push [特殊字符] present

前言

在 iOS 开发中，push 和 present 是两种不同的视图控制器切换方式，它们有着显著的区别。

present和dismiss

特点

• 在当前控制器上方新建视图层级
• 需要手动调用dismiss

ViewController* vc = [[ViewController alloc] init];
[self presentViewController:vc2 animated:YES completion:nil];

对应的dismiss方法：(用于关闭或取消当前显示的视图、对话框等)

[self dismissViewControllerAnimated:YES completion:nil];

• 默认从下向上滑入
• 只保留当前presented的控制器
• 可配置为全屏覆盖

代码演示

新建View02类作为视图控制器二

dimiss方法在View02文件中实现

#import "View02.h"

@interface View02 ()

@end

@implementation View02

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor cyanColor];
}

-(void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event {
    [self dismissViewControllerAnimated:YES completion:nil];
}

作为视图控制器一

present方法在ViewController文件中实现

#import "ViewController.h"
#import "View02.h"
@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    [self creatUIRectButton];
}
- (void)creatUIRectButton {
    UIButton *btn1 = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    btn1.frame = CGRectMake(10, 400, 120, 80);
    [btn1 setTitle:@"test button" forState:UIControlStateNormal];
    [btn1 setTitle:@"按下时候" forState:UIControlStateHighlighted];
    [btn1 addTarget:self action:@selector(press) forControlEvents:UIControlEventTouchUpInside];
    [btn1 setTintColor:[UIColor whiteColor]];
    btn1.backgroundColor = [UIColor grayColor];
    [self.view addSubview: btn1];
}
- (void) press {
    View02* vc = [[View02 alloc] init];
    [self presentViewController:vc animated:YES completion: nil];
}

@end

运行效果：

push和pop

特点

• 用于导航控制器堆栈中的视图控制器的界面切换。压入导航栈，成为栈顶控制器

ViewController* vc = [[ViewController alloc] init];
[self.navigationController pushViewController:vc animated:YES];

对应的消失视图方法为：

[self.navigationController popViewControllerAnimated:YES];

• 系统自动生成返回按钮
• 新视图从右向左滑入
• 保留所有pushed的控制器
• 不能全屏覆盖

代码演示

创建一个导航控制器：

//SceneDelegate.m
#import "SceneDelegate.h"
#import "VCRoot.h"
@interface SceneDelegate ()

@end

@implementation SceneDelegate


- (void)scene:(UIScene *)scene willConnectToSession:(UISceneSession *)session options:(UISceneConnectionOptions *)connectionOptions {
    self.window.frame = [UIScreen mainScreen].bounds;
    UINavigationController *nav = [[UINavigationController alloc] initWithRootViewController:[[VCRoot alloc] init]];
    self.window.rootViewController = nav;
    [self.window makeKeyAndVisible];
}

第一个视图控制器：

#import "VCRoot.h"
#import "VCSecond.h"
@interface VCRoot ()

@end

@implementation VCRoot

- (void)viewDidLoad {
    [super viewDidLoad];
    self.navigationController.navigationBar.translucent = YES;
    self.title = @"title";
    self.navigationItem.title = @"根视图";
    self.view.backgroundColor = [UIColor blueColor];
    self.navigationController.navigationBar.barStyle = UIBarStyleDefault;
    UIBarButtonItem *next = [[UIBarButtonItem alloc] initWithTitle:@"下一级" style:UIBarButtonItemStylePlain target:self action:@selector(pressRight)];
    self.navigationItem.rightBarButtonItem = next;
}
-(void)pressRight {
    VCSecond *vc2 = [[VCSecond alloc] init];
    [self.navigationController pushViewController:vc2 animated:YES];
}

第二个视图控制器：

#import "VCSecond.h"
#import "VCthird.h"
@interface VCSecond ()

@end

@implementation VCSecond

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor yellowColor];
    UIBarButtonItem *btnNext = [[UIBarButtonItem alloc] initWithTitle:@"next" style:UIBarButtonItemStylePlain target:self action:@selector(press)];
    self.navigationItem.rightBarButtonItem = btnNext;
}
-(void)press {
    VCthird *vc3 = [[VCthird alloc] init];
    [self.navigationController pushViewController:vc3 animated:YES];
}

第三个视图控制器：

#import "VCthird.h"

@interface VCthird ()

@end

@implementation VCthird

- (void)viewDidLoad {
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor cyanColor];
    UIBarButtonItem *btnLeft = [[UIBarButtonItem alloc] initWithTitle:@"返回" style:UIBarButtonItemStylePlain target:self action:@selector(pressBack)];
    self.navigationItem.rightBarButtonItem = btnLeft;
}
-(void)pressBack {
    [self.navigationController popToRootViewControllerAnimated:YES];
}

运行效果：