We can use something called Fast Enumeration for this, using a modified for loop: // build an array NSArray *myArray = [[NSArray alloc]initWithObjects:@”One”, @”Two”, @”Three”, @”Four”, nil]; // loop through every element (dynamic typing) for (id tempObject in myArray) { NSLog(@”Single element: %@”, tempObject); } You don’t have to use dynamic typing if you know […]
We can use the C function rand() for this: int i = rand()%10+1; NSLog(@”Random Number: %i”, i); This generates an integer between 1 and 10. Alternatively you can use the arc4random function: int i = arc4random() % 10; NSLog(@”Random Number: %i”, i); This will generate a random number between 0 and 9. One thing of […]
Imagine we had a file called myfile.txt which is a standard text file. On each line we have a new item we’d like to read so that our app can do something with it. Here’s how we do that: // get a reference to our file NSString *myPath = [[NSBundle mainBundle]pathForResource:@”myfile” ofType:@”txt”]; // read the […]
What you really want is a method such as (BOOL)networkIsAvailable, returning YES or NO. Apple made it several megabytes long and requires you to study several years before you get to YES or NO. I hate that! This is such a basic function on an always-connected device that I find it appalling not to have […]
Once you have a reference to the file in question you can call the removeItemAtPath method: // get reference with path and filename NSString *filePath = [[NSString alloc]initWithFormat:@”Documents/myFile.txt”]; NSString *deleteThis = [NSHomeDirectory()stringByAppendingPathComponent:filePath]; // now delete the file [[NSFileManager defaultManager]removeItemAtPath:deleteThis error:nil]; This does not work with wildcards in the file name (for example *.jpg).
You can see the full directory under ~Library/Application Support/iPhone Simulator You’ll be presented with a list of iOS Versions, each of which has several folders to explore. To access data that your apps have written, head over to Applications and see a list of cryptic folders, each one corresponding to one of your apps. In […]
Imagine we had a file that we’ve saved: NSString *myFile = [NSHomeDirectory() stringByAppendingPathComponent:@”Documents/myFile.txt”]; Before accessing it we can determine if it exists or not: BOOL fileExists = [[NSFileManager defaultManager] fileExistsAtPath:[NSHomeDirectory()stringByAppendingPathComponent:myFile]];
When a new iOS version comes out, developers can get pre-release Beta Versions to test their apps. New betas can be installed over the air, but if the release version comes out then there’s no over the air upgrade for those. Instead, it appears that you already have the latest version installed – even though […]
