IOS开发之UI设计---视图控制器(UIVIewController)

UIViewController : NSObject 

视图控制器,管理UIView

MVC模式: Model-View-Controller(模型-视图-控制器)

Delegate:范围小,具体实现某一个功能的时候使用

 

实现代理的步骤:

1.声明一个协议(本质上是声明接口,可以是多个),协议中的接口不实现

2.被代理对象:定义一个成员变量,id<xxx协议> delegate  同时实现delegate的getter和setter方法

3.代理对象要遵循这个协议,并且协议的实现也在代理对象中

 

自定义UIViewController

@interface CustomUIViewController : UIViewController

@end

@implementation CustomUIViewController

@end

 

//UIViewController的执行流程

init->[super init]->initWithNibName ->init

self.window .rootViewController = controller -> loadView -> viewDidLoad 

 

MyUIViewController *controller = [[MyUIViewController alloc]init];

self.view.rootViewController = controller;

[controller release];

- (void)presentViewController:(UIViewController *)viewControllerToPresent animated: (BOOL)flag completion:(void (^)(void))completion NS_AVAILABLE_IOS(5_0);

//从一个UIViewController切换到一个新的UIViewController

 

UITextField : UIView

UITextField是继承自UIVIew的控件,作用是同用户进行交互,动态获取用户输入的信息

UITextField *field = [[UITextFieldalloc]initWithFrame:CGRectMake(0, 0, 240, 40)];

    //设置UITextField的显示类型

    [field setBorderStyle:UITextBorderStyleRoundedRect];

//设置field代理

//必须在声明文件中包含<UITextFieldDelegate>代理,否则会有警告 

field.delegate = self;

// UITextField设置加密显示,默认值为NO

    textField.secureTextEntry = YES;

 

 

在使用协议的时候,通常使用

#pragma mark -

#pragma mark 协议名或者….

 表示将协议要实现的方法与类本身的方法分隔开来

/* 常用的几个个代理方法

- (BOOL)textFieldShouldBeginEditing:(UITextField *)textField;//return NO to disallow editing.设置field是否可编辑,如果不实现该代理,默认返回YES.

- (void)textFieldDidBeginEditing:(UITextField *)textField; // became first responder ,第一响应者

- (void)textFieldDidEndEditing:(UITextField *)textField; // may be called if forced even if shouldEndEditing returns NO (e.g. view removed from window) or endEditing:YES called,结束编辑

- (BOOL)textFieldShouldReturn:(UITextField *)textField;// called when 'return' key pressed. return NO to ignore.点击键盘return时调用,在使用该方法的时候,必须在定义UITextField控件的类的声明文件中加上<UITextFieldDelegate>协议的声明.

*/

    [self.view addSubview:field];

    [field release];

 

- (void)viewDidLoad; // Called after the view has been loaded. For view controllers created in code, this is after -loadView. For view controllers unarchived from a nib, this is after the view is set.

//viewDidLoad 在当前视图控制器加载后,不会再次调用,在UIViewcontroller之间进行切换时,会调用一下几个方法:

- (void)viewWillAppear:(BOOL)animated; // Called when the view is about to made visible. Default does nothing

- (void)viewDidAppear:(BOOL)animated; // Called when the view has been fully transitioned onto the screen. Default does nothing

- (void)viewWillDisappear:(BOOL)animated; // Called when the view is dismissed, covered or otherwise hidden. Default does nothing

- (void)viewDidDisappear:(BOOL)animated;  // Called after the view was dismissed, covered or otherwise hidden. Default does nothing