iOS开发-UI 从入门到精通(三)

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：

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（2）选中Build Settings：

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（3）在输入框内输入count：

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（4）选择Objective-C Automatic Reference Counting 将其设置为 NO：

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(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：

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（2）点击“+”在弹出来的选择框里对 Simulator Name 进行选择：

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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：

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<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word; font-family: "Courier New" !important; font-size: 12px !important;">1 #import <UIKit/UIKit.h>
2
3 @interface AppDelegate : UIResponder <UIApplicationDelegate>
4
5 @property (retain, nonatomic) UIWindow *window; 6
7 @end</pre>

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AppDelegate.m文件中：

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<pre style="margin: 0px; padding: 0px; white-space: pre-wrap; overflow-wrap: break-word; font-family: "Courier New" !important; font-size: 12px !important;"> 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</pre>

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模拟器运行效果图：

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