问题描述

KVO观察者模式不可以这么用吗

• (void)viewDidLoad
  {
  [super viewDidLoad];
  [self dataArray];
  [self createNav];
  [self createTableView];
  [self createsearchBar];

  [_searchBar addObserver:self forKeyPath:@"text" options:NSKeyValueObservingOptionNew context:nil];

}

• (void)observeValueForKeyPath:(NSString *)keyPath ofObject:(id)object change:(NSDictionary *)change context:(void *)context{
  NSLog(@"%@%@%@",keyPath,change,context);
  if (_searchBar.text.length==0) {
  NSLog(@"!!!!!!");
  _searchBar=nil;
  [_tableView reloadData];
  }
  NSLog(@"----");

}