I have been trying to get this one section of my UI to immediatly up date when the document loads into view. The awakeFromNib fires the pasted code and then starts a timer to repeat every 10 seconds...
I load a default storage location: ~/Movies... which shows up immediately.. yet the network location that is saved in the document that gets pulled from the XML only seems to show up after the second firing of the - (void)updateDiskSpaceDisplay timer.
I have set breakpoints and know that the ivars that contain the values that are being put into the *fileSystemAttributes is the network location right when the awakeFromNib occurs...
Im confused why it magically appears after the second time firing instead of immediately displaying the write values.
- (void)updateDiskSpaceDisplay
{
// Obtain information about the file system used on the selected storage path.
NSError *error = NULL;
NSDictionary *fileSystemAttributes = [[NSFileManager defaultManager] attributesOfFileSystemForPath:[[[self settings] containerSettings] storagePath] error:&error];
if( !fileSystemAttributes ) return;
// Get the byte capacity of the drive.
long long byteCapacity = [[fileSystemAttributes objectForKey:NSFileSystemSize] unsignedLongLongValue];
// Get the number of free bytes.
long long freeBytes = [[fileSystemAttributes objectForKey:NSFileSystemFreeSize] unsignedLongLongValue];
// Update the level indicator, and the text fields to show the current information.
[totalDiskSpaceField setStringValue:[self formattedStringFromByteCount:byteCapacity]];
[totalDiskSpaceField setNeedsDisplay:YES];
[usedDiskSpaceField setStringValue:[self formattedStringFromByteCount:(byteCapacity - freeBytes)]];
[usedDiskSpaceField setNeedsDisplay:YES];
[diskSpaceIndicator setMaxValue:100];
[diskSpaceIndicator setIntValue:(((float) (byteCapacity - freeBytes) / (float) byteCapacity) * 100.0)];
[diskSpaceIndicator display:YES];
}
thoughts?
my awakeFromNib:
- (void)awakeFromNib
{
[documentWindow setAcceptsMouseMovedEvents:YES];
[documentWindow setDelegate:self];
[self updateSettingsDisplay];
[self updateDiskSpaceDisplay];
[self setDiskSpaceUpdateTimer:[NSTimer scheduledTimerWithTimeInterval:10.0 target:self selector:#selector(updateDiskSpaceDisplay) userInfo:NULL repeats:YES]];
[self setUpClipInfoTabButtons];
[self performSelector:#selector(setupEngineController) withObject:NULL afterDelay:0.1];
}
awakeFromNib is only a notification to your instance that its IBOutlets have been set up, not that the application has finished launching and is ready to draw.
Try implementing NSApplication's delegate method, applicationDidFinishLaunching:, and call your updateDiskSpaceDisplay method from there.
there was an read from xml method that was occurring after my awakeFromNib that was swizzling the values... I just put the updateDiskSpaceDisplay there and... problem solved. Thanks all for the attempts.
Related
I check the frame of any subclass, if it is change or not with the following code.
- (void)viewDidAppear:(BOOL)animated
{
[super viewDidAppear:animated];
if(imageFrameSize == CGRectZero) {
imageFrameSize = self.recycleBin.frame;
NSLog(#"Frame: %#", NSStringFromCGRect(imageFrameSize));
}
}
Now I want to check the string is same or changed. Basically I am storing history in history.plist. And I run the function in below delegate to save document url in history.plist file.
- (void)webViewDidFinishLoad:(UIWebView *)webView {
//when push to reload is done it will disappear pulltorefresh
[(PullToRefreshView *)[self.view viewWithTag:998] finishedLoading];
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
[self actualizeButtons];
urlPage =[webView stringByEvaluatingJavaScriptFromString:#"document.title"]; //[[[webView request] URL]absoluteString];
[self addHistoryFunction];
NSLog(#"WebView Finish Load %#",[[[webView request] URL]absoluteString] );
}
This function works good. But the problem is that webViewDidiFinishLoad run almost two times for google and three or many times for other websites. So addHistoryFuncation save the history two or more times with same page url.
I want to check the urlPage string before adding to history, if it is updated new string then run the addhistory function, if it is same then skip addhistory function. Just like above CGRectZero code.
Thats my idea to save history in history.plist.
If there is a better then mine please help me or solve my issue.
Thanks in advance.
- (void)webViewDidFinishLoad:(UIWebView *)webView called when ever awebview finish loading an object with in the web page so the best approch to prevent this method to be called more than once to add this line :
if ([webView isLoading]){return;)
this line will make sure that your webview will do the commands when its only finishedl loading.
here is your function after edit try it .
- (void)webViewDidFinishLoad:(UIWebView *)webView {
if ([webView isLoading]){return;)
//when push to reload is done it will disappear pulltorefresh
[(PullToRefreshView *)[self.view viewWithTag:998] finishedLoading];
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
[self actualizeButtons];
urlPage =[webView stringByEvaluatingJavaScriptFromString:#"document.title"]; //[[[webView request] URL]absoluteString];
[self addHistoryFunction];
NSLog(#"WebView Finish Load %#",[[[webView request] URL]absoluteString] );
}
if you want to compare to string this is how
BOOL isTheSameStrings=[mystring isEqualToString:string2];
if (isTheSameStrings){
NSLog(#"the are the same);
}else{
NSLog(#"the are NOT the same);
}
or you want to check if the string found in an array
BOOL myArrayDoesContainMyString=[myArray containsObject:myString];
if (myArrayDoesContainMyString){
NSLog(#"myArray contain myString);
}else{
NSLog(#"myArray does not contain myString);
}
I am using a pin screen for login to my app. The pin screen consists of four labels and a hidden text field. When the user enters text via the keypad, I update the labels with a symbol. This works fine, except that the last label does not get actually get updated before login begins, and remains empty while the login process is completed.
These are the relevant bits of code:
//an observer has been added elsewhere
- (void)textDidChange:(NSNotification *)notification
{
UITextField *field = [notification object];
if (field == inputField)
{
NSString *newText = field.text;
if ([newText length] <= pinLength) [self updatePINDisplay];
}
}
-(void)updatePINDisplay
{
if ([pinText length] > pinLength) return;
for (NSInteger ii = 0; ii < [pinText length]; ii++)
{
UILabel *label = [pinFields objectAtIndex:ii];
[label setText:#"x"];
}
for (NSInteger ii = [pinText length]; ii < pinLength; ii++)
{
UILabel *label = [pinFields objectAtIndex:ii];
[label setText:[NSString string]];
}
if ([pinText length] == pinLength) [self login];
}
The problem arises because [self login] launches other processes which happen before the last pin label is updated, so the login occurs while the last box is still empty.
I have worked around the problem by replacing
[self login]
with
[self performSelector:#selector(login) withObject:nil afterDelay:0.1]
but I don't like the arbitrary time delay. I was hoping that maybe there was a delegate method that I could use to launch my login code after the label has been drawn. Something like:
-(void)labelDidGetDrawn
Any other (non-hack) solution is also welcome:-)
Thanks!
Based on your description, it sounds like the problem is that the 4th item doesn't get drawn until after the [self login] finishes, which is indicative that the login procedure takes some time. In iOS, drawing doesn't happen immediately, which is why you're only getting the draw if you defer the login until after the OS has an opportunity to update the display.
You have used one reasonable solution here. Another (arguably less of a hack) is to have your -[self login] spawn the login on a separate thread, or at least using an asynchronous mechanism (such as the asynchronous modes of NSURLConnection, assuming you're making a network request). Then your main thread will quickly return control to iOS and your box will draw.
With Grand Central Dispatch, you could do most of this by having the -[self login] place the network code on a background thread, and have the background thread call back to your main thread when complete. However, this can cause some problems if you want to respond to user events during the login process.
If you can, using NSURLConnection asynchronously, and setting up the delegate to report back to you when the operation is complete is probably the best choice, as it gives you the operation to cancel the NSURLConnection during the login process if the user requests it.
How about:
[label setNeedsDisplay:YES];
if ([pinText length] == pinLength) [self login];
Yes, that notification exists, in a way. The label will be drawn during the next iteration of the run loop. So do your login at the end of the next run loop iteration, for instance using a performSelector:afterDelay:0 or maybe using
dispatch_async (dispatch_get_main_queue (), ^{ [self login]; });
But a) this depends on the order of execution of rendering versus timers and dispatch_queues. If rendering happens before timer execution, you're all set.
And b) don't block the main thread. Try to perform the login in a background thread/concurrent queue, or do it asynchronously on the main thread if you're using, e.g., NSURLConnection.
I have a program which works normally. Then I downloaded some code from http://github.com/matej/MBProgressHUD to show a progress meter when doing something.
This is the code that makes the progress meter pop up.
[HUD showWhileExecuting:#selector(myTask) onTarget:self withObject:nil animated:YES];
This will show a progress meter while the method myTask is running.
This is the code for the showWhileExecuting method.
- (void)showWhileExecuting:(SEL)method onTarget:(id)target withObject:(id)object animated:(BOOL)animated {
methodForExecution = method;
targetForExecution = [target retain];
objectForExecution = [object retain];
// Launch execution in new thread
taskInProgress = YES;
[NSThread detachNewThreadSelector:#selector(launchExecution) toTarget:self withObject:nil];
// Show HUD view
[self show:animated];
}
If I use this to call the function myTask then one of my class properties will change from an NSMutableString to an NSData object somewhere, and then later on it will change to an NSString. I don't see anywhere in the code that causes this to change, so it's probably some kind of bug. Is memory getting corrupted? What's causing this to happen?
Most likely it's a memory (retain/release issue). If you don't properly retain an object, it may get released out from under you. At that point, the memory will be reclaimed by the OS, which may decide to store something else there. Try turning on NSZombies, and double checking your retain/release/autoreleases.
I have hit the proverbial wall trying to figure out how to populate an NSImage with data returned from an asynchronous NSURLConnection in my desktop app (NOT an iPhone application!!).
Here is the situation.
I have a table that is using custom cells. In each custom cell is an NSImage which is being pulled from a web server. In order to populate the image I can do a synchronous request easily:
myThumbnail = [[NSImage alloc] initWithContentsOfFile:myFilePath];
The problem with this is that the table blocks until the images are populated (obviously because it's a synchronous request). On a big table this makes scrolling unbearable, but even just populating the images on the first run can be tedious if they are of any significant size.
So I create an asynchronous request class that will retrieve the data in its own thread as per Apple's documentation. No problem there. I can see the data being pulled and populated (via my log files).
The problem I have is once I have the data, I need a callback into my calling class (the custom table view).
I was under the impression that I could do something like this, but it doesn't work because (I'm assuming) that what my calling class really needs is a delegate:
NSImage * myIMage;
myImage = [myConnectionClass getMyImageMethod];
In my connection class delegate I can see I get the data, I just don't see how to pass it back to the calling class. My connectionDidFinishLoading method is straight from the Apple docs:
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
// do something with the data
// receivedData is declared as a method instance elsewhere
NSLog(#"Succeeded! Received %d bytes of data",[receivedData length]);
// release the connection, and the data object
[connection release];
[receivedData release];
}
I am hoping this is a simple problem to solve, but I fear I am at the limit of my knowledge on this one and despite some serious Google searches and trying many different recommended approaches I am struggling to come up with a solution.
Eventually I will have a sophisticated caching mechanism for my app in which the table view checks the local machine for the images before going out and getting them form the server and maybe has a progress indicator until the images are retrieved. Right now even local image population can be sluggish if the image's are large enough using a synchronous process.
Any and all help would be very much appreciated.
Solution Update
In case anyone else needs a similar solution thanks to Ben's help here is what I came up with (generically modified for posting of course). Bear in mind that I have also implemented a custom caching of images and have made my image loading class generic enough to be used by various places in my app for calling images.
In my calling method, which in my case was a custom cell within a table...
ImageLoaderClass * myLoader = [[[ImageLoaderClass alloc] init] autorelease];
[myLoader fetchImageWithURL:#"/my/thumbnail/path/with/filename.png"
forMethod:#"myUniqueRef"
withId:1234
saveToCache:YES
cachePath:#"/path/to/my/custom/cache"];
This creates an instance of myLoader class and passes it 4 parameters. The URL of the image I want to get, a unique reference that I use to determine which class made the call when setting up the notification observers, the ID of the image, whether I want to save the image to cache or not and the path to the cache.
My ImageLoaderClass defines the method called above where I set what is passed from the calling cell:
-(void)fetchImageWithURL:(NSString *)imageURL
forMethod:(NSString *)methodPassed
withId:(int)imageIdPassed
saveToCache:(BOOL)shouldISaveThis
cachePath:(NSString *)cachePathToUse
{
NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:imageURL]
cachePolicy:NSURLRequestUseProtocolCachePolicy
timeoutInterval:60.0];
// Create the connection with the request and start loading the data
NSURLConnection *theConnection=[[NSURLConnection alloc] initWithRequest:theRequest delegate:self];
if (theConnection) {
// Create the NSMutableData that will hold
// the received data
// receivedData is declared as a method instance elsewhere
receivedData = [[NSMutableData data] retain];
// Now set the variables from the calling class
[self setCallingMethod:methodPassed];
[self setImageId:imageIdPassed];
[self setSaveImage:shouldISaveThis];
[self setImageCachePath:cachePathToUse];
} else {
// Do something to tell the user the image could not be downloaded
}
}
In the connectionDidFinishLoading method I saved the file to cache if needed and made a notification call to any listening observers:
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
NSLog(#"Succeeded! Received %d bytes of data",[receivedData length]);
// Create an image representation to use if not saving to cache
// And create a dictionary to send with the notification
NSImage * mImage = [[NSImage alloc ] initWithData:receivedData];
NSMutableDictionary * mDict = [[NSMutableDictionary alloc] init];
// Add the ID into the dictionary so we can reference it if needed
[mDict setObject:[NSNumber numberWithInteger:imageId] forKey:#"imageId"];
if (saveImage)
{
// We just need to add the image to the dictionary and return it
// because we aren't saving it to the custom cache
// Put the mutable data into NSData so we can write it out
NSData * dataToSave = [[NSData alloc] initWithData:receivedData];
if (![dataToSave writeToFile:imageCachePath atomically:NO])
NSLog(#"An error occured writing out the file");
}
else
{
// Save the image to the custom cache
[mDict setObject:mImage forKey:#"image"];
}
// Now send the notification with the dictionary
NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc postNotificationName:callingMethod object:self userInfo:mDict];
// And do some memory management cleanup
[mImage release];
[mDict release];
[connection release];
[receivedData release];
}
Finally in the table controller set up an observer to listen for the notification and send it off to the method to handle re-displaying the custom cell:
-(id)init
{
[super init];
NSNotificationCenter *nc = [NSNotificationCenter defaultCenter];
[nc addObserver:self selector:#selector(updateCellData:) name:#"myUniqueRef" object:nil];
return self;
}
Problem solved!
My solution is to use Grand Central Dispatch (GCD) for this purpose, you could save the image to disc too in the line after you got it from the server.
- (NSView *)tableView:(NSTableView *)_tableView viewForTableColumn:(NSTableColumn *)tableColumn row:(NSInteger)row
{
SomeItem *item = [self.items objectAtIndex:row];
NSTableCellView *cell = [_tableView makeViewWithIdentifier:tableColumn.identifier owner:self];
if (item.artworkUrl)
{
cell.imageView.image = nil;
dispatch_async(dispatch_queue_create("getAsynchronIconsGDQueue", NULL),
^{
NSURL *url = [NSURL URLWithString:item.artworkUrl];
NSImage *image = [[NSImage alloc] initWithContentsOfURL:url];
cell.imageView.image = image;
});
}
else
{
cell.imageView.image = nil;
}
return cell;
}
(I am using Automatic Reference Counting (ARC) therefore there are no retain and release.)
Your intuition is correct; you want to have a callback from the object which is the NSURLConnection’s delegate to the controller which manages the table view, which would update your data source and then call -setNeedsDisplayInRect: with the rect of the row to which the image corresponds.
Have you tried using the initWithContentsOfURL: method?
Is there a general template or tutorial or web page that describes the procedure for creating a UIPickerview which selects short sound files and plays them upon selection or with a player? Thanks
You'll need a delegate/data-source class for your picker view - something that implements the protocols UIPickerViewDelegate and UIPickerViewDataSource. This can be whatever view controller you've got handling everything else or a separate class - either way, set the UIPickerView's delegate and dataSource properties to your instance of that class.
The class should have three instance variables - an NSArray soundArr to contain the sounds, an NSTimer timer to provide a delay after selection before the sound plays (more on that below), and an AVAudioPlayer audioPlayer to play the selected sound (for which you'll need to import the AVFoundation framework - it's only available in 2.2, as sound playback used to be a lot more complicated).
When you first load the sounds (in your controller class's -init method or whatever), stick 'em in an array along with the title you want them to display, something like this:
NSBundle *bdl = [NSBundle mainBundle];
soundArr = [[NSArray alloc] initWithObjects:[NSDictionary dictionaryWithObjectsAndKeys:#"Sound One",#"title",[NSURL URLWithString:[bdl pathForResource:#"sound1" ofType:#"wav"]],#"url",nil],
[NSDictionary dictionaryWithObjectsAndKeys:#"Sound Two",#"title",[NSURL URLWithString:[bdl pathForResource:#"sound2" ofType:#"wav"]],#"url",nil],
nil];
The methods you'll need to implement are:
-pickerView:numberOfRowsInComponent: - should return the size of soundArr
-pickerView:titleForRow:forComponent: - should return [[soundArr objectAtIndex:row] objectForKey:#"title"]
-numberOfComponentsInPickerView: - should return 1, since you've only got one column (component) to select from
-pickerView:didSelectRow:inComponent: - see below
You don't want the sound to start immediately when the row-selection delegate method gets called, or snippets of sounds will play continuously as the user scrolls the picker. Instead, use a timer with a short delay, something like this:
if(timer != nil)
{
[timer invalidate]; // remove any timer from an earlier selection
timer = nil;
}
timer = [NSTimer scheduledTimerWithTimeInterval:0.4 target:self selector:#selector(startSoundAtURL:) userInfo:[[soundArr objectAtIndex:row] objectForKey:#"url"] repeats:NO]; // and create the new one
Then, implement a -startSoundAtURL: method that sets up the AVAudioPlayer to play that sound:
- (void)startSoundAtURL:(NSURL *)url
{
if(audioPlayer != nil)
{
[audioPlayer stop];
[audioPlayer release];
}
NSError *err;
audioPlayer = [[AVAudioPlayer alloc] initWithContentsOfURL:url error:&err];
if(err != nil)
{
NSLog([err description]);
return;
}
[audioPlayer play];
}
That should pretty much do it.