20150630_UI之ViewCrontroller初步认识

代码实例:<pre name="code" class="objc">////  ViewController.m//  IOS150630_UI(02)_ViewController////  Created by PengJunlong on 15/6/30.//  Copyright (c) 2015年 Peng Junlong. All rights reserved.//#import "ViewController.h"@interface ViewController ()@end@implementation ViewController- (void)viewWillAppear:(BOOL)animated   //显示ViewController时调用{    NSLog(@"view1 = %@",self.view);    CGRect rect = CGRectMake(20, 100, self.view.frame.size.width-40, self.view.frame.size.height-200);    self.view.frame = rect;    self.view.backgroundColor = [UIColor redColor];}- (void)viewDidLoad {//加载视图调用    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.    CGRect rect = CGRectMake(20, 100, self.view.frame.size.width-40, self.view.frame.size.height-200);    self.view.frame = rect;    UIButton *btn = [UIButton buttonWithType:UIButtonTypeSystem];    [btn setTitle:@"点击me" forState:UIControlStateNormal];    [btn setTitle:@"修改颜色" forState:UIControlStateHighlighted];    NSLog(@"view3 = %@",self.view);    btn.frame = CGRectMake(20, 100, self.view.frame.size.width-40, 50);    btn.backgroundColor = [UIColor yellowColor];    btn.tag = 1;    [btn addTarget:self action:@selector(btnClicked:) forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:btn];        UIButton *btn1 = [UIButton buttonWithType:UIButtonTypeSystem];    [btn1 setTitle:@"点击me" forState:UIControlStateNormal];    [btn1 setTitle:@"修改颜色" forState:UIControlStateHighlighted];    btn1.frame = CGRectMake(20, 200, self.view.frame.size.width-40, 50);    btn1.backgroundColor = [UIColor yellowColor];    btn1.tag = 2;    [btn1 addTarget:self action:@selector(btnClicked:) forControlEvents:UIControlEventTouchUpInside];    [self.view addSubview:btn1];}- (void)btnClicked:(UIButton *)btn{    if (btn.tag == 1)    {        self.view.backgroundColor = [UIColor cyanColor];    }    if (btn.tag == 2)    {        self.view.backgroundColor = [UIColor blueColor];    }}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end

////  AppDelegate.m//  IOS150630_UI(02)_ViewController////  Created by PengJunlong on 15/6/30.//  Copyright (c) 2015年 Peng Junlong. All rights reserved.//#import "AppDelegate.h"@interface AppDelegate ()@end@implementation AppDelegate- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {    //视图控制器    //包含视图部分及控制部分    //通过视图控制器管理视图    //其实是在window上有一个viewController,默认下ViewController和window大小相同    //我们控件都是放在ViewController上    NSLog(@"rootViewController = %@",self.window.rootViewController);    return YES;}- (void)applicationWillResignActive:(UIApplication *)application {    // Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.    // Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.}- (void)applicationDidEnterBackground:(UIApplication *)application {    // Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later.    // If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.}- (void)applicationWillEnterForeground:(UIApplication *)application {    // Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.}- (void)applicationDidBecomeActive:(UIApplication *)application {    // Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.}- (void)applicationWillTerminate:(UIApplication *)application {    // Called when the application is about to terminate. Save data if appropriate. See also applicationDidEnterBackground:.}@end