1 - (void)viewDidLoad {
 2     [super viewDidLoad];
 3     
 4     [self setTitle:@"Test"];
 5     
 6     //以下是主要实现代码
 7     UIButton *moreBtn = [[UIButton alloc]initWithFrame:CGRectMake(0, 0, 50, 50)];
 8     [moreBtn setTitle:@"more" forState:UIControlStateNormal];
 9     [moreBtn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
10     [moreBtn addTarget:self action:@selector(didClickMoreBtn) forControlEvents:UIControlEventTouchUpInside];
11     UIBarButtonItem *moreItem  = [[UIBarButtonItem alloc] initWithCustomView:moreBtn];
12     self.navigationItem.leftBarButtonItem = moreItem;
13     
14 }
15 
16 - (void)didClickMoreBtn
17 {
18     NSLog(@"hello more");
19 }