设置UINavigationBar的leftBarButtonItem和rightBarButtonItem

navBar = [[UINavigationBar alloc] initWithFrame:CGRectMake(0,  0, self.view.frame.size.width, 40)];[self.view addSubview:navBar];navBar.barStyle = UIBarStyleDefault;[navBar release];UIBarButtonItem* cancelBtnItem = [[UIBarButtonItem alloc] initWithTitle:@"取消" style:UIBarButtonItemStylePlain target:self action:@selector(cancelBtnPress)];UIBarButtonItem* sureBtnItem = [[UIBarButtonItem alloc] initWithTitle:@"确定" style:UIBarButtonItemStyleDone    target:self action:@selector(sureBtnPress)];UINavigationItem* navItem = [[UINavigationItem alloc] initWithTitle:@"设置经度"];navItem.leftBarButtonItem = cancelBtnItem;navItem.rightBarButtonItem = sureBtnItem;navItem.hidesBackButton  = YES;[cancelBtnItem release];[sureBtnItem release];[navBar pushNavigationItem:navItem animated:NO];[navItem release];