平时经常会遇到无论如何设置item的frame都不不能靠左或者靠右边。b不能满足PM的需求。
其实有个非常简单的办法。话不多说直接上代码。

UIImage *image = [UIImage imageNamed:@"back1"];
    
    UIButton *backBtn = [[UIButton alloc] initWithFrame:CGRectMake(10, 0, 40, 30)];
    backBtn.imageEdgeInsets = UIEdgeInsetsMake(0, -10, 0, 0);

    [backBtn setImage:image forState:UIControlStateNormal];
    [backBtn addTarget:self action:@selector(backBarButtonItemClick:) forControlEvents:UIControlEventTouchUpInside];

    UIBarButtonItem *backBarItem = [[UIBarButtonItem alloc] initWithCustomView:backBtn];
    UIBarButtonItem * spaceItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];
    spaceItem.width = -10;
    self.navigationItem.leftBarButtonItems = @[spaceItem,backBarItem];