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

    [[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(search:) name:UITextFieldTextDidChangeNotification object:nil];

}

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

    NSString*str = [NSString stringWithFormat:@"SELF like [c] '*%@*'",_tf.text];
   
    NSPredicate*predicate = [NSPredicate predicateWithFormat:str];
   
    _dataAarray = [_dataArray1 filteredArrayUsingPredicate:predicate];
   
    [_collection reloadData];

//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;