Challenge:Who have solutions to give a percentage score

[grass]

Challenge:When the user has answered all the questions, he displays a toast message and gives the percentage form

[grass]

Hi,evrybody:
I am actually working through this great book and am solving now the second challenge exercises of chapter 3,and the title is: when the user has finished all, he displays a toast message and gives a percentage score .
But i have no idea about this,as toast messages should not be String type?

[cstewart]

You can show toasts with strings too. You can use either a resource ID or a string value.

This version of makeText can operate off of a String value: https://developer.android.com/reference/android/widget/Toast.html#makeText(android.content.Context, java.lang.CharSequence, int).

[grass]

Thanks,I’ll try.It’s really a good book to improve myself.

[saly]

I can’t open this link.
can you share code in this net?
Thank you !

[jayssss]

Here is my solution for the two challenges in chapter 3. The code is marked.

package com.bignerdranch.android.geoquiz;

…
// challenge 3.1
import java.util.ArrayList;

public class QuizActivity extends AppCompatActivity {

private static final String TAG = "QuizActivity";
private static final String KEY_INDEX = "index";

private Button mTrueButton;
private Button mFalseButton;
private Button mNextButton;
private TextView mQuestionTextView;
// challenge 3.1
private ArrayList<Integer> mQuestionAsked = new ArrayList<Integer>(6);
// challenge 3.2
private int mTrueAnswer = 0;

@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
Log.d(TAG, “onCreate(Bundle) called”);
setContentView(R.layout.activity_quiz);

    if (savedInstanceState != null) {
        mCurrentIndex = savedInstanceState.getInt(KEY_INDEX, 0);
        // challenge 3.1
        mQuestionAsked = savedInstanceState.getIntegerArrayList("myArray");
    }

    mQuestionTextView = (TextView) findViewById(R.id.question_text_view);
    mQuestionTextView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            mCurrentIndex = (mCurrentIndex + 1) % mQuestionBank.length;
            updateQuestion();
        }
    });

…

private void updateQuestion() {
    int question = mQuestionBank[mCurrentIndex].getTextResId();
    mQuestionTextView.setText(question);

    /* challenge 3.1................*/
    mFalseButton.setVisibility(View.VISIBLE);
    mTrueButton.setVisibility(View.VISIBLE);

    for (Integer i = 0; i < mQuestionAsked.size(); i++) {
        if (mCurrentIndex == mQuestionAsked.get(i)) {
            mFalseButton.setVisibility(View.INVISIBLE);
            mTrueButton.setVisibility(View.INVISIBLE);
        }
    }
    /*...............................*/
    // challenge 3.2
    int resultResId = (mTrueAnswer*100) / 6;
    if (mQuestionAsked.size() > 5) {
        Toast.makeText(this, Integer.toString(resultResId)+"% correct answers", Toast.LENGTH_LONG)
                .show();
    }
}

 @Override
protected void onSaveInstanceState(Bundle savedInstanceState) {
    super.onSaveInstanceState(savedInstanceState);
    Log.i(TAG, "onSaveInstanceState");
    savedInstanceState.putInt(KEY_INDEX, mCurrentIndex);
    // challenge 3.1
    savedInstanceState.putIntegerArrayList("myArray", mQuestionAsked);
}

private void checkAnswer(boolean userPressedTrue) {
    boolean answerIsTrue = mQuestionBank[mCurrentIndex].isAnswerTrue();

    // challenge 3.1
    mQuestionAsked.add(mCurrentIndex);
    mFalseButton.setVisibility(View.INVISIBLE);
    mTrueButton.setVisibility(View.INVISIBLE);
    /*...............................*/

    int messageResId = 0;

    if (userPressedTrue == answerIsTrue) {
        messageResId = R.string.correct_toast;
        // challenge 3.2
        mTrueAnswer = mTrueAnswer + 1;
    } else {
        messageResId = R.string.incorrect_toast;
    }
    Toast.makeText(this, messageResId, Toast.LENGTH_SHORT)
            .show();
}

}

[nistix]

My solution:

...
private int correctAnswers = 0;
...

private void checkAnswer(boolean userPressedTrue) {
    questionsAnswered[currentIndex] = true;
    setButtonsEnabled(false);

    boolean answerIsTrue = questionBank[currentIndex].isAnswerTrue();

    int messageResId;

    if (userPressedTrue == answerIsTrue) {
        messageResId = R.string.toast_correct;
        correctAnswers++;
    } else {
        messageResId = R.string.toast_incorrect;
    }

    Toast.makeText(this, messageResId, Toast.LENGTH_SHORT).show();
    calculateScore();
}

private void calculateScore() {
    // check all questions answered
    for (boolean answered : questionsAnswered) {
        if (!answered) return;
    }
    // all answered, show message
    int score = correctAnswers * 100 / questionBank.length;
    String message = getString(R.string.toast_score, score);
    Toast.makeText(this, message, Toast.LENGTH_SHORT).show();
}

And my strings.xml with placeholder

<resources>
    ...
    <string name="toast_score">You have %1$d%% correct answers!</string>
    ...
</resources>

[hmddahy]

My solution for both challenges

Comments are encouraged

public class QuizActivity extends AppCompatActivity {

    private static final String KEY_INDEX = "index";
    private static final String KEY_SCORE = "score";
    private static final String KEY_ANSWERED = "answered";

    private static final int QUESTION_GRADE = 1;

    private Button mTrueButton;
    private Button mFalseButton;
    private Button mNextButton;
    private Button mPrevButton;
    private TextView mQuestionTextView;

    private Question[] mQuestionBank = new Question[]{
        new Question(R.string.question_australia, true),
        new Question(R.string.question_oceans, true),
        new Question(R.string.question_middleeast, false),
        new Question(R.string.question_africa, false),
        new Question(R.string.question_americas, true),
        new Question(R.string.question_asia, true),
    };

    private int mCurrentIndex = 0;

    private boolean[] mQuestionStatus = new boolean[mQuestionBank.length];
    private int[] mScore = new int[mQuestionBank.length];

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

        if (savedInstanceState != null) {
            mCurrentIndex = savedInstanceState.getInt(KEY_INDEX);

            if (savedInstanceState.containsKey(KEY_ANSWERED)) {
                mQuestionStatus = savedInstanceState.getBooleanArray(KEY_ANSWERED);
            }

            if (savedInstanceState.containsKey(KEY_SCORE)) {
                mScore = savedInstanceState.getIntArray(KEY_SCORE);
            }
        }

        // question text view
        mQuestionTextView = (TextView) findViewById(R.id.question_text_view);
        /*
        mQuestionTextView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                nextQuestion();
            }
        });
        */

        // True button
        mTrueButton = (Button) findViewById(R.id.true_button);
        mTrueButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                checkAnswer(true);
            }
        });

        // False button
        mFalseButton = (Button) findViewById(R.id.false_button);
        mFalseButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                checkAnswer(false);
            }
        });

        // Next button
        mNextButton = (Button) findViewById(R.id.next_button);
        mNextButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                nextQuestion();
            }
        });

        // Previous button
        mPrevButton = (Button) findViewById(R.id.previous_button);
        mPrevButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                previousQuestion();
            }
        });

        // At app run, display the first question
        updateQuestion();
    }

    @Override
    public void onStart() {
        super.onStart();
    }

    @Override
    public void onResume() {
        super.onResume();
    }

    @Override
    public void onPause() {
        super.onPause();
    }

    @Override
    public void  onSaveInstanceState(Bundle savedInstanceState) {
        super.onSaveInstanceState(savedInstanceState);
        savedInstanceState.putInt(KEY_INDEX, mCurrentIndex);
        savedInstanceState.putBooleanArray(KEY_ANSWERED, mQuestionStatus);
        savedInstanceState.putIntArray(KEY_SCORE, mScore);
    }

    @Override
    public void onStop() {
        super.onStop();
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
    }

    /*
     * Updates the text view with the question statement
     * corresponding to current index
     */
    private void updateQuestion() {
        int question = mQuestionBank[mCurrentIndex].getTextResId();
        mQuestionTextView.setText(question);

        // if question has not been answered already, activate answer buttons
        if (!mQuestionStatus[mCurrentIndex % mQuestionBank.length]) {
            activateAnswerButton();
        } else {
            deactivateAnswerButton();
        }
    }

    /*
     * Display a toast message indicating correctness of user answer
     * @param userPressedTrue A falg indicating whether the user answered True
     */
    private void checkAnswer(boolean userPressedTrue) {
        // Mark question as answered
        mQuestionStatus[mCurrentIndex % mQuestionBank.length] = true;

        deactivateAnswerButton();

        int toastResId;

        boolean isCorrectAnswer = userPressedTrue == mQuestionBank[mCurrentIndex].isAnswerTrue();
        if (isCorrectAnswer) {
            mScore[mCurrentIndex % mQuestionBank.length] = QUESTION_GRADE;
            toastResId = R.string.correct_toast;
        } else {
            // when user answered again, report his inccorect answeres(depend on business logic)
            mScore[mCurrentIndex % mQuestionBank.length] = 0;
            toastResId = R.string.incorrect_toast;
        }

        Toast toast = Toast.makeText(QuizActivity.this, toastResId,
                Toast.LENGTH_LONG);
        toast.setGravity(Gravity.BOTTOM, 0, 0);
        toast.show();

        if (allAnswered()) {
            DisplayScore();
            reset();
        }
    }

    /*
     * Checks whether the user has answered all the questions
     * @return true if the user has answered all questions
     */
    private boolean allAnswered() {
        for (boolean status : mQuestionStatus) {
            if (!status) {
                return false;
            }
        }
        return true;
    }

    /*
     * Reset score and answered questions
     */
    private void reset() {

        // set all questions unanswered
        for (int i = 0; i < mQuestionStatus.length ; i++) {
            mQuestionStatus[i] = false;
        }

        // set all scores to zero
        for (int i = 0; i < mScore.length ; i++) {
            mScore[i] = 0;
        }
    }

    /*
     * Displays the score
     */
    private void DisplayScore() {
        Toast.makeText(this,
                "Score: " + getScore() + "%",
                Toast.LENGTH_LONG).show();
    }

    /*
     * Gets the score as a percentage
     * @return The score
     */
    private double getScore() {
        double score = 0;
        for (int i = 0; i < mScore.length ; i++) {
            score += mScore[i];
        }
        return  (score / mQuestionBank.length) * 100;
    }

    /*
     * Proceeds to next question
     */
    private  void nextQuestion() {
        // keep looping forward in the questions
        mCurrentIndex = (mCurrentIndex + 1) % mQuestionBank.length;
        updateQuestion();
    }

    /*
     * Returns to previous question
     */
    private  void previousQuestion() {
        // keep looping backward in the questions
        if(mCurrentIndex == 0) {
            mCurrentIndex = mQuestionBank.length - 1;
        }  else {
            mCurrentIndex = mCurrentIndex - 1;
        }
        updateQuestion();
    }

    /*
     * Deactivates True and False buttons
     */
    private void deactivateAnswerButton() {
        mTrueButton.setEnabled(false);
        mFalseButton.setEnabled(false);
    }

    /*
     * Activates True and False buttons
     */
    private void activateAnswerButton() {
        mTrueButton.setEnabled(true);
        mFalseButton.setEnabled(true);
    }

[BatelSh]

private int mTrueAnswer = 0;
private int mCurrentNumberAnswered = 0;

 private void updateQuestion(){
    mTrueButton.setEnabled(!mQuestionAnswered[mCurrentIndex]); 
    mFalseButton.setEnabled(!mQuestionAnswered[mCurrentIndex]);

    int question = mQuestionnBank[mCurrentIndex].getTextResId();
    mQuestionTextView.setText(question);
    **mCurrentNumberAnswered++;**

**int resultResId = (mTrueAnswer*100)/6;**
**        if(mCurrentNumberAnswered==mQuestionnBank.length+1){**
**            Toast.makeText(this, Integer.toString(resultResId)+"% correct answers", Toast.LENGTH_LONG).show();**
}
}

if(userPressedTrue == answerIsTrue){
messageResId = R.string.correct_toast;
mTrueAnswer = mTrueAnswer +1;

    }else{
        messageResId = R.string.incorrect_toast;
    }
    Toast.makeText(this,messageResId,Toast.LENGTH_SHORT).show();
}

[SergiuS]

I am trying to solve this challenge but I still don’t know what the toast message is not displayed.
Can anyone help please?
Below is my code:

private fun checkAnswer(userAnswer: Boolean) {

    binding.falseButton.isEnabled = false
    binding.trueButton.isEnabled = false
    questionBank[currentIndex].answered = true
    val correctAnswer = questionBank[currentIndex].answer
    val messageResId = if (userAnswer == correctAnswer) {
        R.string.correct_toast
    } else {
        R.string.incorrect_toast
    }
    if (isAllQuestionsAnswered()) {
        val score = getString(R.string.percentage_toast, calculateScore())
        Toast.makeText(this, score, Toast.LENGTH_SHORT).show()
    } else {
        Toast.makeText(this, messageResId, Toast.LENGTH_SHORT).show()
    }
    correctAnswers++
}

private fun isAnswered(index: Int) {
    val isQuestionAnswered = questionBank[index].answered
    binding.trueButton.isEnabled = !isQuestionAnswered
    binding.falseButton.isEnabled = !isQuestionAnswered

}

private fun isAllQuestionsAnswered(): Boolean {
    for (question in questionBank) {
        if (question.answered) {
            return false
        }
    }
    return true

}

private fun calculateScore():Double {
return (correctAnswers.toDouble() / questionBank.size) * 100
}