1 基本说明
话说做了iOS几年,对于UIViewController和UIView的生命周期函数一直不是很重视,导致了很多模糊的地方。今天专门写一个Demo来验证一下,发现不同加载方式差别还是蛮大的。
2 加载UIViewController
每一种加载方式所调用的加载方法不同,而且还有一些细节地方不同。苹果为我们提供了四种默认的加载方式,不过我是纯代码党,AutoLayout以后,我们通过Masonry这个第三方布局利器来布局,在我Git上也有专门总结的不同布局解决方案。接下来我们看看系统的四种方式,犹豫没有什么理论性的东西,我就直接上代码为主了:
通过XIB加载。
通过StoryBoard加载。
通过NSCoding协议加载。
通过代码加载。
2.1 用XIB加载UIViewController
首先看初始化代码:
- (IBAction)loadControllerFromXIB:(id)sender {
XIBViewController *xibVC = [[XIBViewController alloc]initWithNibName:@"XIBViewController" bundle:[NSBundle mainBundle]];
[self.navigationController pushViewController:xibVC animated:YES];
}
当我们不实现loadView
的时候打印结果:
2017-04-15 12:05:32.974 UIViewController和UIView生命周期加载和卸载[59883:1192231] initWithNibName
2017-04-15 12:05:32.987 UIViewController和UIView生命周期加载和卸载[59883:1192231] viewDidLoad
2017-04-15 12:05:32.987 UIViewController和UIView生命周期加载和卸载[59883:1192231] viewWillAppear
2017-04-15 12:05:32.996 UIViewController和UIView生命周期加载和卸载[59883:1192231] viewWillLayoutSubviews
2017-04-15 12:05:32.997 UIViewController和UIView生命周期加载和卸载[59883:1192231] viewDidLayoutSubviews
2017-04-15 12:05:33.002 UIViewController和UIView生命周期加载和卸载[59883:1192231] viewWillLayoutSubviews
2017-04-15 12:05:33.002 UIViewController和UIView生命周期加载和卸载[59883:1192231] viewDidLayoutSubviews
2017-04-15 12:05:33.506 UIViewController和UIView生命周期加载和卸载[59883:1192231] viewDidAppear
2017-04-15 12:05:37.142 UIViewController和UIView生命周期加载和卸载[59883:1192231] clickButton
//pop以后
2017-04-15 12:05:42.334 UIViewController和UIView生命周期加载和卸载[59883:1192231] viewWillDisappear
2017-04-15 12:05:42.837 UIViewController和UIView生命周期加载和卸载[59883:1192231] viewDidDisappear
2017-04-15 12:05:42.838 UIViewController和UIView生命周期加载和卸载[59883:1192231] dealloc
我发现一个很奇怪的现象。如果用XIB加载的控制器,并且实现了一个空loadView
,那么我们在XIB设置的视图都失效了,应该是系统返回了一个默认的视图覆盖了。但是用Storyboard加载的视图,实现一个空的loadView
则不会丢失Storyboard里面的视图,这个是用XIB和Storyboard的一个注意点
。
-(void)loadView{
[super loadView];
NSLog(@"loadView");
}
2.2 用Storyboard加载UIViewController
初始化代码:
- (IBAction)laodControllerFromSB:(id)sender {
UIStoryboard *sb = [UIStoryboard storyboardWithName:@"Second" bundle:[NSBundle mainBundle]];
SBViewController *sbVC = [sb instantiateViewControllerWithIdentifier:@"SBViewController"];
[self.navigationController pushViewController:sbVC animated:YES];
}
运行结果:
2017-04-15 12:26:45.364 UIViewController和UIView生命周期加载和卸载[59932:1194239] initWithCoder
2017-04-15 12:26:45.365 UIViewController和UIView生命周期加载和卸载[59932:1194239] awakeFromNib
2017-04-15 12:26:45.368 UIViewController和UIView生命周期加载和卸载[59932:1194239] loadView
2017-04-15 12:26:45.368 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidLoad
2017-04-15 12:26:45.368 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewWillAppear
2017-04-15 12:26:45.372 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewWillLayoutSubviews
2017-04-15 12:26:45.373 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidLayoutSubviews
2017-04-15 12:26:45.877 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidAppear
//pop以后
2017-04-15 12:26:50.669 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewWillDisappear
2017-04-15 12:26:51.172 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidDisappear
2017-04-15 12:26:51.172 UIViewController和UIView生命周期加载和卸载[59932:1194239] dealloc
对于Storyboard,使用一个空的loadView
没有影响。
2.3 用NSCodeing加载UIViewController
初始化代码:
//这里我就不实现NSCoding协议了,直接传入一个nil参数。
- (IBAction)loadControllerFromCoder:(id)sender {
CoderViewController *coderVC = [[CoderViewController alloc]initWithCoder:nil];
[self.navigationController pushViewController:coderVC animated:YES];
}
运行结果:
2017-04-15 12:30:25.962 UIViewController和UIView生命周期加载和卸载[59932:1194239] initWithCoder
2017-04-15 12:30:25.963 UIViewController和UIView生命周期加载和卸载[59932:1194239] loadView
2017-04-15 12:30:25.963 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidLoad
2017-04-15 12:30:25.963 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewWillAppear
2017-04-15 12:30:25.967 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewWillLayoutSubviews
2017-04-15 12:30:25.967 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidLayoutSubviews
2017-04-15 12:30:25.968 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewWillLayoutSubviews
2017-04-15 12:30:25.968 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidLayoutSubviews
2017-04-15 12:30:26.470 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidAppear
//pop以后
2017-04-15 12:30:28.034 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewWillDisappear
2017-04-15 12:30:28.537 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidDisappear
2017-04-15 12:30:28.537 UIViewController和UIView生命周期加载和卸载[59932:1194239] dealloc
2.4 用代码加载UIViewController
初始化代码:
- (IBAction)loadControllerWithNone:(id)sender {
CodeViewController *codeVC = [[CodeViewController alloc]init];
[self.navigationController pushViewController:codeVC animated:YES];
}
运行结果:
2017-04-15 12:31:48.785 UIViewController和UIView生命周期加载和卸载[59932:1194239] initWithNibName
2017-04-15 12:31:48.786 UIViewController和UIView生命周期加载和卸载[59932:1194239] init
2017-04-15 12:31:48.787 UIViewController和UIView生命周期加载和卸载[59932:1194239] loadView
2017-04-15 12:31:48.787 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidLoad
2017-04-15 12:31:48.788 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewWillAppear
2017-04-15 12:31:48.792 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewWillLayoutSubviews
2017-04-15 12:31:48.792 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidLayoutSubviews
2017-04-15 12:31:48.792 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewWillLayoutSubviews
2017-04-15 12:31:48.792 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidLayoutSubviews
2017-04-15 12:31:49.293 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidAppear
//pop以后
2017-04-15 12:31:55.594 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewWillDisappear
2017-04-15 12:31:56.098 UIViewController和UIView生命周期加载和卸载[59932:1194239] viewDidDisappear
2017-04-15 12:31:56.098 UIViewController和UIView生命周期加载和卸载[59932:1194239] dealloc
3 加载UIView
3.1 用XIB加载UIView
初始化代码:
- (IBAction)loadViewFromXib:(id)sender {
XibView *xibView = [[[NSBundle mainBundle]loadNibNamed:@"XIBView" owner:self options:nil] lastObject];
[self.view addSubview:xibView];
}
运行结果:
2017-04-15 12:33:22.194 UIViewController和UIView生命周期加载和卸载[59932:1194239] initWithCoder
2017-04-15 12:33:22.195 UIViewController和UIView生命周期加载和卸载[59932:1194239] awakeFromNib
2017-04-15 12:33:22.195 UIViewController和UIView生命周期加载和卸载[59932:1194239] willMoveToWindow
2017-04-15 12:33:22.195 UIViewController和UIView生命周期加载和卸载[59932:1194239] willMoveToSuperview
2017-04-15 12:33:22.196 UIViewController和UIView生命周期加载和卸载[59932:1194239] didMoveToWindow
2017-04-15 12:33:22.196 UIViewController和UIView生命周期加载和卸载[59932:1194239] didMoveToSuperview
2017-04-15 12:33:22.197 UIViewController和UIView生命周期加载和卸载[59932:1194239] layoutSubviews
//这里是点击移除以后
2017-04-15 12:33:25.769 UIViewController和UIView生命周期加载和卸载[59932:1194239] willMoveToSuperview
2017-04-15 12:33:25.770 UIViewController和UIView生命周期加载和卸载[59932:1194239] willMoveToWindow
2017-04-15 12:33:25.771 UIViewController和UIView生命周期加载和卸载[59932:1194239] didMoveToWindow
2017-04-15 12:33:25.771 UIViewController和UIView生命周期加载和卸载[59932:1194239] didMoveToSuperview
2017-04-15 12:33:25.771 UIViewController和UIView生命周期加载和卸载[59932:1194239] dealloc
3.2 用代码加载UIView
初始化代码:
- (IBAction)loadViewWithNone:(id)sender {
CodeView *codeView = [[CodeView alloc]init];
codeView.backgroundColor = [UIColor greenColor];
codeView.frame = CGRectMake(0, 500, 100, 50);
[self.view addSubview:codeView];
}
运行结果:
2017-04-15 12:38:57.562 UIViewController和UIView生命周期加载和卸载[60323:1208772] initWithFrame
2017-04-15 12:38:57.562 UIViewController和UIView生命周期加载和卸载[60323:1208772] init
2017-04-15 12:38:57.562 UIViewController和UIView生命周期加载和卸载[60323:1208772] willMoveToWindow
2017-04-15 12:38:57.563 UIViewController和UIView生命周期加载和卸载[60323:1208772] willMoveToSuperview
2017-04-15 12:38:57.563 UIViewController和UIView生命周期加载和卸载[60323:1208772] didMoveToWindow
2017-04-15 12:38:57.563 UIViewController和UIView生命周期加载和卸载[60323:1208772] didMoveToSuperview
2017-04-15 12:38:57.564 UIViewController和UIView生命周期加载和卸载[60323:1208772] layoutSubviews
//点击移除以后
2017-04-15 12:39:02.751 UIViewController和UIView生命周期加载和卸载[60323:1208772] willMoveToSuperview
2017-04-15 12:39:02.752 UIViewController和UIView生命周期加载和卸载[60323:1208772] willMoveToWindow
2017-04-15 12:39:02.752 UIViewController和UIView生命周期加载和卸载[60323:1208772] didMoveToWindow
2017-04-15 12:39:02.752 UIViewController和UIView生命周期加载和卸载[60323:1208772] didMoveToSuperview
2017-04-15 12:39:02.752 UIViewController和UIView生命周期加载和卸载[60323:1208772] 点击移除
2017-04-15 12:39:02.753 UIViewController和UIView生命周期加载和卸载[60323:1208772] dealloc
4 总结
UIViewController不同加载方式钩子函数总结:
XIB加载方式
initWithNibName
loadView(
注意:如果实现一个空的方法,则XIB设置的属性无效,会覆盖XIB中的设置
)viewDidLoad
Storyboard加载方式
initWithCoder
awakeFromNib
loadView(
实现是一个空方法或者不实现没有影响
)viewDidLoad
NSCoding加载方式
initWithCoder
loadView
viewDidLoad
代码加载方式
initWithNibName
init(
这个是我初始化的时候主动调用,如果用initWithNibName传入nil参数则不会调用
)loadView
viewDidLoad
我们可以发现,代码加载方式和XIB加载方式一模一样,如果有XIB则加载XIB,如果没有XIB则可以代码添加视图。
UIView不同加载方式钩子函数总结:
XIB加载方式
initWithCoder
awakeFromNib
willMoveToWindow
代码加载方式
initWithFrame(
设置frame。
)init(
init方法调用
)willMoveToWindow
我们发现,如果通过init初始化,然后手动设置Frame。则会导致上面的调用顺序。
源码链接UIViewController和UIView生命周期加载和卸载。博客地址博客地址。