Suppose I have two atomic object methods operation1 and operation2, that register their own undo actions to undoManager. If I make bulk operation3, that calls previous two operations and groups undo callbacks with beginUndoGrouping/endUndoGrouping, when undoing, NSUndoManager doesn't group redo actions. How to make NSUndoManager map undo group to redo group?
Sample code:
- (void)operation3
{
[undoManager beginUndoGrouping];
[self operation1]; // [undoManager setActionName:#"op1"];
[self operation2]; // [undoManager setActionName:#"op2"];
[undoManager endUndoGrouping];
[undoManager setActionName:#"op3"];
// call operation3 -> "Edit - Undo op3" -- OK
// press Command+Z -> "Edit - Redo op1" -- not OK
}
You must set the action name again during the undo. I think you set only "op1" during the undo.
Related
I would like to use the item that has been just been saved in the completion block of Magical Record saveWithBlock method. For example:
//Get the ID of an existing NSManagedObject to use in the save block (if it exists)
NSManagedObjectID *objectRef = [self.object objectID];
[MagicalRecord saveWithBlock:^(NSManagedObjectContext *localContext){
//This method either loads an existing object and makes changes or creates a new entity in localContext
NSManagedObject *itemToSave = [self prepareItemInContext:localContext WithID: objectRef];
} completion:^(BOOL success, NSError *error) {
if (success) {
//here I want to get at the object 'itemToSave' that was either created in the save block (with a new objectID) or updated (with the ID objectRef)
Well, you need to have a reference to your external context to load the object with that ID:
NSManagedObjectContext *outsideContext = //...
NSManagedObjectID *objectID = //...
[MagicalRecord saveWithBlock:^(NSManagedObjectContext *localContext) {
} completion:^(BOOL success, NSError *error) {
NSManagedObject *newlySavedObject = [outsideContext existingObjectWithID:objectID];
//...do stuff here
}];
Generally, however, I would discourage this usage. I would instead recommend keeping any predicates or means of reloading your data set handy, and dump and refetch fresh data from the store. This will give you proper object references. Another, more precise way of updating objects in other contexts is to listen to the NSManagedObjectContextDidSaveNotification and merge this updates into your context. From there, your data will be "refreshed" and as long as you're KVO'ing a property, or using a NSFetchedResultsController with a delegate, your updates will propagate to the UI (or other destination).
Either just use self.object or, if you create a new object and insert it (presumably because objectRef is nil) then you should get the corresponding new object from the main thread context and use that.
How you do that shuffle is the interesting part. It isn't exactly clear why you're using a background context at the moment so you can also consider changing that, which removes all of the complexity.
If you need to keep the background context then you need to decide on how to get that data back to the main thread. Generally, you could use performBlockAndWait: inside your current block to get the new object from the main context and then store it into a property on your class so you can use it in the completion block. This would be setting the self.object property.
I have an entity called Practice and I use a View Controller called SelectorViewController to select one of the practices, selectedPractice. I then return selectedPractice to a view Controller called RegularViewController where I display some of the selectedPractice attributes. All of this works fine. However the app has a number of other View Controllers which can be reached by modal segues from instances of RegularViewController. As a result, if I leave and then come back to RegularViewController, selectedPractice is reset as null. I would also like to save selectedPractice so that it is available at app initialisation if it has previously been set in SelectorViewController. How do I achieve this by making selectedPractice persistent across the app, and available at runtime?
Regards
Thanks to the post above, which was great, I managed to sort it. Here is my code, which may be very clumsy, but it works.
Firstly, as I loaded the fetchedObjects into a PickerView in SelectorView Controller, I set an attribute "isSelectedPractice" to "NO" with the following code:
for (Practice *fetchedPractice in [self.fetchedResultsController fetchedObjects]) {
[fetchedPractice setValue:#"NO" forKey:#"isSelectedPractice"];
[self.managedObjectContext save:nil];
I then identified for the selected Practice:
- (void)pickerView:(UIPickerView *)pickerView didSelectRow:(NSInteger)row inComponent:(NSInteger)component {
Practice *practice = [[self.fetchedResultsController fetchedObjects] objectAtIndex:row];
self.selectedPractice = practice;
NSLog(#"The '%#' practice was selected using the picker", self.selectedPractice.name);
}
as the view Segue'd back to RegularViewController I set the isSelectedPractice attribute for selectedPractice to YES. I kept it this late as I didn't want more than one selection in the PickerView to result in multiple objects with isSelectedPractice YES.
- (void)prepareForSegue:(UIStoryboardSegue *)segue sender:(id)sender
{
if ([segue.identifier isEqualToString:#"SavedPractice Segue"])
{
[self.selectedPractice setValue:#"YES" forKey:#"isSelectedPractice"];
[self.managedObjectContext save:nil];
NSLog(#"Setting SelectedPractice as '%#' in RegularViewController with isSelectedPractice as '%#'",self.selectedPractice.name,self.selectedPractice.isSelectedPractice );
RegularViewController *rvc= segue.destinationViewController;
rvc.delegate = self;
rvc.selectedPractice = self.selectedPractice;
}
else {
NSLog(#"Unidentified Segue Attempted!");
}
}
I then set the following Predicate in the setupFetchedResultsController method of RegularViewController:
request.predicate = [NSPredicate predicateWithFormat:#"isSelectedPractice = %#", #"YES"];
Many thanks for the help
Without seeing your actual project, one way I know will work but might be a little too round a bout would be to add an attribute "isSelectedPractice" to your entity. You could make it a BOOL, but I've had mixed results with BOOL's in Core Data, I prefer to just leave it as a NSString and set it to "yes" or "no". Then when you pull it down, modify it or add it to core Data as a entity with isSelectedPractice set to "yes". Then in your other controllers, do a
if (self.managedObjectContext == nil) {
self.managedObjectContext = [(AppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext];
}
then do a fetch request to get entities with a predicate which is looking for isSelectedPractice equaling "yes". If you need actual code samples on how to do this let me know and I'll edit them in.
I currently have a map displaying 10 or so co ordinates.The map gets the users location and centers on it as soon as it is opened. When panning the page or zooming different levels it eventually resets and centers in on the first position of the user.I have tried "stopupdating location" and Animated as "NO".I can not get it to stay in positon when the user scrolls the map.
- (void)viewDidLoad {
[super viewDidLoad];
self.petrolMap.delegate = self;
self.location = [[CLLocationManager alloc] init];
[location setDelegate:self];
[location setDistanceFilter:0]; // Do not apply a distance filter to the map
[location setDesiredAccuracy:kCLLocationAccuracyBest]; // Use the best accuracy possible when displaying the map
petrolMap.delegate=self; // Display on "Petrol Map" , the mapview for the application}
-(void) mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation{MKCoordinateRegion mapRegion;
mapRegion.center = petrolMap.userLocation.coordinate;
mapRegion.span.latitudeDelta=0.02;
mapRegion.span.longitudeDelta=0.02;
[petrolMap setRegion:mapRegion animated:NO];}
Your 'location' is a location manager, when it works out where you are it'll send its delegate
locationManager:didUpdateToLocation:fromLocation:
which you don't seem to have, so all those settings you're doing to 'location' are wasted (as far as the code you've given us, it may be useful elsewhere) and telling it to stop tracking the user is of no use.
"(void) mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation{MKCoordinateRegion mapRegion;" is what petrolMap is sending to its delegate. Somewhere you must have set petrolMap to track the user, it can be done in the .xib.
Anyway, to stop petrolMap sending messages make sure you run
[petrolMap setUserTrackingMode:MKUserTrackingModeNone animated:NO];
Some extra notes:
Within didUpdateUserLocation you don't need to refer to petrolMap directly because the mapView parameter is set to which ever MKMapView sent the message.
Also within didUpdateUserLocation you are using petrolMap's userLocation instead of the parameter userLocation, and even building your region. The entire code for that function could be one line
[mapView setRegion:mapRegion animated:NO];
'Animated' controls how the change in region is done. Yes means it will slide between locations, No means it will snap from one to the other instantly, either way the map will move to the new region.
Your viewDidLoad method could be cut to two lines like follows
[super viewDidLoad];
self.petrolMap.delegate = self;
Addendum:
locationManager:didUpdateToLocation:fromLocation
is deprecated in iOS6.
Unfortunately this is a few years to late for you James - but hopefully it'll help others who are stuck in this situation (like myself).
I ended up adding...
[self.mapView setUserTrackingMode:MKUserTrackingModeFollow];
Into my -(void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation
You should normally add "animated:YES" at the end, but this again would ping it back to my current location, even if I changed the commander to "NO" - so tried deleting it and it worked!!!
Just for reference my whole code became:
-(void)mapView:(MKMapView *)mapView didUpdateUserLocation:(MKUserLocation *)userLocation{
if(userLocationShown) return;
MKCoordinateRegion region;
MapView.showsUserLocation = YES;
region.center.latitude = MapView.userLocation.coordinate.latitude;
region.center.longitude = MapView.userLocation.coordinate.longitude;
region.span = MKCoordinateSpanMake(0.02,0.02);
[MapView setRegion:region animated:YES];
[self.mapView setUserTrackingMode:MKUserTrackingModeFollow];
[locationManager startUpdatingLocation];
[locationManager stopUpdatingLocation];
userLocationShown = YES;
and I added...
- (void)viewDidLoad {
[super viewDidLoad];
[locationManager setDistanceFilter:kCLDistanceFilterNone];
[locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
MapView.delegate = self;
I have a page that checks if there is a list of employees on the bundle, and if there is it displays them in a table view. But if there is no list on the bundle it throws up a modal view controller. That then requires someone to login, the login is authenticated and then data is downloaded.
The ModalView is setup to be a delegate of the first page. I can call the delegate method just fine and pass the list, but when the ModalView is dismissed the table does not reload the tableview with the data. If i run the project again it loads the list up in the table view instantly.
Here is the method on the ViewDidLoad of the first page
[self checkLastLoginDate];
[self loadDataIntoArray];
if (currentData && dataLoadedIntoArray) {
NSLog(#"sweet the data is current");
[self createIndexedArray];
}
else{
NSLog(#"Data not loaded and not current");
//push login view
///if ipad do this
if (UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPad)
{
//the above code was working fine. I am just testing pushing a dynamic xib
LoginViewControlleriPad *loginControlleriPad = [[LoginViewControlleriPad alloc] initWithNibName:#"LoginViewControlleripad" bundle:nil];
loginControlleriPad.modalPresentationStyle = UIModalPresentationFormSheet;
loginControlleriPad.delegate = self;
[self presentModalViewController:loginControlleriPad animated:YES];
[self createIndexedArray];
[loginControlleriPad dismissModalViewControllerAnimated:NO];
[self.tableView reloadData];
}
The first two methods check to make sure the data exists on the bundle and that the last login date is within 15 days.
if it is then I create an IndexedArray and it displays nicely.
If the data is not on the bundle or the date is to old I check the device and use a modal view. The delegates are set and the ModalView Appears.
In the ModalView I use a syncronus and asyncronus request to hit a server for the required information. Then I create the list and pass it back to the first page.
Once the connection is made and we do a little work on the list we save it to the bundle.
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *path = [documentsDirectory stringByAppendingPathComponent:kEMPLOYEE_PLIST];
/////write to file/////
[cleanResults writeToFile:path atomically:YES];
employeeList = [[NSMutableArray alloc ]initWithContentsOfFile:path];
if (employeeList != nil)
{
[delegate passUserInfo:employeeList];
//cant get login view to dismiss
//[self dismissModalViewControllerAnimated:YES];
}
Once I get the list I right it to file and then read it back in. If there is info in the list I call the delegate method.
UPDATE
Here is the delgate method
- (void)passUserInfo: (NSMutableArray *)employeeDataArray
{
employeeData = [[NSMutableArray alloc] initWithArray:employeeDataArray];
[self.tableView reloadData];
/////FIX////////
[createIndexedArray];
}
Once that is called nothing happens. I tried dismissing the modal view, which works, but then the first page does not refresh and my app gets lost in the oblivion. I am just confused at were it is going and how i can refresh the tableview on the first page.
Is there a step I are missing? I have tried tracking it and lose it after this step.
I actually figured out that my code was setup right, i just needed to call a method that sorted the array into an alphabetic array. Once i called that method from the delegate method it worked like a snake charm.
UPDATE
I had a method that created an indexed array. When i called that inside the delegate method it reloaded the page and inserted the new into the table view. I am pretty sure it was reloading the whole time, i was just not calling the method that was populating the array that was being being displayed in the tableview.
I have a UIButton in my application and an action which is triggered when I TouchDown UIButton.
Is it possible to detect a Touch-and-Hold on the UIButton on the iPhone? I want my action to trigger when the user holds the button for 2 seconds or more.
Any Ideas?
UILongPressGestureRecognizer is what you need. For example,
UILongPressGestureRecognizer *longPress_gr = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(doAction:)];
[longPress_gr setMinimumPressDuration:2]; // triggers the action after 2 seconds of press
[yourButton addGestureRecognizer:longPress_gr];
To let your action get triggered only once(ie., when the 2 seconds duration is over), make sure you have your doAction: method looks something like this,
- (void)doAction:(UILongPressGestureRecognizer *)recognizer {
if (recognizer.state == UIGestureRecognizerStateBegan) {
// Your code here
}
}
On the other way you can use this NBTouchAndHoldButton. This is exactly what you want, and it is very easy to implement it:
TouchAndHoldButton * pageDownButton = [TouchAndHoldButton buttonWithType:UIButtonTypeCustom];
[pageDownButton addTarget:self action:#selector(pageDownAction:) forTouchAndHoldControlEventWithTimeInterval:0.2];
Good luck!