我的表和我的自定义单元格有以下代码：
以下是我的viewcontroller的代码
public void SearchHotel (){
Hotel hotel = new Hotel();
var distribution = new HotelDistribution[]{new HotelDistribution(){ Adults = 1, Children = 0, ChildrenAges = new int[0]} };
var items = hotel.SearchHotels(Convert.ToDateTime("2013-08-08"),Convert.ToDateTime("2013-09-09 "),"(MIA)", distribution,"","","",0);
List<DtoHotelinformation> data = new List<DtoHotelinformation>();
foreach (var item in items)
{
DtoHotelinformation DtoHotelinformation = new DtoHotelinformation();
DtoHotelinformation.price = item.Price.ToString();
DtoHotelinformation.title = item.Name.ToString();
DtoHotelinformation.subtitle = item.Address.ToString();
DtoHotelinformation.price = item.Price.ToString();
DtoHotelinformation.imageUlr = item.ImageUrl;
data.Add(DtoHotelinformation);
}
hud.Hide(true);
hud.RemoveFromSuperview();
HotelSearchTable.Source = new HotelTableSource(data.ToArray());
HotelSearchTable.ReloadData();
}
这是我的tablesource的代码
public class HotelTableSource : UITableViewSource
{
DtoHotelinformation[] tableItems;
NSString cellIdentifier = new NSString("TableCell");
public HotelTableSource (DtoHotelinformation[] items)
{
tableItems = items;
}
public override int RowsInSection (UITableView tableview, int section)
{
return tableItems.Length;
}
public override void RowSelected (UITableView tableView, NSIndexPath indexPath)
{
new UIAlertView("Row Selected", tableItems[indexPath.Row].title, null, "OK", null).Show();
tableView.DeselectRow (indexPath, true); // normal iOS behaviour is to remove the blue highlight
}
public override UITableViewCell GetCell (UITableView tableView, MonoTouch.Foundation.NSIndexPath indexPath)
{
CustomCell cell = tableView.DequeueReusableCell(cellIdentifier) as CustomCell;
if (cell == null)
cell = new CustomCell(cellIdentifier);
cell.UpdateCell(tableItems[indexPath.Row].title, tableItems[indexPath.Row].subtitle, tableItems[indexPath.Row].price,
tableItems[indexPath.Row].imageUlr );
return cell;
}
public override float GetHeightForRow(UITableView tableView, NSIndexPath indexPath)
{
return 60;
}
}
}
这是自定义单元代码：
public class CustomCell : UITableViewCell
{
UILabel headingLabel, subheadingLabel, priceLabel;
UIImageView imageService;
UIImageView star, star2, star3, star4, star5;
public CustomCell (NSString cellId) : base (UITableViewCellStyle.Default, cellId)
{
imageService = new UIImageView();
star = new UIImageView();
star2 = new UIImageView();
star3 = new UIImageView();
star4 = new UIImageView();
star5 = new UIImageView();
headingLabel = new UILabel(){
Font = UIFont.FromName("Verdana-Bold", 14f),
BackgroundColor = UIColor.Clear,
TextColor = UIColor.FromRGB(241, 241, 211)
};
subheadingLabel = new UILabel(){
Font = UIFont.FromName("Verdana-Bold", 8f),
TextColor = UIColor.FromRGB(60, 0, 100),
BackgroundColor = UIColor.Clear
};
priceLabel = new UILabel(){
Font = UIFont.FromName("Verdana", 14f),
TextColor = UIColor.FromRGB(241, 241, 211),
BackgroundColor = UIColor.Clear
};
AddSubview(imageService);
AddSubview(headingLabel);
AddSubview(subheadingLabel);
AddSubview(priceLabel);
}
public void UpdateCell (string title, string subtitle, string price, string imageUlr )
{
if (imageUlr != null) {
NSUrl nsUrl = new NSUrl(imageUlr);
NSData data = NSData.FromUrl(nsUrl);
imageService.Image = new UIImage(data);
} else {
imageService.Image = UIImage.FromFile("generic_no_image_tiny.jpg");
}
headingLabel.Text = title;
subheadingLabel.Text = subtitle;
priceLabel.Text = price;
}
public override void LayoutSubviews ()
{
base.LayoutSubviews ();
imageService.Frame = new RectangleF(10, 10, 50, 33);
headingLabel.Frame = new RectangleF(70, 4, 220, 25);
subheadingLabel.Frame = new RectangleF(100, 30, 100, 20);
priceLabel.Frame = new RectangleF(250, 30, 100, 20);
}
}
该表运行良好，我得到了我需要的数据，但它的工作速度非常慢。我的意思是当我试图滚动桌子时，一切都变得非常缓慢。任何想法？
答案 0 :(得分：2)
不覆盖GetHeightForRow以返回常量值。而是将RowHeight的{{1}}属性设置为您需要显示单元格的常量值。
这背后的原因是，当您覆盖UITableView iOS GetHeightForRow时，需要查询每个单元格以计算总高度。一旦你拥有数以千计的潜在细胞，那就非常缓慢（充其量）并且无法使用。
答案 1 :(得分：1)
避免分配可能很大且易于重用的对象。在这里，每次要显示单元格时都要创建一个UIImage。更糟糕的是，你可能正在打开一个文件，读取它并将其解压缩然后创建可显示的UIImage。您应该使用缓存来避免同一UIImage的重复实例。这个小班应该做的工作：
public class ImageCache {
private Dictionary<string, UIImage> cache = new Dictionary<string, UIImage>();
public static readonly ImageCache SharedInstance = new ImageCache();
public ImageCache() {
}
private UIImage ImageForUrl(string url) {
UIImage image = null;
if (!this.cache.TryGetValue(url, out image)) {
NSUrl url = new NSUrl(url);
NSData data = NSData.FromUrl(url);
image = UIImage.FromData(data);
if (image != null) {
this.cache[url] = image;
}
}
return image;
}
public UIImage this[string url] {
get { return this.ImageForUrl(url); }
}
}
我刚写了它并没有尝试过，但它应该做的伎俩。像
一样使用它UIImage image = ImageCache.SharedInstance["blabla.png"];
注意：poupou还有一个错误，解释了每次更新时添加视图的位置。
答案 2 :(得分：0)
我的问题是图像，这里是如何使用MonoTouch.Dialog.Utilities.ImageLoader解决问题
using System;
using System.Drawing;
using MonoTouch.Foundation;
using MonoTouch.UIKit;
using MonoTouch.Dialog.Utilities;
namespace Zurfers.Mobile.iOS
{
public class CustomCell : UITableViewCell, IImageUpdated
{
UILabel headingLabel, subheadingLabel, priceLabel;
UIImageView imageService;
UIImageView star, star2, star3, star4, star5;
public CustomCell (NSString cellId) : base (UITableViewCellStyle.Default, cellId)
{
imageService = new UIImageView();
star = new UIImageView();
star2 = new UIImageView();
star3 = new UIImageView();
star4 = new UIImageView();
star5 = new UIImageView();
headingLabel = new UILabel(){
Font = UIFont.FromName("Verdana-Bold", 14f),
BackgroundColor = UIColor.Clear,
TextColor = UIColor.FromRGB(241, 241, 211)
};
subheadingLabel = new UILabel(){
Font = UIFont.FromName("Verdana-Bold", 8f),
TextColor = UIColor.FromRGB(255, 255, 255),
BackgroundColor = UIColor.Clear
};
priceLabel = new UILabel(){
Font = UIFont.FromName("Verdana", 14f),
TextColor = UIColor.FromRGB(241, 241, 211),
BackgroundColor = UIColor.Clear
};
AddSubview(imageService);
AddSubview(headingLabel);
AddSubview(subheadingLabel);
AddSubview(priceLabel);
AddSubview(star);
AddSubview(star2);
AddSubview(star3);
AddSubview(star4);
AddSubview(star5);
}
public void UpdateCell (string title, string subtitle, string price, string imageUlr, string rating )
{
if (imageUlr != null) {
var u = new Uri(imageUlr);
ImageLoader MyLoader= new ImageLoader(50,50);
imageService.Image = MyLoader.RequestImage(u,this);
} else {
imageService.Image = UIImage.FromFile("generic_no_image_tiny.jpg");
}
headingLabel.Text = title;
subheadingLabel.Text = subtitle;
if (subtitle.Length > 40) {
subheadingLabel.LineBreakMode = UILineBreakMode.WordWrap;
subheadingLabel.Lines = 0;
}
switch (rating) {
case "T":
star.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
star2.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
break;
case "S":
star.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
star2.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
star3.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
break;
case "F":
star.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
star2.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
star3.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
star4.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
break;
case "L":
star.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
star2.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
star3.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
star4.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
star5.Image = UIImage.FromFile("ZurfersMovil-Stars.png");
break;
}
priceLabel.Text = "USD" + price;
priceLabel.Font = UIFont.BoldSystemFontOfSize (16);
}
public void UpdatedImage (Uri uri)
{
imageService.Image = ImageLoader.DefaultRequestImage(uri, this);
}
public override void LayoutSubviews ()
{
base.LayoutSubviews ();
imageService.Frame = new RectangleF(10, 10, 50, 33);
headingLabel.Frame = new RectangleF(70, 4, 240, 25);
subheadingLabel.Frame = new RectangleF(70, 25, 240, 20);
priceLabel.Frame = new RectangleF(220, 45, 100, 20);
star.Frame = new RectangleF(70, 45, 15, 15);
star2.Frame = new RectangleF(85, 45, 15, 15);
star3.Frame = new RectangleF(100, 45, 15, 15);
star4.Frame = new RectangleF(115, 45, 15, 15);
star5.Frame = new RectangleF(130, 45, 15, 15);
}
}
}
非常感谢你的帮助。