This is how to get the version number of your app at run time. I find this helpful in to use in the “about” section of my apps. The version number is read from your apps info.plist file.
NSString *version = [[[NSBundle mainBundle] infoDictionary] objectForKey:@"CFBundleVersion"];
There are several ways to problematically detect if an iPhone has an internet connection, but most of them cant tell you how the iPhone is connected to the internet.
Apple has sample code to accomplish just this task. The Reachability class is not shipped with the SDK, but is part of a sample project of the same name. http://developer.apple.com/iphone/library/samplecode/Reachability/index.html
Set up:
Sample Usage:
Reachability *reachability = [Reachability sharedReachability];
[reachability setHostName:@"www.JoshHighland.com"];
NetworkStatus remoteHostStatus = [reachability remoteHostStatus];
if(remoteHostStatus == NotReachable) {
//no internet connection
}
else if (remoteHostStatus == ReachableViaWiFiNetwork) {
//wifi connection found
}
else if (remoteHostStatus == ReachableViaCarrierDataNetwork) {
//EDGE or 3G connection found
}
The wrong way to do string comparisons in the iPhone SDK
if(myTitle == @"HELLO")
The right way
if([myTilte isEqualToString:@"HELLO"])
I found an interesting issues with the iPhone SDK and the UIPickerView
The didSelectRow method gets called after a users selects a new value on a picker wheel. The method knows what wheel (component) was spun and the index of the newly selected value. This works great for a picker with a single wheel. My picker had 5 wheels in it.
If I spun two components of the picker at the same time. I would only get one call to the didSelectRow method. More specifically, if I spin one component and move another component no call was received until the first component stops spinning, and so the second component move is never registered.
Long story short, I didn’t catch this problem when I submitted my app, “Ka-Ching”, to the iTunes store. As a result of not catching this, Apple rejected my app. I could argue that the iPhone SDK should have so programmatic hooks that would only allow one component to be spun at a time, or even a method to return the state of all of components in the picker.
Trying to figure out a solution to the problem I expanded on my idea of recording the state of all the components in the picker when the didSelectRow method was called. Realistically, by the time that didSelectRow gets processed it is possible that all 5 of the components had changed.
Looking through the SDK documentation for the UIPickerView I came across this:
- (NSInteger)selectedRowInComponent:(NSInteger)component
With this method you can determine the selected row index for any of the components in your picker. you don’t have to rely on the values passed into the didSelectRow method.
- (void)pickerView:(UIPickerView *)thePickerView
didSelectRow:(NSInteger)row
inComponent:(NSInteger)component
{
//get the value of the component that was changed
if(component == 0)
{
currency_value = [currency objectAtIndex:row];
}
else if(component == 1)
{
hundereds_value = [hundereds objectAtIndex:row];
}
else if(component == 2)
{
tens_value = [tens objectAtIndex:row];
}
else if(component == 3)
{
ones_value = [ones objectAtIndex:row];
}
else if(component == 4)
{
change_value = [cents objectAtIndex:row];
}
//some code here to save the values
}
- (void)pickerView:(UIPickerView *)thePickerView
didSelectRow:(NSInteger)row
inComponent:(NSInteger)component
{
//get the values
NSInteger currency_NewRow = [thePickerView selectedRowInComponent:0];
NSInteger hundereds_NewRow = [thePickerView selectedRowInComponent:1];
NSInteger tens_NewRow = [thePickerView selectedRowInComponent:2];
NSInteger ones_NewRow = [thePickerView selectedRowInComponent:3];
NSInteger cents_NewRow = [thePickerView selectedRowInComponent:4];
//some code to save the values
}