TimeSpan.FromDays (6.0)) {
dateStr = _ev.StartTime.Value.ToString ("dddd");
} else {
dateStr = _ev.StartTime.Value.ToShortDateString ();
}
}
}
} else {
dateStr = "Date TBA";
}
// Setup counts
string counts = "Staff & Volunteers: {0} reg, {1} in, {2} out\n";
counts += "Students & Visitors: {3} reg, {4} in, {5} out";
counts = string.Format (
counts,
_ev.CountOfStaffAndVolunteersRegistered,
_ev.CountOfStaffAndVolunteersCheckedIn,
_ev.CountOfStaffAndVolunteersCheckedOut,
_ev.CountOfStudentsAndVisitorsRegistered,
_ev.CountOfStudentsAndVisitorsCheckedIn,
_ev.CountOfStudentsAndVisitorsCheckedOut
);
float left = 13f;
// Draw
sizeF = this.StringSize (dateStr, EventListingElement.EventTitleFont);
float num2 = sizeF.Width + 21f + 5f;
RectangleF dateFrame = new RectangleF (
this.Bounds.Width - num2,
6f,
num2,
14f
);
this.DrawString (
dateStr,
dateFrame,
EventListingElement.DatesFont,
UILineBreakMode.Clip,
UITextAlignment.Left
);
float num3 = this.Bounds.Width - left;
UIColor.Black.SetColor ();
if (!string.IsNullOrWhiteSpace (_ev.EventType)) {
this.DrawString (
_ev.EventType,
new PointF (left, 2f),
num3 - num2,
EventListingElement.EventTypeFont,
UILineBreakMode.TailTruncation
);
}
this.DrawString (
_ev.Name,
new PointF (left, 23f),
num3 - left - num,
EventListingElement.EventTitleFont,
UILineBreakMode.TailTruncation
);
UIColor.Gray.SetColor ();
this.DrawString (
counts,
new RectangleF (left, 40f, num3 - num, 34f),
EventListingElement.CountsFont,
UILineBreakMode.TailTruncation,
UITextAlignment.Left
);
}
}
public class MyDataCell : UITableViewCell
{
MyDataView _myDataView;
public MyDataCell (EventListingItem myData, string identKey) : base (UITableViewCellStyle.Default, identKey)
{
_myDataView = new MyDataView (myData);
ContentView.Add (_myDataView);
}
public override void LayoutSubviews ()
{
base.LayoutSubviews ();
_myDataView.Frame = ContentView.Bounds;
_myDataView.SetNeedsDisplay ();
}
public void UpdateCell (EventListingItem myData)
{
_myDataView.Update (myData);
}
}