For example, this screenshot from Xcode looks rather innocuous:

However, if I copy and paste the same code into the editor that I am using to write this post, the formatting looks as follows:

- (void)applicationDidFinishLaunching:(UIApplication *)application 
{   
  // Create and initialize the window
	window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
  window.backgroundColor = [UIColor blackColor];
 
	// Create test view controller
	vc = [[MainViewController alloc] init];
 
  [window makeKeyAndVisible];
  [window addSubview:[vc view]];
 
}

Within Xcode 4, in the Editor drop-down menu there is an option to Show Invisibles. Once enabled, you can see where tabs and spaces are embedded within the code.

Space characters are shown as a diamond shape – the red boxes (I added) highlight where tab characters are embedded in the source code, resulting in the funky formatting shown above. Replace the tabs with spaces and all is well.

Notice in the figure above one of the options is the Includes list, which provides quick access to files included in both the interface (.h) and the implementation (.m) file that is open. Here’s something interesting to try – click on a source file (.m) and choose the Assembly option. This offers a look at the assembly language code created by the compiler, makes one appreciate higher level languages…

The contents of the related files changes (ever so slighty) based on which Navigator is active and which entry in active navigator is selected. For example, in the screenshot that follows the Project navigator is active (red box) and the project entry is selected (yellow box) – in this scenario, the related files shown are only the recently opened files and the unsaved files.

There is a popup menu available by clicking on each separate section of the Jump Bar. For example, clicking on the title SandboxAppDelegate.m will bring up a list of all the other files stored at the same location in the project hierarchy. Notice in the screenshot below that the file list shown in the popup is the same as shown in the project navigator.

Jump Bar Tip #1 – Sorting

You can sort the entries in the popup list by Command-clicking the Jump Bar. In the screenshot below is the same popup shown above, however, all the entries are now sorted.

Jump Bar Tip #2 – Type Ahead

Once a popup is displayed, you can type ahead to narrow the list of entries. This is really handy if you have a long list of files or methods and are looking for a specific entry.

The screenshot below shows the popup for the file list:

As I type characters, the list of the entries narrows based on my search:

Jump Bar Tip #3 – Open in Assistant Editor

To open a file in the assistant editor, from within the popup showing the file list, Option-click the desired file. If you are viewing a popup of the methods in a file, if you Option-click, the file containing the method will be opened in the assistant editor, and the selected method will be highlighted:

Now, select a variable within your code, and notice that all references within the current scope will be highlighted. For example, below I selected (double tapped) username and all references are now underlined.

In the above figure notice the drop down arrow next to the first instance that I referenced. Tapping this arrow brings up an dialog, given the configuration of my system, the dialog looks as follows:

The values in your dialog may be different based on your system configuration.

If you choose the Edit All in Scope, Xcode will highlight all references and allow you to change the name of the selected variable. Changes will cascade through to each reference of the variable.

Using this tip you can quickly change all references to a variable in the current scope, watching the changes take place as you type.

To update a project (if Xcode does not notify you when opening a project):

- Switch to the Project Navigator

- From the Editor menu, choose Modernize Project

Interestingly, when viewing the Editor menu, sometimes an option to Validate Settings (versus Modernize Project) is shown:

In either case, a dialog box appears listing a number of options you can elect to have updated:

Once complete, your projects will be compatible with Xcode 4.

One additional option to initiate updating a project is to click the Modernize Project button (shown below) from with the Project Navigator when viewing the Build Settings – thanks Andrea for the email pointing this out:

> Xcode – Preferences
> Select Fonts and Colors tab (across the top)
> Select a theme on the left menu

Below are screenshots of the Default, Sunset and Midnight themes. There is also a Presentation theme where the font sizes have been increased, this is handy if you ever need to show your code to others via an overhead projector.

Create a New Theme

You can create a new theme and customize the look however you like – click the + at the bottom left of the preference dialog to create a new theme – you will be shown a list of available themes to duplicate as a starting point:

Hidden Theme

There is a theme that is not shown in the original theme list – look at the figure above, I’ve drawn a rectangle around Spartan, which is only shown when creating a new theme. To give this theme a try, create a new theme and select Spartan as the theme to duplicate.

In a tip nearly a year ago, Xcode and #pragma mark, I described how to insert pragma mark directives to organize your code.

#pragma mark -
#pragma mark Initialization

Here is how things may look with multiple pragma directives:

With Xcode 4, you can now combine both pragma statements into one line:

#pragma mark - Initialization

To remove a documentation begin by clicking the arrow enclosed in the box on the lower left corner (shown in the red box in the Figure above).

A window will expand showing additional information about the documentation. The Installed Location value is a link showing where on your system the documentation is installed.

If you click on the link, Finder will open showing the folder with the API document.

Delete the document in Finder and return to Xcode, you’ll now see the doc set removed from the list.

In the screenshot below, I highlighted the local variable dict and then entered Control-Command-T. Notice that each reference to this variable is now highlighted. An important note, you don’t need to necessarily highlight the first instance of the variable for this to work.

Once all the variables are highlighted, make the change to the new name and you’ll see all references updated in unison, see the figure below:

Tap your mouse anywhere outside the variable to complete the change.

The tool doing the optimization is pngcrush, an open source utility available on SourceForge.

Undo pngcrush Optimizations

If you have iPhone SDK 3.2 or greater installed (and did not change the default install path), pngcrush is located here: /Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/pngcrush

If you would like view or otherwise open PNG files within an Xcode build (.app file), you will need to revert the optimizations on the file, the command line syntax for this is shown below:

/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin/pngcrush
-revert-iphone-optimizations -q OptimizedPNG.png RevertedPNG.png

OptimizedFile.png is the name of the optimized PNG inside the .app bundle, RevertedPNG.png is the file output by pngcrush after the optimizations are removed.