Question

我有一个滚动视图，我需要在我的应用运行时经常重新加载内容。现在，我正在使用以下代码行删除子视图，然后再将它们添加回来：

[scrollView.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];

我应该使用以下内容吗？

scrollView.subviews = nil;

出于某种原因，上面的第一行代码似乎每运行16次就会使应用程序崩溃。我在某处泄漏记忆吗？以下方法采用视图数组，滚动条（常量）和方向。

修改

- (void)loadViews:(NSArray *)views IntoScroller:(UIScrollView *)scroller withDirection:(NSString *)direction{
//Set up the scrollView

[scrollView.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];

if([direction isEqualToString:@"horizontal"]){
    scrollView.frame = CGRectMake(0, 0, 1024, 768);
    scrollView.contentSize = CGSizeMake(scrollView.frame.size.width * [[NSNumber numberWithUnsignedInt:[views count]] floatValue], scrollView.frame.size.height);
}else if([direction isEqualToString:@"vertical"]){
    scrollView.frame = CGRectMake(0, 0, 1024, 768);
    scrollView.contentSize = CGSizeMake(scrollView.frame.size.width, scrollView.frame.size.height * [[NSNumber numberWithUnsignedInt:[views count]] floatValue]);
}

for (int i=0; i<[[NSNumber numberWithUnsignedInt:[views count]] intValue]; i++) {

    [[[views objectAtIndex:[[NSNumber numberWithInt:i] unsignedIntValue]] view] setFrame:scrollView.frame];

    if([direction isEqualToString:@"horizontal"]){
        [[[views objectAtIndex:[[NSNumber numberWithInt:i] unsignedIntValue]] view] setFrame:CGRectMake(i * [[views objectAtIndex:[[NSNumber numberWithInt:i] unsignedIntValue]] view].frame.size.width, 0, scrollView.frame.size.width, scrollView.frame.size.height)];//CGRectMake(i * announcementView.view.frame.size.width, -scrollView.frame.origin.x, scrollView.frame.size.width, scrollView.frame.size.height)];
    }else if([direction isEqualToString:@"vertical"]){
        [[[views objectAtIndex:[[NSNumber numberWithInt:i] unsignedIntValue]] view] setFrame:CGRectMake(0, i * [[views objectAtIndex:[[NSNumber numberWithInt:i] unsignedIntValue]] view].frame.size.height, scrollView.frame.size.width, scrollView.frame.size.height)];
    }

    [scrollView addSubview:[[views objectAtIndex:[[NSNumber numberWithInt:i] unsignedIntValue]] view]];
}

}

Answer 1

您提供的第一个示例是从UIScrollView删除子视图的正确方法。

[scrollView.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];

将subviews设置为nil可以有效地清除管理子视图的集合对象，从而无法添加新的子视图。

Answer 2

以下是从滚动视图中删除所有子视图的代码：

for(UIView *subview in [scrollview  subviews]) 
        {
         [subview removeFromSuperview];

        }

删除UIScrollView的所有子视图的好方法是什么？

2 个答案: