Sight Words: Select Suggested Items

The Select Suggested words dialog is a very handy one.  It has some nice features.

• There is a search bar that allows you to enter text.  Every time a character is entered, a fetchcontroller is updated with a new search criteria.
• When an item is selected, it will fully populate the search bar.
• When the add button is selected, it will create a GUI image of the search bar and animate it going towards the add button.
• It is fairly generic.  It takes as parameters the table, and search key allowing it to hit any single table query for selecting/searching items.  When an item is selected a delegate is called with the selection data.
• When the keyboard is displayed the list shrinks so that it doesn't go behind the keyboard.

It has a few flaws as well

• These nice features are embedded in a special purpose class.
• The add button is a standard button next to the search bar.  This doesn't look as nice as the standard (and easier) adding a button the navigation controller.
• The .xib file is a problem when using this library.  I had it go out of date, and had to manually copy changes to the main project.  There probably is a better way to send xib files to a main project, but I haven't figured it out yet.

The original source and .xib file can be found at:

Original XIB file

The original source file

Some Choice tidbits:
Shrinking the view


In viewDidLoad place the following code:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardAppearing:) name:UIKeyboardWillShowNotification object:nil];

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(keyboardDisappearing:) name:UIKeyboardWillHideNotification object:nil];

and then add the following two methods.   Note that suggestions is the outlet for the list being displayed.

- (void)keyboardDisappearing:(NSNotification *)notification {

suggestions.frame=originalSize;

}

- (void)keyboardAppearing:(NSNotification *)notification {

NSDictionary *keys=[notification  userInfo];

NSValue *value=[keys objectForKey:UIKeyboardBoundsUserInfoKey];

CGRect bounds;

[value getValue:&bounds];

CGRect myFrame=[suggestions frame];

originalSize=myFrame;

suggestions.frame=CGRectMake(myFrame.origin.x,myFrame.origin.y,myFrame.size.width,

myFrame.size.height-bounds.size.height);

}

Delegating item creation and actions:
By defining a simple protocol and ensuring a delegate exists we can delegate out the selection of an
existing item and also the actual action that takes place upon selection.

@protocol SuggesionActionHandler<NSObject>

- (id)   createNewItem:(NSString *) searchValue;

- (void) doActionForItem:(id) item;

@end

Adding an item

Adding an item: Note that this combines the animation and action into the same area.  It really should be separated out.  I'm not sure I like how I search for the currently existing item.  At the very least it should be broken out into another method.

- (IBAction) addCurrentItem:(id) sender

{

NSManagedObject *matchingItem=nil;  

NSString *currentText=searchBar.text;

UIGraphicsBeginImageContext(searchBar.bounds.size);

[searchBar.layer renderInContext:UIGraphicsGetCurrentContext()];

UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

UIImageView *imageView=[[UIImageView alloc] initWithImage :viewImage];

imageView.frame=searchBar.frame;

[self.view addSubview:imageView];

[UIView beginAnimations:nil context:imageView];

[UIView setAnimationCurve:UIViewAnimationCurveEaseInOut];

[UIView setAnimationDuration:0.25];

[imageView setFrame:addButton.frame];

// Search for the existing item if one.

if (fetchController!=nil)

{

if (fetchController.sections!=nil)

{

for (id<NSFetchedResultsSectionInfo> sectionInfo in fetchController.sections)

{

for (NSManagedObject *object in [sectionInfo objects])

{

NSString *keyForSearch=[object valueForKey:self.searchVariable];

if ([keyForSearch isEqualToString: currentText])

{

matchingItem=object;

break;

}

}

if (matchingItem!=nil)

break;

}

}

}

if (delegate!=nil)

{

if (matchingItem==nil)

{

matchingItem=[delegate createNewItem:currentText];

}

[delegate doActionForItem:matchingItem];

}

else

{

NSLog(@"Delegate is nil, no action can be performed ");

}

[UIView setAnimationDelegate:self];

[UIView setAnimationDidStopSelector:@selector(animationDidStop:finished:context:)];

[UIView commitAnimations];

}


Updating a Fetch controller with a search predicate:
This was slightly tricky, since the examples assumed a hardcoded search variable.  I had to format the string twice so that I could build the format string with the field name prior to doing substitution.

NSFetchRequest *request=[[NSFetchRequest alloc] init];

NSEntityDescription *entity=[NSEntityDescription entityForName:managedTable 

 

  inManagedObjectContext:coreControl.managedObjectContext];

[request setEntity:entity];

[request setFetchBatchSize:20];

NSSortDescriptor *sortDesc=[[NSSortDescriptor alloc] initWithKey:searchVariable ascending:YES];

NSArray *sortDescs=[[NSArray alloc] initWithObjects:sortDesc,nil];

NSString *searchString=[searchText stringByAppendingString:@"*"];

NSString *predicateFormat=[[NSString alloc]  initWithFormat:@"%@ like[cd] %%@",searchVariable];

NSLog(@"Searching table %@ %@ for %@",managedTable,searchVariable,searchString);

NSPredicate *predicate = [NSPredicate

  predicateWithFormat:predicateFormat,

 

  searchString];

    NSLog(@"Pred Desc %@", [predicate description]);

[request setPredicate:predicate];

[request setSortDescriptors:sortDescs];

if (fetchController!=nil)

{

  [fetchController release];

}

self.fetchController=[[NSFetchedResultsController alloc] initWithFetchRequest:request managedObjectContext:coreControl.managedObjectContext sectionNameKeyPath:nil cacheName:managedTable];

self.fetchController.delegate=self;

NSError *error;

[self.fetchController performFetch:&error] ;

// NSLog(@"Unresolved error %@", error);

// NSLog(@"Fetch count %d",fetchController.sections);

[self.suggestions reloadData];

[predicateFormat release];

[request release];

[sortDesc release];

[sortDescs release];