iOS 修改通用的返回圖片

    UIImage *backButtonImage = [[UIImage imageNamed:@"icon_sys_fanhihei"] resizableImageWithCapInsets:UIEdgeInsetsMake(0, 15, 0, 0)];//15爲圖片寬度＋間距
    [[UIBarButtonItem appearance] setBackButtonBackgroundImage:backButtonImage forState:UIControlStateNormal barMetrics:UIBarMetricsDefault];
    //將返回按鈕的文字position設置不在屏幕上顯示
//    [[UIBarButtonItem appearance] setBackButtonTitlePositionAdjustment:UIOffsetMake(NSIntegerMin, NSIntegerMin) forBarMetrics:UIBarMetricsDefault];