I am VERY new to xcode but what i am trying to accomplish is when you open the app it shows a map and my location and the current food places that are around me. I dont have my own database for the locations i am trying to use google for this function. what i was able to do is find a tutorial but it has a search bar and when i search for something it shows me but i want it to automatically show me and not have the function of searching.
Is this possible? any help/tutorial is greatly appreciated. Thank you
You can try to use Place search api.
http://code.google.com/apis/maps/documentation/places/#PlaceSearches
They support a "restaurant" and "food" type.
http://code.google.com/apis/maps/documentation/places/supported_types.html
So you can remove the search bar and instead send a request to google places api with current location and types="restaurant" or types="restaurant|food".
You can get the results as JSON data wich you can easily use in your app.
Next step would be to make annotations and add them to a map.
__
Here are details on the first parts.
Once you get this working you can move on to getting an API-key for google places, get current position and then start adding json results to a map using map annotations. :)
The async url connection is the biggest part here. So once you get this working, you are well on your way to finding nearby locations.
To setup the JSON part..
Download a json library.. https://github.com/johnezang/JSONKit
Add JSONKit.h and JSONKit.m to your project. (add files.. or drag them over)
Add #import "JSONKit.h" (in your .m file)
Look in the final method below to see how to setup the variables and get data from json.
For the url connection part...
Based on: http://developer.apple.com/library/mac/#documentation/Cocoa/Conceptual/URLLoadingSystem/Tasks/UsingNSURLConnection.html
PS: You would make a change later to use google places json api-url, api-key, current location and the "restaurant" type (to get the needed response in json from google).
Create a request:
- (void)viewDidLoad
{
// Create the request.
NSURLRequest *theRequest=[NSURLRequest requestWithURL:[NSURL URLWithString:#"http://www.google.com/calendar/feeds/developer-calendar#google.com/public/full?alt=json"]
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 to hold the received data.
receivedData = [[NSMutableData data] retain];
} else {
// Inform the user that the connection failed.
}
}
Then you need to implement the delegate methods.. (copy this into .m file)
This one is invoked when you get response (not the actual data, hence they reset it).
- (void)connection:(NSURLConnection *)connection didReceiveResponse:(NSURLResponse *)response
{
// This method is called when the server has determined that it
// has enough information to create the NSURLResponse.
// It can be called multiple times, for example in the case of a
// redirect, so each time we reset the data.
[receivedData setLength:0];
}
This one is invoked when data is received - can happen several times, so they append data each time.
- (void)connection:(NSURLConnection *)connection didReceiveData:(NSData *)data
{
// Append the new data to receivedData.
[receivedData appendData:data];
}
Sometimes the connection would fail, then this delegate method is invoked - and you can present a message to the user (apple says to always inform users of what is happening)..
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
{
// release the connection, and the data object
[connection release];
[receivedData release];
// inform the user
NSLog(#"Connection failed! Error - %# %#",
[error localizedDescription],
[[error userInfo] objectForKey:NSURLErrorFailingURLStringErrorKey]);
}
Finally, this method is invoked when the connection finished successfully. Now you have your complete data, and you save it to a variable. Here we also place the data into jsonDict.
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
// do something with the data ...
// Your data is now stored in "receivedData",
// set up this mutable variable in the header file, then synthesize.
// in the .h file, inside the #interface block.:
//
// NSMutableData *receivedData;
// NSDictionary *jsonDict;
// }
//
// #protocol (nonatomic, retain) NSMutableData *receivedData;
// #protocol (nonatomic, retain) NSDictionary *jsonDict;
// And in the .m file, under the #implementation line.
// #synthesize receivedData, jsonDict;
// Log to test your connection
NSLog(#"Succeeded! Received %d bytes of data",[receivedData length]);
// Place the received data into a json dictionary
jsonDict = [receivedData objectFromJSONData];
// Get sections from your data
NSString *feed = [jsonDict objectForKey:#"feed"]; // asumes there is only one title in your json data, otherwise you would use an array (with dictionary items) ..look in your feed to find what to use.
// Log your data
NSLog(#"My feed: %#", feed);
// release the connection, and the data object
[connection release];
[receivedData release];
}
Try to get this going, then we can get back to using places search and adding results to a map.
Refer the following link
http://www.raywenderlich.com/13160/using-the-google-places-api-with-mapkit
The link shows the from the scratch development of map API project
Related
in getting familiar with core data i have found myself puzzled by the question of what to pass various view controllers (VCs) when trying to add data.
for example, in the CoreDataRecipes project that apple provides as an example (http://developer.apple.com/library/ios/#samplecode/iPhoneCoreDataRecipes/Introduction/Intro.html) they use the following approach
when the user wants to add a recipe to the list of recipes presented in the master table view, and hits the Add button, the master table view controller (called RecipeListTableViewController) creates a new managed object (Recipe) as follows:
- (void)add:(id)sender {
// To add a new recipe, create a RecipeAddViewController. Present it as a modal view so that the user's focus is on the task of adding the recipe; wrap the controller in a navigation controller to provide a navigation bar for the Done and Save buttons (added by the RecipeAddViewController in its viewDidLoad method).
RecipeAddViewController *addController = [[RecipeAddViewController alloc] initWithNibName:#"RecipeAddView" bundle:nil];
addController.delegate = self;
Recipe *newRecipe = [NSEntityDescription insertNewObjectForEntityForName:#"Recipe" inManagedObjectContext:self.managedObjectContext];
addController.recipe = newRecipe;
UINavigationController *navigationController = [[UINavigationController alloc] initWithRootViewController:addController];
[self presentModalViewController:navigationController animated:YES];
[navigationController release];
[addController release];
}
this newly created object (a Recipe) is passed to the RecipeAddViewController. the RecipeAddViewController has two methods, save and cancel, as follows:
- (void)save {
recipe.name = nameTextField.text;
NSError *error = nil;
if (![recipe.managedObjectContext save:&error]) {
/*
Replace this implementation with code to handle the error appropriately.
abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button.
*/
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
[self.delegate recipeAddViewController:self didAddRecipe:recipe];
}
- (void)cancel {
[recipe.managedObjectContext deleteObject:recipe];
NSError *error = nil;
if (![recipe.managedObjectContext save:&error]) {
/*
Replace this implementation with code to handle the error appropriately.
abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. If it is not possible to recover from the error, display an alert panel that instructs the user to quit the application by pressing the Home button.
*/
NSLog(#"Unresolved error %#, %#", error, [error userInfo]);
abort();
}
[self.delegate recipeAddViewController:self didAddRecipe:nil];
}
i am puzzled about this design approach. why should the RecipeListViewController create the object before we know if the user wants to actually enter a new recipe name and save the new object? why not pass the managedObjectContext to the addRecipeController, and wait until the user hits save to create the object and populate its fields with data? this avoids having to delete the new object if there is no new recipe to add after all. or why not just pass a recipe name (a string) back and forth between the RecipeListViewController and the RecipeAddController?
i'm asking because i am struggling to understand when to pass strings between segues, when to pass objects, and when to pass managedObjectContexts...
any guidance much appreciated, incl. any links to a discussion of the design philosophies at issue.
Your problem is that NSManagedObjects can't live without a context. So if you don't add a Recipe to a context you have to save all attributes of that recipe in "regular" instance variables. And when the user taps save you create a Recipe out of these instance variables.
This is not a huge problem for an AddViewController, but what viewController do you want to use to edit a recipe? You can probably reuse your AddViewController. But if you save all data as instance variables it gets a bit ugly because first you have to get all data from the Recipe, save it to instance variables, and when you are done you have to do the reverse.
That's why I usually use a different approach. I use an editing context for editing (or adding, which is basically just editing).
- (void)presentRecipeEditorForRecipe:(MBRecipe *)recipe {
NSManagedObjectContext *editingContext = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
editingContext.parentContext = self.managedObjectContext;
MBRecipe *recipeForEditing;
if (recipe) {
// get same recipe inside of the editing context.
recipeForEditing = (MBRecipe *)[editingContext objectWithID:[recipe objectID]];
NSParameterAssert(recipeForEditing);
}
else {
// no recipe for editing. create new one
recipeForEditing = [MBRecipe insertInManagedObjectContext:editingContext];
}
// present editing view controller and set recipeForEditing and delegate
}
Pretty straight forward code. It creates a new children context which is used for editing. And gets a recipe for editing from that context.
You must not save the context in your EditViewController! Just set all desired attributes of Recipe, but leave the context alone.
After the user tapped "Cancel" or "Done" this delegate method is called. Which either saves the editingContext and our context or does nothing.
- (void)recipeEditViewController:(MBRecipeEditViewController *)editViewController didFinishWithSave:(BOOL)didSave {
NSManagedObjectContext *editingContext = editViewController.managedObjectContext;
if (didSave) {
NSError *error;
// save editingContext. this will put the changes into self.managedObjectContext
if (![editingContext save:&error]) {
NSLog(#"Couldn't save editing context %#", error);
abort();
}
// save again to save changes to disk
if (![self.managedObjectContext save:&error]) {
NSLog(#"Couldn't save parent context %#", error);
abort();
}
}
else {
// do nothing. the changes will disappear when the editingContext gets deallocated
}
[self dismissViewControllerAnimated:YES completion:nil];
// reload your UI in `viewWillAppear:`
}
I'm curious to know what the best way is to create a new NSManagedObject in RestKit 0.20? Currently my code looks something like this:
#pragma mark - navigation buttons
- (void)createButtonDidTouch
{
// create new album object
NSManagedObjectContext *context = [[NSManagedObjectContext alloc] initWithConcurrencyType:NSMainQueueConcurrencyType];
NSManagedObjectContext *parentContext = RKObjectManager.sharedManager.managedObjectStore.mainQueueManagedObjectContext;
context.parentContext = parentContext;
NSEntityDescription *entityDescription = [NSEntityDescription entityForName:#"Album" inManagedObjectContext:parentContext];
Album *newAlbum = [[Album alloc] initWithEntity:entityDescription insertIntoManagedObjectContext:context];
// pass object to create view to manipulate
AlbumCreateViewController *createViewController = [[AlbumCreateViewController alloc] initWithData:newAlbum];
createViewController.delegate = self;
createViewController.managedObjectContext = context;
UINavigationController *navController = [[UINavigationController alloc] initWithRootViewController:createViewController];
navController.modalTransitionStyle = UIModalTransitionStyleCoverVertical;
[self presentViewController:navController animated:YES completion:nil];
}
#pragma mark - create view controller delegate
- (void)createViewControllerDidSave:(NSManagedObject *)data
{
// dismiss the create view controller and POST
// FIXME: add restkit code to save the object
NSLog(#"save the object...");
NSDictionary *userInfo = [KeychainUtility load:#"userInfo"];
NSString *path = [NSString stringWithFormat:#"/albums/add/%#/%#", userInfo[#"userID"], userInfo[#"apiKey"]];
[RKObjectManager.sharedManager postObject:data path:path parameters:nil success:^(RKObjectRequestOperation *operation, RKMappingResult *mappingResult) {
operation.targetObject = data;
} failure:^(RKObjectRequestOperation *operation, NSError *error) {
NSLog(#"create album error: %#", error);
}];
[self dismissViewControllerAnimated:YES completion:nil];
}
- (void)createViewControllerDidCancel:(NSManagedObject *)data
{
// dismiss the create view controller
NSLog(#"delete the object...");
// FIXME: add restkit code to delete the object
[self dismissViewControllerAnimated:YES completion:nil];
}
I'm also curious to know what my responsibilities are for saving / deleting this object. If I POST to the server via RestKit is the managed object context saved?
What if I decide to cancel this creation process — what's the preferred way to delete this object?
Basically how much is RestKit doing for me, and what should I make sure I'm doing. I haven't found much documentation on this and would like to be clear on it.
When you initialize an RKManagedObjectRequestOperation for a given object, RestKit will obtain a permanent object ID for that object and then create a child managed object context whose parent context is the context the object is inserted into. The operation then executes the HTTP request to completion and obtains a response.
If the response is successful and the mapping of the response is successful (note that the mapping occurs within this private child context), then the private child context is saved. The type of save invoked is determined by the value of the savesToPersistentStore property (see http://restkit.org/api/0.20.0/Classes/RKManagedObjectRequestOperation.html#//api/name/savesToPersistentStore).
When YES, the context is saved recursively all the way back to the persistent store via the NSManagedObjectContext category method saveToPersistentStore (see http://restkit.org/api/0.20.0/Categories/NSManagedObjectContext+RKAdditions.html).
When NO, the context is saved via a vanilla [NSManagedObjectContext save:] message, which 'pushes' the changes back to the parent context. They will remain local to that context until you save them back. Keep in mind that managed object context parent/child hierarchies can be as long as you create within the application.
If the HTTP request failed or there was an error during the mapping process, the private context is not saved and the operation is considered failed. This means that no changes are saved back to the original MOC, leaving your object graph just as it was before the operation was started (except the object being sent, if temporary, now has a permanent object ID but is still unsaved).
The way you do it should works (calling each time the MOC in each of your VC), but is not "recommended".
What Apple suggests, just like any Core Data app, is the "pass the baton" style.
Nested contexts make it more important than ever that you adopt the
“pass the baton” approach of accessing a context (by passing a context
from one view controller to the next) rather than retrieving it
directly from the application delegate.
See here:
http://developer.apple.com/library/ios/#releasenotes/DataManagement/RN-CoreData/_index.html
As for your second question, RestKit should manage saving/updating your Core Data stack upon success of your api calls if everything is well mapped/setup.
From blake the RK creator:
if you POST or PUT a Core Data object, RK obtains a permanent object
ID for it and then creates a secondary managed object context, fires
the request, and maps the response (if possible). if the response and
the mapping are successful, it will either save it back to the parent
context or all the way back to the persistent store (i.e. into SQLite)
based on the value of the savesToPersistentStore.
I'm implementing support for Lion's "Resume" feature in my OS X app.
I have a custom subclass of NSViewController in which I implemented the method
encodeRestorableStateWithCoder: as:
#implementation MyClass (Restoration)
-(void)encodeRestorableStateWithCoder:(NSCoder*)coder {
[coder encodeObject:_dataMember forKey:#"object_key"]; // I get the warning below when this line is executed for the second time
}
- (void)restoreStateWithCoder:(NSCoder *)coder {
_dataMember = [coder decodeObjectForKey:#"object_key"];
}
#end
However, since I have multiple instances of MyClass, different values are saved into the same key ("object_key") and I get the following warning from Cocoa:
NSKeyedArchiver warning: replacing existing value for key
'object_key'; probable duplication of encoding keys in class hierarchy
What is the best practice to overcome this problem?
Edit: I found here that each instance automatically has its own namespace to avoid collisions, so the problem might be in the way I'm manually calling encodeRestorableStateWithCoder to different instances with the same NSCoder object without telling it that these are different instances. However, I still can't figure out how to do that properly.
Thanks in advance!
To overcome this problem, it is possible to create a new NSMutableData where each of which is written by a separate (new) NSKeyArchiver, and store them all in an array which is stored in the original NSCoder object.
Here is an example for encoding the restorable state of subitems. The decoding part can be straight-forward given this code.
- (void)encodeRestorableStateWithCoder:(NSCoder *)coder
{
[super encodeRestorableStateWithCoder:coder];
// Encode subitems states:
NSArray* subitems = self.items;
NSMutableArray* states = [NSMutableArray arrayWithCapacity: subitems.count];
for (SubItemClass* item in subitems)
{
NSMutableData* state = [NSMutableData data];
NSKeyedArchiver *archiver = [[NSKeyedArchiver alloc] initForWritingWithMutableData:state];
[item encodeRestorableStateWithCoder:archiver];
[archiver finishEncoding];
[states addObject:state];
}
[coder encodeObject:states forKey:#"subitems"];
}
I'm VERY new to Objective C and iOS development (like 5 hours new :-). I've got some code that calls an API to authenticate a user and returns a simple OK or FAIL. I can get the result to write to the console but what I need to do is get that result as part of my IBAction.
Here's the IBAction code:
- (IBAction) authenticateUser
{
[txtEmail resignFirstResponder];
[txtPassword resignFirstResponder];
[self performAuthentication];
if (authResult == #"OK")
What I need is for authResult to be the JSON result (OK or FAIL). Here is the code that gets the result:
- (void)connectionDidFinishLoading:(NSURLConnection *)connection
{
[connection release];
NSString *responseString = [[NSString alloc] initWithData:responseData encoding:NSUTF8StringEncoding];
NSLog(#"%#", responseString);
[responseData release];
NSMutableDictionary *jsonResult = [responseString JSONValue];
if (jsonResult != nil)
{
NSString *jsonResponse = [jsonResult objectForKey:#"Result"];
NSLog(#"%#", jsonResponse);
}
}
Thank you so much for any help and sorry if I'm missing something obvious!
I'm a little confused as to what's going on here... it looks like your -performAuthentication method must start an asynchronous network request via NSURLConnection, and your connection's delegate's -connectionDidFinishLoading: gets to determine the result of the request. So good so far? But your -authenticateUser method expects authResult to be determined as soon as -performAuthentication returns. If the network request is asynchronous, that's not going to happen. If I'm following you, I think you need to do the following:
Fix up -connectionDidFinishLoading: so that it actually sets authResult based on the Result value in jsonResponse. I'm sure you'd get around to this at some point anyway.
Change -authenticateUser such that it doesn't expect to have an answer immediately. You've got to give the network request a chance to do its thing.
Add another method, possibly called -authenticationDidFinish or something along those lines. Everything currently in -authenticateUser from the 'if (authResult...' to the end goes in this new method.
Call the new method from -connectionDidFinishLoading:.
Fix your string comparison. If you want to compare two strings in Cocoa, you say (for example):
if ([authResult isEqualToString:#"OK") { }
Can someone help me. I have a coredata application but I need to save the objects from a fetchedResultsController into an NSDictionary to be used for sending UILocalNotifications.
Should I use an NSMutableSet, or a NSDictionary, or an array. I'm not used to using collections and I can't figure out the best way to do that.
Could you please give me clues on how to do that please ?
Thanks,
Mike
If I'm reading your question correctly, you're asking how you should pack objects into the userInfo dictionary of a UILocalNotification. Really, it's however works best for you; userInfo dictionaries are created by you and only consumed by you.
I'm not sure why you would be using an NSFetchedResultsController - that class is for managing the marshaling of managed objects between UI classes (like UITableView) efficiently, whereas here it sounds like you would be better off just getting an NSArray of results from your managedObjectContext and the corresponding request, like this:
NSError *error = nil;
NSArray *fetchedObjects = [myManagedObjectContext executeFetchRequest: myRequest error: &error];
if (array == nil)
{
// Deal with error...
}
where you have a pre-existing managed object context and request. You don't need to use an NSFetchedResultsController here.
From there, the simplest suggestion would be to build your userInfo dictionary like this:
NSDictionary* myUserInfo = [NSDictionary dictionaryWithObject: fetchedObjects forKey: #"AnythingYouWant"];
UILocalNotification *localNotif = [[UILocalNotification alloc] init];
// ... do other setup tasks ...
localNotif.userInfo = myUserInfo;
[[UIApplication sharedApplication] scheduleLocalNotification:localNotif];
[localNotif release];
Then when it comes time to receive that notification, you can read that dictionary like this:
- (void)application:(UIApplication *)app didReceiveLocalNotification:(UILocalNotification *)notif
{
NSArray* myFetchedObjects = [notif.userInfo objectForKey: #"AnythingYouWant"];
for(id object in myFetchedObjects)
{
// ... do other stuff ...
}
}
Now, hopefully that's clarified how the userInfo dictionary works. I don't know the details of your app, so it's hard to say, but I'm suspicious that actually passing fetched objects is NOT what you want to do here, mainly because I'm not sure that you have any guarantee that the receiving delegate method will be working with the same object context as the sending method. I would suggest perhaps putting the entity name and predicate in the dictionary and then refetching the objects at receive time with whatever the current MOC is at that moment.
Good luck!