用谓词查询核心数据 - iPhone [英] Querying Core Data with Predicates - iPhone

问题描述

所以我正在尝试从核心数据中获取对象。我有80个对象的列表，我希望能够使用UISearchBar搜索它们。它们显示在表格中。

So I'm trying to fetch objects from core data. I have list of say 80 objects, and I want to be able to search through them using a UISearchBar. They are displayed in a table.

在谓词上使用apple文档，我将以下代码放在UISearchBar委托方法的一个
中。

Using the apple documentation on predicates, I've put the following code in one of the UISearchBar delegate methods.

- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar {
  if (self.searchBar.text !=nil)
  {
    NSPredicate *predicate =[NSPredicate predicateWithFormat:@"name LIKE %@", self.searchBar.text];
    [fetchedResultsController.fetchRequest setPredicate:predicate];
  }
  else
  {
    NSPredicate *predicate =[NSPredicate predicateWithFormat:@"All"];
    [fetchedResultsController.fetchRequest setPredicate:predicate];
  }

  NSError *error = nil;
  if (![[self fetchedResultsController] performFetch:&error]) {
        // Handle error
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();  // Fail
    }       

  [self.tableView reloadData];

    [searchBar resignFirstResponder];   
    [_shadeView setAlpha:0.0f];
}

如果我在搜索字段中输入与一个名称属性的完全匹配在这些对象中，搜索工作，并使用具有对象名称的单个单元格重新填充表。如果我不搜索确切的名称，我最终没有结果。

If I type in the search field an exact match to the name property of one of those objects, the search works, and it repopulates the table with a single cell with the name of the object. If I don't search the name exact, I end up with no results.

有什么想法吗？

推荐答案

好像iPhone似乎并没有喜欢LIKE运算符。我用'contains [cd]'替换它，它按照我想要的方式工作。

It seems as though iPhone doesn't like the LIKE operator. I replaced it with 'contains[cd]' and it works the way I want it to.

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