2016-12-02 29 views
-1

我正在處理這個for循環,它的工作原理是完美的..我經常返回找到的數字列表,但我需要循環以降序給我回數字......從現在30到18歲,而不是18到30歲...有人可以'給我一個幫助嗎?在一個循環中反轉NSInteger對於

我張貼有問題的代碼

for (NSInteger i = 18; i <= 30; i += 2) { 


    self.axisY_Label = [[UILabel alloc] initWithFrame:CGRectMake(10, paddingValue, 35, 20)]; 
    self.axisY_Label.text = [NSString stringWithFormat:@"%ld", (long)i]; 
    self.axisY_Label.textColor = [UIColor whiteColor]; 
    self.axisY_Label.font = [UIFont fontWithName:@"HelveticaNeue" size:13]; 


    UIView *line = [[UIView alloc] initWithFrame:CGRectMake(_axisY_Label.frame.size.width, _axisY_Label.center.y, self.frame.size.width, 0.3)]; 
    line.backgroundColor = [UIColor whiteColor]; 
    line.alpha = .2; 
    [self addSubview:line]; 

    paddingValue += _axisY_Label.frame.size.width; 
    [self addSubview:_axisY_Label]; 

} 

回答

1

交易所fromto參數和計數向後

for (NSInteger i = 30; i >= 18; i -= 2) { ...