iOS--界面弹出、color

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前言

pop,present都是iOS中界面弹出的方式

UIColor,CGColor是iOS中的颜色

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present

简介：

present和dismiss对应。present用于推出新的界面，dismiss用于返回上一界面
present和dismiss只能用于跳转至下一界面和返回上一界面
present弹出的视图是模态视图，所以只能逐级返回。
present一般用于不同业务的界面切换

使用方法：

//  text.9.15
//
//  Created by 王璐 on 2022/9/15.
//

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

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    NSLog(@"loadView 1");
    self.view.backgroundColor = [UIColor orangeColor];
    UIButton* button = [[UIButton alloc] init];
    button.frame = CGRectMake(100, 100, 100, 50);
    [button setTitle:@"跳转" forState:UIControlStateNormal];
    button.backgroundColor = [UIColor blueColor];
    [button addTarget:self action:@selector(press) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
    // Do any additional setup after loading the view.
}
- (void)press{
    SecondViewController* second = [[SecondViewController alloc] init];
    [self presentViewController:second animated:YES completion:nil];
}




//  SecondViewController.m
//  text.9.15
//
//

#import "SecondViewController.h"
#import "ViewController.h"


@interface SecondViewController ()

@end

@implementation SecondViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    NSLog(@"loadView 2");
    self.view.backgroundColor = [UIColor greenColor];
    UIButton* button = [[UIButton alloc] init];
    button.frame = CGRectMake(100, 100, 100, 50);
    button.backgroundColor = [UIColor blueColor];
    [button setTitle:@"返回" forState:UIControlStateNormal];
    [button addTarget:self action:@selector(press) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
    // Do any additional setup after loading the view.
}
- (void)press{
    ViewController* First = [[ViewController alloc] init];
    [self dismissViewControllerAnimated:YES completion:nil];
}

使用方法present弹出的视图都称之为模态视图，模态视图出现的场景一般是临时弹出的场景，比如登陆窗口，注册窗口。

动画效果的设置
注意一定添加
second.modalPresentationStyle = UIModalPresentationFullScreen才可以设置动画

	SecondViewController* second = [[SecondViewController alloc] init];
    second.modalPresentationStyle = UIModalPresentationFullScreen;
    //出现时从下到上，消失时从上到下。默认效果
    //second.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
    //边角翻页效果
    //second.modalTransitionStyle = UIModalTransitionStylePartialCurl;
    //淡入淡出效果
    //second.modalTransitionStyle = UIModalTransitionStyleCrossDissolve;
    //水平翻转，开始时从右至左，返回时从左至右
    //second.modalTransitionStyle = UIModalTransitionStyleFlipHorizontal;

push

简介：

push和pop对应
push由视图栈控制，可以返回任一级视图，不像present只能返回上一级视图
push一般用于同一业务不同界面切换。例如从微信“消息”界面跳转至微信”我的“界面

//  SceneDelegate.m
//  text.9.15
//
//

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

@end

@implementation SceneDelegate


- (void)scene:(UIScene *)scene willConnectToSession:(UISceneSession *)session options:(UISceneConnectionOptions *)connectionOptions {
    self.window = [[UIWindow alloc]initWithWindowScene:(UIWindowScene*)scene];
    self.window.rootViewController = [[UINavigationController alloc] initWithRootViewController:[[ViewController alloc] init]];
    [self.window makeKeyAndVisible];
    // Use this method to optionally configure and attach the UIWindow `window` to the provided UIWindowScene `scene`.
    // If using a storyboard, the `window` property will automatically be initialized and attached to the scene.
    // This delegate does not imply the connecting scene or session are new (see `application:configurationForConnectingSceneSession` instead).
}




//  ViewController.m
//  text.9.15
//
//

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

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    NSLog(@"loadView 1");
    self.view.backgroundColor = [UIColor whiteColor];
    UIButton* button = [[UIButton alloc] init];
    button.frame = CGRectMake(100, 100, 100, 50);
    [button setTitle:@"跳转" forState:UIControlStateNormal];
    button.backgroundColor = [UIColor blueColor];
    [button addTarget:self action:@selector(press) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
    // Do any additional setup after loading the view.
}
- (void)press{
    SecondViewController* second = [[SecondViewController alloc] init];

    [self.navigationController pushViewController:second animated:YES];
}
@end



//  SecondViewController.m
//  text.9.15
//
//

#import "SecondViewController.h"
#import "ViewController.h"


@interface SecondViewController ()

@end

@implementation SecondViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    NSLog(@"loadView 2");
    self.view.backgroundColor = [UIColor whiteColor];
    UIButton* button = [[UIButton alloc] init];
    button.frame = CGRectMake(100, 100, 100, 50);
    button.backgroundColor = [UIColor blueColor];
    [button setTitle:@"返回" forState:UIControlStateNormal];
    [button addTarget:self action:@selector(press) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
    // Do any additional setup after loading the view.
}
- (void)press{
    //ViewController* First = [[ViewController alloc] init];
    [self.navigationController popoverPresentationController];
}

/*
#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

使用push跳转到第二界面时，第二界面顶部会出现一个导航栏，左上方有<Back按钮可以直接返回第一界面

UIColor，CGColor，ClColor

UIColor

UIColor是继承于UIKit中储存颜色信息的一个重要的类，一个UIColor对象包括了颜色和透明度的值。
UIColor可以直接创建一些常见的颜色，这些颜色的色彩空间也不尽相同（白色和黑色是kCGColorSpaceDeviceGray，红色的色彩空间是kCGColorSpaceDeviceRGB）。
此外UIColor还有两个重要的属性：一个是CGColor，一个是CIColor(5.0之后添加)。

CGColor

CGColor主要用于CoreGaphics框架之中，CGColor其实是个结构体，而我们通常在使用的CGColor的时候使用的是它的引用类型CGColorRef。CGColor主要由CGColorSapce和Color Components两个部分组成。
同样的颜色组成，如果颜色空间不同的话，解析出来的结果可能会有所不同。

ClColor

CIColor主要是用于和CoreImage框架中其他类，比如CIFilter，CIContext以及CIImage。CIColor中颜色值的范围是0.0-1.0之间，0.0代表该颜色分量为最小值，1.0代表改颜色分量为最大值。其中alpha值的范围也是0.0到1.0之间，0.0代表全透明，1.0代表完全不透明，同时CIColor的颜色分量通常都是没有乘以alpha值。
可以使用initWithCGColor:函数，通过CGColor创建一个CIColor。其中传入的CGColorRef对象可以使任何任何颜色空间，但是Core Image框架会在传入filter kernel之前把所有的颜色空间转换到core image工作颜色空间。core image工作颜色空间使用三个颜色分量加上一个alpha分量组成(其实就是kCGColorSpaceDeviceRGB)