viewWillAppear:(BOOL)animated不执行

UITableViewController或UIViewController中使(<UITableViewDataSource,UITableViewDelegate>)
后viewWillAppear:(BOOL)animated不执行

解决方法如下：

先在 *.h 头文件里加上<UINavigationControllerDelegate>
接着在*.m 文件里加上相关代码
self.navigationController.delegate=self;
再使用此时navigationController的代理函数，就OK了。
-(void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    [viewController viewWillAppear:animated];
}

-(void)viewWillAppear:(BOOL)animated
{
    NSLog(@"现在可以使用了");
}

代码实例：
MyOrders.h

@interface MyOrders : UIViewController<UITableViewDataSource,UITableViewDelegate,UINavigationControllerDelegate>{
   
}
@property(nonatomic,retain)IBOutlet UITableView *table;


MyOrders.m

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.navigationController.delegate=self;
}

-(void)navigationController:(UINavigationController *)navigationController willShowViewController:(UIViewController *)viewController animated:(BOOL)animated
{
    [viewController viewWillAppear:animated];
}

-(void)viewWillAppear:(BOOL)animated
{
    NSLog(@"现在可以使用了");
}