根据输入的textField首字符排序

textfield的值发生改变时.调用方法筛选

    [[NSNotificationCenterdefaultCenter]addObserver:selfselector:@selector(search:)name:UITextFieldTextDidChangeNotificationobject:nil];

}

-(void)search:(NSNotification*)notification{

    NSString*str = [NSStringstringWithFormat:@"SELF like [c] '*%@*'",_tf.text];
   
    NSPredicate*predicate = [NSPredicatepredicateWithFormat:str];
   
    _dataAarray = [_dataArray1filteredArrayUsingPredicate:predicate];
   
    [_collectionreloadData];

//label内容自适应

 _label.contentMode=UIViewContentModeScaleAspectFit

获得导航栏上按钮的视图

    UIView*v = self.navigationItem.rightBarButtonItem.customView;