Question

我有一个标签，当某些条件不符合时会作为警告。但是当我尝试使用以下代码将标签设置为隐藏时：

infoWarning.hidden = YES;

对于上下文，这是完整的代码：

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)
    {

    }
}

我认为这样可行，但（显然）没有。它在行上给我一个EXC_BAD_ACCESS错误：

infoWarning.hidden = YES;

infoWarning确实存在，已合成，并且已连接到Interface Builder中的UILabel。你能帮我找出问题并使其有效吗？

这是.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

问题已得到解决，感谢那些做出回应并对其进行调查的人。问题实际上是一个限制太小的数组（我不知道为什么会导致这种情况破坏，它们根本没有相关...）所以我增加了限制，现在infoWarning工作得很好。

Answer 1

来自控制台的完整错误可能有所帮助，但在行中出现“EXC_BAD_ACCESS错误”

infoWarning.hidden = NO;

表示infoWarning.hidden存在问题，@property和@synthesize语句是什么？

比较字符串的内容使用：

[warning is equalToString:@""]

不

warning != @""

比较指向字符串的指针。

但在你的情况下，为什么不使用：

warning.length != 0

尝试将标签设置为隐藏时出现IOS 5错误

1 个答案: