In my app I am using coredata to store details about the document
Here's my code
-(void)writeToDatabase:(UIManagedDocument *)newdocument
{
Images *image =[NSEntityDescription insertNewObjectForEntityForName:#"Images" inManagedObjectContext:newdocument.managedObjectContext];
image.album = #"Album 1";
image.date = #"October";
image.share = #"Not shared yet"; }
In the above code
1.Images is the core data entity.
2.I have inserted data in this fashion(temporarily) just to check.
How can I NSLog the values?
Try this,
Assume the attribute values in the coredata are Strings
NSLog(#"Image Name %#",image.album);
NSLog(#"Data %#",image.date);
NSLog(#"Share Name %#",image.share);
Hope it helps.
Related
I was having an excel file.
I have converted that file to .csv format and import that file to base and converted it into .sqlite file.
So the question is that:
Is there any way to import it into an ios app and manipulate the data.
Is there any way to use it like core data or import that file into core data.
Kindly refer any good tutorial preferably video tutorial or some other good one.
You can use it directly with FMDB library: https://github.com/ccgus/fmdb
Another option is to import that file into core data, but it is a little tricky. You can do it if you follow these steps:
Create empty SQLite database in your application and run your app in simulator.
Open simulator directory on your computer and locate SQLite database file.
Look inside it with SQLite command line tool or something like "SQLite Data Browser" GUI tool (http://sqlitebrowser.sourceforge.net/).
Import your data to this database file without changing structure and data in core data meta tables.
Finally you have SQLite database file ready to be used with core data. So you put it into your app bundle.
On first application launch you should copy your SQLite database file to appropriate directory (you know where you should put your file - you already found it in simulator app directory) before configuring core data stack.
It sounds a bit complicated but it works ;)
Nice article about shipping pre-populated data for core data: http://www.objc.io/issue-4/importing-large-data-sets-into-core-data.html
Update
Please note the updated response.
Is there any way to import it (SQLite) into an ios app and manipulate the data?
You can import a sqlite file into Xcode, by simply adding it as a resource using Add New File... However you would have limited ability to use it jointly with Core Data (unless it was created with Core Data). One can review the objc.io article referenced earlier that covers how to deal with prepopulated data in an Xcode project. Here is the pertinent section of that article.
NSFileManager* fileManager = [NSFileManager defaultManager];
NSError *error;
if([fileManager fileExistsAtPath:self.storeURL.path]) {
NSURL *storeDirectory = [self.storeURL URLByDeletingLastPathComponent];
NSDirectoryEnumerator *enumerator = [fileManager enumeratorAtURL:storeDirectory
includingPropertiesForKeys:nil
options:0
errorHandler:NULL];
NSString *storeName = [self.storeURL.lastPathComponent stringByDeletingPathExtension];
for (NSURL *url in enumerator) {
if (![url.lastPathComponent hasPrefix:storeName]) continue;
[fileManager removeItemAtURL:url error:&error];
}
// handle error
}
NSString* bundleDbPath = [[NSBundle mainBundle] pathForResource:#"seed" ofType:#"sqlite"];
[fileManager copyItemAtPath:bundleDbPath toPath:self.storeURL.path error:&error];
NSDictionary *infoDictionary = [NSBundle mainBundle].infoDictionary;
NSString* bundleVersion = [infoDictionary objectForKey:(NSString *)kCFBundleVersionKey];
NSString *seedVersion = [[NSUserDefaults standardUserDefaults] objectForKey:#"SeedVersion"];
if (![seedVersion isEqualToString:bundleVersion]) {
// Copy the seed database
}
// ... after the import succeeded
[[NSUserDefaults standardUserDefaults] setObject:bundleVersion forKey:#"SeedVersion"];
Assuming one wanted to import a CSV file rather than an Excel or SQLite... Since this is a common question, here is a simple parser that one can use to incorporate CSV data into an Xcode project.
func parseCSV (contentsOfURL: NSURL, encoding: NSStringEncoding, error: NSErrorPointer) -> [(name:String, detail:String, price: String)]? {
// Load the CSV file and parse it
let delimiter = ","
var items:[(name:String, detail:String, price: String)]?
if let content = String(contentsOfURL: contentsOfURL, encoding: encoding, error: error) {
items = []
let lines:[String] = content.componentsSeparatedByCharactersInSet(NSCharacterSet.newlineCharacterSet()) as [String]
for line in lines {
var values:[String] = []
if line != "" {
// For a line with double quotes
// we use NSScanner to perform the parsing
if line.rangeOfString("\"") != nil {
var textToScan:String = line
var value:NSString?
var textScanner:NSScanner = NSScanner(string: textToScan)
while textScanner.string != "" {
if (textScanner.string as NSString).substringToIndex(1) == "\"" {
textScanner.scanLocation += 1
textScanner.scanUpToString("\"", intoString: &value)
textScanner.scanLocation += 1
} else {
textScanner.scanUpToString(delimiter, intoString: &value)
}
// Store the value into the values array
values.append(value as! String)
// Retrieve the unscanned remainder of the string
if textScanner.scanLocation < count(textScanner.string) {
textToScan = (textScanner.string as NSString).substringFromIndex(textScanner.scanLocation + 1)
} else {
textToScan = ""
}
textScanner = NSScanner(string: textToScan)
}
// For a line without double quotes, we can simply separate the string
// by using the delimiter (e.g. comma)
} else {
values = line.componentsSeparatedByString(delimiter)
}
// Put the values into the tuple and add it to the items array
let item = (name: values[0], detail: values[1], price: values[2])
items?.append(item)
}
}
}
return items
}
(Source article)
Another option is to use the Core Data Editor tool originally mentioned in the Ray W. list of tools. This GUI editor tries to make handling CSV data imports easier.
Is there any way to use it like core data or import that file into core data?
So a SQLite database is not the same as Core Data (which is an object graph persistence...). I was about to go into my diatribe here, but Apple's Core Data FAQ says it better than I could...:
How do I use my existing SQLite database with Core Data?
You don’t. Although Core Data supports SQLite as one of its persistent
store types, the database format is private. You cannot create a
SQLite database using native SQLite API and use it directly with Core
Data (nor should you manipulate an existing Core Data SQLite store
using native SQLite API). If you have an existing SQLite database, you
need to import it into a Core Data store (see Efficiently Importing
Data).
So that's the official answer. Anything else offered is just a way to work around the fact that one is not supposed to do this.
However, given that you also have a CSV file you do have some other options. In the past I've built a file reader to examine the contents of a CSV file using a stream reader. Here is the gist of that, however my file likely had some other formatting so this probably needs tweaking. You can also look at using any object that reads the contents of a file. For example; a much simpler technique comes to mind:
Use the initWithContentsOfFile on the NSString class
Gives you a string with the CSV in memory
Iterate the string for each line
Loop through the line using commas and do something with each piece of data
NSString *fileContents = [NSString stringWithContentsOfFile:#"myfile.txt"];
NSArray *lines = [fileContents componentsSeparatedByString:#"\n"];
//loop and split each line in lines array into useful data
Let's say you really want to use SQLite in iOS, warnings notwithstanding... You can add the sqlite3 library to your project. Full details are available on how to use SQLite instead of Core Data. One of the many online tutorials is at AppCoda
The basics are covered (sample project):
Saving...
- (IBAction)saveInfo:(id)sender {
// Prepare the query string.
NSString *query = [NSString stringWithFormat:#"insert into peopleInfo values(null, '%#', '%#', %d)", self.txtFirstname.text, self.txtLastname.text, [self.txtAge.text intValue]];
// Execute the query.
[self.dbManager executeQuery:query];
// If the query was successfully executed then pop the view controller.
if (self.dbManager.affectedRows != 0) {
NSLog(#"Query was executed successfully. Affected rows = %d", self.dbManager.affectedRows);
// Pop the view controller.
[self.navigationController popViewControllerAnimated:YES];
}
else{
NSLog(#"Could not execute the query.");
}
}
Editing...
-(void)loadInfoToEdit{
// Create the query.
NSString *query = [NSString stringWithFormat:#"select * from peopleInfo where peopleInfoID=%d", self.recordIDToEdit];
// Load the relevant data.
NSArray *results = [[NSArray alloc] initWithArray:[self.dbManager loadDataFromDB:query]];
// Set the loaded data to the textfields.
self.txtFirstname.text = [[results objectAtIndex:0] objectAtIndex:[self.dbManager.arrColumnNames indexOfObject:#"firstname"]];
self.txtLastname.text = [[results objectAtIndex:0] objectAtIndex:[self.dbManager.arrColumnNames indexOfObject:#"lastname"]];
self.txtAge.text = [[results objectAtIndex:0] objectAtIndex:[self.dbManager.arrColumnNames indexOfObject:#"age"]];
}
Deleting...
-(void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath{
if (editingStyle == UITableViewCellEditingStyleDelete) {
// Delete the selected record.
// Find the record ID.
int recordIDToDelete = [[[self.arrPeopleInfo objectAtIndex:indexPath.row] objectAtIndex:0] intValue];
// Prepare the query.
NSString *query = [NSString stringWithFormat:#"delete from peopleInfo where peopleInfoID=%d", recordIDToDelete];
// Execute the query.
[self.dbManager executeQuery:query];
// Reload the table view.
[self loadData];
}
}
Re: Kindly refer any good tutorial preferably video tutorial or some
other good one.
The following tutorial should fill your need. There are quite a few tutorials on this topic you can check out www.lynda.com for a detailed walk through on building an iOS app with SQLite (some cost involved for full access however search Youtube as they post sample movies covering these topics all the time).
http://www.youtube.com/watch?v=bC3F8a4F_KE (see 1:17 in video)
If you have an .sql file, you just import it to your project by going to File - Add Files.
Also, keep in mind that if you leave your .sql file in your bundle, it will be read only.
So, unless you want it to be read only, you should make new group and put your .sql there.
I´m using Core Data as local storage in my app. I´ve set it up properly and made subclasses of NSManagedObject for each entity. However, when I´m trying to insert values into my store, it only inserts the last object from my JSON feed.
res = [JSONHandler requestJSONResponse:jsonString];
shows = [res valueForKeyPath:#"Show.Name"];
NSUInteger showIndex = 0;
for(NSString *showName in shows){
showObject = [NSEntityDescription insertNewObjectForEntityForName:#"Show" inManagedObjectContext:managedObjectContext_];
showObject.name = showName;
showObject.iD = [[res valueForKeyPath:#"Show.Id"]objectAtIndex:showIndex];
showObject.desc = [[res valueForKeyPath:#"Show.Description"]objectAtIndex:showIndex];
showObject.activityType = [[res valueForKeyPath:#"Show.ActivityType"]objectAtIndex:showIndex];
showIndex++;
}
This only stores the last object from my JSON feed. Any idea why?
EDIT: It works fine when I do this:
res = [JSONHandler requestJSONResponse:jsonString];
shows = [res valueForKeyPath:#"Show.Name"];
NSUInteger index = 0;
for(NSString *showName in shows){
show = [NSEntityDescription insertNewObjectForEntityForName:#"Show" inManagedObjectContext:managedObjectContext_];
[show setValue:showName forKey:#"name"];
[show setValue:[[res valueForKeyPath:#"Show.Id"]objectAtIndex:index] forKey:#"iD"];
[show setValue:[[res valueForKeyPath:#"Show.Description"]objectAtIndex:index] forKey:#"desc"];
[show setValue:[[res valueForKeyPath:#"Show.ActivityType"]objectAtIndex:index] forKey:#"activityType"];
index++;
}
It´s basically the same thing, isn´t it? But I want to use subclasses of NSManagedObject instead of doing like I did above. Because in the snippet above show is NSManagedObject *show instead of what it should be: Show *show.
How many shows are there? You can find this by doing: NSLog(#"Number of shows: %d.", shows.count);, assuming that shows is an NSArray. It could be that your Core Data code is fine and the JSON parsing itself is at fault.
EDIT: Also, are you correctly saving the changes to the persistent store?
Usually when you see just one of several objects being saved like this, the problem is that a relationship that should be to-many is improperly set as to-one. No matter how many objects you try to add to the relationship, only the last one is set because the relationship can hold only one value.
I think in this circumstance the problem is most likely in the code of the custom subclass instead of the data model itself given that the data model works with generic NSManagedObjects.
I'm new to this, so here goes..
I'm having a problem with displaying images in uitableview, that are downloaded from a mysql database. Here's what I'm doing:
converting images using UIImagePNGRepresentation.
uploading to MYSQL database via webservice.
So far so good..
The images are downloaded from MYSQL using JSON.
NSDictionary used to create array of image data from JSON String.
[UIImage imageWithData:[imageArray objectAtIndex:indexpath.row]] fails with error: [NSCFString bytes]: unrecongnised selector sent to instance.
I can understand why this is happening, but don't know how to resolve it. The imageWithData is expecting NSData object, but I've converted the string to NSData with no success.
Any help will be greatly appreciated.
Are you converting to and from data properly?
To data:
NSData* theData;
theData = [theNSString dataUsingEncoding:NSASCIIStringEncoding];
To string:
NSString* theNSString;
theNSString = [[NSString alloc] initWithData:theData encoding:NSASCIIStringEncoding];
Thanks for your response.
Yes I was doing the conversion to/from data, as you stated, the only difference being that I was using NSUTF8StringEncoding rather than NSASCIIStringEncoding.
I've tried it with NSASCIIStringEncoding, but the results is the same. It seems that the converted data is different to that stored on the database.
The data from the JSON string (NSData to NSString) is:
<89504e47 0d0a1a0a 0000000d 49484452 00000087 0000005a 08020000 001d25d2 ac000020 00494441 54780174 bd7778dc e775e73b bdf78e19 f40e1004 c002764a ec942cdb b12ccb55 b6e3123b 8e539e44 cecd3ad7 bbc9c6eb f4dc2789 b3297e9c 4d1cc5b1 2dc9b264 4bb22a25 52ec0401 16f45e07 184ceff3 ....
However, the conversion back to NSData gives the following data:
<3c383935 30346534 37203064 30613161 30612030 30303030 30306420 34393438 34343532 20303030 30303038 37203030 30303030 35612030 38303230 30303020 30303164 32356432 20616330 30303032 30203030 34393434 34312035 34373830.....
This may be the same, but [UIImage imageWithData:theData] returns null image.
i am new in iphone prog...
i am using UITextView to view my data from database...
my app is showing high scores from database.... i stored every row of data in a dictionary and then this dictionary in an array...
then i did reverse of that here....
here nextclass is object of that class where the actual method of select command is......
and highscore is my textview
NSArray *scores = [nextclass score];
NSMutableDictionary *DD;
int a = [scores count];
while(a>0)
{
DD=[scores objectAtIndex:a-1];
highscore.text=[NSString stringWithFormat:#"%# -------------------------- %#",[DD objectForKey:#"name"],[DD objectForKey:#"score"]];
a--;
}
the problem is that it replaces the data which was previously added to the textview.....
but i want to show the whole data row by row
waiting for your response......
please help.....
highscore.text=[NSString stringWithFormat:#"%#%# -------------------------- %#",highscore.text, [DD objectForKey:#"name"],[DD objectForKey:#"score"]];
is one option, also you could use the method
stringByAppendingString
I'm having a problem with relationships between to entities in Core Data. I'm parsing some JSON and adding the entities:
if ([hourSets isKindOfClass:[NSArray class]]) { // check to see that we have got some hours back
for (NSDictionary *hourSet in hourSets) {
Hourset *thisHourSet = (Hourset *)[NSEntityDescription
insertNewObjectForEntityForName:#"Hourset"
inManagedObjectContext:managedObjectContext];
[thisHourSet setStartDate:[hourSet objectForKey:#"start_date"]];
[thisHourSet setEndDate:[hourSet objectForKey:#"end_date"]];
[record addHoursetsObject:thisHourSet];
}
}
...and then later trying to grab them again:
NSSet *hourSets = [self.listing valueForKeyPath:#"hoursets.hourset"];
NSLog(#"There are %# hourSets", [hourSets count]);
I'm getting Program received signal: “EXC_BAD_ACCESS”. when trying to access that hourSets NSSet in any way, including just counting the items in it.
Any suggestions? Pretty stumped. Thanks!
I am inferring your entity graph here but:
[self.listing valueForKeyPath:#"hoursets.hourset"]
... translates to a keypath of listing.hoursets.hourset which does not appear to return a set. Both the first and last elements are singular and therefore by convention not sets.
I would suggest logging the class of the return to confirm what, if anything, you're getting back.
Update:
(Forehead slap) The problem is actually the log statement itself. It should be:
NSLog(#"There are %d hourSets", [hourSets count]);
... because count returns an NSUInteger.