iPhone - UISegmentedControl段寬度= 0？

Question

我有一個UISegmentedControl 3段，我想改變一個段1的寬度，當用戶選擇任何段。這裏是代碼：

// the UISegmentedControl is created 
[segmentedControl addTarget:self action:@selector(changeIt:) 
       forControlEvents:UIControlEventValueChanged]; 

//... 

// and this is the changeIt method: 


- (void) changeIt:(id)sender { 

    // discover the original width of segment 1, to restore it later 
    UISegmentedControl *seg = (UISegmentedControl*)sender; 
    CGFloat segWidth = [seg widthForSegmentAtIndex:1]; 
    // At this point segWidth = 0 ????????????????? 
    // note: seg is not nil at this point. Printing seg to console shows it is 
    // a valid UISegmentedControl... 

} 

任何線索？謝謝。

Answer 1

文檔說「默認值是{0.0}，它告訴UISegmentedControl自動調整段的大小。」

Answer 2

你可能想使用UISegmentedController方法– removeSegmentAtIndex:animated:，要麼– insertSegmentWithTitle:atIndex:animated:或– insertSegmentWithImage:atIndex:animated:，這取決於你是否希望有一個標題，或者片段的圖像。