UITextField添加圖片以及文字置中

最右側加圖片是以下代碼:
    UIImageView *img = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"right.png"]];<br />text.rightView = img;<br />text.rightViewMode = UITextFieldViewModeAlways;   
如果是在最左側加圖片就換成:
text.leftView = img;<br />text.leftViewMode = UITextFieldViewModeAlways;   
UITextField 繼承自 UIControl,此類中有一個屬性contentVerticalAlignment
所以想讓UITextField裡面的text垂直置中可以這樣寫:
text.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;