保存并加载 UIScrollView 位置

Question

我正在创建一个应用程序，该应用程序使用滚动图像的 UIScrollView 和加载新视图并允许新图像层（有点像 Photoshop 分层）的分段控件 - 出于某种原因，当我单击该层时，它记住该位置但创建一个新层.... 我怎样才能阻止这种情况发生，所以一旦选择了一个层并选择了一个图像，当用户返回它时，它会转到最后加载的位置？

另外，作为一个附带的事情...当 UIScrollView 加载时，我不能使用我的手势识别或 UIAlertView？有谁知道为什么？

这是我的代码....提前致谢:)

- layerControl:(NSInteger)index
{
UIScrollView *scroll = [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
scroll.pagingEnabled = YES;
NSInteger viewCount = 15;
for (int i = 0; i < viewCount; i++) {
    CGFloat yOrigin = i * self.view.frame.size.width;
    UIImageView *filterViewOverlay = [[UIImageView alloc] initWithFrame:CGRectMake(yOrigin, 0, self.view.frame.size.width, self.view.frame.size.height)];
    [filterViewOverlay setImage:[filterManager objectAtIndex:i]];
    [scroll addSubview:filterViewOverlay];
    [filterViewOverlay release];
}
scroll.contentSize = CGSizeMake(self.view.frame.size.width * viewCount, self.view.frame.size.height);
  [self.view addSubview:scroll];
[scroll release];

switch (index)
{
    case 0: scroll = self.scroll1;
    case 1: scroll = self.scroll2;
    case 2: scroll = self.scroll3;
    case 4: scroll = self.scroll4;
    case 5: scroll = self.scroll5;

}

/* if (scroll == nil)
{
    [[UIScrollView alloc] initWithFrame:CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height)];
    scroll.pagingEnabled = YES;
    NSInteger viewCount = 15;
    for (int i = 0; i < viewCount; i++) {
        CGFloat yOrigin = i * self.view.frame.size.width;
        UIImageView *filterViewOverlay = [[UIImageView alloc] initWithFrame:CGRectMake(yOrigin, 0, self.view.frame.size.width, self.view.frame.size.height)];
        [filterViewOverlay setImage:[filterManager objectAtIndex:i]];
        [scroll addSubview:filterViewOverlay];
        //[filterViewOverlay release];
    }
    scroll.contentSize = CGSizeMake(self.view.frame.size.width * viewCount, self.view.frame.size.height);
    [self.view addSubview:scroll];
    [scroll autorelease]; */


} 
}



//Method to add a filter to the page
- (void)addFilter:(id)sender
{
    UISegmentedControl *filterController = (UISegmentedControl *)sender;

[self layerControl:[filterController selectedSegmentIndex]];
}

 - (UIImage*)saveImages
{

UIImage *image = [UIImage imageNamed:@"UrbanPhoto##1"];

UIGraphicsBeginImageContext(self.view.bounds.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
image = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();

return image;

}  

Answer 1

尝试在用户操作之前保存UIScrollView.contentOffset 的值，然后在操作完成后恢复该值。