iOS开发从入门到精通--UIViewController使用

UIViewController使用：从ViewController.m跳转到ViewController02.m，ViewController.m的生命周期问题，ViewController02消失之后再显示ViewController的过程

ViewController.m里面的代码：

#import "ViewController.h"
#import "ViewController02.h"
@interface ViewController ()

@end

@implementation ViewController

//当屏幕被点击时，调用此函数
- (void) touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    //创建视图控制器2
    ViewController02 *vc =[[ViewController02 alloc]init];

    //显示一个新的视图控制器到屏幕上
    //p1:新的视图控制器对象
    //p2:使用动画切换动画效果
    //p3:切换结束后功能调用，不需要直接传nil
    [self presentViewController:vc animated:YES completion:nil];
}

//第一次程序加载视图时调用
- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.

    self.view.backgroundColor=[UIColor blueColor];

    NSLog(@"viewDidLoad 第一次加载视图");

}

//当视图控制器的视图即将显示时，调用此函数
//视图分为：1显示前（不显示）2正在处于显示状态 3已经被隐藏
//参数：表示是否用动画切换后显示
//每一次视图显示时都会被调用
- (void) viewWillAppear:(BOOL)animated{
    NSLog(@"viewWillAppear 视图即将显示");

}

//视图即将消失时，调用此函数
//参数：表示是否调用动画切换后消失
//当前状态：视图还是显示在屏幕上的
- (void) viewWillDisappear:(BOOL)animated{
    NSLog(@"viewDidDisappear 视图即将消失");
}

//当视图已经显示到屏幕后的瞬间调用此函数
//参数：表示是否调用动画切换显示
//当前状态：已经显示到屏幕上
- (void) viewDidAppear:(BOOL)animated{

    NSLog(@"viewDidAppear 视图已经显示");
}

//当前视图已经消失从屏幕上
//参数：表示是否调用动画
//当前状态：当前视图控制视图已经消失从屏幕上
- (void) viewDidDisappear:(BOOL)animated{

    NSLog(@"viewDidDisappear 视图已经消失");
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

@end

创建一个ViewController02，在ViewController02.m里代码如下：

#import "ViewController02.h"

@interface ViewController02 ()

@end

@implementation ViewController02

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    //控制器2的颜色为红色
    self.view.backgroundColor=[UIColor redColor];
}

//点击当前控制器2的界面屏幕时
- (void) touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{
    //使当前的控制器消失掉
    //p1:是否有动画效果
    //p2:结束后是否调用功能block块操作
    [self dismissViewControllerAnimated:YES completion:nil];
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

/*
#pragma mark - Navigation

// In a storyboard-based application, you will often want to do a little preparation before navigation
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender {
    // Get the new view controller using [segue destinationViewController].
    // Pass the selected object to the new view controller.
}
*/

@end