[[UIBarButtonItem appearance]setBackButtonTitlePositionAdjustment:UIOffsetMake(0, -60)forBarMetrics:UIBarMetricsDefault];

//显示下划线

//中划线

// NSDictionary *attribtDic = @{NSStrikethroughStyleAttributeName: [NSNumber numberWithInteger:NSUnderlineStyleSingle]};

//下划线