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cordova-plugin-hello-c

1.1.1 • Public • Published

cordova-plugin-hello-c

A simple example of a Cordova plugin that uses pure C code.

It illustrates how to use platform-specific (either Android or iOS) C code and how to share C code cross-platform (between Android and iOS).

For Android it utilizes the Android NDK to compile architecture-specific libraries and a JNI wrapper to expose the C functions to the Java plugin API.

For iOS it uses the pure C source code in place alongside the Objective-C plugin wrapper, as well as an example cross-platform library compiled as a static library for iOS.

usage example

  • Clone the test project
  • Add Android and iOS platforms: cordova platform add android && cordova platform add ios
  • Run: cordova run android / cordova run ios

Plugin structure

  • plugin.xml - Specifies the plugin's source files and libraries to copy to the platforms of the Cordova project into which the plugin is installed
  • compile-android and compile-android.cmd - Script to recompile C source code as a shared library for use with Android platform
  • compile-ios - Script to recompile cross-platform C library as static library for use with iOS platform
  • src/ - C source code and build scripts
    • common/ - cross-platform C source code to run on both Android and iOS
      • mylib/ - example cross-platform C library
    • android/ - source code and build scripts for Android platform
      • build-extras.gradle - Gradle build script to link up the NDK make file for debugging C code in Android Studio
      • HelloCPlugin.java - Provides the native Java implementation for Android of the Cordova plugin
      • HelloCJni.java - Provides the Java interface to the underlying JNI C implementation
        • jni/ - JNI C implementation and build script
          • HelloJni.c - C implementation of the JNI interface defined by HelloCJni.java, including
            • Android-specific implementation to get current CPU architecture
            • interfaces to cross-platform C functionality
          • Android.mk - NDK Make script to build the C source code into architecture-specific shared libraries
        • libs/ - contains folders for the various architecture-specific shared libraries built by the NDK Make script
    • ios/ - source code and build scripts for iOS platform
      • c_getArch.c & c_getArch.h - iOS-specific implementation to get current CPU architecture
      • HelloCPlugin.c & HelloCPlugin.h - Provides the native Objective-C implementation for iOS of the Cordova plugin
      • ios_compile.sh - Script to compile the cross-platform example library in src/common/mylib/ as a static library
      • Makefile - Make script invoked by the above script to perform the C compilation.
      • libs/ - the compiled cross-platform library
        • libmylib.a - the compiled cross-platform library as a multi-architecture static library
        • headers/ - the header files of the cross-platform library (static libraries require the headers externally)

Recompiling libraries

If you modify the C source files, be sure to re-build the compiled libraries.

Android

You can re-build the libhelloc.so binaries using the ndk-build script.

To do so:

  • Install Android NDK as instructed here
  • Add the NDK install path to your path environment variable
    • By default it's installed under $ANDROID_SDK_HOME/ndk-bundle
    • e.g. export PATH=$PATH;$ANDROID_SDK_HOME/ndk-bundle
  • Set the ANDROID_NDK_HOME environment variable to your NDK install path
    • e.g. export ANDROID_NDK_HOME=$ANDROID_SDK_HOME/ndk-bundle
  • Open terminal in plugin root folder
  • Run ./compile-android (compile-android.cmd on Windows)

If you are editing the C source code of the plugin in place in the example project:

  • Modify the C source in plugins/cordova-plugin-hello-c/src/android/jni or plugins/cordova-plugin-hello-c/src/common
  • Open terminal in plugins/cordova-plugin-hello-c
  • Delete src/android/libs and src/android/obj
  • Run compile-android (compile-android.cmd on Windows)
  • From the project root, remove and re-add the android platform to apply the plugin changes to the project cordova platform rm android && cordova platform add android

iOS

If you modify the C source code in common/mylib/ you'll need to rebuild the static library and headers in src/ios/libs.

  • Open terminal in plugin root folder
  • Run ./compile-ios

If you are editing the C source code of the plugin in place in the example project:

  • Modify the C source in plugins/cordova-plugin-hello-c/src/ios/ or plugins/cordova-plugin-hello-c/src/common
  • Open terminal in plugins/cordova-plugin-hello-c
  • Run ./compile-ios
  • From the project root, remove and re-add the platform to apply the plugin changes to the project cordova platform rm ios && cordova platform add ios

Debugging C source code

Android

  • The Android NDK enables C/C++ source code to be debugged in Android Studio alongside Java.
  • To do so, the source code must be included but not the compiled libraries.
  • To debug this plugin in Android Studio do the following:
    • Edit plugin.xml and in the <platform name="android"> block, comment out the source-file lines in the PRODUCTION block which include the compiled libraries
    • Remove/re-add the plugin or Android platform in your project to update the plugin files in the platform project
    • Open the Android platform project (platforms/android) in Android Studio
    • Connect an Android device for debugging
    • Use the Project Explorer to find and open one of the .c source files
    • Place a breakpoint, for example on a return statement
    • Select "Run" > "Debug ..." from the menu

iOS

  • Since iOS is a C-based platform, C debugging is inherently supported in the Xcode IDE
  • However, to debug the C code in the static library src/ios/libs/libmylib.a, you'll need to comment out the library files and comment in the source code for it:
  • Edit plugin.xml and in the <platform name="ios"> block
    • comment out the lines in the PRODUCTION block which include the compiled library and headers.
    • comment in the the commented-out lines in the DEBUG block which will include the uncompiled C source code for the library
  • Remove/re-add the plugin or iOS platform in your project to update the plugin files in the platform project
  • Use the OSX Finder to browse to platforms/ios/ in your Cordova project and double-click the .xcodeproj file to open it in Xcode.

Install

npm i cordova-plugin-hello-c

DownloadsWeekly Downloads

23

Version

1.1.1

License

MIT

Unpacked Size

444 kB

Total Files

40

Last publish

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