我正在编写一个generig Monotouch.Dialog元素来显示一个Image(不显示图像选择器),我正在重用UIViewElement和ImageElement中的代码,添加了一些参数,以便它可以在登录屏幕中使用例如(显示公司徽标等)。
到目前为止,我有这个:
public class ImageViewElement : Element, IElementSizing
{
protected UIImage Image;
public CellFlags Flags = 0;
public UIViewContentMode Alignment;
public enum CellFlags {
Transparent = 1,
DisableSelection = 2,
Both = 3
}
/// <summary>
/// Constructor
/// </summary>
/// <param name="caption">
/// The caption, only used for RootElements that might want to summarize results
/// </param>
/// <param name="view">
/// The view to display
/// </param>
/// <param name="transparent">
/// If this is set, then the view is responsible for painting the entire area,
/// otherwise the default cell paint code will be used.
/// </param>
public ImageViewElement (UIImage image, bool transparent, bool selectable, UIViewContentMode alignment) : base ("")
{
this.Alignment = alignment;
this.Image = image;
if(transparent)
{Flags+=1;}
if(!selectable)
{Flags+=2;}
}
public override UITableViewCell GetCell (UITableView tv)
{
var cell = tv.DequeueReusableCell (CellKey);
if (cell == null)
{
cell = new UITableViewCell (UITableViewCellStyle.Default, CellKey);
cell.ContentMode = UIViewContentMode.BottomRight;
switch(Flags)
{
case CellFlags.Transparent:
cell.BackgroundColor = UIColor.Clear;
//
// This trick is necessary to keep the background clear, otherwise
// it gets painted as black
//
cell.BackgroundView = new UIView (RectangleF.Empty) {BackgroundColor = UIColor.Clear};
break;
case CellFlags.DisableSelection:
cell.SelectionStyle = UITableViewCellSelectionStyle.None;
break;
case CellFlags.Both:
cell.BackgroundColor = UIColor.Clear;
//
// This trick is necessary to keep the background clear, otherwise
// it gets painted as black
//
cell.BackgroundView = new UIView (RectangleF.Empty) {
BackgroundColor = UIColor.Clear};
cell.SelectionStyle = UITableViewCellSelectionStyle.None;
break;
}
cell.ImageView.ContentMode = Alignment;
cell.ContentMode = Alignment;
cell.ImageView.Image = Image;
}
return cell;
}
public float GetHeight (UITableView tableView, NSIndexPath indexPath)
{
return Image.Size.Height;
}
}
到目前为止,除了对齐之外,一切都有效,图像始终显示在左侧,我尝试在单元格和单元格的Imageview上设置ContentMode,但它不起作用,我该怎么办?
cell.ContentMode = UIViewContentMode.Right;
var test = new UIImageView(Image);
cell.ContentView.Add (test);
现在我的ContentView边界与单元格边界相同,0,0,320,40,它们不正常,但我只是寻找,我的测试边界是0,0,256,256,但对齐仍然无法正常工作... dunno怎么做
编辑:一些进展!!!
我向IRC寻求建议
(2012-11-13 10:10:12) CENSORED: Implement a subclass of UITableViewCell
(2012-11-13 10:10:26) CENSORED: add the Image as a subview in the init method of the new class
(2012-11-13 10:10:33) CENSORED: and override layouSubviews
(2012-11-13 10:10:36) CENSORED: with the line:
(2012-11-13 10:10:56) CENSORED: imageView.Center = this.Center;
(2012-11-13 10:11:14) CENSORED: (call super first as well)
(2012-11-13 10:11:25) CENSORED: that way the image will always remain centred in the cell
(2012-11-13 10:38:23) CENSORED: AndreSM: UITableViewCell already has a UIImageView property (named ImageView)
(2012-11-13 10:38:36) CENSORED: you can just use that instead of creating a new one
所以我继续创建了一个子类:
public class ImageViewCell: UITableViewCell
{
UIImage cellImage;
public ImageViewCell (UIImage image, NSString key) : base(UITableViewCellStyle.Default, key)
{
cellImage = image;
ImageView.Image = cellImage;
}
public override void LayoutSubviews ()
{
base.LayoutSubviews ();
ImageView.Center = ContentView.Center;
ImageView.SetNeedsDisplay ();
}
}
但是图片仍然偏离中心,这是截图,所以你可以得到我的意思:
我没理由这个,我检查了什么是新的中心,值是正确的(X轴为160)。
答案 0 :(得分:2)
问题是中心是在PARENT坐标空间中定义的。因此,ContentView的Center属性在其PARENT(UITableViewCell,它本身就是一个视图)的空间中定义。但ImageView中心是在imageView的父级坐标空间中定义的,它是ContentView。
此代码应通过计算contentviews自身坐标空间中的中心来解决它
public override void LayoutSubviews ()
{
base.LayoutSubviews ();
ImageView.Center = new PointF(ContentView.Bounds.Width/2,ContentView.Bounds.Height/2);
ImageView.SetNeedsDisplay ();
}