I ran across a strange problem today. Tried something like this:

switch(controlVariable) {

case 0:

NSInteger x = kSomeConstant;

// some other code…

break;

case 1:

// …

default:

// …

}

And to my surprise, XCode complained saying that “Parse error: Expected Expression”. Upon googling, this is what I found.

So, the solution is to put some statement before you initialize NSInteger. If there is no statement that logically fit, you can simply insert a semi-colon “;” before declaring and initializing the integer.

switch(controlVariable) {

case 0:

;

NSInteger x = kSomeConstant;

// some other code…

break;

case 1:

// …

default:

// …

}

If you see this problem, try following these steps.

a) quit Xcode (and the GDB it is running)
b) unplug device
c) delete app from device (hold icon until the ‘X’ appears)
d) turn off device
e) turn on device
f) plug in device (if itunes wants to sync, let it finish)
g) launch Xcode

There are scenarios when one does some heavy weight fetching of data from an external database thats time consuming. During the fetching, we want to give appropriate feedback to user that something is being done. Thats when Activity Indicator (UIActivityIndicator) object comes in handy. Its a spinner that shows and spins and then stops animating and disappears when the process is finished.

A point to be noted is that one should always start Spinner in a separate thread.

Wrong (works only sometimes):

[activityindicator startanimating];
//Some code
[activityindicator stopanimating];

Right

[NSThread detachNewThreadSelector:@selector(threadStartAnimating: ) toTarget:self withObject:nil];
// Some code  
[spinner stopAnimating];
[self.navigationcontroller pushviewcontroller:viewcontroller animated:YES]; 

-(void)threadStartAnimating: (id)data
{
[spinner startAnimating];
}