嘗試將標籤設置爲隱藏時發生IOS 5錯誤

Question

當某些條件未得到滿足時，我有一個標籤用作警告。但是，當我試圖設置爲隱藏用下面的代碼標籤：

infoWarning.hidden = YES; 

上下文，這裏是全碼：

if (weightC < 50 || (waistM1 < 20 && waistM2 < 20 && waistM3 < 20) || (ageC < 18)) 
{ 
    infoWarning.hidden = NO; 

    NSString *warning = @""; 
    if(ageC < 18) 
    { 
     warning = @" an age over 17"; 
    } 
    if (averageWaistM < 20) { 
     if (warning != @"") { 
      warning = [NSString stringWithFormat:@"%@, and", warning]; 
     } 
     warning = [NSString stringWithFormat:@"%@ a waist measurement", warning]; 
    } 
    if (weightC < 50) { 
     if (warning != @"") { 
      warning = [NSString stringWithFormat:@"%@, and", warning]; 
     } 

     warning = [NSString stringWithFormat:@"%@ a weight", warning]; 

    } 


    if (warning!=@"") { 
     [infoWarning setText:[NSString stringWithFormat:@"Please add%@.", warning]] ; 
    } 


} else { 
    if(gender.selectedSegmentIndex == 0) 
    { 

    } 

    else if(gender.selectedSegmentIndex == 1) 
    { 

    } 
} 

那我想會的工作，但（顯然）不。它給我一條線上的EXC_BAD_ACCESS錯誤：

infoWarning.hidden = YES;

infoWarning確實存在，被合成並連接到Interface Builder中的UILabel。你能幫我找出問題並讓它工作嗎？

這是.h文件：

#import <UIKit/UIKit.h> 
#import <QuartzCore/QuartzCore.h> 

@class Preferences; 
@class Utilities; 


@interface BodyFatCalculatorViewController : UIViewController { 

    IBOutlet UITextField *age; 
    IBOutlet UITextField *waist1; 
    IBOutlet UITextField *waist2; 
    IBOutlet UITextField *waist3; 
    IBOutlet UITextField *weight; 

    IBOutlet UILabel *waist; 
    IBOutlet UILabel *currentWeight; 

    IBOutlet UILabel *bodyFat; 
    IBOutlet UILabel *averageWaist; 
    IBOutlet UILabel *veryLean; 
    IBOutlet UILabel *veryLeanBorder; 
    IBOutlet UIImageView *veryLeanCheckmark; 
    IBOutlet UILabel *fit; 
    IBOutlet UILabel *fitBorder; 
    IBOutlet UIImageView *fitheckmark; 
    IBOutlet UILabel *average; 
    IBOutlet UILabel *averageBorder; 
    IBOutlet UIImageView *averageCheckmark; 
    IBOutlet UILabel *atRisk; 
    IBOutlet UILabel *atRiskBorder; 
    IBOutlet UILabel *atModRisk; 
    IBOutlet UILabel *atModRiskBorder; 
    IBOutlet UILabel *atHighRisk; 
    IBOutlet UILabel *atHighRiskBorder; 

    IBOutlet UILabel *infoWarning; 

    IBOutlet UISegmentedControl *gender; 

    NSMutableArray *arrayAge; 
} 

@property (nonatomic, retain) IBOutlet UITextField *age; 
@property (nonatomic, retain) IBOutlet UITextField *waist1; 
@property (nonatomic, retain) IBOutlet UITextField *waist2; 
@property (nonatomic, retain) IBOutlet UITextField *waist3; 
@property (nonatomic, retain) IBOutlet UITextField *weight; 

@property (nonatomic, retain) IBOutlet UILabel *waist; 
@property (nonatomic, retain) IBOutlet UILabel *currentWeight; 

@property (nonatomic, retain) IBOutlet UILabel *bodyFat; 
@property (nonatomic, retain) IBOutlet UILabel *averageWaist; 
@property (nonatomic, retain) IBOutlet UILabel *veryLean; 
@property (nonatomic, retain) IBOutlet UILabel *veryLeanBorder; 
@property (nonatomic, retain) IBOutlet UIImageView *veryLeanCheckmark; 
@property (nonatomic, retain) IBOutlet UILabel *fit; 
@property (nonatomic, retain) IBOutlet UILabel *fitBorder; 
@property (nonatomic, retain) IBOutlet UIImageView *fitCheckmark; 
@property (nonatomic, retain) IBOutlet UILabel *average; 
@property (nonatomic, retain) IBOutlet UILabel *averageBorder; 
@property (nonatomic, retain) IBOutlet UIImageView *averageCheckmark; 
@property (nonatomic, retain) IBOutlet UILabel *atRisk; 
@property (nonatomic, retain) IBOutlet UILabel *atRiskBorder; 
@property (nonatomic, retain) IBOutlet UILabel *atModRisk; 
@property (nonatomic, retain) IBOutlet UILabel *atModRiskBorder; 
@property (nonatomic, retain) IBOutlet UILabel *atHighRisk; 
@property (nonatomic, retain) IBOutlet UILabel *atHighRiskBorder; 

@property (nonatomic, retain) IBOutlet UILabel *infoWarning; 

@property (nonatomic, retain) IBOutlet UISegmentedControl *gender; 

-(IBAction)valueChanged:(id)sender; 
-(IBAction)textFieldDoneEditing:(id)sender; 
-(void)calculate; 


@end 

問題已得到修復，謝謝你對那些誰回答，看着它。這個問題實際上是一個限制太小的數組（我不知道爲什麼會導致這個問題被打破，他們根本就沒有關係......），所以我增加了限制，現在infoWarning工作的很好。

Answer 1

從控制檯完整的錯誤可能有助於但鑑於「EXC_BAD_ACCESS錯誤」的行

infoWarning.hidden = NO; 

表明，有與infoWarning.hidden一個問題，什麼是@property和@synthesize報表？

比較字符串的內容使用：

[warning is equalToString:@""] 

不是：

warning != @"" 

該指針比較字符串。

但在你的情況下爲什麼不使用：

warning.length != 0