Xcode Debugger: view value of variable

Question

My code in a UITableViewController:

delegate.myData = [myData objectAtIndex:indexPath.row];

How can I see the values of delegate.myDa

Answer 1

Check this How to view contents of NSDictionary variable in Xcode debugger?

I also use

po variableName
print variableName

in Console.

In your case it is possible to execute

print [myData objectAtIndex:indexPath.row]  

or

po [myData objectAtIndex:indexPath.row]

Answer 2

Your confusion stems from the fact that declared properties are not (necessarily named the same as) (instance) variables.

The expresion

indexPath.row

is equivalent to

[indexPath row]

and the assignment

delegate.myData = [myData objectAtIndex:indexPath.row];

is equivalent to

[delegate setMyData:[myData objectAtIndex:[indexPath row]]];

assuming standard naming for synthesised properties.

Furthermore, delegate is probably declared as being of type id<SomeProtocol>, i.e., the compiler hasn’t been able to provide actual type information for delegate at that point, and the debugger is relying on information provided at compile-time. Since id is a generic type, there’s no compile-time information about the instance variables in delegate.

Those are the reasons why you don’t see myData or row as variables.

If you want to inspect the result of sending -row or -myData, you can use commands p or po:

p (NSInteger)[indexPath row]
po [delegate myData]

or use the expressions window (for instance, if you know your delegate is of actual type MyClass *, you can add an expression (MyClass *)delegate, or right-click delegate, choose View Value as… and type the actual type of delegate (e.g. MyClass *).

That being said, I agree that the debugger could be more helpful:

• There could be an option to tell the debugger window to use run-time type information instead of compile-time information. It'd slow down the debugger, granted, but would provide useful information;

• Declared properties could be shown up in a group called properties and allow for (optional) inspection directly in the debugger window. This would also slow down the debugger because of the need to send a message/execute a method in order to get information, but would provide useful information, too.

Answer 3

This gets a little complicated. These objects are custom classes or structs, and looking inside them is not as easy on Xcode as in other development environments.

If I were you, I'd NSLog the values you want to see, with some description.

i.e:

NSLog(@"Description of object & time: %i", indexPath.row);

Answer 4

Try Run->Show->Expressions

Enter in the name of the array or whatever you're looking for.

Answer 5

Also you can:

1. Set a breakpoint to pause the execution.
2. The object must be inside the execution scope
3. Move the mouse pointer over the object or variable
4. A yellow tooltip will appear
5. Move the mouse over the tooltip
6. Click over the two little arrows pointing up and down
7. A context menu will pop up
8. Select "Print Description", it will execute a [object description]
9. The description will appear in the console's output

IMHO a little bit hidden and cumbersome...

Answer 6

You can print values onto console window at run-time. Below are steps :

1. Place a break-point for which you want to get values
2. Now perform step-by-step debug.
3. Place a cursor on variable/delegate whose value is to be checked at run-time.
4. Now this will show description of variable/delegate
5. Clicking on "i" will show detailed description
6. This will also print details onto console window.