添加右上UIBarButton

- (void)setRightNavigatorItem{

    UIButton *rightBtn = [UIButtonbuttonWithType:UIButtonTypeCustom];

    rightBtn.frame =CGRectMake(0,0, 40,44);

    [rightBtn setImage:IMAGE(@"add_something.png")forState:UIControlStateNormal];

    [rightBtn addTarget:selfaction:@selector(addSomething)forControlEvents:UIControlEventTouchUpInside];

    

    UIBarButtonItem *negativeSpacer = [[UIBarButtonItemalloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpacetarget:nilaction:nil];

    /*

     width为负数时，相当于btn向右移动width数值个像素，由于按钮本身和边界间距为5pix，所以width设为-5时，间距正好调整

     为0；width为正数时，正好相反，相当于往左移动width数值个像素

     */

    negativeSpacer.width = -10;

    UIBarButtonItem *editButton = [[UIBarButtonItemalloc] initWithCustomView:rightBtn];

    self.navigationItem.rightBarButtonItems =@[negativeSpacer, editButton];

}