UIBarButtonItem导航按钮

初始化方法

• (nullable instancetype)initWithCoder:(NSCoder *)aDecoder NS_DESIGNATED_INITIALIZER;
• (instancetype)initWithImage:(nullable UIImage *)image style:(UIBarButtonItemStyle)style target:(nullable id)target action:(nullable SEL)action;
• (instancetype)initWithImage:(nullable UIImage *)image landscapeImagePhone:(nullable UIImage *)landscapeImagePhone style:(UIBarButtonItemStyle)style target:(nullable id)target action:(nullable SEL)action NS_AVAILABLE_IOS(5_0); // landscapeImagePhone will be used for the bar button image when the bar has Compact or Condensed bar metrics.
• (instancetype)initWithTitle:(nullable NSString *)title style:(UIBarButtonItemStyle)style target:(nullable id)target action:(nullable SEL)action;
• (instancetype)initWithBarButtonSystemItem:(UIBarButtonSystemItem)systemItem target:(nullable id)target action:(nullable SEL)action;
• (instancetype)initWithCustomView:(UIView *)customView