Objective c Xcode NSPredicate

我正在尝试过滤一组对象，如下所示：

{
    "id": "0",
    "title": "Crucifix and sarcophagus of Ariberto da Intimiano",
    "categoryName": "COMMEMORATIVE MONUMENTS",
    "audioFile": "Crucifix-and-sarcophagus-of-Ariberto-da-Intimiano",
    "videoFile": null,
    "textFile": "Crucifix-and-sarcophagus-of-Ariberto-da-Intimiano",
    "image": "content/0/Crucifix-and-sarcophagus-of-Ariberto-da-Intimiano_flow.jpg",
    "numPictures": "1",
    "didascalie": ["dida 1", "dida 2", "dida 3"],
    "description": "Crucifix and sarcophagus of Ariberto da Intimiano",
    "link": ""
},
{
    "id": "1",
    "title": "The sundial of Duomo",
    "categoryName": "THE SUNDIAL",
    "audioFile": "The-sundial-of-Duomo",
    "videoFile": null,
    "textFile": "The-sundial-of-Duomo",
    "image": "content/1/The-sundial-of-Duomo_flow.jpg",
    "numPictures": "2",
    "didascalie": ["dida 1", "dida 2", "dida 3"],
    "description": "The sundial of Duomo",
    "link": ""
}


NSPredicate *key1Predicate = [NSPredicate predicateWithFormat:@"title == '%@'",_searchAZ.text];

    _ArtWorksTableResults = [[_ArtWorksTable filteredArrayUsingPredicate:key1Predicate] mutableCopy];

    NSLog(@"%i",_ArtWorksTableResults.count);

NSPredicate *key1Predicate = [NSPredicate predicateWithFormat:@"title == 'The sundial of duomo'"];

    _ArtWorksTableResults = [[_ArtWorksTable filteredArrayUsingPredicate:key1Predicate] mutableCopy];

    NSLog(@"%i",_ArtWorksTableResults.count);

执行搜索时，

\u ArtWorksTableResults.count

始终为

0

但是如果我写谓词而不是像这样使用搜索栏文本：

{
    "id": "0",
    "title": "Crucifix and sarcophagus of Ariberto da Intimiano",
    "categoryName": "COMMEMORATIVE MONUMENTS",
    "audioFile": "Crucifix-and-sarcophagus-of-Ariberto-da-Intimiano",
    "videoFile": null,
    "textFile": "Crucifix-and-sarcophagus-of-Ariberto-da-Intimiano",
    "image": "content/0/Crucifix-and-sarcophagus-of-Ariberto-da-Intimiano_flow.jpg",
    "numPictures": "1",
    "didascalie": ["dida 1", "dida 2", "dida 3"],
    "description": "Crucifix and sarcophagus of Ariberto da Intimiano",
    "link": ""
},
{
    "id": "1",
    "title": "The sundial of Duomo",
    "categoryName": "THE SUNDIAL",
    "audioFile": "The-sundial-of-Duomo",
    "videoFile": null,
    "textFile": "The-sundial-of-Duomo",
    "image": "content/1/The-sundial-of-Duomo_flow.jpg",
    "numPictures": "2",
    "didascalie": ["dida 1", "dida 2", "dida 3"],
    "description": "The sundial of Duomo",
    "link": ""
}


NSPredicate *key1Predicate = [NSPredicate predicateWithFormat:@"title == '%@'",_searchAZ.text];

    _ArtWorksTableResults = [[_ArtWorksTable filteredArrayUsingPredicate:key1Predicate] mutableCopy];

    NSLog(@"%i",_ArtWorksTableResults.count);

NSPredicate *key1Predicate = [NSPredicate predicateWithFormat:@"title == 'The sundial of duomo'"];

    _ArtWorksTableResults = [[_ArtWorksTable filteredArrayUsingPredicate:key1Predicate] mutableCopy];

    NSLog(@"%i",_ArtWorksTableResults.count);

\u ArtWorksTableResults.count

是

1

，这是正确的

我做错了什么

我还尝试记录搜索栏文本，一切正常

---

我不明白为什么我直接在代码中写搜索键会起作用

在提供参数时，谓词格式不应包含引号：

[NSPredicate predicateWithFormat:@"title == %@",_searchAZ.text];

不需要额外的“符号”，它们是由格式化程序添加的

最后：

@"%K == '%@'"
This predicate checks whether the value of the key %K is equal to the string literal “%@“ (note the single quotes around %@). The key name %K is supplied at runtime as an argument to predicateWithFormat:.

---

非常感谢。我删除了引号，但执行搜索时数组仍然为空！我快疯了！您可能希望使用特定于字符串的比较，以便使其不区分大小写（

如[cd]

），而不是

=

。同时检查

\u searchAZ

是否实际连接。此外，确保\u searchAZ不是ninspredicate*key1Predicate=[redinscate predicateWithFormat:@]（标题如[cd]@），\u searchAZ.text]；你是说像这样吗？