I'm writing a database project on the iPhone and I'd like to store some big SQL queries in a separate, project-included file.
Then, I'd like to read this query into an NSString * (or, well, const char * is also ok) reference, and then perform it with an sqlite3.
I'm a newbie to iPhone developing, and I have never worked with files, neither I know any details of their storage.
Could you please give me a hint on:
The appropriate file format to store the strings.
How do I store it into the iPhone;
How do I read from it.
Thanks a lot!
You can use:
Any simple character based (text) file would be more than enough
Just put it in a folder in your project, it will get deployed with your Application
Use NSString class.
For issue #3 you can use:
NSString *sqlString =
[NSString
stringWithContentsOfFile:#"yourqueryfile.sql"
encoding:NSUTF8StringEncoding
errors:nil //unless yuo are interested in errors.
];
Related
I want to parse CSV data, which is downloaded to the app. Right now I have the following data - "SPY",186.33,"3/17/2014","4:00pm",**+1.67**,185.59,186.77,185.51,93784328. I used NSLog to display it on the console. What I want to do is read the 1.67 (or whatever it may be) and turn it into an NSString. The url where I get the information from will be consistent, but the numbers will change day to day. Thanks in advance!
If you're able to capture the row of data as a string (which it sounds like you've done, since you're able to NSLog it to the console), then you should be able to split the string apart like so:
NSArray *stringComponents = [yourDataRow componentsSeparatedByString:#","];
NSString *desiredComponent = [stringComponents objectAtIndex:4];
Then, your +1.67 (or whatever) will be available as desiredComponent.
Note: This solution assumes that the +1.67 component of the row will always occupy the 5th position in the row.
I use CHCSVParser by Dave DeLong, it supports parsing this format from a file, NSString, or NSInputStream. Probably your best bet! https://github.com/davedelong/CHCSVParser
On my iOS application I'm unziping files in "app/temp" folder like this:
NSString *unzipFolder = [[CommonFunctions getCachePath] stringByAppendingPathComponent:#"/temp/"];
and once im done with it im deleting item with:
[[NSFileManager defaultManager] removeItemAtPath:unzipFolder error:&e];
Issue is that bcz im creating mulital copy of unzip files some of the files Images name are same and displaying wrong images, and i dont find error on why my deleting function does not work!
IS there any way that i can do unziping of folder on diffrent path for each message that open by user?
Thanks :)
It sounds like all you're asking is how to generate a unique name for your unzipFolder each time.
Just don't use a hardcoded name. Almost anything will do. For example:
NSString *unzipFolderTemplate = [[CommonFunctions getCachePath] stringByAppendingPathComponent:#"temp.XXXXXX"];
char *template = strdup([template fileSystemRepresentation]);
if (mkdtemp(template)) {
NSString *unzipFolder = [NSString stringWithFileSystemRepresentation:template
length:strlen(template)];
free(template);
// do the work
[[NSFileManager defaultManager] removeItemAtPath:unzipFolder error:&e];
}
The nice thing about mkdtemp is that it creates the directory for you, and guarantees there are no race conditions, somehow-left-over directories, or other problems. It's also more secure against, say, someone writing a crack or other jailbreak hack that exploits your code by predicting the path. The downside is, of course, that you have to drop down to C strings (which means an explicit free). But, as I said, there are many possibilities, and almost anything will do.
Also, note that I'm using #"temp.XXXXXX", not #"/temp.XXXXXX/". That's because -[stringByAppendingPathComponent:] already adds any necessary slashes for you (that is, in fact, the whole point of the method), and directory-creation functions don't need a trailing slash, so both of the slashes are unnecessary.
Meanwhile, I'm still a bit confused by what you're trying to do. If you need to keep a unique folder around for each message, and delete the folder when you're done with that message, and you could have multiple messages open at once, you need some way to remember which folder goes with which message.
For that, create an NSMutableDictionary somewhere, and right after the free(template) you'll want to do something like [tempFolderMap addObject:unzipFolder forKey:messageName]. Then, when closing a message, you'll do [tempFolderMap objectForKey:messageName] and use the result to the removeItemAtPath:error: message (and then you can also remove the key from tempFolderMap).
I am making an Iphone drinking card game app.
All the card mean something different and i want the user to be able to press an info button and then show a new screen with information about the current card. How can i make a document to load text from instead of using a bunch og long strings?
Thanks
You could look into plist files - they can be loaded quite easily into the various collection objects and edited with the plist editor in Xcode.
For instance, if you organize your data as a dictionary, the convenience constructor
+ (id)dictionaryWithContentsOfURL:(NSURL *)aURL
from NSDictionary would provide you with as many easily accessible strings as you need.
This method is useful if you consider your strings primarily data as opposed to UI elements.
Update:
As #Alex Nichol suggested, here is how you can do it in practice:
To create a plist file:
In your Xcode project, for instance in the Supporting Files group, select New File > Resource > Property List
You can save the file in en.lproj, to aid in localization
In the Property list editing pane, select Add Row (or just hit return)
Enter a key name (for instance user1) and a value (for instance "Joe")
To read the contents:
NSURL *plistURL = [[NSBundle mainBundle] URLForResource:#"Property List" withExtension:#"plist"];
NSLog(#"URL: %#", plistURL);
NSDictionary *strings = [NSDictionary dictionaryWithContentsOfURL:plistURL];
NSString *user1 = [strings objectForKey:#"user1"];
NSLog(#"User 1: %#", user1);
A plist, a JSON string, and an SQLite database walked into a bar ...
Oops!! I mean those are the three most obvious alternatives. The JSON string is probably the easiest to create and "transport", though it's most practical to load the entire thing into an NSDictionary and/or NSArray, vs read from the file as each string is accessed.
The SQLite DB is the most general, and most speed/storage efficient for a very large number (thousands) of strings, but it takes some effort to set it up.
In my other answer, I suggest the use of a dictionary if your texts are mostly to be considered as data. However, if your strings are UI elements (alert texts, window titles, etc.) you might want to look into strings files and NSBundle's support for them.
Strings files are ideally suited for localization, the format is explained here.
To read them into you app, use something like this:
NSString *text1 = NSLocalizedStringFromTable(#"TEXT1", #"myStringsFile", #"Comment");
If you call your file Localizable.strings, you can even use a simpler form:
NSString *str1 = NSLocalizedString(#"String1", #"Comment on String1");
A useful discussion here - a bit old, but still useful.
My application contains 8 TextFields. When I click the submit button I want to save all the values from the TextFields into an XML file (and generate a XML file if required). How can I do this?
Another XML writer which will get the job done is XSWI (shameless plug - I wrote that code).
There are many ways you could do this. One quick and dirty way of doing it is to generate a string in your code and insert the values
e.g.
NSString *myXML = [NSString stringWithFormat:#"<myxml><value1>%#</value1><value2>%#</value2></myxml>", textfield1, textfield2];
Then open a file and write myXML to it.
Not very elegant, but it depends on what exactly you want.
Do you need the XML file to be in a specific format? If not the easiest way is to save it as a plist (a type of xml file) by putting your strings into an array and then saving the array as a plist using
NSArray *array = [NSArray arrayWithObjects:label1.text, label2.text, label3.text, etc, nil];
[array writeToFile:fileName atomically:YES];
The nice thing about the plist is that you can easily load the string again by calling:
NSArray *array = [NSArray arrayWithContentsOfFile:filename];
If you need your XML in a different format from what the plist produces, the easiest way is probably just to build the XML yourself using string concatenation, e.g.
NSString *xml = [NSSString stringWithFormat:#"<root><label>%#</label><label>%#</label><label>%#</label>etc</root>", label1.text, label2.text, label3.text, etc];
You can use GDATAXML to read and write XML to file.
Refer this link to see how its done.
http://www.raywenderlich.com/725/how-to-read-and-write-xml-documents-with-gdataxml
I have a NSString like that? (in iPhone application)
NSString *xmlStr = "<?xml version=1.0 encoding=UTF-8>
<information>
<name>John</name>
<id>435346534</id>
<phone>045635456</phone>
<address>New York</address>
</information>"
How I can get elements value?
(Do i need convert to XML format and get elements value? or split string? any way please tell me?)
Thank you guys.
If you want to use split string, you can use tokenization of strings using "componentsSeparatedByString" method. This is a more cumbersome method of course, rather than the recommended XMLParser
To get the name.
NSArray *xmlStr_first_array = [xmlStr componentsSeparatedByString: #"<name>"];
NSString *xmlStr_split = [NSString stringWithFormat:#"%#",[xmlStr_first_array objectAtIndex:1]];
NSArray *xmlStr_second_array = [xmlStr_split componentsSeparatedByString: #"</name>"];
NSString *name = [NSString stringWithFormat:#"%#",[xmlStr_second_array objectAtIndex:0]];
The most obvious solution is to use an XML parser to retrieve the values from each element.
You could use the excellent TBXML for this task. It provides a really simple interface where it wouldn't take more than a few lines to retrieve the desired values. The drawback to using this small library is that it (as far as I know) loads the entire XML data into memory. In this particular case, however, that is not problem at all.
There's of course also the option of using the NSXMLParser, though this is an event-driven parser, and thus a bit less simple to use.
Your string is in xml format already and you need to parse it to retrieve data. There're several options available - for example you can use NSXMLParser class or libxml library.
Edit: XMLPerformance sample project shows how to use both approaches and compare their performance.