Release build issues in converting json to list

Question

I have a json file in main/assets folder -

[
  {
    "topic": "Studies",
    "subMessage": "....",
    "people": [
      ....
    ]
  },
  {
    "topic": "....",
    "subMessage": "...",
    "people": []
  }
]

I use this method below to parse the json and return a custom list of mine -

final List<MyList> readJson() {
        try {
            InputStream raw = context.getAssets().open(context.getResources().getString(R.string.read_the_json)); 
            Reader reader = new InputStreamReader(raw, "UTF-8);
            return new Gson().fromJson(reader, new TypeToken<List<MyList>>() {
            }.getType());
        } catch (Exception e) {
            Log.e(TAG, "Error : " + e.getMessage());
            return null;
        }
    }

For Release build, I have minifyEnabled true . But for debug build it is false.

What I found is if I set minifyEnabled to false in release build it works but I need proguard for release builds.

The problem is in Release build the method returns me [][] . But in debug build, the method returns me the values from JSON.

What could be the problem?

Answer 1

It happened because the proguard tool modified your class. You will need to stop proguard from obfuscating the model classes.

Not so good but easiest way:

• Make all your model classes such as MyList implement the interface Serializable .

• Then in the file proguard-rules.pro , add the following line:

  -keepclassmembers class * implements java.io.Serializable { *; }

Better Way:

• Directly include your model class in the file proguard-rules.pro file. For eg.

  -keepclassmembers class com.example.MyList { *; }