How to incorporate images into SQLite quiz?

问题

I am making a quiz app to introduce myself to android development and would like to be able to ask questions about images (ie, an image appears and the user is asked what it is etc). I am using an SQLite db to store the questions, so my question is, "How do I make the image that the question is about appear each time a new question is loaded?".

This is my question class

public class Question {
    private String question;
    private String option1;
    private String option2;
    private String option3;
    private int answerNr;

    public Question(){}

    public Question(String question, String option1, String option2, String option3, int answerNr) {
        this.question = question;
        this.option1 = option1;
        this.option2 = option2;
        this.option3 = option3;
        this.answerNr = answerNr;
    }

    public String getQuestion() {
        return question;
    }

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

    public String getOption1() {
        return option1;
    }

    public void setOption1(String option1) {
        this.option1 = option1;
    }

    public String getOption2() {
        return option2;
    }

    public void setOption2(String option2) {
        this.option2 = option2;
    }

    public String getOption3() {
        return option3;
    }

    public void setOption3(String option3) {
        this.option3 = option3;
    }

    public int getAnswerNr() {
        return answerNr;
    }

    public void setAnswerNr(int answerNr) {
        this.answerNr = answerNr;
    }
}

And this is the dbHelper I'm using

public QuizDbHelper(Context context) {
        super(context, DATABASE_NAME, null, DATABASE_VERSION);
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        this.db = db;

        final String SQL_CREATE_QUESTIONS_TABLE = "CREATE TABLE " +
                QuestionsTable.TABLE_NAME + " ( " +
                QuestionsTable._ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
                QuestionsTable.COLUMN_QUESTION + " TEXT, " +
                QuestionsTable.COLUMN_OPTION1 + " TEXT, " +
                QuestionsTable.COLUMN_OPTION2 + " TEXT, " +
                QuestionsTable.COLUMN_OPTION3 + " TEXT, " +
                QuestionsTable.COLUMN_ANSWER_NR + " INTEGER" +
                ")";

        db.execSQL(SQL_CREATE_QUESTIONS_TABLE);
        fillQuestionsTable();
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + QuestionsTable.TABLE_NAME);
        onCreate(db);
    }

    private void fillQuestionsTable(){
        Question q1 = new Question("How often do blackbeard mains deserve the kill?", "Always", "Sometimes", "Never", 3);
        addQuestion(q1);
        Question q2 = new Question("How fast is Ash?", "3 speed", "9 speed", "2 speed", 1);
        addQuestion(q2);
        Question q3 = new Question("How thicc is Rook?", "2 armor", "3 armor", "9 armor", 2);
        addQuestion(q3);
    }

    private void addQuestion(Question question){
        ContentValues cv = new ContentValues();
        cv.put(QuestionsTable.COLUMN_QUESTION, question.getQuestion());
        cv.put(QuestionsTable.COLUMN_OPTION1, question.getOption1());
        cv.put(QuestionsTable.COLUMN_OPTION2, question.getOption2());
        cv.put(QuestionsTable.COLUMN_OPTION3, question.getOption3());
        cv.put(QuestionsTable.COLUMN_ANSWER_NR, question.getAnswerNr());
        db.insert(QuestionsTable.TABLE_NAME, null, cv);
    }

    public List<Question> getAllQuestions() {
        List<Question> questionList = new ArrayList<>();
        db = getReadableDatabase();
        Cursor c = db.rawQuery("SELECT * FROM " + QuestionsTable.TABLE_NAME, null);
        if (c.moveToFirst()) {
            do {
                Question question = new Question();
                question.setQuestion(c.getString(c.getColumnIndex(QuestionsTable.COLUMN_QUESTION)));
                question.setOption1(c.getString(c.getColumnIndex(QuestionsTable.COLUMN_OPTION1)));
                question.setOption2(c.getString(c.getColumnIndex(QuestionsTable.COLUMN_OPTION2)));
                question.setOption3(c.getString(c.getColumnIndex(QuestionsTable.COLUMN_OPTION3)));
                question.setAnswerNr(c.getInt(c.getColumnIndex(QuestionsTable.COLUMN_ANSWER_NR)));
                questionList.add(question);
            } while (c.moveToNext());
        }

        c.close();
        return questionList;
    }
}

My QuizActivity (The relevant bits at least)

public class QuizActivity extends AppCompatActivity {

    private TextView textViewQuestion;
    private TextView textViewScore;
    private TextView textViewQuestionCount;
    private TextView textViewTimer;
    private RadioGroup rbGroup;
    private RadioButton rb1;
    private RadioButton rb2;
    private RadioButton rb3;
    private Button buttonConfirmNext;

    private ColorStateList textColorDefaultRb;

    private List<Question> questionList;
    private int questionCounter;
    private int questionCountTotal;
    private Question currentQuestion;

    private int score;
    private boolean answered;

    private long backPressedTime;

    RadioGroup answers;
    RadioButton radioButton;

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

        textViewQuestion = findViewById(R.id.question);
        textViewScore = findViewById(R.id.score);
        textViewQuestionCount = findViewById(R.id.question_num);
        textViewTimer = findViewById(R.id.timer);
        rbGroup = findViewById(R.id.answers);
        rb1 = findViewById(R.id.option_1);
        rb2 = findViewById(R.id.option_2);
        rb3 = findViewById(R.id.option_3);
        buttonConfirmNext = findViewById(R.id.confirm);

        textColorDefaultRb = rb1.getTextColors();

        QuizDbHelper dbHelper = new QuizDbHelper(this);
        questionList = dbHelper.getAllQuestions();
        questionCountTotal = questionList.size();
        Collections.shuffle(questionList);

        showNextQuestion();
...
...
...
...
...

private void showNextQuestion(){
        rb1.setTextColor(textColorDefaultRb);
        rb2.setTextColor(textColorDefaultRb);
        rb3.setTextColor(textColorDefaultRb);
        rbGroup.clearCheck();

        if (questionCounter < questionCountTotal){
            currentQuestion = questionList.get(questionCounter);

            textViewQuestion.setText(currentQuestion.getQuestion());
            rb1.setText(currentQuestion.getOption1());
            rb2.setText(currentQuestion.getOption2());
            rb3.setText(currentQuestion.getOption3());

            questionCounter++;
            textViewQuestionCount.setText("Question: " + questionCounter + "/" + questionCountTotal);
            answered = false;
            buttonConfirmNext.setText("Confirm");
        }
        else {
            finishQuiz();
        }
    }

And my "QuizContract" I'm using to store a few constants

private QuizContract() {}

    public static class QuestionsTable implements BaseColumns {
        public static final String TABLE_NAME = "quiz_questions";
        public static final String COLUMN_QUESTION = "question";
        public static final String COLUMN_OPTION1 = "option1";
        public static final String COLUMN_OPTION2 = "option2";
        public static final String COLUMN_OPTION3 = "option3";
        public static final String COLUMN_ANSWER_NR = "answer_nr";
    }
}

回答1:

You can convert image to base64 and save it to SQLite and on retrival, you can convert it back to bitmap. Here is a code for the conversion.

   //encode image to base64 string
        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.logo);
        bitmap.compress(Bitmap.CompressFormat.JPEG, 100, baos);
        byte[] imageBytes = baos.toByteArray();
        String imageString = Base64.encodeToString(imageBytes, Base64.DEFAULT);

        //decode base64 string to image
        imageBytes = Base64.decode(imageString, Base64.DEFAULT);
        Bitmap decodedImage = BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length);
        image.setImageBitmap(decodedImage);

Hope this will work for you.

来源：https://stackoverflow.com/questions/56184410/how-to-incorporate-images-into-sqlite-quiz