不太了解NSMetadataQuery

问题描述

我正在寻找一个类来使用Cocoa API在整个系统上执行Spotlight搜索。我看着 NSMetadataQuery ，并相信这是类的，但我不明白如何做到这一点;主要是 NSPredicate 。我想搜索系统中的一个文件名为test123.html例如，并得到其完整路径。非常感谢。我的代码：

I am looking for a class to use from the Cocoa API to perform a Spotlight search on the entire system. I looked at NSMetadataQuery and believe this is the class for this, however I don't understanding how to do this; primarily NSPredicate. I would like to search the system for a file named "test123.html" for example and get its full path. Examples are greatly appreciated. My code:

NSMetadataQuery *q = [[NSMetadataQuery alloc] init];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"kMDItemSFName == %@", @"test123456.png"];  
[q setPredicate:predicate];

[q startQuery];
while ([q isGathering]) {
    NSLog(@"%lu", [q resultCount]);
}

[q stopQuery];

这将返回0个结果。为什么？

This returns 0 results. Why?

推荐答案

kMDItemSFName 应为 kMDItemFSName

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