I am using UNIRest to make a call and return a JSON object to my app. I have it returning the proper data as a NSDictionary and it logs our perfect. I am now trying to take that data and display it inside of my view. I cannot use my dictionary outside of the callback.
I have been digging around here on StackOverflow for similar results and posts related to variables. I feel it is a scope issue with it being limited to inside of the callback block.
My header file: (UIViewController)
#property (nonatomic, strong) NSDictionary *tideData;
My implementation:
#interface TideDetailViewController ()
#end
#implementation TideDetailViewController
#synthesize tideData;
- (void)viewDidLoad {
[super viewDidLoad];
// tideData = [[NSDictionary alloc] init];
// location is working, I removed it for testing to call a static string for now
self.locationManager = [[CLLocationManager alloc] init];
self.locationManager.distanceFilter = kCLDistanceFilterNone; // whenever we move
self.locationManager.desiredAccuracy = kCLLocationAccuracyHundredMeters; // 100 m
[self.locationManager startUpdatingLocation];
NSString *locationQueryURL = #"http://api.wunderground.com/api/XXXXXXXXXXXXX/tide/geolookup/q/43.5263,-70.4975.json";
NSLog(#"%#", locationQueryURL);
[[UNIRest get:^(UNISimpleRequest *request) {
[request setUrl: locationQueryURL];
}] asJsonAsync:^(UNIHTTPJsonResponse *response, NSError *error) {
// This is the asyncronous callback block
self.code = [response code];
NSDictionary *responseHeaders = [response headers];
UNIJsonNode *body = [response body];
self.rawResults = [response rawBody];
// I tried this as self as well
tideData = [NSJSONSerialization JSONObjectWithData:self.rawResults options: 0 error: &error];
// this logs perfectly.
NSLog(#"tideData %#", tideData);
// tried setting it to the instance
//self.tideData = tideData;
}];
// returns null
NSLog(#"tideData outside of call back %#", self.tideData);
// this is where I will be setting label text for now, will refactor once I get it working
// rest of file contents........
I have tried a good amount of items related to scoping, clearly just missing the mark. Any ideas? I have searched setting global variables, etc. Been stuck on this for a bit now.
Thanks,
Ryan
The reason you see nil is because you are logging it too soon: when you call
NSLog(#"tideData outside of call back %#", self.tideData);
the get:asJsonAsync: method has not received the results yet.
You can fix this problem by adding a setter for your property, and adding some special handling to it, like this:
-(void)setTideData:(NSDictionary*)dict {
_tideData = dict;
NSLog(#"tideData outside of call back %#", _tideData);
}
This method will be called from the asynchronous code when you do the tideData = ... assignment.
Try setting the object on main thread:
[self performSelectorOnMainThread:#selector(setTideData:) withObject:[NSJSONSerialization JSONObjectWithData:self.rawResults options: 0 error: &error] waitUntilDone:NO];
- (void)setTideData:(NSDictionary*)dict {
self.tideData = dict;
}
Related
looking for little help on accessing readonly property with Kiwi.
In short, I want to test if _myReadOnlyDict gets initialized or not.
Problem is that myReadOnlyDict is still always empty(has no contents), despite that in beforeEach block it is mocked and a value added to it.
// All these return 0
ad.myReadOnlyDict.count;
[[ad myReadOnlyDict] allKeys].count;
[ad myReadOnlyDict].count;
What I am missing here?
Any help is appreciated!
Please see the code below:
In AppDelegate.h I have a porperty.
#property (nonatomic, readonly) NSDictionary * myReadOnlyDict;
In AppDelegate.m I have a method, which is called from AppDelegate's didFinishLaunchingWithOptions method.
- (void)initConfig
{
_myReadOnlyDict = [NSJSONSerialization JSONObjectWithData:[self jsonData] options:nil error:nil];
}
I have a Kiwi test set up
describe(#"App Delegate", ^{
__block AppDelegate *ad;
beforeEach(^{
ad = [[AppDelegate alloc] init];
NSMutableDictionary * mockedDict = [NSJSONSerialization nullMock];
mockedDict[#"my_data"] = #"my_value";
[ad stub:#selector(myReadOnlyDict) andReturn:mockedDict];
});
afterEach(^{
ad = nil;
});
context(#"when smth happens", ^{
it(#"should do smth else", ^{
[[ad should] receive:#selector(initConfig)];
// These three lines fail
[[theValue([ad myReadOnlyDict].count) shouldNot] equal:theValue(0)];
[[theValue(ad.myReadOnlyDict.count) shouldNot] equal:theValue(0)];
[[theValue([[ad myReadOnlyDict] allKeys].count) shouldNot] equal:theValue(0)];
[ad initConfig];
});
});
});
Your problem is caused by the fact that [NSJSONSerialization nullMock]returns a null mock, which is an object that does nothing for any called method, and returns nil/0 to any method that must return something.
This should work:
NSMutableDictionary * mockedDict = [#{#"my_data": #"my_value"} mutableCopy];
[ad stub:#selector(myReadOnlyDict) andReturn:mockedDict];
I am having a lot of trouble wrapping my head around the best way to use blocks. I am trying to retrieve pedometer data, and the method of accessing the data is a block...
[self.pedometer queryPedometerDataFromDate:yesterday
toDate:midnightOfToday
withHandler:^(CMPedometerData *pedometerData, NSError *error) {
dispatch_async(dispatch_get_main_queue(), ^{
if (error) {
NSLog(#"Pedometer is NOT available.");
}
else {
NSLog(#"Steps %#", pedometerData.numberOfSteps);
yesterdaysNumbersLabel.text = [pedometerData.numberOfSteps stringValue];
[pedometerDictionary setValue:[pedometerData.numberOfSteps stringValue] forKey:#"2"];
}
});
}];
Using the above code I am able to get the data, log the data, and update the label on the screen, But I can't figure out how to set the data into an array or dictionary so I can do something else with it.
I understand why the arrays and dictionaries are always null... the blocks are running on a different thread and I am accessing them before the blocks have completed.
Can someone help me get through my head how to do something more with the data.
Update 1:
Right now I have this in .h
#property (strong, atomic) NSMutableDictionary *pedometerDictionary;
and I am synthesizing it in .m and I call this...
[self getNumbersForYesterday];
NSLog(#"Dictionary: %#", pedometerDictionary);
...which runs the above function and immediately tries to log the result. And like I said, I understand all the reasons it is NOT working. I just need to figure out how to change what i am doing to get it working.
Update 2:
This is in .h
#property (strong, atomic) NSMutableDictionary *pedometerDictionary;
and this is in .m
#synthesize pedometerDictionary;
- (id)init {
self = [super init];
if (self != nil) {
self.pedometerDictionary = [[NSMutableDictionary alloc] init];
}
return self;
}
and I am using it like this.
[self getNumbersForYesterday];
NSLog(#"Dictionary: %#", self.pedometerDictionary);
to call this.
- (void)getNumbersForYesterday {
[self.pedometer queryPedometerDataFromDate:yesterday
toDate:midnightOfToday
withHandler:^(CMPedometerData *pedometerData, NSError *error) {
dispatch_async(dispatch_get_main_queue(), ^{
if (error) {
NSLog(#"Pedometer is NOT available.");
}
else {
NSLog(#"Steps %#", pedometerData.numberOfSteps);
yesterdaysNumbersLabel.text = [pedometerData.numberOfSteps stringValue];
[self.pedometerDictionary setValue:[pedometerData.numberOfSteps stringValue] forKey:#"2"];
}
});
}];
}
If I just wanted to keep all the work in the block I would be fine. What I have come to understand is that since blocks are asynchronous, I am trying to NSLog my dictionary, and the block isn't finished running yet. So, my dictionary is still NULL.
Dollars to donuts, your pedometerDictionary was never created in the first place (or it was, but the declaration isn't in a useful spot).
I.e. where is your line of code that says pedometerDictionary = [[NSMutableDictionary alloc] init];? And where is pedometerDictionary declared? How did you try to NSLog() values from it?
Also, use setObject:forKey:.
It is also odd that it is named pedometerDictionary. That is evidence that it is either declared as a global (which it shouldn't be), a local variable of whatever method contains the above code (which won't work), or you are declaring and using an instance variable directly.
The issue you are having is not a block timing issue, your dictionary should never be nil at worst it would contain no values.
You need to create your dictionary before using it. The appropriate place would be init method for most objects. If you are creating your object in Interface Builder then the method should be awakeFromNib.
To do something with the dictionary you can use an NSTimer or call a method from queryPedometerDataFromDate block handler. The use of #synchronized() directive is an example of how to keep access to the dictionary from overlapping at the same time in a threaded environment. This is not the case in this particular example as you are dispatching on the main thread and NSTimer also runs on the main thread. But should you go threaded #synchronized() would keep you from overlapping access.
#interface HelloWorld : NSObject
#property (retain, atomic) NSMutableDictionary *pedometerDictionary;
#property (retain, nonatomic) NSTimer *timer;
#end
#implementation HelloWorld
#synthesize pedometerDictionary, timer;
...
- (id)init {
self = [super init];
if (self != nil) {
self.pedometerDictionary = [NSMutableDictionary dictionary];
self.timer = [NSTimer timerWithTimeInterval:5.0 target:self selector:#selector(doSomethingInterestingWithDictionary:) userInfo:nil repeats:YES];
}
return self;
}
or
- (void)awakeFromNib {
self.pedometerDictionary = [NSMutableDictionary dictionary];
self.timer = [NSTimer timerWithTimeInterval:5.0 target:self selector:#selector(doSomethingInterestingWithDictionary:) userInfo:nil repeats:YES];
}
...
- (void)getNumbersForYesterday {
[self.pedometer queryPedometerDataFromDate:yesterday
toDate:midnightOfToday
withHandler:^(CMPedometerData *pedometerData, NSError *error) {
dispatch_async(dispatch_get_main_queue(), ^{
if (error) {
NSLog(#"Pedometer is NOT available.");
}
else {
NSLog(#"Steps %#", pedometerData.numberOfSteps);
yesterdaysNumbersLabel.text = [pedometerData.numberOfSteps stringValue];
#synchronized (self) {
[self.pedometerDictionary setValue:[pedometerData.numberOfSteps stringValue] forKey:#"2"];
}
[self doSomethingInterestingWithDictionary:nil];
}
});
}];
}
// Will be called when queryPedometerDataFromDate returns and from a timer every 5 seconds.
- (void)doSomethingInterestingWithDictionary:(NSTimer *)aTimer {
#synchronized (self) {
NSLog(#"My days dictionary: %#", self.pedometerDictionary);
}
}
Inside the following method I am saving the current temp of a location, I want to be able to access the temp anywhere inside the class.
[_weatherAPI currentWeatherByCoordinate:CLLocationCoordinate2DMake(location.coordinate.latitude, location.coordinate.longitude) withCallback:^(NSError *error, NSDictionary *result) {
downloadCount++;
if (downloadCount > 1)
if (error) {
}
[_locationManager stopUpdatingLocation];
self.tempLabel.text = [NSString stringWithFormat:#"%.0f°",
[result[#"main"][#"temp"] floatValue] ];
self.locationLabel.text = [NSString stringWithFormat:#"%#",
result[#"name"]
];
self.summaryLabel.text = [NSString stringWithFormat:#"%#",
result[#"weather"][0][#"main"] ];
[self setSaveTemp:result[#"main"][#"temp"]];
}];
I am then saving it to a property
#property (strong, nonatomic) NSString *saveTemp;
And then saving it to this.
-(void)setSaveTemp:(NSString *)saveTemp {
_saveTemp = saveTemp;
}
In my viewDidLoad I am then calling everything
_weatherAPI = [[OWMWeatherAPI alloc] initWithAPIKey:#""];
[_weatherAPI setLangWithPreferedLanguage];
[_weatherAPI setTemperatureFormat:kOWMTempCelcius];
NSLog(#"%#", _saveTemp);
But this returns null as the viewDidLoad is getting called before the _weatherAPI currentWeatherByCoordinate what can I do to be able make _saveTemp not equal null but the actual value?
I think this api will make server call and so it takes time to get the json data.
once json data is available, then it will execute callback block.
saveTemp variable will be initially nil, and you are setting it in completion block.
All you can do is just wait until the download is finished.And if you want to execute some method after download,then call that method in callBack block. so, that way your app can know that download is finished.
I'm using JSONModel to retrieve data from a simple webservice. I need to get the values of key #"message" into a mutable array.
- (void)viewDidLoad
{
[super viewDidLoad];
self.delegate = self;
self.dataSource = self;
NSString *conversationid = #"xx";
NSString *callURL = [NSString stringWithFormat:#"http://mydomain.com/inbox_messages.php?conversation=%#", conversationid];
_feed = [[MessageFeed alloc] initFromURLWithString:callURL
completion:^(JSONModel *model, JSONModelError *err)
{
self.messages = [[NSMutableArray alloc]initWithObjects:[_feed.messagesinconversation valueForKey:#"message"], nil];
NSLog(#"messages %#", self.messages);
}];
NSLog(#"test %#", self.messages);
}
The problem I'm experiencing is that while: NSLog(#"messages %#", self.messages); returns all the right data, NSLog(#"test %#", self.messages); returns (null).
The variable is declared in .h of my class as: #property (strong, nonatomic) NSMutableArray *messages;
This is probably a noob question but I'm a beginner and if somebody could give me a pointer in the right direction, I would be very happy.
Your NSLog for self.messages is outside of the completion block. The completion block is called after the data is loaded. The log is called immediately after creating the MessageFeed request. So, of course, the object self.messages is null because the request has not completed.
The solution to this would be to either handle all of your parsing within the completion block, or call another class method to parse the received data.
Your completion handler is being called after your NSLog("test %#", self.messages); is.
Blocks usually happen concurrently and when a certain event has occurred like the completion handler here or sometimes an error handler. By looking at your code you're probably getting something like:
test nil
messages
So your MessageFeed object is being run but it continues through your code and runs the NSLog outside of the completion handler scope first. When your JSON object has downloaded, which happens after, and parses it then runs the completion handler.
- (void)viewDidLoad
{
[super viewDidLoad];
self.delegate = self;
self.dataSource = self;
NSString *conversationid = #"xx";
NSString *callURL = [NSString stringWithFormat:#"http://mydomain.com/inbox_messages.php?conversation=%#", conversationid];
_feed = [[MessageFeed alloc] initFromURLWithString:callURL //this method takes some time to complete and is handled on a different thread.
completion:^(JSONModel *model, JSONModelError *err)
{
self.messages = [[NSMutableArray alloc]initWithObjects:[_feed.messagesinconversation valueForKey:#"message"], nil];
NSLog(#"messages %#", self.messages); // this is called last in your code and your messages has been has been set as an iVar.
}];
NSLog(#"test %#", self.messages); // this logging is called immediately after initFromURLWithString is passed thus it will return nothing
}
I get this warning in Xcode
warning: Attempting to create USE_BLOCK_IN_FRAME variable with block
that isn't in the frame.
Xcode redirect me to my NSStream
_naturStream = [[NSInputStream alloc] initWithData:natur];
It is random when it does this error, and my application crashes when it is triggered. Anyone tried similar problem ?
thanks
EDIT
in the appDelegate.h
#property (nonatomic, strong) NSInputStream *naturStream;
In the appDelegate.m:
NSData *natur = [NSData dataWithContentsOfURL:[NSURL URLWithString:_locString]];
_naturStream = [[NSInputStream alloc] initWithData:natur];
[_naturStream open];
if (_naturStream) {
NSError *parseError = nil;
id jsonObject = [NSJSONSerialization JSONObjectWithStream:_naturStream options:NSJSONReadingAllowFragments error:&parseError];
if ([jsonObject respondsToSelector:#selector(objectForKey:)]) {
for (NSDictionary *natur in [jsonObject objectForKey:#"results"]) {
_poi = [[POI alloc]init];
[_poi setTitle:[natur objectForKey:#"title"]];
[_poi setLat:[[natur objectForKey:#"lat"]floatValue]];
[_poi setLon:[[natur objectForKey:#"lng"]floatValue]];
[_poi setDistance:[natur objectForKey:#"distance"]];
[_poi setWebUrl:[natur objectForKey:#"webpage"]];
[_naturArray addObject:_poi];
}
}
}
else {
NSLog(#"Failed to open stream.");
}
[_naturStream close];
}
I realized that i forgot [_naturStream close] i don't know if it has solved the problem or not ?
EDIT
Another thing,.... I use a Thread for fetching the JSON data:
dispatch_queue_t jsonParsingQueue = dispatch_queue_create("jsonParsingQueue", NULL);
// execute a task on that queue asynchronously
dispatch_async(jsonParsingQueue, ^{
[self parseJSON];
dispatch_async(dispatch_get_main_queue(), ^{
[_kortvisning updateAnno];
[visListe updateList];
});
});
// release the dispatch queue
dispatch_release(jsonParsingQueue);
Sounds like you're using ARC - if _naturStream is an instance variable for an objective C class, you might need to pull it out and add a __block reference so that ARC knows the scope correctly - but I'm guessing because I don't see how the block is used with the NSInputStream (if you post that part we might know). A good bit is here: http://nachbaur.com/blog/using-gcd-and-blocks-effectively
-- edit --
Ok, now that you posted the rest, I bet it has to do with the _kortvisning and visListe variables. I think you want to pull those out right after you create your queue something like
__block KortVisning *localKortVisning = _kortvisning;
__block NSMutableArray *localVisListe = visListe;
Then access those directly from your final completion handler you're sending back to the main queue.