NSArray删除最后一个类型的对象？

Question

使用UIViews和UIImageViews数组（[[[UIApplication sharedApplication] window]子视图]）。我只需要删除UIImageView类型的最高索引的对象。

Answer 1

您可以使用indexOfObjectWithOptions:passingTest:方法反向搜索使用块传递测试的对象，然后在结果位置删除该对象：

NSUInteger pos = [myArray indexOfObjectWithOptions:NSEnumerationReverse
                          passingTest:^(id obj, NSUInteger idx, BOOL *stop) {
    return [obj isKindOfClass:[UIImageView class]]; // <<== EDIT (Thanks, Nick Lockwood!)
}];
if (pos != NSNotFound) {
    [myArray removeObjectAtIndex:pos];
}

Answer 2

另一个基于块的解决方案

[window.subviews enumerateObjectsWithOptions:NSEnumerationReverse 
                                  usingBlock:^(id view, NSUInteger idx, BOOL *stop) 
    {
        if ([view isKindOfClass:[UIImageView class]]){
            [view removeFromSuperview];
            *stop=YES;
    }
}];

非阻止解决方案：

for (UIView *view in [window.subview reverseObjectEnumerator])
{
    if ([view isKindOfClass:[UIImageView class]]){
            [view removeFromSuperview];
            break;
    }
}

我发布了some demo code，其中显示了两种解决方案。

Answer 3

怎么样：

UIWindow *window = [[UIApplication sharedApplication] window];
UIView *imageView = nil;
for (UIView *view in window.subviews)
{
    if ([view isKindOfClass:[UIImageView class]])
    {
        imageView = view;
    }
}

//this will be the last imageView we found
[imageView removeFromSuperview];