The following is from Apple’s Technical Q&A:
UITabBarController or UINavigationController do not agree on a common orientation set.-(id)init: or -(id)initWithNibName:(NSString *)nibName bundle:(NSBundle *)nibBundle method without calling super. For the object to be initialized properly, you must call super on any init or initWithNibName method you are overriding for your view controllers.For more detail please see:
The code is as follows, rowsToUpdate is NSMutableArray *, [sites count] is greater than 0, and there is value for row index, but [rowsToUpdate count] always returns 0:
for (int i=0; i<[sites count]; i++) {
NSLog(@"row index: %i, %@", i, [NSString stringWithFormat:@"%i", i]);
[rowsToUpdate addObject:[NSString stringWithFormat:@"%i", i]];
NSLog(@"[rowsToUpdate count] = %i", [rowsToUpdate count]);
}
There is no obvious problem with the code, and it doesn’t make sense to return 0.
After a couple of search, I found it on stackoverflow.com that I missed the initialization for “rowsToUpdate”. The fix is as follows (a couple lines of code added):
if (rowsToUpdate == nil) {
rowsToUpdate = [[NSMutableArray alloc] init];
}
else {
[rowsToUpdate removeAllObjects];
}
for (int i=0; i<[sites count]; i++) {
NSLog(@"row index: %i, %@", i, [NSString stringWithFormat:@"%i", i]);
[rowsToUpdate addObject:[NSString stringWithFormat:@"%i", i]];
NSLog(@"[rowsToUpdate count] = %i", [rowsToUpdate count]);
}
# Loading a string from a website
(this will block until it loads)
NSURL *url;
NSData *data;
NSString *blork;
url = [NSURL URLWithString: @"https://langui.net/"];
data = [url resourceDataUsingCache: NO];
blork = [[NSString alloc] initWithData: data encoding: NSASCIIStringEncoding];
# Loading an image from a website
(this will block until it loads)
NSURL *url;
NSData *data;
NSImage *blork;
url = [NSURL URLWithString: @"https://langui.net/wp-content/uploads/2011/03/banner.png"];
data = [url resourceDataUsingCache: NO];
blork = [[NSImage alloc] initWithData: data];
# Open an URL in iphone safari
NSURL *url = [NSURL URLWithString: @"https://langui.net/"];
[[UIApplication sharedApplication] openURL: url];
More tips available here: http://borkware.com/quickies/
As Objective-C is a superset of C, it allows developers to mix pure c source files with Object-C source files.
But to call a C function from Objective-C, you should not import the .c file in your Objective-C .m file, that won’t work.
To call a C function from the Objective-C, you need to create a .h header file to include the C function declaration, and, of cause, include the .h file in the .c source file where the C function resides. Then import the .h file in the .m source file where you would like to call the C function, and simply call the function.