IOS-UI UI初步代码布局添加事件

ISO开发界面，UI是必须学习的一部分，其实很早以前想学来了，一直没有沉下心来学习。看到IOS的代码风格和布局就别扭的不行，跟java代码和android布局比较显得不是那么方便，因此一直到如今。先看一段代码

头文件：
//
//  RootViewController.h
//  UIPickerViewDemo
//
#import <UIKit/UIKit.h>

@interface RootViewController : UIViewController

@end



实现文件
//
//  RootViewController.m
//  UIPickerViewDemo
//

#import "RootViewController.h"

@interface RootViewController ()
@property (weak, nonatomic) IBOutlet UILabel *label;

- (IBAction)onClick:(id)sender;
@end

@implementation RootViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.
    CGRect screen = [[UIScreen mainScreen] bounds];
    CGFloat screenHeight = screen.size.height;
    CGFloat screenWidth = screen.size.width;
    NSLog(@"(%0.00f,%0.00f)",screenWidth,screenHeight);
    
    CGRect buttonFrame = CGRectMake(0, screenHeight*3/5, screenWidth, screenHeight/10);
    UIButton *button = [[UIButton alloc] initWithFrame:buttonFrame];
    [button setTitleColor:UIColor.greenColor forState:UIControlStateNormal];
    [button setTitle:@"底部按钮" forState:UIControlStateNormal];
    [button addTarget:self 
               action:@selector(onButtonClick:)
               forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
}


- (void) onButtonClick:(id)sender {
    UIAlertController *alertController = [UIAlertController alertControllerWithTitle:@"请确认" message:@"这是弹窗控件的消息message！" preferredStyle:UIAlertControllerStyleAlert];
    UIAlertAction *cancelAction = [UIAlertAction actionWithTitle:@"CANCLE" 
        style:UIAlertActionStyleCancel handler:^(UIAlertAction * _Nonnull action) {
        NSLog(@"action cancle!");
    }];
    [alertController addAction:cancelAction];
    [self presentViewController:alertController animated:YES completion:nil];
}
@end


自定义的UIViewController 须要跟AppDelegate先创建链接

//
//  AppDelegate.m
//  UIPickerViewDemo
//
#import "AppDelegate.h"
#import "RootViewController.h"

@interface AppDelegate ()

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    // Override point for customization after application launch.
    self.window = [[UIWindow alloc]initWithFrame:[[UIScreen mainScreen]bounds]];
    self.window.rootViewController = 
               [[RootViewController alloc]initWithNibName:@"RootViewController" bundle:nil];
    
    [self.window makeKeyAndVisible];
    return YES;
}

//省略 只看重点...

@end

其实上面只是先将main.storyboard和xcode自动创建的ViewController.h,ViewController.m文件删除了，而后本身建立了一个RootViewController文件，而后使用它来进行布局，能够一块儿使用xib来布局或者代码布局，可是只是这样运行起来仍是看不到界面，由于工程仍是会默认加载main.stroyboard，因此就须要修改工程属性，按照下面步骤：

1）delete 掉原来的三个文件ViewController.h、ViewController.m、main.storyboard

2）General --> TARGETS --> UIPickerViewDemo -->Deployment Info --> Main Interface 删除Main Interface中的Main，空着，以下图

3）添加视图控制器

Xcode -->  File --> New --> file

选择Cocoa Touch Clas --> Next弹出下面图，写入类名RootViewController，勾选Also create XIB file -->Next

 

而后就是创建链接，须要修改AppDelegate代码

自定义的UIViewController 须要跟AppDelegate先创建链接，见上面源代码
- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
  
    self.window = [[UIWindow alloc]initWithFrame:[[UIScreen mainScreen]bounds]];
    self.window.rootViewController =  [[RootViewController alloc]initWithNibName:@"RootViewController" bundle:nil];
    [self.window makeKeyAndVisible];
    return YES;
}

到此运行command + R 运行，点击“底部按钮”看效果，以下如