Question

我想使用NSMetadataQuery跟踪我上传的文件占icloud的百分比，但它不起作用。

这是我的代码：

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^(void) {
    NSFileCoordinator* fileCoordinator = [[NSFileCoordinator alloc] initWithFilePresenter:nil];
    [fileCoordinator coordinateReadingItemAtURL:backupUrl options:NSFileCoordinatorReadingWithoutChanges error:nil byAccessor:^(NSURL *newURL) {
        NSFileManager*  fm = [NSFileManager defaultManager];
        NSError *theError = nil;

        BOOL success =[fm setUbiquitous:YES itemAtURL:backupUrl destinationURL:[[ubiq URLByAppendingPathComponent:@"Documents" isDirectory:true] URLByAppendingPathComponent:bName] error:&theError];

        if (!(success)) {
            [progView dismiss];
            UIAlertView* alertFail=[[UIAlertView alloc]initWithTitle:@"Backup Error" message:@"Could not backup to iCloud." delegate:Nil cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
            [alertFail show];
            NSLog(@"iCloud error: %@", [theError localizedDescription]);
        }
        else{
            NSURL* destURL=[[ubiq URLByAppendingPathComponent:@"Documents" isDirectory:true] URLByAppendingPathComponent:bName];
            NSMetadataQuery* query=[[NSMetadataQuery alloc]init];
            [query setPredicate:[NSPredicate predicateWithFormat:@"%K > 0",NSMetadataUbiquitousItemPercentUploadedKey]];
            [query setSearchScopes:@[destURL]];
            [query setValueListAttributes:@[NSMetadataUbiquitousItemPercentUploadedKey,NSMetadataUbiquitousItemIsUploadedKey]];

            _alertQuery=query;
            [query enableUpdates];
            [[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(liveupdate:) name:NSMetadataQueryDidUpdateNotification object:query];
`//                [progView dismiss];
            NSLog(@"desturl %@",query);
            [query  startQuery];
        }
    }];

-(void)liveupdate:(NSNotification *)note{
NSMetadataQuery* query=[note object];
if ([query resultCount]==0)
    return;

NSMetadataItem* item=[query resultAtIndex:0];
float progress=[[item valueForAttribute:NSMetadataUbiquitousItemPercentUploadedKey]floatValue];

[progView.progBar setProgress:progress animated:NO];

if ([[item valueForAttribute:NSMetadataUbiquitousItemIsUploadedKey] boolValue]){
    [query stopQuery];
    [query disableUpdates];
    _alertQuery=nil;
    [progView dismiss];
}

}

liveUpdate:note方法未调用。谁可以帮助我如何修复此代码。谢谢

我编辑了我的代码......

这是我的新代码

- (void)loadNotes:(NSString *)bname {
self.alertQuery = [[NSMetadataQuery alloc] init];
[self.alertQuery setPredicate:[NSPredicate predicateWithFormat:@"%K LIKE %@", NSMetadataItemFSNameKey, bname]];
[self.alertQuery setSearchScopes:@[NSMetadataQueryUbiquitousDataScope]];
[[NSNotificationCenter defaultCenter]addObserver:self selector:@selector(liveupdate:) name:NSMetadataQueryDidUpdateNotification object:self.alertQuery];
[self.alertQuery startQuery];
}
-(void)liveupdate:(NSNotification *)note {
    NSMetadataQuery* query=[note object];
    if ([query resultCount]==0){
        return;
    }
    NSMetadataItem* item=[query resultAtIndex:0];
    float progress=[[item valueForAttribute:NSMetadataUbiquitousItemPercentUploadedKey]floatValue];


[progView.progBar setProgress:progress animated:NO];

if ([[item valueForAttribute:NSMetadataUbiquitousItemIsUploadedKey] boolValue]){
    [query stopQuery];
    [query disableUpdates];
    _alertQuery=nil;
    [progView dismiss];
}
}

它仍然无法调用liveupdate方法。我的代码有什么问题？

Answer 1

您的元数据查询似乎有些问题。第一：

[query setPredicate:[NSPredicate predicateWithFormat:@"%K > 0",NSMetadataUbiquitousItemPercentUploadedKey]];

可能这应该有效，但我对此持怀疑态度。你真正需要的是一个使用文件名的谓词。如果文件名保存在名为NSString的{{1}}中，则为：

filename

这是最大的问题。修复它可能就是你所需要的。但是还有其他一些事情我也会改变。下一个：

[query setPredicate:[NSPredicate predicateWithFormat:@"%K LIKE %@", NSMetadataItemFSNameKey, filename]];

同样，这可能是应该有用的东西，但我只看到了更好的结果，并且有更常规的设置：

[query setSearchScopes:@[destURL]];

最后：

[query setSearchScopes:@[NSMetadataQueryUbiquitousDataScope]];

这可能会有效如果您通过[query setValueListAttributes:@[NSMetadataUbiquitousItemPercentUploadedKey,NSMetadataUbiquitousItemIsUploadedKey]];直接在查询对象上查找了值。但我建议完全放弃这条线。如果没有它，您仍然可以从valueListAttributes查找进度和状态。

无法调用NSMetadataQueryDidUpdateNotification

1 个答案: