I'm new to iOS programming, and having trouble finding a beginner-level explanation of how to write the contents of multiple text fields to a local json file in such a way to keep everything organized.
For example, a user form would have Name, Address, Email, etc., which would need to be put into a Customer object.
The purpose of this is to save data from several forms, and eventually pass that data to a database.
You'll need to convert your text fields into a dictionary (or dictionary of dictionaries). Once you have that done, you convert the dictionary into JSON data and save that:
NSError *error = nil;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:myJSONDict options:0 error:&error];
if (jsonData != nil) {
NSString *jsonFilePath = ...;
BOOL status = [jsonData writeToFile:jsonFilePath atomically:YES];
if (!status) {
NSLog(#"Oh no!");
}
} else {
NSLog(#"My JSON wasn't valid: %#", error);
}
You just need to create the path and check the status.
NSMutableDictionary* dict = [NSMutableDictionary dictionary];
[dict setObject:form.name.text forKey:#"name"]'
[dict setObject:form.address.text forKey:#"address"];
...
NSString* jsonString = [yourFavoriteJsonTool convertToJson:dict];
Related
I'm trying to send data from my iOS app to the Watch app. I'm using the updateApplicationContext for this.
I have a json file that I converted in NSDictionary and tried to send it. But there is an error, here it is:
[WCSession updateApplicationContext:error:]_block_invoke failed due to WCErrorCodePayloadUnsupportedTypes
The file is correctly read.
Now here is the code that tries to send the data.
NSString *fileName = [[NSBundle mainBundle] pathForResource:#"data"
ofType:#"json"];
NSLog(fileName);
if (fileName) {
NSData *jsonData = [[NSData alloc] initWithContentsOfFile:fileName];
NSDictionary *data = [NSJSONSerialization JSONObjectWithData:jsonData
options:0
error:&error];
if (error) {
NSLog(#"Something went wrong! %#", error.localizedDescription);
}
else {
NSLog(#"Rsens info: %#", data);
[WatchSessionManager.sharedManager updateApplicationContextWithApplicationContext:#{#"json": data} error:&error];
}
}
else {
NSLog(#"Couldn't find file!");
}
I read somewhere that the types that we could send were limited, but the dictionary was allowed. I'm sending a dictionary though.
Can you find what is the error?
[SOLUTION]
I found out that there were values of type long in my dictionary. In my JSON I had some properties that were transtyped in type long. Here is one of the properties before:
"state": 0
I just put my numbers in string quotes.
"state":"0"
Check the dictionary's content.
WatchConnectivity dictionaries can only contain property list types.
I have this function:
- (void)checkLogin:(NSString *)pLogin andPassword:(NSString*) pPassword {
//Create the data object.
NSMutableDictionary *tLoginAndPasword = [NSMutableDictionary dictionaryWithObjectsAndKeys:pLogin,#"Login",pPassword,#"Password", nil];
NSMutableDictionary *tData = [NSMutableDictionary dictionaryWithObjectsAndKeys:[_Util serializeDictionary:tLoginAndPasword],#"Data", nil];
//Call the login method.
NSData *tResponse = [_Util getLogin:tData];
if (tResponse != Nil) {
_oLabelErrorLogin.hidden = YES;
[_Util setUser:pLogin andPassword:pPassword];
NSMutableDictionary *tJSONResponse =[NSJSONSerialization JSONObjectWithData:tResponse options:kNilOptions error:nil];
NSString *tPayload = [tJSONResponse objectForKey:#"Payload"];
if([[tJSONResponse objectForKey:#"StatusCode"] isEqual: #"424"]) {
//Set global values.
NSData *tPayloadData = [tPayload dataUsingEncoding:NSUTF8StringEncoding];
if ([NSJSONSerialization isValidJSONObject:tPayloadData]) {
_Payload = [NSJSONSerialization JSONObjectWithData:tPayloadData options:kNilOptions error:nil];
_RowCount = _Payload.count;
} else {
NSLog(#"JSON Wrong String %#",tPayload);
}
} else if([[tJSONResponse objectForKey:#"StatusCode"] isEqual: #"200"]){
_Payload = Nil;
}
} else {
//Set global values.
_Payload = Nil;
_oLabelErrorLogin.hidden = NO;
//Clear login data.
_oLogin.text = #"";
_oPassword.text = #"";
[_Util setUser:#"" andPassword:#""];
}
}
The JSON response looks like this:
{
"Payload": "{\"UserName\":\"Marco Uzcátegui\",\"Clients\":[{\"UserProfileId\":4,\"ProfileName\":\"Platform Administrator\",\"ClientName\":\"Smart Hotel Platform\",\"InSession\":true},{\"UserProfileId\":5,\"ProfileName\":\"Administrator\",\"ClientName\":\"La Moncloa de San Lázaro\",\"InSession\":false},{\"UserProfileId\":6,\"ProfileName\":\"Administrator\",\"ClientName\":\"Jardín Tecina\",\"InSession\":false}]}",
"StatusCode": "424",
"StatusDescription": null
}
As you can see, I have a escaped string inside "Payload" that is a correct JSON, so I want to generate another NSMutableDictionary with that string, so I'm doing this:
NSData *tPayloadData = [tPayload dataUsingEncoding:NSUTF8StringEncoding];
if ([NSJSONSerialization isValidJSONObject:tPayloadData]) {
_Payload = [NSJSONSerialization JSONObjectWithData:tPayloadData options:kNilOptions error:nil];
_RowCount = _Payload.count;
} else {
NSLog(#"JSON Wrong String %#",tPayload);
}
So I'm creating an NSData from the NSString and asking if is valid, it always returns false.
I have tried to replace the "\" from the string and is not working.
[tPayload stringByReplacingOccurrencesOfString:#"\\\"" withString:#""]
I have tried to create a NSMutableDictionary with the string, but the result is not a dictionary.
NSMutableDictionary *tPayload = [tJSONResponse objectForKey:#"Payload"];
I'm kind of lost here.
Any help will be appreciated.
Regards.
The issue is this line
[NSJSONSerialization isValidJSONObject:tPayloadData]
From the documentation of isValidJSONObject
Returns a Boolean value that indicates whether a given object can be
converted to JSON data.
given object means an NSArray or NSDictionary but not NSData
Remove that check and implement the error parameter in JSONObjectWithDataoptions:error:
The method NSJSONSerialization.isValidJSONObject: checks if an object (e.g. a NSDictonary or NSArray instance) can be converted to JSON. It doesn't check if a NSData instance can be converted from JSON. For NSData, it will always return false.
So just call NSJSONSerialization.JSONObjectWithData:options: and check the result instead.
I am using AFNetworking to retrieve information about the weather for a specific location, e.g:
http://api.openweathermap.org/data/2.5/weather?q={New%20York%20City}
I am using the AFNetworking framework but I am having the problems parsing some objects of the JSON.
If I have an NSDictionary with the MAIN object information from the JSON:
NSDictionay *main = [responseObject objectForKey:#"main"];
If I log the main NSDictionary I will get the following valid output:
"main":{
"temp":296.78;
"pressure":1011;
"humidity":69;
"temp_min":293.15;
"temp_max":299.82
};
Although if I create a NSDictionary containing the weather object I will get the following information whenever logging it to the console:
NSDictionay *weather = [responseObject objectForKey:#"weather"];
"weather":(
{
"id":801;
"main":"Clouds";
"description":"few clouds";
"icon":"02d"
}
);
The parsed information contains ( brackets instead of [ from the original response. This does not allow me to correctly access the inside attributes of the weather object.
Summing up, I am able to access all the inside variables of the MAIN object, but I cannot access the attributes of the Weather object (e.g access the icon attribute).
Can someone help me with this ?
Thank you,
You calling your service as below.
NSString *query = #"http://api.openweathermap.org/data/2.5/weather?q={New%20York%20City}";
NSLog(#"%#",query);
query = [query stringByAddingPercentEscapesUsingEncoding:NSUTF8StringEncoding];
NSData *jsonData = [[NSString stringWithContentsOfURL:[NSURL URLWithString:query] encoding:NSUTF8StringEncoding error:nil] dataUsingEncoding:NSUTF8StringEncoding];
NSError *error = nil;
NSDictionary *results = jsonData ? [NSJSONSerialization JSONObjectWithData:jsonData options:0 error:&error] : nil;
Now print Response :
NSLog(#"weather==%#",[results objectForKey:#"weather"]);
NSLog(#"description==%#",[[[results objectForKey:#"weather"] objectAtIndex:0] objectForKey:#"description"]);
NSLog(#"icon==%#",[[[results objectForKey:#"weather"] objectAtIndex:0] objectForKey:#"icon"]);
NSLog(#"id==%#",[[[results objectForKey:#"weather"] objectAtIndex:0] objectForKey:#"id"]);
NSLog(#"main==%#",[[[results objectForKey:#"weather"] objectAtIndex:0] objectForKey:#"main"]);
Your Response is :
whwather==(
{
description = "sky is clear";
icon = 01d;
id= 800;
main= Clear;
}
)
description== "sky is clear";
icon == 01d;
id == 800;
main == Clear;
I have in a NSString "[{"van" : 1,312, "vuan":12,123}] and in order to get this values for every key, I am doing this:
NSData *data1 = [jsonResponse1 dataUsingEncoding:NSUTF8StringEncoding];
jsonArray = [NSJSONSerialization JSONObjectWithData:data1 options:kNilOptions error:&err];
self.van = [NSMutableArray arrayWithCapacity:1];
self.vuan = [NSMutableArray arrayWithCapacity:1];
for (NSDictionary *json in jsonArray) {
NSString * value = [json objectForKey:#"van"];
[self.van addObject:value];
lbl1.text = value;
NSString * value1 = [json objectForKey:#"vuan"];
[self.vuan addObject:value1];
lbl4.text = value1;
}
May be I don't have to use an array and instead to convert the NSData directly in a NSDictionary.
Anyway, I don't understand why jsonArray is nil, although jsonResponse1 contains the values I have written above.
EDIT: My boss have written the json string wrong. Thank you all for your suggestions!:)
Your JSON is invalid. Fix it. This site is your friend.
http://jsonlint.com/
You need to code more defensively and you need to report errors as they are found.
Firstly check if the JSON parsing failed and if so report the error:
NSData *data1 = [jsonResponse1 dataUsingEncoding:NSUTF8StringEncoding];
jsonArray = [NSJSONSerialization JSONObjectWithData:data1 options:kNilOptions error:&err];
if (jsonArray == nil)
{
NSLog(#"Failed to parse JSON: %#", [err localizedDescription]);
return;
}
Secondly if those keys are not in the JSON, objectForKey: will return nil and when you attempt to add that to the arrays, it will throw an exception, which is something you want to avoid:
for (NSDictionary *json in jsonArray) {
NSString * value = [json objectForKey:#"van"];
if (value != nil)
{
[self.van addObject:value];
lbl1.text = value;
}
else
{
NSLog(#"No 'van' key in JSON");
}
NSString * value1 = [json objectForKey:#"vuan"];
if (value1 != nil)
{
[self.vuan addObject:value1];
lbl4.text = value1;
}
else
{
NSLog(#"No 'vuan' key in JSON");
}
}
So in summary: runtime errors will occur so you need to ensure you handle them. When they occur you need to report them with as much information possible so that you can diagnose and fix them.
I created a web service which returns JSON or so I think. The data returned look like this:
{"invoice":{"id":44,"number":42,"amount":1139.99,"checkoutStarted":true,"checkoutCompleted":true}}
To me, that looks like valid JSON.
Using native JSON serializer in iOS5, I take the data and capture it as a NSDictionary.
NSError *error;
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:[request responseData] options:kNilOptions error:&error];
NSLog(#"json count: %i, key: %#, value: %#", [json count], [json allKeys], [json allValues]);
The output of the log is:
json count: 1, key: (
invoice
), value: (
{
amount = "1139.99";
checkoutCompleted = 1;
checkoutStarted = 1;
id = 44;
number = 42;
}
)
So, it looks to me that the JSON data has a NSString key "invoice" and its value is NSArray ({amount = ..., check...})
So, I convert the values to NSArray:
NSArray *latestInvoice = [json objectForKey:#"invoice"];
But, when stepping through, it says that latestInvoice is not a CFArray. if I print out the values inside the array:
for (id data in latestInvoice) {
NSLog(#"data is %#", data);
}
The result is:
data is id
data is checkoutStarted
data is ..
I don't understand why it only return the "id" instead of "id = 44". If I set the JSON data to NSDictionary, I know the key is NSString but what is the value? Is it NSArray or something else?
This is the tutorial that I read:
http://www.raywenderlich.com/5492/working-with-json-in-ios-5
Edit: From the answer, it seems like the "value" of the NSDictionary *json is another NSDictionary. I assume it was NSArray or NSString which is wrong. In other words, [K,V] for NSDictionary *json = [#"invoice", NSDictionary]
The problem is this:
NSArray *latestInvoice = [json objectForKey:#"invoice"];
In actual fact, it should be:
NSDictionary *latestInvoice = [json objectForKey:#"invoice"];
...because what you have is a dictionary, not an array.
Wow, native JSON parser, didn't even notice it was introduced.
NSArray *latestInvoice = [json objectForKey:#"invoice"];
This is actually a NSDictionary, not a NSArray. Arrays wont have keys. You seem capable from here.
Here I think You have to take to nsdictionary like this
NSData* data = [NSData dataWithContentsOfURL: jsonURL];
NSDictionary *office = [NSJSONSerialization JSONObjectWithData:data options:kNilOptions error:nil];
NSDictionary *invoice = [office objectForKey:#"invoice"];