如何组织和减少应用程序中的课程数量

Question

I guess this is more of a Design Pattern question than coding question. So here we go... I have an android application that contain many classes and activities. I have classes grouped inside directory according to their function eg: DownloadTask, ScanTask inside the AsyncTask directory. Then I have all all activities inside the activity directory and so on. But I notice that a lot of my code is repeated. For example, I have 3 Activities PingActivity, NetstatActivity, WhoisActivity that basically look entriely the same from the point of view of the code. The only difference is the command their using eg: ping host for PingActivity, netstat -ant for NetstatActivity and so on.. they all instanciate the views from an xml layout that looks very similar since all I have is EditText, button, and TextView. And the classes Call AsyncTask to perform the background process separate from the main thread. With the exception of WhoisActivity which use rest api service to query for domain name. So my question is how can I simplify my design? can I use one single class and pass the command or api depending what menu option the user selected? how can I do that? thanks

Answer 1

Just a few suggestions, in my humble opinion ...

• Reducing the number of classes should never be a goal by itself.
• Multiple pieces of code that look the same, may actually do different things in terms of logic, and may evolve in very different ways in the future ( DRY is about knowledge, not code ).
• Always design with SOLID in mind, when you say "can I use one single class and pass the command or api", that sounds worse for the Single-Responsibility and the Open-Closed principles.

Having said that, if there are pieces of code that look (and actually are) equal, try to factor them out into services that get injected in your classes. Just do not try to reduce complexity by putting all the code that looks similar in a class/method with a few parameters and some if-else/switch blocks, because in long term that's usually much worse than having a lot of small and organised classes.