UITextField默認(rèn)情況下增显，是緊挨著左邊的邊框易稠，有時(shí)候產(chǎn)品為了美觀需要空出一定的間距
-(void)setTextFieldLeftPadding:(UITextField *)textField forWidth:(CGFloat)leftWidth
{
CGRect frame = textField.frame;
frame.size.width = leftWidth;
UIView *leftview = [[UIView alloc] initWithFrame:frame];
textField.leftViewMode = UITextFieldViewModeAlways;
textField.leftView = leftview;
}
