如何将值从一个UIViewController传递到另一个

Question

我正在创建一个应用程序，我必须将一个值从second class传递到first class。我为second class创建了一个代理方法。

在second class我有一个UITextField，如果在这个文本框输入文本时，应该在first view传递到cell在UITableView。

但是，在我的情况下，价值没有被正确传递。我做错了什么？

这是我的代码：

second.h

#import <UIKit/UIKit.h> 
@protocol secondDelegate<NSObject> 
@required 
- (void)setsecond:(NSString *)inputString; 
@end 

@interface second : UIViewController { 
    IBOutlet UITextField *secondtextfield; 
    id<secondDelegate>stringdelegate; 
    NSString *favoriteColorString; 
} 
@property (nonatomic, retain) UITextField *secondtextfield; 
@property (nonatomic, assign) id<secondDelegate>stringdelegate; 
@property (nonatomic, copy) NSString *favoriteColorString; 
@end 

second.m

#import "second.h" 

@implementation second 
@synthesize stringdelegate, secondtextfield, favoriteColorString; 

- (void)viewWillDisappear:(BOOL)animated { 
    [[self stringdelegate] setsecond:secondtextfield.text]; 
    favoriteColorString=secondtextfield.text; 
    NSLog(@"thuis check:%@", favoriteColorString); 
} 

- (BOOL)textFieldShouldReturn:(UITextField *)theTextField { 
    [theTextField resignFirstResponder]; 
    return YES; 
} 

- (void)viewDidLoad { 
    [super viewDidLoad]; 
    //[[self stringdelegate] setsecond:secondtextfield.text]; 
    //favoriteColorString = secondtextfield.text; 
    //NSLog(@"thuis check:%@", favoriteColorString); 
} 
@end  

first.h

#import <UIKit/UIKit.h> 
#import "second.h" 
#import "TextviewExampleAppDelegate.h" 

@interface first : UITableViewController<secondDelegate> { 
    //TextviewExampleAppDelegate *app; 
    TextviewExampleAppDelegate *check; 
} 

种

first.m

@implementation first 

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath { 
    static NSString *CellIdentifier = @"Cell"; 
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier]; 
    if (cell == nil) { 
     cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease]; 
    } 

    // Configure the cell... 
    cell.textLabel.text = @"message"; 
    cell.detailTextLabel.text = check.favoriteColorString; 
    NSLog(@"this second check:%@", check.favoriteColorString); 
    return cell; 
} 

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { 
    second *viewtwo = [[second alloc] initWithNibName:@"second" bundle:nil]; 
    //viewtwo.favoriteColorString = indexPath; 
    viewtwo.stringdelegate = self; 
    [self.navigationController pushViewController:viewtwo animated:YES]; 
    [viewtwo release]; 
} 

- (void)setsecond:(NSString *)inputString { 
    if (nil != self.stringdelegate) { 
     [self.stringdelegate setsecond:inputString]; 
    } 
    [self.tableView reloadData]; 
} 
@end 

Answer 1

1. 移除委托方法。
2. 将第二堂课导入第一堂课。
3. 在二级导入一级并实现id firstClass变量那里。
4. 当你推动第二课时，从（3）到id。
5. 时you'v完毕，并准备通过它，设置firstClass.passedValue = passingValue
6. 弹出第二类

例如：

//first.h: 
#import "second.h" 
@class second 

//second.h: 
#import "first.h" 
@class first 
... 
id firstClass; 

//first.m: 
- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath { 
    second *viewtwo =[[second alloc]initWithNibName:@"second" bundle:nil]; 
    [self.navigationController pushViewController:viewtwo animated:YES]; 
    viewtwo.firstClass = self; 
    [viewtwo release]; 
} 

//second.m: 
firstClass.passedValue = self.passingValue; 

Answer 2

请参考以下粗糙从头开始：

在申请委托书.h

创建变量

NSString *varStr; 

指派属性

@propery (nonatomic, retain) NSString *valStr; 

在委托。米

@synthesize varStr; 

初始化变种

varStr = [NSString strinWithFormat:@"Hi"]; 

头等

创建委托变种;

delegate class *var = (delegate class*)[[UIApplication sharedApplication] delegate]; 

设定值

var.varStr = [NSString strinWithFormat:@"First"]; 

获取价值

NSLog (@"%@",var.varStr); 

在第二类

create delegate var;

delegate class *var = (delegate class*)[[UIApplication sharedApplication] delegate]; 

设定值

var.varStr = [NSString strinWithFormat:@"Second"]; 

获取价值

NSLog (@"%@",var.varStr);