iOS 模拟器不显示文件应用程序作为 NSFileproviderExtension 的选项
<p><p>我在让我的应用显示为 iOS 11 文件应用中的位置时遇到了一些问题。我添加了一个 <code>NSFileproviderExtension</code>。但是，当我运行它时，我只能选择 safari 和其他一些应用程序。当我选择 safari，然后关闭 safari，打开文件时，它确实显示了我的扩展名，但是当我单击任何内容时它崩溃了。关于最好的方法的任何想法？有什么好的教程吗？</p>
<pre><code>@interface FileProviderExtension ()
@property (nonatomic, readonly, strong) NSFileManager *fileManager;
@end
@implementation FileProviderExtension
- (instancetype)init {
if (self = ) {
_fileManager = [ init];
}
return self;
}
- (nullable NSFileProviderItem)itemForIdentifier:(NSFileProviderItemIdentifier)identifier error:(NSError * _Nullable *)error {
// resolve the given identifier to a record in the model
// TODO: implement the actual lookup
NSFileProviderItem item = nil;
return item;
}
- (nullable NSURL *)URLForItemWithPersistentIdentifier:(NSFileProviderItemIdentifier)identifier {
// resolve the given identifier to a file on disk
NSFileProviderItem item = ;
if (!item) {
return nil;
}
// in this implementation, all paths are structured as <base storage directory>/<item identifier>/<item file name>
NSFileProviderManager *manager = ;
NSURL *perItemDirectory = ;
return ;
}
- (nullable NSFileProviderItemIdentifier)persistentIdentifierForItemAtURL:(NSURL *)url {
// resolve the given URL to a persistent identifier using a database
NSArray <NSString *> *pathComponents = ;
// exploit the fact that the path structure has been defined as
// <base storage directory>/<item identifier>/<item file name> above
NSParameterAssert(pathComponents.count > 2);
return pathComponents;
}
- (void)startProvidingItemAtURL:(NSURL *)url completionHandler:(void (^)(NSError *))completionHandler {
// Should ensure that the actual file is in the position returned by URLForItemWithIdentifier:, then call the completion handler
/* TODO:
This is one of the main entry points of the file provider. We need to check whether the file already exists on disk,
whether we know of a more recent version of the file, and implement a policy for these cases. Pseudocode:
if (!fileOnDisk) {
downloadRemoteFile();
callCompletion(downloadErrorOrNil);
} else if (fileIsCurrent) {
callCompletion(nil);
} else {
if (localFileHasChanges) {
// in this case, a version of the file is on disk, but we know of a more recent version
// we need to implement a strategy to resolve this conflict
moveLocalFileAside();
scheduleUploadOfLocalFile();
downloadRemoteFile();
callCompletion(downloadErrorOrNil);
} else {
downloadRemoteFile();
callCompletion(downloadErrorOrNil);
}
}
*/
completionHandler();
}
- (void)itemChangedAtURL:(NSURL *)url {
// Called at some point after the file has changed; the provider may then trigger an upload
/* TODO:
- mark file at <url> as needing an update in the model
- if there are existing NSURLSessionTasks uploading this file, cancel them
- create a fresh background NSURLSessionTask and schedule it to upload the current modifications
- register the NSURLSessionTask with NSFileProviderManager to provide progress updates
*/
}
- (void)stopProvidingItemAtURL:(NSURL *)url {
// Called after the last claim to the file has been released. At this point, it is safe for the file provider to remove the content file.
// TODO: look up whether the file has local changes
BOOL fileHasLocalChanges = NO;
if (!fileHasLocalChanges) {
// remove the existing file to free up space
[ removeItemAtURL:url error:NULL];
// write out a placeholder to facilitate future property lookups
[self providePlaceholderAtURL:url completionHandler:^(NSError * __nullable error) {
// TODO: handle any error, do any necessary cleanup
}];
}
}
#pragma mark - Actions
/* TODO: implement the actions for items here
each of the actions follows the same pattern:
- make a note of the change in the local model
- schedule a server request as a background task to inform the server of the change
- call the completion block with the modified item in its post-modification state
*/
#pragma mark - Enumeration
- (nullable id<NSFileProviderEnumerator>)enumeratorForContainerItemIdentifier:(NSFileProviderItemIdentifier)containerItemIdentifier error:(NSError **)error {
id<NSFileProviderEnumerator> enumerator = nil;
if () {
// TODO: instantiate an enumerator for the container root
} else if () {
// TODO: instantiate an enumerator for the working set
} else {
// TODO: determine if the item is a directory or a file
// - for a directory, instantiate an enumerator of its subitems
// - for a file, instantiate an enumerator that observes changes to the file
}
return enumerator;
}
@end
</code></pre></p>
<br><hr><h1><strong>Best Answer-推荐答案</ strong></h1><br>
<p><p>由于某种原因，Xcode 不会显示 Files 应用程序来调试您的 <code>NSFileproviderExtension</code>。</p>
<p>无论如何要测试它，只需选择任何其他应用程序，在该应用程序中搜索“共享”按钮，然后在共享屏幕中选择"file"。
您还可以关闭应用程序并转到文件，您的扩展程序将在其中显示应用程序并进行调试(断点、控制台消息等)。</p>
<p>对于崩溃，添加一个异常断点以在导致崩溃的代码行处停止(就像调试主程序时所做的那样)。</p></p>
<p style="font-size: 20px;">关于iOS 模拟器不显示文件应用程序作为 NSFileproviderExtension 的选项，我们在Stack Overflow上找到一个类似的问题：
<a href="https://stackoverflow.com/questions/46454839/" rel="noreferrer noopener nofollow" style="color: red;">
https://stackoverflow.com/questions/46454839/
</a>
</p>
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