Parse.com获取查询并将其转换为字符串Java

Question

what I'm trying to do is querying a class and getting some strings. But the below code returns something like ;

com.parse.ParseObject@b4209180

and I couldn't get it to normal string value.

ParseQuery<ParseObject> query = ParseQuery.getQuery("question");
//query.whereKeyExists:@"objectId"
query.whereExists("questionTopic");

query.findInBackground(new FindCallback<ParseObject>() {

    @Override
    public void done(List<ParseObject> topics, ParseException e) {
        // TODO Auto-generated method stub
        if(e==null){


                textview.setText(topics.toString());

            }


        }else{
             Log.d("notretreive", "Error: " + e.getMessage());
        }


    }
});

Answer 1

"topics" in your code is a list of question objects. You need to get the topic from that object. This should get you on the way:

ParseQuery<ParseObject> query = ParseQuery.getQuery("question");
query.whereExists("questionTopic");

query.findInBackground(new FindCallback<ParseObject>() {

    @Override
    public void done(List<ParseObject> questions, ParseException e) {
        // The query returns a list of objects from the "questions" class
        if(e==null){
          for (ParseObject question : questions) {
            // Get the questionTopic value from the question object
            Log.d("question", "Topic: " + question.getString("questionTopic");
          }       
        } else {
             Log.d("notretreive", "Error: " + e.getMessage());
        }
    }
});

Answer 2

from the API I can see that the class ParseObject Inherits toString() from Object class.

That means unless there is implementation of custom toString() it will return the human-readable description of this object.

check here for the toString() being called in your case

EDIT:

First of all you are trying to call toString() on List object by

topics.toString()

you will have to iterate over that List like

for(ParseObject parseObj : topics){
//do something with parseObj like
parseObj.get(<provide_key_here>);
//print to check the value
System.out.println(parseObj.get(<provide_key_here>));
//where key is generally attribute name
}

Answer 3

I can see this is about two years old. But I am currently having the same issue. SO here is what I did.

You can't just call setText.toString because "topics" is returning as a Parse Object. You need to run a for loop to run through each topics object and get the text from that object, store it in a string and THEN you can set text to string. Here is what I did.

final List questions = new ArrayList<String>();

final ParseQuery<ParseObject> query = new ParseQuery<ParseObject>("MasterQuestionList");
query.findInBackground(new FindCallback<ParseObject>() {
  public void done(List<ParseObject> Question, ParseException e) {
    if (e == null) {
      if (Question.size() > 0) {

        for (ParseObject user : Question) {

         String tFile = (String) user.get("Question");
          questions.add(tFile);

        }

        TextView a = (TextView) findViewById(R.id.sentence);
        a.setText(String.valueOf(questions));

I created a list, and added all text values to that list.

Hope this helps anyone running into a similar issue.