开头

• 这是分篇章，整篇请看零基础iOS开发学习日记

界面跳转-modal

• modal方式跳转，针对前后跳转的界面没有任何联系
• nav的跳转请看
• 跳转

- (void)btnClick {
    testViewController *vc = [testViewController new];
    //全屏弹出
    vc.modalPresentationStyle = UIModalPresentationFullScreen;
    [self presentViewController:vc animated:YES completion:nil];
}
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• 消失

- (void)back {
    [self dismissViewControllerAnimated:NO completion:nil];
}
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视图生命周期

系统相关函数

//加载
- (void)loadView {
    [super loadView];
    NSLog(@"ViewController - loadView");
}
//已经加载
- (void)viewDidLoad {
    [super viewDidLoad];
    NSLog(@"ViewController - viewDidLoad");
}
//将要出现
- (void)viewWillAppear:(BOOL)animated {
    [super viewWillAppear:animated];
    NSLog(@"ViewController - viewWillAppear");
}
//已经出现
- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    NSLog(@"ViewController - viewDidAppear");
}
//将要消失
- (void)viewWillDisappear:(BOOL)animated {
    [super viewWillDisappear:animated];
    NSLog(@"ViewController - viewWillDisappear");
}
//已经消失
- (void)viewDidDisappear:(BOOL)animated {
    [super viewDidDisappear:animated];
    NSLog(@"ViewController - viewDidDisappear");
}
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界面出现的顺序

ViewController - loadView
ViewController - viewDidLoad
ViewController - viewWillAppear
ViewController - viewDidAppear
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界面切换的顺序

testViewController - loadView
testViewController - viewDidLoad
ViewController - viewWillDisappear
testViewController - viewWillAppear
testViewController - viewDidAppear
ViewController - viewDidDisappear
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界面跳回的顺序

testViewController - viewWillDisappear
ViewController - viewWillAppear
ViewController - viewDidAppear
testViewController - viewDidDisappear
testViewController - dealloc
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实际使用

• 我在实际开发中，最常操作的还是在loadView和viewDidLoad
• loadView是在控制器的view为nil的时候加载的，也就是说，当你需要更换控制器的根view时，可以在这个函数中写，而且不需要调用super的方法
• 那么，控件加载一般是写在viewDidLoad中

总结

1. 界面跳转就好比叠盘子，一个个叠上去，最下面的会一直被保存，而当上面的界面被撤掉后，则直接被销毁
2. 在整个界面显示的过程中，数据的加载和显示，其实是分开的