Is It Possible To Build Offline-first Mobile Apps Using Aws Appsync?

I'd like to use AWS AppSync for mobile development (Android/iOS) but I’m not sure about its offline capabilities. According to the documentation the data will be accessible while

Solution 1:

It should be possible with Firestore, AWS AppSync or your own Backend solution. Any approach you use, you will control when you want to start saving/syncing things online.

You need to handle all this while designing this app. Suggested approach

Let's take example of simple ToDo app

• I will let User add & save Todos in app

• All this data will be persisted on disk(using SQLLITE, Preferences or File etc.)

• If User does clear data or reinstall app, all this data is lost
• If User wants to go premium, I will let him sync this data with my Backend solution(any one of above-mentioned solution)

Example implementation using Android Shared preference as local storage

publicvoidsaveLocalTodo(String title, String details) {
    ArrayList<Todo> todos;
    Todo todo = newTodo(title, details);
    String listOfTodo = sharedPreference.getString(TODOS_LIST, null);
    if (listOfTodo == null)
        todos = newArrayList<Todo>();
    else
        todos = gson.fromJson(listOfTodo, newTypeToken<ArrayList<Todo>>() {
        }.getType());

    //save at 0th position, recent should always come first
    todos.add(0, todo);
    sharedPreference.edit().putString(TODOS_LIST, gson.toJson(todos)).apply();
}

publicArrayList<Todo> getLocalTodos() {
    ArrayList<Todo> todos;
    String listOfTodos = sharedPreference.getString(TODOS_LIST, null);
    if (listOfTodos == null)
        todos = newArrayList<Todo>();
    else
        todos = gson.fromJson(listOfTodos, newTypeToken<ArrayList<Todo>>() {
        }.getType());
    return todos;
}

publicvoidsaveOnBackend() {
    // Connect to Backend solution// Get all local todos from preference// Save all at once in batches//OR// Get all local todos from preference// Save one by one
}

Solution 2:

Use Realm Database to manage all offline and online data and save if the application uninstall

Solution 3:

you can read https://docs.aws.amazon.com/appsync/latest/devguide/building-a-client-app-reactnative.html

AWS AppSync support offline mode and you can use data base for your app