How do I debug with NSLog(@“Inside of the iPhone Simulator”)?

Question

I\'m used to programming and having log messages be viewable. I know you used to be able to use NSLog() to trace out messages when debugging Cocoa applications.

Answer 1

There's a far more convenient way to trace with log messages in Xcode, and that's using Breakpoint Actions.

On the line of code where you'd be tempted to add a printf or NSLog, set a breakpoint, then control-click it and choose "Edit Breakpoint". In the blue bubble that appears, click the + button on the right to open the Breakpoint Actions: alt text http://idisk.mac.com/cdespinosa/Public/Breakpoint%20Actions.png

Enter your log text there. Any expression that can be printed in the Debugger can be used when delimited by @ signs.

For debugging Objective-C it's generally more useful to choose "Debugger Command" from the popup and enter 'po [[object method] method]' to print the description string of an Objective-C object or the result of a method call.

Make sure to click the "Continue" checkbox at the top right so execution continues after the log.

Advantages of this over NSLog and printf:

• It's on the fly. You don't have to recompile and restart to add or edit log messages. This saves you a lot of time.
• You can selectively enable and disable them. If you learn enough from one, but its spew is interfering, just uncheck its Enabled box.
• All the output is generated on your Mac, never on the iPhone, so you don't have to download and parse through logs after the fact.
• The chance of shipping console spew in your application is significantly decreased.

Also check out the Speak button; it's great for debugging full-screen apps where you can't see the debug log.