iOS开发-UI 从入门到精通(三)是对 iOS开发-UI 从入门到精通(一)知识点的综合练习，搭建一个简单地登陆界面，增强实战经验，为以后做开发打下坚实的基础！
※在这里我们还要强调一下，开发环境和内存管理注意事项（最后一次强调，以后文章中将不会在出现希望大家谨记）：
1、前期iOS-UI开发我们需要手动管理内存，所以我们要把ARC关掉（Xcode关掉ARC的步骤）；
（1）打开Xcode选中当前工程：
（2）选中Build Settings：
（3）在输入框内输入count：
（4）选择Objective-C Automatic Reference Counting 将其设置为 NO：
(5)AppDelegate.h文件中将：@property (assign, nonatomic) UIWindow *window;改成@property (retain, nonatomic) UIWindow *window;
(6)AppDelegate.m文件中重写：- (void)dealloc { [_window release]; [super dealloc]; }
2、在开发当中我们会用到模拟器下面我们来看一下模拟器添加步骤（Xcode环境下）；
（1）打开Xcode选择Window下的Devices：
（2）点击“+”在弹出来的选择框里对 Simulator Name 进行选择：
一、利用所学的知识搭建一个简单地登陆界面界面呈现“账号”、“密码”、“登录”、“忘记密码”、“注册”等：
AppDelegate.h文件中：
1 #import <UIKit/UIKit.h> 2 3 @interface AppDelegate : UIResponder <UIApplicationDelegate> 4 5 @property (retain, nonatomic) UIWindow *window; 6 7 @end
AppDelegate.m文件中：
1 @implementation AppDelegate 2 3 - (void)dealloc 4 { 5 [_window release]; 6 [super dealloc]; 7 } 8 9 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions { 10 // Override point for customization after application launch. 11 #pragma mark--:window窗口 12 self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 13 14 _window.backgroundColor = [UIColor whiteColor]; 15 16 #pragma mark--:创建一个view 17 UIView * view = [[UIView alloc] initWithFrame:[[UIScreen mainScreen] bounds]]; 18 19 view.backgroundColor = [UIColor whiteColor]; 20 21 #pragma mark--:创建两个UILabel(账号密码) 22 UILabel * numLabel = [[UILabel alloc] initWithFrame:CGRectMake(60, 100, 50, 30)]; 23 24 numLabel.text = @"账 号:"; 25 26 UILabel * passLabel = [[UILabel alloc] initWithFrame:CGRectMake(60, 160, 50, 30)]; 27 28 passLabel.text = @"密 码:"; 29 30 #pragma mark--:创建两个UITextField(账号输入框密码输入框) 31 UITextField * numTextField = [[UITextField alloc] initWithFrame:CGRectMake(130, 100, 200, 30)]; 32 33 numTextField.borderStyle = UITextBorderStyleRoundedRect; 34 35 numTextField.placeholder = @"请输入手机号/邮箱"; 36 37 UITextField * passTextField = [[UITextField alloc] initWithFrame:CGRectMake(130, 160, 200, 30)]; 38 39 passTextField.borderStyle = UITextBorderStyleRoundedRect; 40 41 passTextField.placeholder = @"请输入密码"; 42 43 #pragma mark--:创建三个Button(登录忘记密码注册) 44 UIButton * loginBtn = [UIButton buttonWithType:UIButtonTypeSystem]; 45 46 loginBtn.frame = CGRectMake(60, 220, 40, 40); 47 48 [loginBtn setTitle:@"登录" forState:UIControlStateNormal]; 49 50 UIButton * forgetBtn = [UIButton buttonWithType:UIButtonTypeSystem]; 51 52 forgetBtn.frame = CGRectMake(160, 220, 60, 40); 53 54 [forgetBtn setTitle:@"忘记密码" forState:UIControlStateNormal]; 55 56 UIButton * regisBtn = [UIButton buttonWithType:UIButtonTypeSystem]; 57 58 regisBtn.frame = CGRectMake(280, 220, 40, 40); 59 60 [regisBtn setTitle:@"注册" forState:UIControlStateNormal]; 61 62 #pragma mark--:添加到视图上 63 [view addSubview:regisBtn]; 64 65 [view addSubview:forgetBtn]; 66 67 [view addSubview:loginBtn]; 68 69 [view addSubview:passTextField]; 70 71 [view addSubview:numTextField]; 72 73 [view addSubview:passLabel]; 74 75 [view addSubview:numLabel]; 76 77 [_window addSubview:view]; 78 79 [_window makeKeyAndVisible]; 80 81 #pragma mark--:释放 82 [passTextField release]; 83 84 [numTextField release]; 85 86 [passLabel release]; 87 88 [numLabel release]; 89 90 [view release]; 91 92 [_window release]; 93 94 return YES; 95 } 96 97 @end
模拟器运行效果图：
下一篇将持续更新配套知识点及练习；
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