Android Firebase array

Question

I am writing an Android app using Firebase for cloud database. Its basically a multiple choice survey question app. Imported to Firebase I had

{
  "multiple_choice" : {
    "-K2222222222" : {
      "question" : "Question text",
      "opt1" : "answer 1",
      "opt2" : "answer 2",
      "opt3" : "answer 3"
    }
  }
}

I add a MultipleChoice class like so

public class MultipleChoice {

    private String id;
    private String question;
    private String opt1;
    private String opt2;
    private String opt3;

    public MultipleChoice() {
    }

    public MultipleChoice(String question, String opt1, String opt2, String opt3) {
        this.question = question;
        this.opt1 = opt1;
        this.opt2 = opt2;
        this.opt3 = opt3;
    }

    public void setQuestion(String question) {
        this.question = question;
    }

    public String getOpt1() {
        return opt1;
    }

    public void setOpt1(String opt1) {
        this.opt1 = opt1;
    }

    public String getOpt2() {
        return opt2;
    }

    public void setOpt2(String opt2) {
        this.opt2 = opt2;
    }

    public String getOpt3() {
        return opt3;
    }

    public void setOpt3(String opt3) {
        this.opt3 = opt3;
    }

    public String getQuestion() {
        return question;
    }

}

which allows me to retrieve this data in the main class using Firebase references.

Now I want to make it like an array of options although FB doesn't literally work that way, so it can take any number of options instead of a fixed 3 or whatever. This json file loaded into FB

{
      "multiple_choice" : {
        "-K2222222222" : {
          "question" : "Should Britian leave the EU?",
          "options" : {
            "1" : "answer 1",
            "2" : "answer 2",
            "3" : "answer 3"
          },
        }
      }
    }

but I can't figure out how to add methods in the MultipleChoice class. And ideas how to get the effect of an array so I can retrieve options[0] etc. or options/"1"?

score 2 · Accepted Answer · answered Jan 19 '17 at 15:40

An array starts from index 0, so your database structure should be

{
    "multiple_choice" : {
        "-K2222222222" : {
            "question" : "Should Britian leave the EU?",
            "options" : {
                "0" : "answer 1",
                "1" : "answer 2",
                "2" : "answer 3"
            }
        }
    }
}

And the model class for each multiple_choice

public class MultipleChoice {
    private String id;
    private String question;
    private List<String> options;

    public List<String> getOptions() {
        return options;
    }

    public void setOptions(List<String> options) {
        this.options = options;
    }

    ... constructor and other getter setter...
}

This is an example of how to retrieve each option from the list

MultipleChoice multipleChoice = dataSnapshot.getValue(MultipleChoice.class);
String firstOption = multipleChoice.getOptions().get(0);
String secondOption = multipleChoice.getOptions().get(1);
String thirdOption = multipleChoice.getOptions().get(2);

Hope this helps :)

score 1 · Answer 2 · edited May 23 '17 at 11:45

1

You can use Map:

 private Map<String, String> options;

how to get all child list from Firebase android

edited May 23 '17 at 11:45

Community

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answered Jan 19 '17 at 15:29

JoKr

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Android Firebase array

2 Answers2