ApkGenerator

APK Generator

APK Generator is a Python framework that facilitates the execution of experiments involving multiple variations of native Android apps. This framework will allow users to automatically create different versions of their native apps with simple Python code. Note that this framework only runs on Linux distributions using Python3.

How it works

The APK Generator consists of 2 parts: apk_generator.py and config.py. The first, handles all the hard work where it opens all the files in your Android project's Java folder and hands them to the config.py. The config.py implements 2 functions: update_file, which updates an entire Java/Kotlin file, and update_loc which updates individual lines of codes passed down from the apk_generator.py.

apk_generator.py

The APK Generator can be called using:

python 3 %PATH TO%/ApkGenerator/apk_generator.py %PATH TO ANDROID FOLDER% %NUMBER OF RUNS% %KEEP TEMP?%

It accepts the following arguments:

1. Path to Android folder: this is the path to the Android project folder.
2. Number of runs: this is an integer representing how many times the APK creation process is repeated, this is determined by how many different variations you want to create.
3. Keep temp?: this is a boolean (True/False) representing whether to keep the the temporary copy of the Android project with its adjustments.

update_file

The update_file function of config.py looks the following:

def update_file(file_name, file, run):
   # Add your code here
   return False

It receives the following objects:

1. file_name: this is the name of the Java/Kotlin file.
2. file: this is the path to the Java/Kotlin file.
3. run: this is the number of the run. Do keep in mind that this ranges from 0 to (number of runs - 1). This is explicitly done to facilitate the easy use of indexing over lists.

What it should return:

• The function should return a Boolean, whether or not the file has been changed. If False is returned, update_loc will not be called for the individual lines.

update_loc

The update_loc function of config.py looks the following:

def update_loc(file_name, line, run):
   # Add your code here
   return line

It receives the following objects:

1. file_name: this is the name of the Java/Kotlin file that the loc originates from.
2. line: this is a specific line in a Kotlin/Java file.
3. run: this is the number of the run. Do keep in mind that this ranges from 0 to (number of runs - 1). This is explicitly done to facilitate the easy use of indexing over lists.

What it should return:

• The function should return a string object representing the a of code.

How to use

You should only make changes to the config.py and leave the apk_generator.py as-is, unless you want to make changes to the workings of this framework. Alter the update_file and update_loc functions in the config.py to suit your needs. The above section provides you with information on how these functions work. You can also have a look at the examples in the below section. After you have altered config.py, follow these steps on how to use it:

• Run python3 %PATH TO%/ApkGenerator/apk_generator.py %PATH TO ANDROID FOLDER% %NUMBER OF RUNS% %KEEP TEMP?%.
• Find the generated APK's in the Outputs folder.
• OPTIONAL: When you have specified to keep the temporary files, you can find the different versions of the Android project folder in the Temp folder.

Examples

This section contains simple examples of applications for this framework.

update_file

The following application of the update_file function would look for the sentence "Hello World" and replace this with "Hello there". Notice that this does in fact do the exact same as the example of the update_loc function below but the update_file function would allow for greater flexibility in the implementation.

def update_file(file_name, file, run):
   for line in fileinput.input(file, inplace=True):
      if line == "Hello World":
         sys.stdout.write("Hello there")
      else:
         sys.stdout.write(line)
   return True

update_loc

This application of update_loc does the same as the example above but removes the heavy lifting for you so you can easily modify a line of code.

def update_loc(file_name, line, run):
   if line == "Hello World":
      return "Hello there"
   return line

Starting point

The examples in the above section provide a good idea of what Apk Generator can do, but it does not provide the best code to go about your own implementation. The below code section provides a good starting point for your implementation of update_loc. This code searches for the line frequency = low and creates three variations for low, medium, and high frequency.

def update_loc(file_name, line, run):
   lines = ["low", "medium", "high"]
   if (line.strip() == "frequency = low"):
      return line.replace("low", lines[run])
   return line