java - 显示下一个数据库条目

Question

我正在编写我的第一个 Android 应用程序。

我正在尝试创建一个测验应用程序。我有一些问题存储在 SQLite 数据库中，这些问题一个接一个地显示。
用户选择一个答案(单选按钮)，然后单击“下一步按钮”，然后显示下一个问题，依此类推。

以下代码显示我的 Activity 文件一个接一个地显示每个问题，该文件完美运行。

<小时/> ACEActivity(旧版，工作版本)

public class ACEActivity extends Activity {
List<Question> quesList;
int score = 0;
int qid = 0;
Question currentQ;
TextView txtQuestion;
RadioButton rda, rdb, rdc, rdd;
Button butNext;

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

    DatabaseHelper db = new DatabaseHelper(this);

    quesList = db.getAllACEQuestions();
    currentQ = quesList.get(qid);
    txtQuestion = (TextView)findViewById(R.id.textView);
    rda = (RadioButton)findViewById(R.id.radio0);
    rdb = (RadioButton)findViewById(R.id.radio1);
    rdc = (RadioButton)findViewById(R.id.radio2);
    rdd = (RadioButton)findViewById(R.id.radio3);
    butNext = (Button)findViewById(R.id.nextButton);
    setQuestionView();

    butNext.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            RadioGroup grp = (RadioGroup)findViewById(R.id.radioGroup);
            RadioButton answer = (RadioButton)findViewById(grp.getCheckedRadioButtonId());
            Log.d("yourans", currentQ.getANSWER() + " " + answer.getText());
            // If the correct answer was clicked display the next question
            if(currentQ.getANSWER().equals(answer.getText())) {
                currentQ = quesList.get(qid);
                setQuestionView();
            }
        }
    });
}

// Load the next question
private void setQuestionView() {
    txtQuestion.setText(currentQ.getQUESTION());
    rda.setText(currentQ.getOPTA());
    rdb.setText(currentQ.getOPTB());
    rdc.setText(currentQ.getOPTC());
    rdd.setText(currentQ.getOPTD());
    qid++;
    }
}

<小时/>在此 Activity 的新版本中，我加载另一个 Activity ，以便在单击正确或错误答案时向用户提供即时反馈。

显示反馈 Activity 后，我想返回此 Activity 并显示下一个问题。

我尝试通过将问题 ID 从反馈 Activity (ACECorrectActivity) 传递到此 Activity (ACEActivity) 来实现此目的，但没有成功。

<小时/> 我如何尝试解决这个问题:

ACEActivity(新版本，仅针对第一个问题)

public class ACEActivity extends Activity {
List<Question> quesList;
int score = 0;
int qid = 0;
Question currentQ;
TextView txtQuestion;
RadioButton rda, rdb, rdc, rdd;
Button checkBtn;

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

    // THIS PART IS NEW ================================
    // Get the intent
    Intent intent = getIntent();
    // Get the question id (if there are any extras)
    Bundle extras = intent.getExtras();
    if (extras != null) {
        int qid = extras.getInt("nextQuestionID");
    } else {
        int qid = 0;
    }
    // ==================================================

    DatabaseHelper db = new DatabaseHelper(this);

    quesList = db.getAllACEQuestions();
    currentQ = quesList.get(qid);
    txtQuestion = (TextView)findViewById(R.id.textView);
    rda = (RadioButton)findViewById(R.id.radio0);
    rdb = (RadioButton)findViewById(R.id.radio1);
    rdc = (RadioButton)findViewById(R.id.radio2);
    rdd = (RadioButton)findViewById(R.id.radio3);
    checkBtn = (Button) findViewById(R.id.checkButton);

    setQuestionView(qid);

    checkBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            RadioGroup grp = (RadioGroup) findViewById(R.id.radioGroup);
            RadioButton answer = (RadioButton) findViewById(grp.getCheckedRadioButtonId());
            Log.d("yourans", currentQ.getANSWER() + " " + answer.getText());
            // THIS PART IS NEW AND WORKING FINE ================================
            // If the correct answer was clicked
            if (currentQ.getANSWER().equals(answer.getText())) {
                Intent intent = new Intent(ACEActivity.this, CorrectACEActivity.class);
                startActivity(intent);
            // If the wrong answer was clicked
            } else {
                Intent intent = new Intent(ACEActivity.this, FalseACEActivity.class);
                startActivity(intent);
            }
        }
    });
}

private void setQuestionView() {
    txtQuestion.setText(currentQ.getQUESTION());
    rda.setText(currentQ.getOPTA());
    rdb.setText(currentQ.getOPTB());
    rdc.setText(currentQ.getOPTC());
    rdd.setText(currentQ.getOPTD());
    qid++;
    }
}

ACECorrectActivity(选择正确答案并在 ACEActivity 中单击下一步按钮时加载反馈 Activity )

public class CorrectACEActivity extends Activity {
List<Question> quesList;
int score = 0;
int qid = 0;
Question currentQ;
TextView txtQuestion;
RadioButton rda, rdb, rdc, rdd;
Button nextBtn;

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

    DatabaseHelper db = new DatabaseHelper(this);

    quesList = db.getAllACEQuestions();
    currentQ = quesList.get(qid);
    txtQuestion = (TextView) findViewById(R.id.textView);
    rda = (RadioButton) findViewById(R.id.radio0);
    rdb = (RadioButton) findViewById(R.id.radio1);
    rdc = (RadioButton) findViewById(R.id.radio2);
    rdd = (RadioButton) findViewById(R.id.radio3);
    nextBtn = (Button) findViewById(R.id.nextButton);

    // Set colors according to correct answer
    rda.setBackgroundColor(Color.RED);
    rdb.setBackgroundColor(Color.RED);
    rdc.setBackgroundColor(Color.RED);
    rdd.setBackgroundColor(Color.RED);

    if(currentQ.getANSWER().equals(currentQ.getOPTA())) {
        rda.setBackgroundColor(Color.GREEN);
    } else if(currentQ.getANSWER().equals(currentQ.getOPTB())) {
        rdb.setBackgroundColor(Color.GREEN);
    } else if(currentQ.getANSWER().equals(currentQ.getOPTC())) {
        rdc.setBackgroundColor(Color.GREEN);
    } else if(currentQ.getANSWER().equals(currentQ.getOPTD())) {
        rdd.setBackgroundColor(Color.GREEN);
    }

    setQuestionView();

    // WHEN NEXT BUTTON IS CLICKED RETURN TO ACEActivity AND LOAD NEXT QUESTION
    nextBtn.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent intent = new Intent(CorrectACEActivity.this, ACEActivity.class);
            intent.putExtra("nextQuestionID", currentQ + 1);
            startActivity(intent);
        }
    });
}

private void setQuestionView() {
    txtQuestion.setText(currentQ.getQUESTION());
    rda.setText(currentQ.getOPTA());
    rdb.setText(currentQ.getOPTB());
    rdc.setText(currentQ.getOPTC());
    rdd.setText(currentQ.getOPTD());
    qid++;
    }
}

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第一个问题完美。然而，当我回答第一个问题后返回 ACEActivity 时，我又遇到了第一个问题。

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正如您所看到的，我对此非常陌生，并且非常乐意提供任何帮助!谢谢!!

Answer 1

 intent.putExtra("nextQuestionID", currentQ + 1);

你在 CorrectACEActivity 中设置了额外的错误，不应该是这样吗？

 intent.putExtra("nextQuestionID", qid+ 1);