app m

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

@end

@implementation AppDelegate


- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
    
 
// Override point for customization after application launch.
    self.window.backgroundColor = [UIColor whiteColor];
    [self.window makeKeyAndVisible];
    ViewController* first=[[ViewController alloc]init];
    self.window.rootViewController=first;
    
 
    return YES;
}

UIView m

#import "ViewController.h
 
"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
//    self.view.backgroundColor=[UIColor orangeColor];
    //UIView 螢幕上的一塊巨型區域
    //UIView
    //1.初始化View
    UIView* view1 =[[UIView alloc]initWithFrame:CGRectMake(100, 100, 100, 100)];
    //2.設定view的背景色
 

    view1.backgroundColor=[UIColor greenColor];
    //3.新增
    [self.view addSubview:view1];
    NSLog(@"%@",self.view);
    
    UIView* view2=[[UIView alloc]initWithFrame:CGRectMake(200, 300,  100, 100)];
    view2.backgroundColor=[UIColor blueColor];
    [self.view addSubview:view2];
    
    //UI View常用的屬性
    //1.透明度（0-1）
    view1.alpha=1;
    view2.alpha=1;
    //2.是否隱藏
    view1.hidden=NO;
    //3.中心點
    view1.center=self.view.center;
    //4.tag (標籤) 值
    view1.tag=99;
    // 根據編號找到這個view
    UIView* resltView = [self.view viewWithTag:99];
    resltView.backgroundColor=[UIColor redColor];
    
    // 將一個子檢視放在 前面 resltView
    [self.view bringSubviewToFront:resltView];
    // 將一個檢視移動到 後面
    [self.view sendSubviewToBack:resltView];
    // 子檢視 自殺
    [view1 removeFromSuperview];
    

}