iOS开发-Day30 参数传递的五种方法
2015-08-24 17:27
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1、属性传参(前->后)
2、单例(全局)
3、代理(没有前后顺序)
4、代码块
5、通知
//属性传值 将A页面所拥有的信息通过属性传递到B页面使用 //B页面定义了一个naviTitle属性,在A页面中直接通过属性赋值将A页面中的值传到B页面。 //A页面DetailViewController.h文件 #import <UIKit/UIKit.h> #import "DetailViewController.h" @interface RootViewController :UIViewController<ChangeDelegate> { UITextField *tf; } @end A RootViewController.m页面实现文件 #import "RootViewController.h" #import "DetailViewController.h" @interface RootViewController () @end @implementation RootViewController //核心代码 -(void)loadView { UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect]; btn.frame = CGRectMake(0, 0, 100, 30); [btn setTitle:@"Push" forState:0]; [btn addTarget:self action:@selector(pushAction:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:btn]; } -(void)pushAction:(id)sender { tf = (UITextField *)[self.viewviewWithTag:1000]; //导航push到下一个页面 //pushViewController 入栈引用计数+1,且控制权归系统 DetailViewController *detailViewController = [[DetailViewControlleralloc]init]; //属性传值,直接属性赋值 detailViewController.naviTitle =tf.text; //导航push到下一个页面 [self.navigationControllerpushViewController:detailViewController animated:YES]; [detailViewControllerrelease]; } B页面DetailViewController.h文件 #import <UIKit/UIKit.h> @interface DetailViewController :UIViewController { UITextField *textField; NSString *_naviTitle; } @property(nonatomic,retain)NSString *naviTitle; @end //B页面.m实现文件 #import "DetailViewController.h" @interface DetailViewController () @end @implementation DetailViewController @synthesize naviTitle =_naviTitle; -(void)loadView { self.view = [[[UIViewalloc]initWithFrame:CGRectMake(0,0, 320,480)]autorelease]; self.title = self.naviTitle ; }
2、单例(全局)
//单例传值(实现共享) //AppStatus.h 创建一个单例类 AppStatus #import <Foundation/Foundation.h> @interface AppStatus : NSObject { NSString *_contextStr; } @property(nonatomic,retain)NSString *contextStr; +(AppStatus *)shareInstance; @end AppStatus.m #import "AppStatus.h" @implementation AppStatus @synthesize contextStr = _contextStr; static AppStatus *_instance = nil; +(AppStatus *)shareInstance { if (_instance == nil) { _instance = [[super alloc]init]; } return _instance; } -(id)init { if (self = [super init]) { } return self; } -(void)dealloc { [super dealloc]; } @end //A页面RootViewController.h #import "RootViewController.h" #import "DetailViewController.h" #import "AppStatus.h" @interface RootViewController () @end @implementation RootViewController -(void)loadView { //核心代码 UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect]; btn.frame = CGRectMake(0, 0, 100, 30); [btn setTitle:@"Push" forState:0]; [btn addTarget:self action:@selector(pushAction:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:btn]; } -(void)pushAction:(id)sender { tf = (UITextField *)[self.view viewWithTag:1000]; //单例传值 将要传递的信息存入单例中(共享中) // [[AppStatus shareInstance]setContextStr:tf.text]; 跟下面这种写法是等价的 [AppStatus shareInstance].contextStr = tf.text; //导航push到下一个页面 //pushViewController 入栈引用计数+1,且控制权归系统 DetailViewController *detailViewController = [[DetailViewController alloc]init]; //导航push到下一个页面 [self.navigationController pushViewController:detailViewController animated:YES]; [detailViewController release]; } @end //B页面DetailViewController.h #import <UIKit/UIKit.h> @protocol ChangeDelegate;//通知编译器有此代理 @interface DetailViewController : UIViewController { UITextField *textField; } @end //B页面DetailViewController.m #import "DetailViewController.h" #import "AppStatus.h" @interface DetailViewController () @end @implementation DetailViewController @synthesize naviTitle = _naviTitle; -(void)loadView { self.view = [[[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 480)]autorelease]; //单例 self.title = [AppStatus shareInstance].contextStr; textField = [[UITextField alloc]initWithFrame:CGRectMake(100, 100, 150, 30)]; textField.borderStyle = UITextBorderStyleLine; [self.view addSubview:textField]; [textField release]; UIBarButtonItem *doneItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDonetarget:self action:@selector(doneAction:)]; self.navigationItem.rightBarButtonItem = doneItem; [doneItem release]; } //这个方法是执行多遍的 相当于刷新view -(void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; tf = (UITextField *)[self.view viewWithTag:1000]; tf.text = [AppStatus shareInstance].contextStr; } //pop回前一个页面 -(void)doneAction:(id)sender { // 单例传值 [AppStatus shareInstance].contextStr = textField.text; [self.navigationController popToRootViewControllerAnimated:YES]; }
3、代理(没有前后顺序)
//代理传值 //A页面push到B页面,如果B页面的信息想回传(回调)到A页面,用用代理传值,其中B定义协议和声明代理,A确认并实现代理,A作为B的代理 //A页面RootViewController.h文件 #import <UIKit/UIKit.h> #import "DetailViewController.h" @interface RootViewController : UIViewController<ChangeDelegate> { UITextField *tf; } @end //A页面RootViewController.m实现文件 #import "RootViewController.h" #import "DetailViewController.h" @interface RootViewController () @end @implementation RootViewController //核心代码 -(void)loadView { UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect]; btn.frame = CGRectMake(0, 0, 100, 30); [btn setTitle:@"Push" forState:0]; //A页面push到B页面 [btn addTarget:self action:@selector(pushAction:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:btn]; } -(void)pushAction:(id)sender { tf = (UITextField *)[self.view viewWithTag:1000]; //导航push到下一个页面 //pushViewController 入栈引用计数+1,且控制权归系统 DetailViewController *detailViewController = [[DetailViewController alloc]init]; //代理传值 detailViewController.delegate =self;//让其自身作为代理人 //导航push到下一个页面 [self.navigationController pushViewController:detailViewController animated:YES]; [detailViewController release]; } //实现代理方法 -(void)changeTitle:(NSString *)aStr { tf = (UITextField *)[self.view viewWithTag:1000]; tf.text = aStr;//将从B页面传入的参数赋给A页面中的TextField tf.text = aStr; } //B页面DetailViewController.m文件 #import <UIKit/UIKit.h> @interface DetailViewController : UIViewController { UITextField *textField; //定义代理 id<ChangeDelegate>_delegate; } @property(nonatomic,assign)id<ChangeDelegate> delegate; @end //定义协议 @protocol ChangeDelegate <NSObject> -(void)changeTitle:(NSString *)aStr;//协议方法 @end //B页面DetailViewController.h实现文件 #import "DetailViewController.h" @interface DetailViewController () @end @implementation DetailViewController -(void)loadView { self.view = [[[UIView alloc]initWithFrame:CGRectMake(0, 0, 320, 480)]autorelease]; UIBarButtonItem *doneItem = [[UIBarButtonItemalloc]initWithBarButtonSystemItem:UIBarButtonSystemItemDonetarget:selfaction:@selector(doneAction:)]; self.navigationItem.rightBarButtonItem = doneItem; [doneItemrelease]; } //pop回前一个页面 -(void)doneAction:(id)sender { if (self.delegate && [self.delegaterespondsToSelector:@selector(changeTitle:)])//若代理存在且响应了changeTitle这个方法 { //[self.delegate changeTitle:textField.text]; [self.delegatechangeTitle:textField.text];//将textField.text参数传给changeTitle方法 让代理,也就是A页面去实现这个方法 NSLog(@"%@",self.navigationController.viewControllers); [self.navigationControllerpopViewControllerAnimated:YES]; } }
4、代码块
//关于Block //几种形式的Block //无返回值 void (^block1) (void); block1 = ^{ NSLog(@"bock demo"); }; block1(); //int返回类型 int (^block2) (void); block2 = ^(void) { int a = 1 ,b =1; int c = a+b; return c; }; //有返回 有参数 int (^block3)(int, int)= ^(int a, int b) { int c = a +b; return c; }; NSLog(@"bock=%d",block3(1,2)); //有返回值,有参数并且可以修改block之外变量的block static int sum = 10;// __blcik and static关键字 或者 _block int sum = 10 int (^block4) (int) =^(int a) { sum=11; int c = sum+a; //此时sum就是可以修改的了,若没加static或_block关键字则不能修改block之外变量 return c; }; NSLog(@"block4= %d",block4(4)); //Block传值 //例如A(Ablock)页面的值传道B(Bblock)页面 //在A页面中ABlock.h @interface Ablock : UIViewController<UITableViewDelegate,UITableViewDataSource> { UITableView *_tableview; UILabel *labe; UIImageView *imagevies; } @end -(void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { [_tableview deselectRowAtIndexPath:indexPath animated:YES]; Bblcok *bblock = [[Bblcok alloc] initwithBlock:Block_copy(^(NSString *aBlock){ labe.text = aBlock; NSLog(@"%@",aBlock); })]; bblock.imgeviews = imagevies.image; bblock.String = labe.text; [self.navigationController pushViewController:bblock animated:YES]; [bblock release]; } //在A页面中Bblock.h #import <UIKit/UIKit.h> typedef void (^MyBlock) (NSString *); @interface Bblcok : UIViewController { UIImageView *image; UITextField *aField; UIButton *aButt; NSString *_String; id _imgeviews; MyBlock myBlock; } @property(nonatomic,copy)MyBlock myBlock; @property(nonatomic,retain) id imgeviews; @property(nonatomic,retain) NSString *String; -(id)initwithBlock:(MyBlock)aBlcok; @end // Bblcok.m #import "Bblcok.h" @interface Bblcok () @end @implementation Bblcok @synthesize imgeviews = _imgeviews , String = _String; @synthesize myBlock = _myBlock; -(id)initwithBlock:(MyBlock)aBlcok { if (self = [super init]) { self.myBlock = aBlcok; } return self; } -(void) dealloc { [super dealloc]; } -(void) loadView { UIControl *cont = [[UIControl alloc] initWithFrame:CGRectMake(0, 0, 320, 568-44)]; [cont addTarget:self action:@selector(Clcik) forControlEvents:UIControlEventTouchUpInside]; self.view = cont; aField = [[UITextField alloc] initWithFrame:CGRectMake(60, 10, 160, 30)]; aField.borderStyle = UITextBorderStyleLine; aField.placeholder = self.String; [self.view addSubview:aField]; aButt = [UIButton buttonWithType:UIButtonTypeRoundedRect]; aButt.frame = CGRectMake(60, 50, 70, 30); [aButt setTitle:@"修改" forState:0]; [aButt addTarget:self action:@selector(aButtClcik:) forControlEvents:UIControlEventTouchUpInside]; [self.view addSubview:aButt]; image = [[UIImageView alloc] initWithFrame:CGRectMake(60, 100, 210, 260)]; image.backgroundColor = [UIColor blueColor]; image.image = self.imgeviews; [self.view addSubview:image]; [image release]; } -(IBAction)aButtClcik:(id)sender { NSString *sting = aField.text; myBlock(sting); [self.navigationController popToRootViewControllerAnimated:YES]; } -(void)Clcik { [aField resignFirstResponder]; } - (void)viewDidLoad { [super viewDidLoad]; // Do any additional setup after loading the view. } - (void)didReceiveMemoryWarning { [super didReceiveMemoryWarning]; // Dispose of any resources that can be recreated. } @end
5、通知
//通知传值 谁要监听值的变化,谁就注册通知 特别要注意,通知的接受者必须存在这一先决条件 //A页面RootViewController.h #import <UIKit/UIKit.h> #import "DetailViewController.h" @interface RootViewController : UIViewController<ChangeDelegate> { UITextField *tf; } @end //A页面RootViewController.m #import "IndexViewController.h" #import "DetailViewController.h" #import "AppStatus.h" @implementation IndexViewController -(void)dealloc { [[NSNotificationCenter defaultCenter] removeObserver:self name:@"CHANGE_TITLE" object:nil]; [super dealloc]; } -(id)init { if (self = [super init]) { [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(change:)name:@"CHANGE_TITLE" object:nil]; } return self; } -(void)change:(NSNotification *)aNoti { // 通知传值 NSDictionary *dic = [aNoti userInfo]; NSString *str = [dic valueForKey:@"Info"]; UITextField *tf = (UITextField *)[self.view viewWithTag:1000]; tf.text = str; } -(void)viewWillAppear:(BOOL)animated { [super viewWillAppear:animated]; /* // 单例传值 UITextField *tf = (UITextField *)[self.view viewWithTag:1000]; tf.text = [AppStatus shareInstance].contextStr; */ } @end DetailViewController.h #import <UIKit/UIKit.h> @protocol ChangeDelegate;//通知编译器有此代理 @interface DetailViewController : UIViewController { UITextField *textField; } @end DetailViewController.m #import "DetailViewController.h" #import "AppStatus.h" @implementation DetailViewController @synthesize naviTitle = _naviTitle; -(void)loadView { UIBarButtonItem *doneItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemDonetarget:self action:@selector(doneAction:)]; self.navigationItem.rightBarButtonItem = doneItem; [doneItem release]; } // pop回前一个页面 -(void)doneAction:(id)sender { NSDictionary *dic = [NSDictionary dictionaryWithObject:textField.text forKey:@"Info"]; [[NSNotificationCenter defaultCenter] postNotificationName:@"CHANGE_TITLE" object:nil userInfo:dic]; [self.navigationController popViewControllerAnimated:YES]; }
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