Phasic Labs Dev Blog game development musings from Phasic Labs

XCode, iPhone, and updating resources

A bit of a techy blog post this time, but hopefully this will be of use to any iPhone developers out there.

It's a well know problem that if you add resources to your App using Folder References, rather than manually adding each resource to your project, then if you update the contents of the folder externally to XCode, XCode does not always update the resources in your App next time you build.

See http://majicjungle.com/blog/123/ for more info on this, and a workaround that seems to work for some people (a script that touches the resource files).

I've tried using a similar script to the one described at the previous link however, and still find that I have to regularly clean and rebuild my app to get the latest levels into my game.
This can be vey time consuming when you are tweaking a level, and need to make small changes and restart the game often.

I finally came up with a solution that works for me every time.

Rather than letting XCode manage my resources (using the Target's default Copy Bundle Resources script), I wrote my own script to copy resources directly into the built App.

I'll walk through an example of how I did this for the game I'm currently developing.

The game has a folder called Levels, with a number of subfolders (world0, world1, etc.), and each subfolder has a load of individual level definition files.

I had originally dragged the Levels folder into my project Resources, as a folder reference. XCode automatically adds the folder to the Copy Bundle Resources script of the project Target.

To see this in your own project, expand the Targets section in the project tree-view, then expand the actual target node, and you'll see all the build phases. Expand the Copy Bundle Resources node, and you'll see everything that XCode will try and copy into your App.

So, I deleted the Level folder from the Copy Bundle Resources script, right-clicked on the target, and select Add->New Build Phase->New Run Script Build Phase.

I then renamed the new script to something meaningful, and double-clicked it to begin editing.

Firstly, I set the Shell to /bin/bash, and then entered a script that deletes any existing Levels folder from the built App, and then copies it back in from the game's source folder.

The script is as follows :

#!/bin/bash

echo "forcing refresh of level XMLs...";

if [ -d "${BUILT_PRODUCTS_DIR}/${EXECUTABLE_NAME}.app/levels" ]; then
rm -r ${BUILT_PRODUCTS_DIR}/${EXECUTABLE_NAME}.app/levels;
fi

cp -R -p ${SRCROOT}/levels ${BUILT_PRODUCTS_DIR}/${EXECUTABLE_NAME}.app/levels;

This ensures any old levels are cleaned out (as XCode can also leave old files behind), and that all of the levels copied back in are the latest ones.
Nice and simple! No more having to fully clean and rebuild each time a file is modified.

Another useful feature of writing your own copy script is that you can copy different things depending on your build configuration, or target, eg.

echo build config : ${CONFIGURATION}, target : ${CURRENT_ARCH};

if ( [ "${CURRENT_ARCH}" = "i386" ] && [ "${CONFIGURATION}" = "Debug" ] );
then
...
else
...
fi

This script would do one thing if you were build a Debug App for the Simulator, and another thing for every other build configuration/target.