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我想使用另一种方法捕获的NSDate变量。经过多次阅读和搜索,我认为我在这个网站上找到了答案:http://www.everydayone.com/2009/08/nsdate-as-global-variable/。我首先尝试在文章中指定的AppDelegate.h中声明变量。在ViewController实现文件中导致2次失败:firstDate和startDate未声明。然后我试着在ViewController.h中声明它们,它允许代码无误地编译。但是,当方法运行如下所示时,应用程序崩溃,并收到以下消息“GDB:Program received signal:EXC_BAD_ACCESS”。如果我取消注释“NSDate *今天”行并使用该变量而不是secondDate,则代码正常工作。你的帮助将不胜感激。全球NSDate变量
.H:
@interface DatesViewController : UIViewController {
NSDate *firstDate;
NSDate *secondDate;
}
@property (nonatomic, retain) NSDate *firstDate;
@property (nonatomic, retain) NSDate *secondDate;
.M:
@synthesize firstDate;
@synthesize secondDate;
-(IBAction)getFirstDate:(id)sender{
firstDate = [picker date];
}
-(IBAction)getSecondDate:(id)sender{
secondDate = [picker date];
//NSDate *today = [[NSDate alloc] initWithTimeIntervalSinceNow:0];
NSTimeInterval interval = [firstDate timeIntervalSinceDate: secondDate];