/ios-static-library

Exemple how to create a static library

Apache License 2.0Apache-2.0

Video Tutorial for create a static library on ios

@rubijn

This is help for video http://youtu.be/f7lxkv-sZA0

1. Create Static Library
2. Create Project who use the library
3. Use categories in library
4. Add Automate for merging categories

###1. Create static library

####1.1 Create from template First we must create a static library project

  • File > New > Project
  • Chose iOs / Framework & Library
  • Select Cocoa Touch Static Library
  • Name the project MyStaticLibrary

####1.2 Create a custom object

  • File > New > File
  • Choose iOs / Cocoa Touch
  • Select Objective-C class
  • Name the file MyCustomObject
  • Add this method to the @interface and @implementation

MyCustomObject.h

@interface MyCustomObject : NSObject
  -(void)aMethod;
@end

MyCustomObject.m

@implementation MyCustomObject
  -(void)aMethod {
    NSLog(@"call MyCustomObject method !");
}
@end

  • Add MyCustomObject.h to build phase

    • Select target MyStaticLibrary
    • Select Build Phases tab
    • Expend Copy Files
    • Click on + to add MyCustomObject.h

  • Add MyCustomObject.h to MyStaticLibrary.h (optional)

MyStaticLibrary.h

#import <Foundation/Foundation.h>
#import "MyCustomObject.h"

@interface MyStaticLibrary : NSObject
@end

####1.3 Compile the lib for ios et simulator We need now to build .a file (compiled library file)

We must compile for ios device AND for ios simulator (i386 arch)

  • Select MyStaticLibrary > iOs Device and Build (⌘ + B)
  • Select MyStaticLibrary > iPhone 6.1 Simulator and Build (⌘ + B)

####1.4 Look at the directory we must merge the two library

  • Expand Products in File Browser view
  • Select libMyStaticLibrary.a
  • Right Button > Show in Finder
  • Move up in directory

You must have this hierarchy

  • Products/Debug-iphoneos/libMyStaticLibrary.a
  • Products/Debug-iphonesimulator/libMyStaticLibrary.a

For using this two library in a new project, we must merge it in one single file .a

  • open Terminal
  • cd /Products/

Launch this command

lipo -create Products/Debug-iphoneos/libMyStaticLibrary.a Products/Debug-iphonesimulator/libMyStaticLibrary.a -output libMyStaticLibrary.a

After that we can use this new merged library in a new project

================== ###2. Create a new project who use the library

####2.1 Create from simple view

  • File > New > Project
  • Chose Application / Single View Application
  • Name the project MyAppUsingCustomLibrary

####2.2 Drag the .a file and include from the build directory

  • Drag merged library libMyStaticLibrary.a into project
  • Drag include from Debug-iponeos or Debug-iphonesimulator in the project

####2.3 in Viewcontroller add a call to MyCustomObject Edit Viewcontroller.m

MyCustomObject *obj = [[MyCustomObject alloc] init];
[obj aMethod];
[obj release];

####2.4 compile it's work Look at the output pannel

2013-09-16 23:38:27.838 MyAppUsingCustomLibrary[1138:c07] call MyCustomObject method !

================== ###3. Use categories in library

When we want to use a custom category in your library follow this method.

####3.1 create a UIImage-Custom class

  • File > New > File
  • Choose iOs / Cocoa Touch
  • Select Objective-C class
  • Name the file UIImage-Custom
  • Add this method to the @interface and @implementation

UIImage-Custom.h

@interface UIImage (Alpha)
-(BOOL)hasAlpha;
@end

UIImage-Custom.m

@implementation UIImage (Alpha)
-(BOOL)hasAlpha {
  return NO;
}
@end

####3.2 import the UIKit in library project

  • Select MyStaticLibrary Target
  • Select Build Phases
  • Expend Link Binary
  • Add UIKit

####3.3 compile for iphone an simulator

  • Build / iOs Device
  • Build / iPhone Simulator
  • Merge the two .a with the lipo command see at 1.4

####3.4 return to app who use the library Add usage of UIImage hasAlpha

Edit Viewcontroller.m

UIImage *img = [[UIImage alloc] init];
NSLog(@"hasAlpha ? %i", [img hasAlpha]);
[img release];

####3.5 Compile = Error

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', 
reason: '-[UIImage hasAlpha]: unrecognized selector sent to instance 0x8a437a0'

We need to add flags to the Build Settings

####3.6 Add -ObjC -all_load to Other link flags

  • Select Target
  • Select Build Settings tab
  • In the search input enter "other linker"
  • Select Other Linker Flags
  • Add -ObjC and -all_load

####3.7 Compile it's work Build and now the categroy working

2013-09-16 23:51:44.621 MyAppUsingCustomLibrary[1289:c07] hasAlpha ? 0

================== ###4. Automate the merge for iphone and simulator

####4.1 Add a Aggregate target to library project MyStaticLibraryAggregate

  • File > New > Target
  • Select Other
  • Select Aggregate
  • Enter name MyStaticLibraryAggregate

####4.2 Add Build Script

  • Select target MyStaticLibraryAggregate
  • Select Build Phases Tab
  • Click on Add Build Phase (bottom right)
  • Add Run Scripts

####4.3 Enter the scripts bellow

# set target for final .a file
TARGET_OUTPUT=${BUILD_DIR}/${CONFIGURATION}-universal

# compile projet in 2 version iphoneos and iphonesimulator
xcodebuild -target MyStaticLib ONLY_ACTIVE_ARCH=NO -configuration ${CONFIGURATION} -sdk iphoneos BUILD_DIR="${BUILD_DIR}" BUILD_ROOT="${BUILD_ROOT}"
xcodebuild -target MyStaticLib -arch i386 -configuration ${CONFIGURATION} -sdk iphonesimulator BUILD_DIR="${BUILD_DIR}" BUILD_ROOT="${BUILD_ROOT}"

# create universal directory if not exists
mkdir -p "${TARGET_OUTPUT}"

# merge two lib in universal one
lipo -create "${BUILD_DIR}/${CONFIGURATION}-iphoneos/lib${PROJECT_NAME}.a" "${BUILD_DIR}/${CONFIGURATION}-iphonesimulator/lib${PROJECT_NAME}.a" -output "${TARGET_OUTPUT}/lib${PROJECT_NAME}.a"

# copy header to universal lib
cp -R "${BUILD_DIR}/${CONFIGURATION}-iphoneos/include" "${TARGET_OUTPUT}/"

####4.4 Compile and go to build dir for see new directory

  • Build > MyStaticLibraryAggregate

Check if no error come from sh script
Now whe have a new Directory

Products/Debug-universal/

Containing merged (universal) library and headers

####4.5 Change link in app project for use the new directory

  • Return to MyAppUsingCustomLibrary
  • Remove old libMyStaticLibrary.a and includes link
  • Add from Products/Debug-universal/libMyStaticLibrary.a and Products/Debug-universal/includes

That all !

Inspired from
http://www.raywenderlich.com/41377/creating-a-status-library-in-ios-tutorial
and
http://blog.coderow.com/2012/08/23/building-an-ios-universal-static-library/