从另一个类访问字符串的问题 [英] Problem with access to string from another class

问题描述

我有两个视图控制器：FirstViewController和SecondViewController

Hi i have two view controller: FirstViewController and SecondViewController

FirstViewController.h

#import <UIKit/UIKit.h>

@interface FirstViewController: {
 NSString *prStr;
  } 

 -(IBAction)setString;
 @property (nonatomic, retain) NSString *prStr;

 @end

---

---

 FirstViewController.m

 #import"FirstViewController.h"

 @implementation FirstViewController

 @synthesize prStr;

 -(IBAction)setString{
  prStr = [[NSString alloc]initWithFormat:@"1"];

   }

---

---

 SecondViewController.h

#import <UIKit/UIKit.h>

@class FirstViewController;

@interface SecondViewController: {
 FirstViewController *pr;
  } 

 -(IBAction)example;
 @property (nonatomic, retain) FirstViewController *pr;

 @end

---

---

 SecondViewController.m

 #import"SecondViewController.h"
 #import "FirstViewController.h"

 @implementation SecondViewController

 @synthesize pr;

 -(IBAction)example{
  NSLog(pr.prStr);
  if([pr.prStr isEqualToString:@"1"]==YES){

     //Do Something            }

   }

当我构建并运行应用程序时，在执行IBAction示例时，在调试器控制台上没有任何显示！！如何从SecondViewController的操作访问FirstViewController的字符串，以便在调试器控制台上显示它？？

When i build and run app, at execution of IBAction example, on debugger console doesn't appear anything!! How can access to the string of FirstViewController from action of SecondViewController, in order to display it on the debugger console???

推荐答案

第一个问题是您尚未分配它。
即使分配了它，也应该将其分配为单例对象。

First problem is that you haven't alloced it. Even if you alloc that, you should alloc as a singleton object.

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