-(void)_init{
 //初期化
}

-(id) initWithCoder:(NSCoder *)aDecoder{
 self = [super initWithCoder:aDecoder];
 if (self) {
   [self _init];
 }
 return self;
}

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
 self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
 if (self) {
   [self _init];
 }
 return self;
}