Question

在我的viewcontroller中，视图很少。所有视图的帧都取决于变量

CGFloat borderWidth

这些视图定义为

sec1 = [[MSSectionView alloc]initWithFrame:CGRectMake(self.borderWidth, self.borderWidth,self.frame.size.width/2-(self.borderWidth*3/2),self.frame.size.height/2 - (self.borderWidth*3/2) ) ];

当我从另一个类更改borderwidth的值时，我想更改sec1的帧。我们怎么能这样做？我知道

[sec1 setFrame:CGRectMake(self.borderWidth, self.borderWidth,self.frame.size.width/2-(self.borderWidth*3/2),self.frame.size.height/2 - (self.borderWidth*3/2) )];

会更改框架，但有很多uiviews。所以我不能在这个方法中为所有这些设置框架。

Answer 1

你可以这样实现：

在MSSectionView.m中：

#import "MSSectionView.h"

@implementation MSSectionView

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if ([keyPath isEqualToString: @"borderWidth"])
    {
        CGFloat borderWidth = [(NSNumber*)[change objectForKey:NSKeyValueChangeNewKey] floatValue];
        [self setFrame: CGRectMake(borderWidth, borderWidth, self.frame.size.width/2 - (borderWidth * 3/2), self.frame.size.height/2 - (borderWidth * 3/2))];
    }
    else
    {
        [super observeValueForKeyPath: keyPath
                             ofObject: object
                               change: change
                              context: context];
    }
}

@end

在viewcontroller中，它拥有一些MSSectionView作为子视图：

@implementation TSViewController

@synthesize borderWidth;

- (void) viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    NSArray* views = [self.view subviews];

    for (UIView* subview in views)
    {
        if ([subview isKindOfClass: [MSSectionView class]])
        {
            MSSectionView* sectionView = (MSSectionView*) subview;
            [self addObserver: sectionView
                   forKeyPath: @"borderWidth"
                      options: NSKeyValueObservingOptionNew | NSKeyValueObservingOptionOld
                      context: NULL];
        }

    }
}

在viewcontroller.h中：

@interface TSViewController : UIViewController
{
    CGFloat borderWidth;
}

@property(nonatomic,readwrite,assign)CGFloat borderWidth;

Answer 2

为实现这一目标，请采用一个循环并更改所有帧。

for(UIView *subview in yourview.subviews)
{
    // Here you can change your frames based on the condition
    //here you will get old frame value of subview so you can change by using the old frame values of all the subviews.
    [subview setFrame:CGRectMake(self.borderWidth, self.borderWidth,self.frame.size.width/2-(self.borderWidth*3/2),self.frame.size.height/2 - (self.borderWidth*3/2) )];
}

Answer 3

您可以考虑使用KVO。观察borderWidth课程中sec1的更改。这样，如果borderWidthe发生变化，您的sec1课程就会相应更改。

- (void)viewDidLoad
{
    [super viewDidLoad];

    [self addObserver:self forKeyPath:@"borderWidth" options:NSKeyValueObservingOptionNew context:&self->borderWidth];
}

- (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context
{
    if (context == &self.borderWidth) {
        if ([keyPath isEqualToString:@"borderWidth"]) {
            // Calculate your subview's frame.
        }
    }
}

如何在变量值更改时更改视图的框架？

3 个答案: