Android Open Source - Trivial Quiz Activity

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License

The source code is released under:

Apache License

Java Source Code

/*
 *    Copyright 2010 Chris Sinjakli/*www.j a  v  a 2s . c o m*/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/**
 * @author Chris Sinjakli
 */
package uk.co.sinjakli.trivial;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Random;

import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;


public class QuizActivity extends Activity {
  
  // Private Constants
  private static final String TAG = "QuizActivity";
  public static final int DEFAULT_NUMBER_OF_QUESTIONS = 20;
  
  // Private member variables
  private ArrayList<Question> questions;
  private long seed;
  private int currentQuestion;
  private int correctAnswers;
  private int incorrectAnswers;
  private int numberOfQuestions;
  
  /**
   * Sets up the initial state of the QuizActivity by loading the questions from the asset files.
   * 
   * @param savedInstanceState Any state which was saved about an ongoing quiz at an earlier time.
   */
  @Override
  public void onCreate(final Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    questions = new ArrayList<Question>();
    
    // Either load saved state of this Activity, or initialise it with new values
    if (null != savedInstanceState) {
      if (savedInstanceState.containsKey("seed")) {
        seed = savedInstanceState.getLong("seed");
      } else {
        seed = new Random().nextLong();
      }
      
      if (savedInstanceState.containsKey("currentQuestion")) {
        currentQuestion = savedInstanceState.getInt("currentQuestion");
      } else {
        currentQuestion = 0;
      }
      
      if (savedInstanceState.containsKey("correctAnswers")) {
        correctAnswers = savedInstanceState.getInt("correctAnswers");
      } else {
        correctAnswers = 0;
      }
      
      if (savedInstanceState.containsKey("incorrectAnswers")) {
        incorrectAnswers = savedInstanceState.getInt("incorrectAnswers");
      } else {
        incorrectAnswers = 0;
      }  
    } else {
      // There is no saved instance data, set it all up from scratch
      seed = new Random().nextLong();
      currentQuestion = 0;
      correctAnswers = 0;
      incorrectAnswers = 0;
    }
    
    // Get number of questions this quiz activity should display
    if (null != savedInstanceState && savedInstanceState.containsKey("numberOfQuestions")) {
      numberOfQuestions = savedInstanceState.getInt("numberOfQuestions");
    } else if (null != getIntent().getExtras() && getIntent().getExtras().containsKey("numberOfQuestions")) {
      numberOfQuestions = getIntent().getExtras().getInt("numberOfQuestions");
    } else {
      Log.w(TAG, "QuizActivity has been started without a specified number of questions. This indicates an error in the way it is being called."); // Dev String
      numberOfQuestions = DEFAULT_NUMBER_OF_QUESTIONS;
    }

    new LoadQuestionsTask().execute("questions");
  }
  
  @Override
  protected void onSaveInstanceState(final Bundle outState) {
    outState.putLong("seed", seed);
    outState.putInt("currentQuestion", currentQuestion);
    outState.putInt("correctAnswers", correctAnswers);
    outState.putInt("incorrectAnswers", incorrectAnswers);
    outState.putInt("numberOfQuestions", numberOfQuestions);
    super.onSaveInstanceState(outState);
  }

  /**
   * Loads questions stored in all files at the specified file path. Returns an empty {@link ArrayList} if there are no questions found.
   * 
   * @param questionFilePath The file path from which questions should be loaded.
   * @return An {@link ArrayList} of all questions found at the specified path.
   */
  private ArrayList<String> loadQuestions(final String questionFilePath) {
    final ArrayList<String> questions = new ArrayList<String>();
    // TODO: This try block surrounds far too much code that it doesn't need to, figure out what can go outside
    try {
      for (final String fileName : getAssets().list(questionFilePath)) {
        final InputStream input = getAssets().open(questionFilePath + "/" + fileName);
        final BufferedReader reader = new BufferedReader(new InputStreamReader(input));
        
        // Populate the questions ArrayList
        String inputLine;
        while (null != (inputLine = reader.readLine())) {
          // Ignore any comments in the question file
          if (!inputLine.startsWith("//") && !(inputLine.length() == 0)) {
              questions.add(inputLine);
          }
        }
      }
    } catch (final IOException e) {
      Log.e(TAG, "IOException while reading questions from file.", e); // Dev String
      Toast.makeText(getApplicationContext(), getResources().getString(R.string.question_reading_exception), Toast.LENGTH_LONG).show();
    }
    return questions;
  }
  
  private class LoadQuestionsTask extends AsyncTask<String, Integer, Void> {
    
    // TODO: Move some of the logic from loadQuestions into here. loadQuestions should just deal with an individual file.
    @Override
    protected Void doInBackground(String... params) {
      final ArrayList<String> questionsTemp = new ArrayList<String>();
      
      // Load all questions available at each path given as an argument
      for (String path : params) {
        questionsTemp.addAll(loadQuestions(path));
      }
      
      // Randomise the output order of the questions
      final Random rand = new Random(seed);
      Collections.shuffle(questionsTemp, rand);

      // TODO: Get rid of horrible duplicated code below
      // Trim the questions to the number specified by the user
      if (numberOfQuestions < questionsTemp.size()) {
        int failedParses = 0;
        questions = new ArrayList<Question>();
        for (String s : questionsTemp.subList(0, numberOfQuestions)) {
          try {
            questions.add(Question.parse(s));
          } catch (final IllegalArgumentException e) {
            failedParses++;
            Log.e(TAG, "Unable to parse question: " + s, e); // Dev String
          }
        }

        // If any questions failed to parse, summarise (to the user) how many failed
        if (0 < failedParses) {
          Toast.makeText(getApplicationContext(), String.format(getResources().getQuantityString(R.plurals.question_reading_parse_fail_number, failedParses), failedParses), Toast.LENGTH_LONG).show();
        }
      } else {
        int failedParses = 0;
        questions = new ArrayList<Question>();
        for (String s : questionsTemp) {
          try {
            questions.add(Question.parse(s));
          } catch (final IllegalArgumentException e) {
            failedParses++;
            Log.e(TAG, "Unable to parse question: " + s, e); // Dev String
          }
        }

        // If any questions failed to parse, summarise (to the user) how many failed
        if (0 < failedParses) {
          Toast.makeText(getApplicationContext(), String.format(getResources().getQuantityString(R.plurals.question_reading_parse_fail_number, failedParses), failedParses), Toast.LENGTH_LONG).show();
        }
      }

      return null;
    }
    
    @Override
    protected void onPostExecute(Void result) {
      
      // If no questions were loaded, close the Activity
      if (questions.isEmpty()) {
        // TODO: This could return some sort of status to the HomeActivity, which could then display a failure message
        QuizActivity.this.finish();
      } else {
        displayQuestion(currentQuestion);
      }
    }

    /**
     * 
     */
    private void displayQuestion(final int questionID) {
      setContentView(R.layout.quiz);
      
      // Display the topic of the question
      final TextView quizTopic = (TextView) findViewById(R.id.quiz_topic);
      quizTopic.setText(questions.get(questionID).getQuestionType());
      
      // Display the question
      final TextView quizQuestion = (TextView) findViewById(R.id.quiz_question);
      quizQuestion.setText(questions.get(questionID).getQuestion());
      
      // Display the answers to the question
      final ListView quizAnswers = (ListView) findViewById(R.id.quiz_answers);
      // TODO: Use my own TextView for this list to control appearance, make it look like the rest of the app
      final ArrayAdapter<String> adapter = new ArrayAdapter<String>(QuizActivity.this, R.layout.quiz_answer_row, questions.get(questionID).getAnswers().toArray(new String[0]));
      quizAnswers.setAdapter(adapter);
      
      // Set up an OnClickListener for the ListView
      quizAnswers.setOnItemClickListener(new AdapterView.OnItemClickListener() {

        public void onItemClick(final AdapterView<?> parent, final View view, final int position, final long id) {
          final String selectedAnswer = ((TextView) view).getText().toString();
          if (selectedAnswer.equals(questions.get(questionID).getAnswer())) {
            correctAnswers++;
            Toast.makeText(getApplicationContext(), getResources().getString(R.string.answer_correct), Toast.LENGTH_SHORT).show();
          } else {
            incorrectAnswers++;
            Toast.makeText(getApplicationContext(), getResources().getString(R.string.answer_incorrect), Toast.LENGTH_SHORT).show();
          }
          
          // Display the next question
          currentQuestion++;
          
          if (currentQuestion <= questions.size() - 1) {
            displayQuestion(currentQuestion);
          } else {
            // Fire off a new Intent, and end this Activity
            final Intent i = new Intent(QuizActivity.this, QuizEndActivity.class);
            i.putExtra("correctAnswers", correctAnswers);
            i.putExtra("incorrectAnswers", incorrectAnswers);
            startActivity(i);
            
            QuizActivity.this.finish();
          }
        }
      });
    }
  }
}

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