UIButton title换行

  UIButton title换行关键代码：

  

    [_button setTitle:@"123\n456"forState:UIControlStateNormal];

    _button.titleLabel.numberOfLines = 0;

    _button.titleLabel.lineBreakMode = NSLineBreakByWordWrapping;

    _button.titleLabel.textAlignment = NSTextAlignmentCenter;

    _button.titleLabel.font=[UIFontsystemFontOfSize:14];