参考代码:主要设置创建一个UIBarButtonSystemItemFixedSpace样式的UIBarButtonItem,然后设置间距,代码如下:

UIButton *searchBtn = [UIButton buttonWithType:UIButtonTypeCustom];

searchBtn.frame = CGRectMake(0,0,21, 21);

//[searchBtn setTitle:@"搜索" forState:UIControlStateNormal];

[searchBtn setBackgroundImage:[UIImage imageNamed:@"search_icon"] forState:UIControlStateNormal];

[searchBtn setBackgroundImage:[UIImage imageNamed:@"search_icon"] forState:UIControlStateHighlighted];

searchBtn.titleLabel.font = [UIFont systemFontOfSize:14];

[searchBtn addTarget:self action:@selector(searchBtnClick) forControlEvents:UIControlEventTouchUpInside];

UIBarButtonItem *rightItem = [[UIBarButtonItem alloc]initWithCustomView:searchBtn];

UIBarButtonItem *rightSpace = [[UIBarButtonItem alloc]initWithBarButtonSystemItem:UIBarButtonSystemItemFixedSpace target:nil action:nil];

rightSpace.width = -7;

self.navigationItem.rightBarButtonItems = @[rightSpace,rightItem];