iOS的navigationbar设置左边按钮文字

实例代码：

 - (void)viewDidLoad {
     [super viewDidLoad];

     [self setTitle:@"Test"];

     //以下是主要实现代码
     UIButton *moreBtn = [[UIButton alloc]initWithFrame:CGRectMake(, , , )];
     [moreBtn setTitle:@"more" forState:UIControlStateNormal];
     [moreBtn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
     [moreBtn addTarget:self action:@selector(didClickMoreBtn) forControlEvents:UIControlEventTouchUpInside];
     UIBarButtonItem *moreItem  = [[UIBarButtonItem alloc] initWithCustomView:moreBtn];
     self.navigationItem.leftBarButtonItem = moreItem;

 }

 - (void)didClickMoreBtn
 {
     NSLog(@"hello more");
 }

效果：