Re: How to cancel a loading document in NSDocument's readFromURL:ofType:error method ?
Re: How to cancel a loading document in NSDocument's readFromURL:ofType:error method ?
- Subject: Re: How to cancel a loading document in NSDocument's readFromURL:ofType:error method ?
- From: Gilles Celli <email@hidden>
- Date: Fri, 10 Feb 2012 22:25:07 +0100
Opening the ASCII file can take up to 15-20 sec ( > 150MB), so I made some changes as you suggested by moving the progressWindowController alloc/init before the allocation of asciiFileContents...
And you're right I should have put addWindowController: in makeWindowController....
This makes the opening of the file a little more responsive (clicking the button) but not really what I expect...
>Never blindly assign to error pointers. Check the caller is actually interested in receiving an error first.
Which caller do you mean ?
Maybe the way to go is to use a new detached thread only for the progress window, or to use Kyle's approach by using NSOperationQueue..
Of course if you guys have any other suggestions they will be greatly appreciated :-)
Gilles
On 10 févr. 2012, at 17:08, Mike Abdullah wrote:
>> I'm sure I'm doing something wrong here :-(
>>
>> Any clues ?
>
> Yep, here we go:
>
> On 10 Feb 2012, at 15:28, Gilles Celli wrote:
>
>> In my NSDocument readFromURL:ofType:error: method it init's a progressLoading WindowController (which shows up the window with progress bar and Cancel button).
>> In my progressLoadingWC I have a BOOL cancelLoadingFlag which is checked in readFromURL method…however nothing seems to happen if I call NSError…the document is still opened...
>>
>> Also opening the file and trying to click the button is nearly impossible since it slows down heavily. Here's an excerpt of my code
>>
>> -(BOOL)readFromURL:(NSURL *)absoluteURL ofType:(NSString *)typeName error:(NSError **)outError
>> {
>> asciiFileContents = [[NSString alloc] initWithContentsOfURL:absoluteURL
>> encoding:NSISOLatin1StringEncoding error:outError];
>
> OK, good, you're grabbing file contents on the worker thread. How long does this typically take? Why not show your progress display before this?
>
>> if (!progressLoadingWindowController)
>> {
>> progressLoadingWindowController = [[ProgressLoadingWindowController alloc] init];
>> [[progressLoadingWindowController fileNameOutlet] setStringValue:[absoluteURL lastPathComponent]];
>> [[progressLoadingWindowController loadProgressBar] setUsesThreadedAnimation:YES];
>> [[progressLoadingWindowController loadProgressBar] startAnimation:self];
>>
>> }
>
> Don't do this. AppKit is not thread safe. Creating a window controller on a secondary thread is not supported.
>>
>> // Display the progressLoading window
>> [progressLoadingWindowController showWindow:self];
>>
>> if ( [progressLoadingWindowController cancelLoadingFlag] )
>> {
>> NSLog(@"User cancelled opening...");
>>
>> *outError = [NSError errorWithDomain:NSCocoaErrorDomain
>> code:NSUserCancelledError userInfo:nil];
>
> Never blindly assign to error pointers. Check the caller is actually interested in receiving an error first.
>> }
>>
>> myDocWindowController = [[TsoftViewerWindowController alloc] initWithTsfFileString:asciiFileContents];
>
> Or is it this line of code that takes a long time to run? If so, what's it doing?
>>
>> [self addWindowController:myDocWindowController];
>
> Furthermore, it is not this method's job to create the UI. That should be done in -makeWindowControllers instead.
>>
>> [asciiFileContents release];
>>
>>
>> return YES;
>>
>> }
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