objective-c - 你能看出这段代码有什么问题吗？因为我不能，但它仍然不起作用

Question

// When row is selected
- (void)pickerView:(UIPickerView *)pickerTimer didSelectRow:(NSInteger)row inComponent:(NSInteger)component {   
    int minutes;
    int seconds;

    if (component == 0) {
        if (row < 0){
            minutes = row;
        } else {
            minutes = 0;
        }
    }
    if (component == 1) {
        if (row < 0){
            seconds = row;
        } else {
            seconds = 0;
        }
    }
    NSLog([NSString stringWithFormat:@"%f %f %d", minutes, seconds, row]);
    if (minutes != 0 && seconds != 0){
        [buttonTimer setTitle:[NSString stringWithFormat:@"%@ minutes and %@ seconds", minutes, seconds] forState:UIControlStateNormal];
    // Yes, I am trying to set the label of a button.
    }
    if (minutes == 0 && seconds != 0){
        [buttonTimer setTitle:[NSString stringWithFormat:@"%@ seconds", seconds] forState:UIControlStateNormal];
    }
    if (minutes != 0 && seconds == 0){
        [buttonTimer setTitle:[NSString stringWithFormat:@"%@ minutes", minutes] forState:UIControlStateNormal];    
    }
    if (minutes == 0 && seconds == 0){
        [buttonTimerFarts setTitle:[NSString stringWithFormat:@"Set time before play starts..."] forState:UIControlStateNormal];
    }

}

控制台将显示诸如

0.000000 -1.993950 2751746

前三个 if(minutes seconds) 语句从不运行。

那么，你能看出有什么不对吗？

Answer 1

row < 0在您的代码中，仅当minutes或seconds设置为row. 但是在您的示例中，row是肯定的，因此minutesandseconds仍然是两者0，并且前三个 if 永远不会为真。

而且我对Objective-C了解不多，但是您正在使用％f打印一个整数，这可能会让您胡说八道。