为什么我无法将 ZoomScale 设置为低于 1？

Question

我正在使用从 PhotoScroller 示例 (WWDC10) 中提取的一些代码。但我使用的是 UIView 而不是 UIImageView。这是我所做的唯一更改（在 UIScrollView 子类上）。
我的问题是当我调用“configureForViewSize”时。它尝试应用 0.66 的 ZoomScale（以显示完整视图），但它不起作用。
设置 self.minimumZoomScale = minScale 后，我查看 self.zoomScale 的值，它始终等于 1

- (void)displayView:(UIView *)mView
{
    // clear the previous view
    [view removeFromSuperview];
    [view release];
    view = nil;  

    // reset our zoomScale to 1.0 before doing any further calculations
    self.zoomScale = 1.0;

    [self addSubview:mView];

    [self configureForViewSize:mView.frame.size];
}

- (void)configureForViewSize:(CGSize)viewSize 
{
    CGSize boundsSize = [self bounds].size;

    // set up our content size and min/max zoomscale
    CGFloat xScale = boundsSize.width / viewSize.width;    // the scale needed to perfectly fit the image width-wise
    CGFloat yScale = boundsSize.height / viewSize.height;  // the scale needed to perfectly fit the image height-wise
    CGFloat minScale = MIN(xScale, yScale);                 // use minimum of these to allow the image to become fully visible

    // on high resolution screens we have double the pixel density, so we will be seeing every pixel if we limit the
    // maximum zoom scale to 0.5.
    CGFloat maxScale = 1.0 / [[UIScreen mainScreen] scale];

    // don't let minScale exceed maxScale. (If the view is smaller than the screen, we don't want to force it to be zoomed.) 
    if (minScale > maxScale) {
        minScale = maxScale;
    }

    NSLog(@"contentSize %f %f", viewSize.width, viewSize.height);
    NSLog(@"minScale %f", minScale);
    NSLog(@"maxScale %f", maxScale);

    self.contentSize = viewSize;
    self.maximumZoomScale = maxScale;
    self.minimumZoomScale = minScale;
        //--> THIS IS NOT WORKING! =(
    self.zoomScale = minScale;  // start out with the content fully visible 

    NSLog(@"self.zoomScale %f", self.zoomScale);
}

控制台消息为：

2011-03-29 10:18:39.950 MyProj[6259:207] contentSize 1536.000000 893.000000
2011-03-29 10:18:39.953 MyProj[6259:207] minScale 0.666293
2011-03-29 10:18:39.954 MyProj[6259:207] maxScale 1.000000
2011-03-29 10:18:39.955 MyProj[6259:207] self.zoomScale 1.000000

编辑：

我自己想出来了。我忘记在“displayView”方法中分配 view = mView =(