Store static data in Android - custom resource?

Question

I\'m new to Android development, and I\'ve been playing around with it a bit. I was trying to create a program that has a small database-like collection of never-changing d

Answer 1

According to the doc, /xml is the way to go.

Providing Resources

xml/ Arbitrary XML files that can be read at run-time by calling

Resources.getXML().

Various XML configuration files must be saved here, such as a searchable configuration.

Documentation for getXML()

I also made a working example:

• the XML structure:

  
  
      
          ic_help_black_24dp
          What is the Capital of U.S.A.?
          Radio
          New York City
          Washington D.C.
          Chicago
          Philadelphia
      
  
      
          ic_help_black_24dp
          What is the family name of the famous dutch painter Vincent Willem van .... ?
          EditText              
          Gogh
      
  
  

• the Java class to hold parsed data:

  public class QuizQuestion {
      private int headerImageResId;
      private String question;
      private String inputType;
      private ArrayList answers;
      private ArrayList answerIsCorrect;
      private ArrayList correctAnswerIndexes;
  
      /**
       * constructor for QuizQuestion object
       */
      QuizQuestion() {
          headerImageResId = 0;
          question = null;
          inputType = null;
          answers = new ArrayList<>();
          answerIsCorrect = new ArrayList<>();
          correctAnswerIndexes = new ArrayList<>();
      }
  
  
      public void setHeaderImageResId(int headerImageResId) {
          this.headerImageResId = headerImageResId;
      }
  
      public int getHeaderImageResId() {
          return headerImageResId;
      }
  
  
      void setQuestion(String question) {
          this.question = question;
      }
  
      public String getQuestion() {
          return question;
      }
  
  
      void setInputType(String inputType) {
          this.inputType = inputType;
      }
  
      public String getInputType() {
          return inputType;
      }
  
      void addAnswer(String answer, boolean isCorrect)
      {
          if (isCorrect)
              correctAnswerIndexes.add(answers.size());
          answers.add(answer);
          answerIsCorrect.add(isCorrect);
      }
  
  
      public ArrayList getAnswers() {
          return answers;
      }
  
      public String getAnswer(int index)
      {
          // check index to avoid out of bounds exception
          if (index < answers.size()) {
              return answers.get(index);
          }
          else
          {
              return null;
          }
      }
  
      public int size()
      {
          return answers.size();
      }
  
  }
  

• the parser itself:

  /**
   * Created by bivanbi on 2017.02.23..
   *
   * class to parse xml resource containing quiz data into ArrayList of QuizQuestion objects
   *
   */
  
  public class QuizXmlParser {
  
      public static String lastErrorMessage = "";
  
      /**
       * static method to parse XML data into ArrayList of QuizQuestion objects
       * @param activity is the calling activity
       * @param xmlResourceId is the resource id of XML resource to be parsed
       * @return null if parse error is occurred or ArrayList of objects if successful
       * @throws XmlPullParserException
       * @throws IOException
       */
      public static ArrayList parse(Activity activity, int xmlResourceId)
              throws XmlPullParserException, IOException
      {
          String logTag = QuizXmlParser.class.getSimpleName();
          Resources res = activity.getResources();
          XmlResourceParser quizDataXmlParser = res.getXml(R.xml.quiz_data);
  
          ArrayList xmlTagStack = new ArrayList<>();
          ArrayList quizQuestions = new ArrayList<>();
  
          QuizQuestion currentQuestion = null;
  
          boolean isCurrentAnswerCorrect = false;
  
          quizDataXmlParser.next();
          int eventType = quizDataXmlParser.getEventType();
          while (eventType != XmlPullParser.END_DOCUMENT)
          {
              //  begin document
              if(eventType == XmlPullParser.START_DOCUMENT)
              {
                  Log.d(logTag,"Begin Document");
              }
              //  begin tag
              else if(eventType == XmlPullParser.START_TAG)
              {
                  String tagName = quizDataXmlParser.getName();
                  xmlTagStack.add(tagName);
                  Log.d(logTag,"Begin Tag "+tagName+", depth: "+xmlTagStack.size());
                  Log.d(logTag,"Tag "+tagName+" has "+quizDataXmlParser.getAttributeCount()+" attribute(s)");
  
                  // this is a beginning of a quiz question tag so create a new QuizQuestion object
                  if (tagName.equals("quizquestion")){
                      currentQuestion = new QuizQuestion();
                  }
                  else if(tagName.equals("answer"))
                  {
                      isCurrentAnswerCorrect = quizDataXmlParser.getAttributeBooleanValue(null,"correct",false);
                      if (isCurrentAnswerCorrect == true) {
                          Log.d(logTag, "Tag " + tagName + " has attribute correct = true");
                      }
                      else
                      {
                          Log.d(logTag, "Tag " + tagName + " has attribute correct = false");
                      }
                  }
              }
              //  end tag
              else if(eventType == XmlPullParser.END_TAG)
              {
                  String tagName = quizDataXmlParser.getName();
                  if (xmlTagStack.size() < 1)
                  {
                      lastErrorMessage = "Error 101: encountered END_TAG "+quizDataXmlParser.getName()+" while TagStack is empty";
                      Log.e(logTag, lastErrorMessage);
                      return null;
                  }
                  xmlTagStack.remove(xmlTagStack.size()-1);
                  Log.d(logTag,"End Tag "+quizDataXmlParser.getName()+", depth: "+xmlTagStack.size());
  
                  //  reached the end of a quizquestion definition, add it to the array
                  if (tagName.equals("quizquestion")){
                      if (currentQuestion != null)
                          quizQuestions.add(currentQuestion);
                      currentQuestion = null;
                  }
              }
              //  text between tag begin and end
              else if(eventType == XmlPullParser.TEXT)
              {
                  String currentTag = xmlTagStack.get(xmlTagStack.size()-1);
                  String text = quizDataXmlParser.getText();
                  Log.d(logTag,"Text: "+text+", current tag: "+currentTag+", depth: "+xmlTagStack.size());
  
                  if (currentQuestion == null) {
                      Log.e(logTag,"currentQuestion is not initialized! text: "+text+", current tag: "+currentTag+", depth: "+xmlTagStack.size());
                      continue;
                  }
  
                  if (currentTag.equals("header_image_src"))
                  {
                      int drawableResourceId = activity.getResources().getIdentifier(text, "drawable", activity.getPackageName());
                      currentQuestion.setHeaderImageResId(drawableResourceId);
                  }
                  else if (currentTag.equals("question"))
                  {
                      currentQuestion.setQuestion(text);
                  }
                  else if (currentTag.equals("answer"))
                  {
                      currentQuestion.addAnswer(text, isCurrentAnswerCorrect);
                  }
                  else if (currentTag.equals("input_type"))
                  {
                      currentQuestion.setInputType(text);
                  }
                  else
                  {
                      Log.e(logTag,"Unexpected tag "+currentTag+" with text: "+text+", depth: "+xmlTagStack.size());
                  }
              }
              eventType = quizDataXmlParser.next();
          }
          Log.d(logTag,"End Document");
          return quizQuestions;
      }
  
  }
  

• and finally, calling the parser:

  //  read quiz data from xml resource quiz_data
  try {
      quizQuestions = QuizXmlParser.parse(this,R.xml.quiz_data);
      Log.d("Main","QuizQuestions: "+quizQuestions);
  
  } catch (XmlPullParserException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
      quizQuestions = null;
  } catch (IOException e) {
      // TODO Auto-generated catch block
      e.printStackTrace();
      quizQuestions = null;
  }
  
  if (quizQuestions == null)
  {
      Toast.makeText(this,"1001 Failed to parse Quiz XML, sorry", Toast.LENGTH_LONG).show();
      finish();
  }