在我的iPad应用中，我注意到iOS6和iOS7之间的UITextFields行为不同。我创建UITextField如下:UIButton*theButton=(UIButton*)sender;UITextField*textField=[[UITextFieldalloc]initWithFrame:[theButtonframe]];[textFieldsetDelegate:self];[textFieldsetContentVerticalAlignment:UIControlContentVerticalAlignmentCenter];[textFieldsetConte