这已然是一个老生常谈的话题，这里再重复记录一下:

Viewcontroller生命周期

<pre>- (instancetype)init{
self= [super init];
if(self) {
debugMethod();
}
return self;
}</pre>

<pre>- (void)loadView{
[super loadView];
debugMethod();
}</pre>

<pre>- (void)viewDidLoad {
[super viewDidLoad];
self.view.backgroundColor= [UIColorwhiteColor];
debugMethod();
}</pre>

<pre>- (void)viewWillAppear:(BOOL)animated{
[super viewWillAppear:animated];
debugMethod();
}</pre>

<pre>- (void)viewDidAppear:(BOOL)animated{
[super viewDidAppear:animated];
debugMethod();
}</pre>

<pre>- (void)viewWillDisappear:(BOOL)animated{
[super viewWillDisappear:animated];
debugMethod();
}</pre>

<pre>- (void)viewDidDisappear:(BOOL)animated{
[super viewDidDisappear:animated];
debugMethod();
}</pre>

打印：

-[NextViewController init]

-[NextViewController loadView]

-[NextViewController viewDidLoad]

-[NextViewController viewWillAppear:]

-[NextViewController viewDidAppear:]

-[NextViewController viewWillDisappear:]

-[NextViewController viewDidDisappear:]