将变量从一个视图传递到另一个视图

问题描述

我知道这个问题是一遍又一遍地问到的，但是对我来说还是很模糊的，所以我想用我的代码编写示例可能会更容易.

I know this question as been asked over and over but it's still quite obscure to me, so I guess making an example with my code instead will probably be easier .

我知道您可以使用:

• 一个全局变量，(不是一个好习惯).
• 使用委托人
• 使用单例

说我的第一个视图控制器标题中有这段代码:

Say I've got this piece of code here in my first view controller header :

#import <UIKit/UIKit.h>


@interface FirstViewController : UIViewController {

    IBOutlet UITextField *Te;
NSInteger evTe;
}


@property (nonatomic, retain) UITextField *Te;
@property (nonatomic) NSInteger evTe;


- (IBAction) makeKeyboardGoAway;

@end

然后在我的实现文件中

#import "FirstViewController.h"


@implementation FirstViewController

@synthesize Te;

- (IBAction) makeKeyboardGoAway;
{
    [Te resignFirstResponder];
    evTe = [Te.text intValue];
}

如何在SecondViewController中调用 evTe ? (也许使用委托人?).

How would I call evTe in my SecondViewController ? ( maybe using a delegate ?) .

这是我在第二个视图控制器头中得到的内容:

This is what I've got in the second view Controller, header :

@interface SecondViewController : UIViewController {


        NSInteger evTe;

}



@property (nonatomic) NSInteger evTe;

和实现:

- (IBAction) makeKeyboardGoAway;
{



    FirstViewController *first = [[FirstViewController alloc] init];
    first.evTe = self.evTe;

    NSLog(@"second value is %i",evTe);

}

非常感谢！

编辑Tob

FirstViewController.m

FirstViewController.m

- (IBAction) makeKeyboardGoAway;
{
    evTe = [Te.text intValue];
    NSLog(@"The value of integer num is %i", evTe);

    NSDictionary *changedValues = [NSDictionary dictionaryWithObject:[NSNumber numberWithInt:evTe] forKey:@"evTe"];
    [[NSNotificationCenter defaultCenter] postNotificationName:@"evTeChanged" object:self userInfo:changedValues];


}

SecondViewController.m

SecondViewController.m

 - (void)viewDidLoad {
     [super viewDidLoad];
     [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(methodToCall:) name:@"evTeChanged" object:nil];

 }

- (void)methodToCall:(NSNotification *)aNotification{

    NSDictionary *changedValues = [[aNotification userInfo]  objectForKey:@"evTe"];
    NSString *dictionaryString = [changedValues description];
    NSLog(@"Notification returning %d",dictionaryString);

}

不幸的是，我没有从SecondView中获取任何日志..

Unfortunately I'm not getting any log from the SecondView ..

推荐答案

通过在两个视图控制器中创建一个称为evTe的@property或其他属性.

By creating a @property called evTe or whatever in both view controllers.

如果FirstViewController负责创建SecondViewController，则可以将evTe的值存储在FirstViewController的属性中，然后在创建SecondViewController之后，也要在其中设置evTe属性.

If the FirstViewController is responsible for creating the SecondViewController you could store the value of evTe in a property in FirstViewController and then after you have created the SecondViewController you set the evTe property there as well.

- (IBAction) makeKeyboardGoAway;
{
    [Te resignFirstResponder];
    self.evTe = [Te.text integerValue];
}

//创建SecondViewController的其他方法

// other method where SecondViewController is created

SecondViewController* second = [[SecondViewController alloc] init];
second.evTe = self.evTe;
// do what ever

-编辑-

@interface FirstViewController : UIViewController {

    IBOutlet UITextField *Te;
    NSInteger evTe;

}

@property (nonatomic, retain) UITextField *Te;
@property (nonatomic) NSInteger evTe;

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