在iOS中使用循環

Question

我在我的秒錶應用程序中有此代碼，但是我有循環問題，我的數組中的所有值都是相同的。我想把時間觀察一個接一個地排列。進行觀察，添加到陣列並採取新的觀察並繼續進行，直到樣本大小爲t。我如何使用循環，非常感謝幫助。

- (IBAction)onLapPressed:(id)sender { 

    timeData = [[NSMutableArray alloc] init]; 

    for (NSInteger k = 0; k < t; ++k) 
    { 
    [timeData addObject:[NSNull null]]; 
    } 

    NSDate *currentDate = [NSDate date]; 
    NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:startDate]; 
    NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:timeInterval]; 

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; 
    [dateFormatter setDateFormat:@"ss.S"]; 
    [dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]]; 
    NSString *timeString=[dateFormatter stringFromDate:timerDate]; 

    CGFloat timeStringFloat = (CGFloat) [timeString floatValue]; 
    [timeData replaceObjectAtIndex:i withObject:timeString];  
    lap1.text = [timeData objectAtIndex:i]; 
    NSString *iyaz = [NSString stringWithFormat: @"%d",i+1]; 
    NSString *tyaz = [NSString stringWithFormat: @"%d",t]; 
    NSString *baseString = [NSString stringWithFormat: @"%@/%@",iyaz,tyaz]; 

    lap2.text = baseString; 

    totaltime = totaltime + timeStringFloat; 

    x2 = x2 + powf(timeStringFloat, 2); 
    n = round((40* sqrtf(t*x2 - powf(totaltime, 2))/totaltime)); 

    avgtime = totaltime/(i+1); 

    NSString *strtotaltime =  [NSString stringWithFormat:@"%f", avgtime]; 
    NSString *toobserve = [NSString stringWithFormat:@"%d", n]; 
    avglap.text = strtotaltime; 
    obsno.text = toobserve; 
    startDate = [[NSDate date]retain]; 
    i=i+1; 

} 

Answer 1

試着用這個。每次運行時不要將您的值與該循環重疊。而且，使用數組的當前大小而不是試圖跟上值'i'會更簡單一些。然後讓你的數組隨着它獲得新的值而增長。

- (IBAction)onLapPressed:(id)sender { 
    if(!timeData) timeData = [[NSMutableArray alloc] init]; 

    NSDate *currentDate = [NSDate date]; 
    NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:startDate]; 
    NSDate *timerDate = [NSDate dateWithTimeIntervalSince1970:timeInterval]; 

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init]; 
    [dateFormatter setDateFormat:@"ss.S"]; 
    [dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0.0]]; 
    NSString *timeString=[dateFormatter stringFromDate:timerDate]; 

    CGFloat timeStringFloat = (CGFloat) [timeString floatValue]; 
    [timeData addObject:timeString]; 
    lap1.text = timeString; 
    NSString *iyaz = [NSString stringWithFormat: @"%d",[timeData count]+1]; 
    NSString *tyaz = [NSString stringWithFormat: @"%d",t]; 
    NSString *baseString = [NSString stringWithFormat: @"%@/%@",iyaz,tyaz]; 

    lap2.text = baseString; 

    totaltime = totaltime + timeStringFloat; 

    x2 = x2 + powf(timeStringFloat, 2); 
    n = round((40* sqrtf(t*x2 - powf(totaltime, 2))/totaltime)); 

    avgtime = totaltime/([timeData count]+1); 

    NSString *strtotaltime =  [NSString stringWithFormat:@"%f", avgtime]; 
    NSString *toobserve = [NSString stringWithFormat:@"%d", n]; 
    avglap.text = strtotaltime; 
    obsno.text = toobserve; 
    startDate = [[NSDate date]retain]; 
}