Expected BEGIN_ARRAY but was BEGIN_OBJECT | ArrayList issue

问题

I'm using the Gson library to save and retrieve an ArrayList of Players Objects.

My onStop()

@Override
protected void onStop() {
    super.onStop();
    SharedPreferences prefs = getSharedPreferences("X", MODE_PRIVATE);
    SharedPreferences.Editor editor = prefs.edit();
    Gson gson = new Gson();

    String guardJSON = gson.toJson(playersNoGuard);
    editor.putString(GUARD, guardJSON);

    editor.putString("lastActivity", getClass().getName());
    editor.apply();
}

My onCreate important part

ArrayList<Player> playersNoGuard;
RecyclerView myList;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_list_players_guard);

    SharedPreferences prefs = getSharedPreferences("X", MODE_PRIVATE);
    String guardJSON = prefs.getString(GUARD, null);
    Type arrayListPlayers = new TypeToken<ArrayList<Player>>(){}.getType();
    Gson gson = new Gson();

    if(guardJSON != null) {
        playersNoGuard = gson.fromJson(guardJSON, arrayListPlayers);
    }

    // Get the players and remove the Clairvoyant
    Intent intent = this.getIntent();
    playersNoGuard = intent.getParcelableArrayListExtra("PLAYERS");

    [...] // Code skipped

    }

But when this Activity is run, I get the following error log:

Caused by: java.lang.IllegalStateException: Expected BEGIN_ARRAY but was BEGIN_OBJECT at line 1 column 2 path $

What's wrong in this code?

回答1:

You probably write to the same preferences entry somewhere else. Ensure that your key (GUARD) is unique throughout the application.

回答2:

The problem is with your Response while Gson converting a response it expected Array in response but in your response you have made you are passing Object.

This is already answered here and here

here is reverse situation described.

来源：https://stackoverflow.com/questions/38525205/expected-begin-array-but-was-begin-object-arraylist-issue

标签

android

gson