I'm trying to use this string inside this NSURL however I don't think its right and in turn giving me an ASI HTTP request failed error.
NSURL *url = [NSURL URLWithString:[NSString stringWithFormat:#"https://furious-ice-356.heroku.com/places/%#/reviews.xml",self.identifier]];
self.identifier returns (in most cases) an object of the type id. You cannot cast this object to a NSString*.
The only exception is the in 10.7 newly introduced identifier property of NSString* in the NSUserInterfaceItemIdentification protocol.
Can you elaborate your question so we can see what type self has?
Related
I am trying to resolve an alias file's original path using Objective-C(or maybe C++; it's an .mm file). Not being very much familiar, I am somehow missing + and - methods' usage. I am aware of them being class and instance methods respectively, but in practice, the following the code, with the indicated lines give me following warning and error(at build):
Class method '+bookmarkDataWithContentsOfURL:' not found (return type defaults to 'id')
-
*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '+[NSData bookmarkDataWithContentsOfURL:]: unrecognized selector sent to class 0x7fff88942cb8'
with 0x7fff88942cb8 being the NSData address as per lldb.
Which files should I make the changes in, to get bookmarkDataWithContentsOfURL:error: and URLByResolvingBookmarkData to work?
void *pathclass::resolveAliasFromURL(const char *filepath) const
{
NSError *error = nil;
NSString *filepathh = [[NSString alloc] initWithUTF8String:filepath];
NSData *bookmarkk = [NSData bookmarkDataWithContentsOfURL:filepathh]; /*problematic line*/
BOOL isstale = NO;
NSURL *actual = [NSURL URLByResolvingBookmarkData:bookmarkk bookmarkDataIsStale:isstale error:error];/*another problematic line, but build fails already*/
NSString *urlString = [actual absoluteString];
NSLog(#"%#",urlString);
}
If there are any other faults, please point out.
Your call to bookmarkDataWithContentsOfURL: is wrong in a few ways:
The signature looks like this:
+ (NSData *)bookmarkDataWithContentsOfURL:(NSURL *)bookmarkFileURL error:(NSError * _Nullable *)error;
First, the first parameter is of type NSURL*, not NSString*. Next, you miss off the error parameter completely (despite defining a variable for it). Lastly, the method is a class method on NSURL not NSData (NSData* is the return type).
So, first, make your file path into an NSURL*:
NSURL* bookmarkUrl = [NSURL URLWithString:filepathh];
Then, call the function using the proper arguments:
NSData *bookmarkk = [NSURL bookmarkDataWithContentsOfURL:bookmarkUrl error:&error];
You should check the returned value against nil - if it's nil, then an error occurred, and the error information will be contained inside error.
The documentation is quite helpful.
Your call to URLByResolvingBookmarkData:options:relativeToURL:bookmarkDataIsStale:error: has similar problems: you are missing several parameters, the first parameter should be NSURL, etc. Again, the documentation should help.
I have an assets library url to a photo:
"assets-library://asset/asset.JPG?id=8D4D7820-EDD6-4CA4-A44A-2ACD53A112FC&ext=JPG"
I have this in a string property imgURLString.
I am trying to convert this to NSURL in the following way:
NSURL *imageURL = [NSURL URLWithString:self.imgURLString];
However, I am getting an exception:
[NSURL length]: unrecognized selector sent to instance 0xa8281f0
I am sure I have the above mentioned string in self.imgURLString and it is not trying to convert an empty string. So why am I getting this exception and how do I solve it?
I am basically trying to convert the string to an NSURL to fetch the photo using the assets library url.
Your self.imgURLString is actually already an NSURL, not an NSString. You are assigning the asset URL (an NSURL) to your NSString property. Change your property to be an NSURL.
i want to check if a URL is accessible or correct, how can i send a request and see of it is available?
Simply rely on Foundation Framework..
From NSURL documentation
URLWithString: Creates and returns an NSURL object initialized with a
provided string.
+ (id)URLWithString:(NSString *)URLString
Parameters
URLString : The string with which to initialize the NSURL object. Must
conform to RFC 2396. This method parses URLString according to RFCs
1738 and 1808.
Return Value
An NSURL object initialized with URLString. If the string was
malformed, returns nil.
This will validate if the URL does not confirm to specified standards..
Next case , to find out whether URL is accessible, Implement NSURLConnectionDelegate, override
- (void)connection:(NSURLConnection *)connection didFailWithError:(NSError *)error
And try to connect to specified URL..If URL is inaccessible above given delegate will fire and see error case there..
I have an int containing a number. I am wanting to declare an NSString so I can use use format specifiers when assigning a value to it.
I thought it might be something like this:
NSString[NSString stringWithFormat] myString;
myString = [#"http://myurl.com/%d",myInt];
I gather this is not the case, so question one is: How do I declare an NSString that can handle format specifiers and then assign it a value using format specifiers? The purpose of this NSString is to hold a URL, exactly like the second line above.
Question two is, How do I then use this string as a URL to open in a UIWebView?
I assume I use something like this:
[webView loadRequest:
Sadly, this is as far as my knowledge stretches. Is there a way I can tell my UIWebView (webView above) to use the NSString with the URL I mentioned earlier?
I intend on having the NSString as a global variable, as it will be assigned it's value inside a C function. And 'webView' will use it inside a (what I think is a) method. All of this code is in the same file, the Delegate.m file. It is all executed on launch of the application.
Your string should look like this:
NSString *myString = [NSString stringWithFormat:#"http://myurl.com/%d", myInt];
What you missed: adding the * to indicate a pointer, and thinking that you had to/could first state that the string would have a format and then later state the format. It all happens at once, creating the string with the specified format.
Edited to add NSURL
To create a url you're creating an object of class NSURL, like this:
NSURL *myURL = [[NSURL alloc] initWithString:myString];
And then you create the url request:
NSURLRequest *request = [NSURLRequest requestWithURL:myURL];
And finally, tell your webView to load the request:
[webView loadRequest:request];
For your first part:
NSString *myString = [NSString stringWithFormat:#"http://myurl.com/%d", myInt];
Then, based on a tutorial from iphonesdkarticles.com:
//Create a URL object.
NSURL *url = [NSURL URLWithString:myString];
//URL Request Object
NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];
//Load the request in the UIWebView.
[webView loadRequest:requestObj];
I'm working through Cocoa smoothly, but this problem seems so basic it cancels out all the cool stuff I learned. :/
I have a generated file path, and it needs to be in NSURL format. From research, this is the code I wrote:
NSLog(#"Old path = %#", pathToFile);
NSURL *xmlURL = [[[NSURL alloc] init] fileURLWithPath:pathToFile];
NSLog(#"New path = %#", [xmlURL absoluteString]);
And the output:
2010-01-27 15:39:22.105 MusicLibraryStats[28574:a0f] Old path = file://localhost/Users/[username]/Music/iTunes/iTunes%20Music%20Library.xml
2010-01-27 15:39:22.105 MusicLibraryStats[28574:a0f] New path = (null)
First off, the alloc-init shouldn't even be necessary; other people seem to get away with it. In this case, if I don't alloc-init, I get an 'unrecognized selector' error on that line. Of course, now I'm just getting plain old (null).
Where did I goof?
Thanks!
The [[NSURL alloc] init] is not just unnecessary, it's invalid. fileURLWithPath: is a class method, which means you can only call it on the class object (that is, NSURL itself). It does not produce a compile error because -(NSURL *)init returns an object of type id, and does not result in a runtime error because -(NSURL *)init actually returns nil, and messages sent to nil will just cascade another nil as their return value.
This code should work:
NSString* pathToFile = #"/this/is/a/path";
NSURL* url = [NSURL fileURLWithPath:pathToFile];
I found your problem.
-[NSOpenPanel URLs] returns an array of NSURL objects, which you treat as NSString objects. That's not right. You should use the following:
NSURL* url = [[oPanel URLs] objectAtIndex:0];
The debugger could've show you that if you looked at the pathToFile variable. Make sure to check it next time. :) Hovering a variable with your mouse should get you its type.
However, remember that there are situations where you will legitimately encounter another type than the one you expected. For instance, the private NSPathStore2 class is part of the NSString cluster, and you can do everything NSString supports on NSPathStore2 objects. (If this happens and you're not too sure, check the documentation to see if the type you expect is a cluster type. That's how they're called in the documentation.)