UIBarButtonItem

UIBarButtonItem.h

1、UIBarButtonItemStyle:

    UIBarButtonItemStylePlain:纯文本风格，默认按钮的风格，按下时会闪动；

    UIBarButtonItemStyleBordered:与UIBarButtonItemStylePlain显示相同，但显示的按钮有边框；

    UIBarButtonItemStyleDone:一个加粗蓝色的按钮；

2、UIBarButtonSystemItem:

    UIBarButtonSystemItemDone,    //Done按钮

    UIBarButtonSystemItemCancel,      //Cancel按钮

    UIBarButtonSystemItemEdit,      //Edit按钮

    UIBarButtonSystemItemSave,     //Save按钮

    UIBarButtonSystemItemAdd,      //+号按钮

    UIBarButtonSystemItemFlexibleSpace,   //可变宽度的占位按钮

    UIBarButtonSystemItemFixedSpace,      //固定宽度

    UIBarButtonSystemItemCompose,

    UIBarButtonSystemItemReply,       //回复按钮

    UIBarButtonSystemItemAction,      //

    UIBarButtonSystemItemOrganize,     //

    UIBarButtonSystemItemBookmarks,     //

    UIBarButtonSystemItemSearch,      //

    UIBarButtonSystemItemRefresh,      //

    UIBarButtonSystemItemStop,      //

    UIBarButtonSystemItemCamera,     //

    UIBarButtonSystemItemTrash,      //

    UIBarButtonSystemItemPlay,      //

    UIBarButtonSystemItemPause,      //

    UIBarButtonSystemItemRewind,     //

    UIBarButtonSystemItemFastForward,     //

    UIBarButtonSystemItemUndo NS_ENUM_AVAILABLE_IOS(3_0),     //

    UIBarButtonSystemItemRedo NS_ENUM_AVAILABLE_IOS(3_0),     //

    UIBarButtonSystemItemPageCurl NS_ENUM_AVAILABLE_IOS(4_0),    //

3、初始化UIBArButtonItem的方法

    - (instancetype)initNS_DESIGNATED_INITIALIZER;

    //初始化实例变量，用反序列化数据构造

    - (nullableinstancetype)initWithCoder:(NSCoder *)aDecoderNS_DESIGNATED_INITIALIZER;

    //使用图片初始化

    - (instancetype)initWithImage:(nullableUIImage *)image style:(UIBarButtonItemStyle)style target:(nullableid)target action:(nullableSEL)action;

    - (instancetype)initWithImage:(nullableUIImage *)image landscapeImagePhone:(nullableUIImage *)landscapeImagePhone style:(UIBarButtonItemStyle)style target:(nullableid)target action:(nullableSEL)action NS_AVAILABLE_IOS(5_0);// landscapeImagePhone will be used for the bar button image when the bar has Compact or Condensed bar metrics.

    //初始化时设置按钮标题

    - (instancetype)initWithTitle:(nullableNSString *)title style:(UIBarButtonItemStyle)style target:(nullableid)target action:(nullableSEL)action;

    //使用（2、UIBarButtonSystemItem）中的风格初始化按钮为系统风格

    - (instancetype)initWithBarButtonSystemItem:(UIBarButtonSystemItem)systemItem target:(nullableid)target action:(nullableSEL)action;

    //使用自定义按钮初始化

    - (instancetype)initWithCustomView:(UIView *)customView;

4、按钮的面貌修改方法

   //为任意风格的按钮设置背景图片

   - (void)setBackgroundImage:(nullableUIImage *)backgroundImage forState:(UIControlState)state barMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR;

   - (nullableUIImage *)backgroundImageForState:(UIControlState)state barMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR;

   //为特定风格的按钮设置背景图片，当时UIBarButtonItem实例调用下面方法时，其风格必须和按钮风格一致

   - (void)setBackgroundImage:(nullableUIImage *)backgroundImage forState:(UIControlState)state style:(UIBarButtonItemStyle)style barMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(6_0) UI_APPEARANCE_SELECTOR;

   - (nullableUIImage *)backgroundImageForState:(UIControlState)state style:(UIBarButtonItemStyle)style barMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(6_0) UI_APPEARANCE_SELECTOR;

    //为有边框的按钮调节其在bar中的垂直中心的位置

    - (void)setBackgroundVerticalPositionAdjustment:(CGFloat)adjustment forBarMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR; 

    - (CGFloat)backgroundVerticalPositionAdjustmentForBarMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR;

    //调节有边框按钮的文字在bar中的位置

    - (void)setTitlePositionAdjustment:(UIOffset)adjustment forBarMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR; 

    - (UIOffset)titlePositionAdjustmentForBarMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR;

    //以上所有的修改方法针对导航栏的返回按钮有专门对应的方法

    - (void)setBackButtonBackgroundImage:(nullableUIImage *)backgroundImage forState:(UIControlState)state barMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR__TVOS_PROHIBITED;

    - (nullableUIImage *)backButtonBackgroundImageForState:(UIControlState)state barMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR__TVOS_PROHIBITED;

    - (void)setBackButtonTitlePositionAdjustment:(UIOffset)adjustment forBarMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR__TVOS_PROHIBITED;

    - (UIOffset)backButtonTitlePositionAdjustmentForBarMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR__TVOS_PROHIBITED;

    - (void)setBackButtonBackgroundVerticalPositionAdjustment:(CGFloat)adjustment forBarMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR__TVOS_PROHIBITED;

    - (CGFloat)backButtonBackgroundVerticalPositionAdjustmentForBarMetrics:(UIBarMetrics)barMetricsNS_AVAILABLE_IOS(5_0) UI_APPEARANCE_SELECTOR__TVOS_PROHIBITED;