How to show current Git branch in an Android application programatically?

Question

I want to show the current Hash/Branch Ref of the GIT repo in the About dialog of my Android Application. I can copy it by hand, but it's much more interesting to do it programmatically.

I have a library for my apps, so my activities and my applications inherit from my own library classes. So, I thought of adding a method [getGitHash()] to my library application class. I can refer to the current branch by reading .git/HEAD, which is virtually referenced in a res/raw file under Eclipse project (look here to see how it's done). My project has the R.raw.HEAD resource now.

But now the library can't reference the R.raw.HEAD, so I can't implement the method in the library. The method in the library should be something like this:

public static String getGitHash(int nDigits) {
    
    String hash = "";
    SB_ResourceReader.LoadRAWFile(R.raw.HEAD,SB_Application.getContext());
    return hash;
}

LoadRAWFile() is a static method to read raw file content and SB_Application.getContext() is another static method to retrieve... well, the app context.

Is it possible for the library to 'trust' that there will be a certain resource although it is not accessible when compiling?

Answer 1

More easily (without any plugin), you can achieve this by setting a new resource in your app.gradle like so:

android {
    defaultConfig {
        minSdkVersion 16
        targetSdkVersion 25
        versionCode 1
        versionName "1"
        resValue "string", "gitBranch", gitBranch()
    }
    buildTypes {...}
}


def gitBranch() {
    def branch = ""
    def proc = "git rev-parse --abbrev-ref HEAD".execute()
    proc.in.eachLine { line -> branch = line }
    proc.err.eachLine { line -> println line }
    proc.waitFor()
    branch
}

So you'll have access to a new string resource

getString(R.string.gitBranch)

Answer 2

write in the end of build.gradle reuse fun to execute some commands,

static def getExecute(command) {
  def result = ""
  def proc = command.execute()
  proc.in.eachLine { line -> result = line }
  proc.err.eachLine { line -> println line }
  proc.waitFor()
  return result 
}

then you have 2 options:

• 1: buildConfig

   buildConfigField "String", "BUILD_TIME", "\"${getExecute("git rev-parse --abbrev-ref HEAD")}\""
   buildConfigField "String", "GIT_BRANCH", "\"${getExecute("git rev-parse --abbrev-ref HEAD")}\""
   buildConfigField "String", "GIT_COMMIT", "\"${getExecute("git rev-parse --short HEAD")}\""
   buildConfigField "String", "GIT_COMMIT_NAME", "\"${getExecute("git show-branch --no-name HEAD")}\""
   buildConfigField "String", "GIT_LAST_COMMIT_TIME", "\"${getExecute(" git log -1 --format=%cd")}\""
   buildConfigField "String", "GIT_UESRNAME", "\"${getExecute("git config user.name")}\""
   buildConfigField "String", "GIT_EMAIL", "\"${getExecute("git config user.email")}\""
  

  and call them like this,

  private fun getGitInfo() :String {
    var gitInfo = ""
  
    gitInfo += "build time: " + BuildConfig.BUILD_TIME + "\n"
    gitInfo += "branch: " + BuildConfig.GIT_BRANCH + "\n"
    gitInfo += "commit: " + BuildConfig.GIT_COMMIT + "\n"
    gitInfo += "commit name: " + BuildConfig.GIT_COMMIT_NAME + "\n"
    gitInfo += "time: " + BuildConfig.GIT_LAST_COMMIT_TIME + "\n"
    gitInfo += "username: " + BuildConfig.GIT_UESRNAME
    gitInfo += "email: " + BuildConfig.GIT_EMAIL
  
    return gitInfo
  }
  

• 2: resValue

  resValue "string", "build_time", getExecute("date")
  resValue("string", "git_branch", "\"${getExecute("git rev-parse --abbrev-ref HEAD")}\"")
   resValue("string", "git_commit", "\"${getExecute("git rev-parse --short HEAD")}\"")
   resValue("string", "git_commit_name", "\"${getExecute("git show-branch --no-name HEAD")}\"")
   resValue("string", "git_last_commit_time", "\"${getExecute(" git log -1 --format=%cd")}\"")
   resValue("string", "git_username", "\"${getExecute("git config user.name")}\"")
   resValue("string", "git_email", "\"${getExecute("git config user.email")}\"")
  

  and call them like this,

  private fun getGitInfo() :String {
    var gitInfo = ""
    gitInfo += "build time: " + getString(R.string.build_time) + "\n"
    gitInfo += "branch: " + getString(R.string.git_branch) + "\n"
    gitInfo += "commit: " + getString(R.string.git_commit) + "\n"
    gitInfo += "commit name: " + getString(R.string.git_commit_name) + "\n"
    gitInfo += "time: " + getString(R.string.git_last_commit_time) + "\n"
    gitInfo += "username: " + getString(R.string.git_username) + "\n"
    gitInfo += "email: " + getString(R.string.git_email)
  
    return gitInfo
  }