如何找到两次之间的差异？

Question

我有这个代码:

-(IBAction)startTime:(id)sender {
    NSDate *myDateTime1 = [[NSDate alloc] init];
    NSLog(@"%@", myDateTime1);
    [myDateTime1 release];
}

-(IBAction)stopTime:(id)sender {
    NSDate *myDateTime2 = [[NSDate alloc] init];
    NSLog(@"%@", myDateTime2);
    [myDateTime2 release];
}

我想找到两次之间的区别.我怎么能做到这一点？

Answer 1

您需要将日期设为ivars.目前他们不知道彼此的存在.

MyClass.m(替换任何类的MyClass)

@interface MyClass ()

@property (nonatomic, retain) NSDate *startDate; // Add an ivar to hold the startDate

@end

@implementation MyClass

@synthesize startDate = _startDate;

// More of your class

- (void)dealloc;
{
    [_startDate release];
    // release anything else
    [super dealloc];
}

-(IBAction)startTime:(id)sender
{
    self.startDate = [NSDate date];
}

- (IBAction)stopTime:(id)sender
{
    NSDate *endDate = [NSDate date];

    NSLog(@"%f", [endDate timeIntervalSinceDate:self.startDate]);
}

// More of your class

@end