iOS 中的傳值方式

1、 屬性傳值   將A頁面所擁有的信息經過屬性傳遞到B頁面使用

很經常使用的傳值，也很方便，可是要拿到類的屬性。例如：

B頁面定義了一個naviTitle屬性，在A頁面中直接經過屬性賦值將A頁面中的值傳到B頁面。

A頁面DetailViewController.h文件

#import <UIKit/UIKit.h>

#import "DetailViewController.h"

@interface RootViewController :UIViewController<ChangeDelegate>

{

    UITextField *tf;

}

@end

A RootViewController.m頁面實現文件

#import "RootViewController.h"

#import "DetailViewController.h"

@interface RootViewController ()

@end

@implementation RootViewController

//核心代碼

-(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];

    //導航push到下一個頁面

    //pushViewController 入棧引用計數+1，且控制權歸系統

    

    DetailViewController *detailViewController = [[DetailViewControlleralloc]init];

    //屬性傳值，直接屬性賦值

    detailViewController.naviTitle =tf.text;

    //導航push到下一個頁面

    [self.navigationControllerpushViewController:detailViewController animated:YES];

    [detailViewControllerrelease];   

}

 

B頁面DetailViewController.h文件

#import <UIKit/UIKit.h>

@interface DetailViewController :UIViewController

{

   UITextField *textField;

   NSString *_naviTitle;

}

@property(nonatomic,retain)NSString *naviTitle;

@end

B頁面.m實現文件

#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、 代理傳值  delegate

 

拿不到屬性怎麼辦？使用代理吧~

 

A頁面push到B頁面，若是B頁面的信息想回傳（回調）到A頁面，用用代理傳值，其中B定義協議和聲明代理，A確認並實現代理，A做爲B的代理

A頁面RootViewController.h文件

#import <UIKit/UIKit.h>

#import "DetailViewController.h"

@interface RootViewController : UIViewController<ChangeDelegate> //繼承代理，表示A類接受B類的協議

{

    UITextField *tf;

}

@end

A頁面RootViewController.m實現文件

#import "RootViewController.h"

#import "DetailViewController.h"

@interface RootViewController ()

@end

@implementation RootViewController

//核心代碼

-(void)loadView

{

 

    UIButton *btn = [UIButton buttonWithType:UIButtonTypeRoundedRect];

    btn.frame = CGRectMake(0, 0, 100, 30);

    [btn setTitle:@"Push" forState:0];

    //A頁面push到B頁面

    [btn addTarget:self action:@selector(pushAction:) forControlEvents:UIControlEventTouchUpInside];

    [self.view addSubview:btn];

}

 

-(void)pushAction:(id)sender

{

    tf = (UITextField *)[self.view viewWithTag:1000];

    //導航push到下一個頁面

    //pushViewController 入棧引用計數+1，且控制權歸系統

    DetailViewController *detailViewController = [[DetailViewController alloc]init]; 

 

     //代理傳值

　　//讓當前類對象做爲代理人

   detailViewController.delegate = self;

    //導航push到下一個頁面

    [self.navigationController pushViewController:detailViewController animated:YES];

    [detailViewController release];   

}

 

//實現代理方法//須要代理人作的事情

-(void)changeTitle:(NSString *)aStr

{

    tf = (UITextField *)[self.view viewWithTag:1000];

    tf.text = aStr;//將從B頁面傳入的參數賦給A頁面中的TextField

 

}

 

 

B頁面DetailViewController.h文件

#import <UIKit/UIKit.h>

 

//定義協議

 

@protocol ChangeDelegate <NSObject>

 

-(void)changeTitle:(NSString *)aStr;//聲明協議方法

 

@end

 

@interface DetailViewController : UIViewController

{

    UITextField *textField;

   //定義代理

  id <ChangeDelegate> _delegate;

}

 

@property(nonatomic,assign)id<ChangeDelegate> delegate;

@end

 

B頁面DetailViewController.m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回前一個頁面

-(void)doneAction:(id)sender

{

　　//若代理存在且響應了changeTitle這個方法

   if (self.delegate && [self.delegaterespondsToSelector:@selector(changeTitle:)])

    {

        //[self.delegate changeTitle:textField.text];

　　　　//將textField.text參數傳給changeTitle方法  讓代理，也就是A類的對象去實現這個方法

      [self.delegate changeTitle:textField.text];

        NSLog(@"%@",self.navigationController.viewControllers);

 

        [self.navigationControllerpopViewControllerAnimated:YES];

    }

}

 

3、 單例傳值（實現共享）

 

類只有一個對象，這時候單例很方便~

AppStatus.h  建立一個單例類 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頁面RootViewController.h

#import "RootViewController.h"

#import "DetailViewController.h"

#import "AppStatus.h"

@interface RootViewController ()

@end

@implementation RootViewController

-(void)loadView

{
    //核心代碼 

    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];

    

 //單例傳值  將要傳遞的信息存入單例中（共享中）

  //  [[AppStatus shareInstance ]setContextStr:tf.text]; 跟下面這種寫法是等價的

    [AppStatus shareInstance].contextStr = tf.text;

    //導航push到下一個頁面

    //pushViewController 入棧引用計數+1，且控制權歸系統

    

    DetailViewController *detailViewController = [[DetailViewController alloc]init];

    

    //導航push到下一個頁面

    [self.navigationController pushViewController:detailViewController animated:YES];

    [detailViewController release];

} 
@end
 
B頁面DetailViewController.h

#import <UIKit/UIKit.h>

@protocol ChangeDelegate;//通知編譯器有此代理

@interface DetailViewController : UIViewController

{

    UITextField *textField;

}

@end

B頁面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];

    

    //單例

    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];

    

}

//這個方法是執行多遍的  至關於刷新view

-(void)viewWillAppear:(BOOL)animated

{

    [super viewWillAppear:animated];

    

    tf = (UITextField *)[self.view viewWithTag:1000];

    tf.text = [AppStatus shareInstance].contextStr;

     

}

//pop回前一個頁面

-(void)doneAction:(id)sender

{

    //  單例傳值

    [AppStatus shareInstance].contextStr = textField.text;

    [self.navigationController popToRootViewControllerAnimated:YES];

 
4、通知傳值 誰要監聽值的變化，誰就註冊通知  特別要注意，通知的接受者必須存在這一先決條件

A頁面RootViewController.h

#import <UIKit/UIKit.h>

#import "DetailViewController.h"

@interface RootViewController : UIViewController<ChangeDelegate>

{

    UITextField *tf;

}

@end 
 
A頁面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:)//註冊通知

                                                     name:@"CHANGE_TITLE"

                                                   object:nil];

    }

    return self;

}

-(void)change:(NSNotification *)aNoti

{

    // 通知傳值

    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];

    

    /*

    // 單例傳值

    UITextField *tf =  (UITextField *)[self.view viewWithTag:1000];

    tf.text = [AppStatus shareInstance].contextStr;

    */

}

@end

DetailViewController.h
 

#import <UIKit/UIKit.h>

@protocol ChangeDelegate;//通知編譯器有此代理

@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回前一個頁面

-(void)doneAction:(id)sender

{

    

NSDictionary *dic = [NSDictionary dictionaryWithObject:textField.text forKey:@"Info"];

[[NSNotificationCenter defaultCenter] postNotificationName:@"CHANGE_TITLE" object:nil userInfo:dic];//發送通知

[self.navigationController popViewControllerAnimated:YES];

}

五、 Block

幾種形式的Block

    //無返回值
    void (^block1) (void);
    block1 = ^{
        NSLog(@"bock demo");
    };
    block1();
    
    //int返回類型
    int (^block2) (void);
    block2  = ^(void)
    {
        int a  = 1 ,b =1;
        int c = a+b;
        return  c;
    };
    
    //有返回 有參數
    int (^block3)(int, int)= ^(int a, int b)
    {
        int c = a +b;
        return c;
        
    };
    NSLog(@"bock=%d",block3(1,2));
    
    //有返回值，有參數而且能夠修改block以外變量的block
    static int sum = 10;// __blcik and static關鍵字 或者 _block int sum = 10
    int (^block4) (int) =^(int a)
    {
        sum=11;
        int c = sum+a;   //此時sum就是能夠修改的了，若沒加static或_block關鍵字則不能修改block以外變量
        return c;
    };
    NSLog(@"block4= %d",block4(4));

Block傳值

例如A(Ablock)頁面的值傳道B(Bblock)頁面 

在A頁面中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頁面中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
//  Blcok
//
//  Created by zhu  on 13-8-12.
//  Copyright (c) 2013年 Zhu Ji Fan. All rights reserved.
//

#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

 

 

參考連接： http://www.cnblogs.com/JuneWang/p/3850859.html

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