LayoutSubViews - 1

首先感谢写出这么好文章的大神：
http://bachiscoding.com/blog/2014/12/15/when-will-layoutsubviews-be-invoked/ http://www.cnblogs.com/pengyingh/articles/2417211.html
- (void)layoutSubviews;
来看看官方文档对这个方法的说明：



顾名思义，这个方式是对于subView的布局、大小等一些更新式，响应变化式的操作，上面提到另外两个方法：setNeedsLayout 和 layoutIfNeeded，我们先不讨论这额外的两个方法，我们单纯从方面的功能入手

开门见山，触发这个方法的几个最常用的（很多需要注意的地方，请移步大神博客，讲得非常好，本人的原则是在项目实际中遇到后才去甄别）



上面的几个情况我都亲自代码验证过了！参考第二篇文章，写了一个随屏幕布局变化的例子：





可以看到随屏幕方向不同，两张大图可以自己适应，但是红色框标出的自定义视图内部子视图发生了布局的变化，代码：

头文件：

@interface LBOrientationLayoutViewController : UIViewController

@end

#pragma mark - LBDynamicLayoutView

@interface LBDynamicLayoutView: UIView

@property (nonatomic, strong) UIImageView* iconImageView;
@property (nonatomic, strong) UILabel* profileLabel;

@end

实现文件：

#import "UIColor+RandomColor.h"
#import "LBOrientationLayoutViewController.h"

@interface LBOrientationLayoutViewController ()

@property (nonatomic, strong) LBDynamicLayoutView* dynamicLayoutView;
@property (nonatomic, strong) UIImageView* stuffImageView;
@property (nonatomic, strong) UIImageView* coolImageView;

@end

@implementation LBOrientationLayoutViewController

- (void)viewDidLoad
{
[super viewDidLoad];

[[UIDevice currentDevice] beginGeneratingDeviceOrientationNotifications];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(handleOrientationDidChange:) name:UIDeviceOrientationDidChangeNotification object:nil];

self.stuffImageView = [[UIImageView alloc] init];
[self.stuffImageView setFrame:CGRectMake(20, 20 + 50, self.view.frame.size.width - 40, 120)];
[self.stuffImageView setImage:[UIImage imageNamed:@"stuff.jpg"]];
[self.view addSubview:self.stuffImageView];

self.coolImageView = [[UIImageView alloc] init];
[self.coolImageView setFrame:CGRectMake(20,
self.stuffImageView.frame.origin.y + self.stuffImageView.frame.size.height + 10,
self.view.frame.size.width - 40,
250 - 10 - 120)];
[self.coolImageView setImage:[UIImage imageNamed:@"cool.jpg"]];
[self.view addSubview:self.coolImageView];

CGRect rect = CGRectMake(20,
self.coolImageView.frame.origin.y + self.coolImageView.frame.size.height + 10,
self.view.frame.size.width - 40,
270);
self.dynamicLayoutView = [[LBDynamicLayoutView alloc] initWithFrame:rect];
[self.dynamicLayoutView.profileLabel setText:@"海贼王，我当定了！"];
[self.view addSubview:self.dynamicLayoutView];

}

- (void)handleOrientationDidChange:(id)sender
{
UIInterfaceOrientation interfaceOrientation = [[UIApplication sharedApplication] statusBarOrientation];

if (interfaceOrientation == UIInterfaceOrientationPortrait || interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
{
CGRect rect = CGRectMake(20,
self.coolImageView.frame.origin.y + self.coolImageView.frame.size.height + 10,
self.view.frame.size.width - 40,
270);
[self.dynamicLayoutView setFrame:rect];
}

else if (interfaceOrientation == UIInterfaceOrientationLandscapeLeft || interfaceOrientation == UIInterfaceOrientationLandscapeRight)
{
CGRect rect = CGRectMake(self.stuffImageView.frame.origin.x + self.stuffImageView.frame.size.width + 10,
self.stuffImageView.frame.origin.y,
self.view.frame.size.width - self.stuffImageView.frame.origin.x - self.coolImageView.frame.size.width - 10 - 20,
self.stuffImageView.frame.size.height + 10 + self.coolImageView.frame.size.height);
[self.dynamicLayoutView setFrame:rect];
}
}

@end

#pragma mark - LBDynamicLayoutView

@implementation LBDynamicLayoutView

- (id)initWithFrame:(CGRect)frame
{
self = [super initWithFrame:frame];

if (self)
{
self.backgroundColor = [UIColor randomColor];
self.autoresizesSubviews = YES;

self.iconImageView = [[UIImageView alloc] init];
[self.iconImageView setFrame:CGRectMake(50, 10, self.frame.size.width - 100, 160)];
[self.iconImageView setBackgroundColor:[UIColor randomColor]];
[self.iconImageView setImage:[UIImage imageNamed:@"luffy.jpg"]];
[self addSubview:self.iconImageView];

self.profileLabel = [[UILabel alloc] init];
[self.profileLabel setFrame:CGRectMake(10, self.iconImageView.frame.origin.y + self.iconImageView.frame.size.height + 10, self.frame.size.width - 20, 80)];
[self.profileLabel setBackgroundColor:[UIColor randomColor]];
[self.profileLabel setTextColor:[UIColor randomColor]];
[self.profileLabel setNumberOfLines:0];
[self addSubview:self.profileLabel];
}

return self;
}

- (void)layoutSubviews
{
[super layoutSubviews];

UIInterfaceOrientation interfaceOrientation = [[UIApplication sharedApplication] statusBarOrientation];

if (interfaceOrientation == UIInterfaceOrientationPortrait || interfaceOrientation == UIInterfaceOrientationPortraitUpsideDown)
{
[self setVerticalFrame];
}

else if (interfaceOrientation == UIInterfaceOrientationLandscapeLeft || interfaceOrientation == UIInterfaceOrientationLandscapeRight)
{
[self setHorizontalFrame];
}
}

- (void)setVerticalFrame
{
NSLog(@"竖屏");

CGRect rect0 = CGRectMake(50, 10, self.frame.size.width - 100, 160);
[self.iconImageView setFrame:rect0];

CGRect rect1 = CGRectMake(10, self.iconImageView.frame.origin.y + self.iconImageView.frame.size.height + 10, self.frame.size.width - 20, 80);
[self.profileLabel setFrame:rect1];

}

- (void)setHorizontalFrame
{
NSLog(@"横屏");

CGRect rect0 = CGRectMake(10, 10, 100, self.frame.size.height - 20);
[self.iconImageView setFrame:rect0];

CGRect rect1 = CGRectMake(self.iconImageView.frame.origin.x + self.iconImageView.frame.size.width + 10,
10,
self.frame.size.width - self.iconImageView.frame.origin.x - self.iconImageView.frame.size.width - 10 - 10,
self.frame.size.height - 20);
[self.profileLabel setFrame:rect1];

}

@end

参考：
http://bachiscoding.com/blog/2014/12/15/when-will-layoutsubviews-be-invoked/ http://www.cnblogs.com/pengyingh/articles/2417211.html http://stackoverflow.com/questions/728372/when-is-layoutsubviews-called