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Creating your own iOS framework

It took a while to make xcode happy with my custom built Python for iOS framework for  enaml native.

Most of it was pretty straightforward (they describe it in their Anatomy of Frameworks docs). You need to simply create the directory structure  they give.

MyFramework.framework/
    MyFramework  -> Versions/Current/MyFramework
    Resources    -> Versions/Current/Resources
    Versions/
        A/
            MyFramework
            Resources/
                English.lproj/
                    InfoPlist.strings
                Info.plist
        Current  -> A


Simple enough. Make a few folders add a few symlinks. Resources is optional, so skip that. Add it into xcode, link it, then either add it as embedded executable or create a copy files rule. Click run, all looks good. Then boom!


Failed to load Info.plist from bundle at path /Users/jrm/Library/Developer/CoreSimulator/Devices/76...FC/data/Library/Caches/com.apple.mobile.installd.staging/temp.zziu4R/extracted/Payload/demo.app/Frameworks/Python.framework


Ok, `Info.plist` missing. Create a Resources folder, add an Info.plist file with what?

Table 2  Framework configuration keys
Key
Description
CFBundleName
The framework display name
CFBundleIdentifier
The framework identifier (as a Java-style package name)
CFBundleVersion
The framework version
CFBundleExecutable
The framework shared library
CFBundleSignature
The framework signature
CFBundlePackageType
The framework package type (which is always 'FMWK')
NSHumanReadableCopyright
Copyright information for the framework
CFBundleGetInfoString
A descriptive string for the Finder

If you create a new Cocoa project with xcode it generates this for you. With content like this:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
   <key>CFBundleDevelopmentRegion</key>
   <string>en</string>
   <key>CFBundleExecutable</key>
   <string>$(EXECUTABLE_NAME)</string>
   <key>CFBundleIdentifier</key>
   <string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
   <key>CFBundleInfoDictionaryVersion</key>
   <string>6.0</string>
   <key>CFBundleName</key>
   <string>$(PRODUCT_NAME)</string>
   <key>CFBundlePackageType</key>
   <string>FMWK</string>
   <key>CFBundleShortVersionString</key>
   <string>1.0</string>
   <key>CFBundleVersion</key>
   <string>$(CURRENT_PROJECT_VERSION)</string>
   <key>NSPrincipalClass</key>
   <string></string>
</dict>
</plist>


So now, create `Info.plist` in the Resrouces of the framework with the above variables filled in. If your using python you can use the `plistlib` built into the standard library to create this for you.

#: Create new  Info.plistplist = dict(
    CFBundleDevelopmentRegion="en",  #: Shouldn't hard code..    CFBundleExecutable=self.name,    CFBundleIdentifier=self.bundle_id or self.name,    CFBundleInfoDictionaryVersion="6.0",    CFBundleName=self.name,    CFBundlePackageType="FMWK",    CFBundleShortVersionString=self.version,    CFBundleVersion=self.version,    NSPrincipalClass="",)

#: Update with any customized paramsplist.update(self.plist)

#: Save itplistlib.writePlist(plist,'Info.plist')


Now copy it to your framework and xcode is happy as a clam!

The Python for iOS toolchain I modified for enaml-native allows you to create or add to frameworks in python using one of the recipes.  Once done it's really simple to add python support to an iOS project (WITH compiled extensions)!

Happy coding!


P.S. Sorry that blogger has pretty terrible support for code! Anyone at blogger heard of markdown? 

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