Question

所以我想在我的测验应用中创建一个后退按钮。这些问题都来自SQ数据库。我希望按钮能够在没有弄乱计数器的情况下转到上一个问题。知道我怎么做这个??? :-) 谢谢你的期待。我的代码是

import java.util.List;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.TextView;

import com.tmm.android.chuck.quiz.GamePlay;
import com.tmm.android.chuck.quiz.Question;
import com.tmm.android.chuck.util.Utility;

/**
 * @author Derek McAuley
 *
 */
public class QuestionActivity extends Activity implements OnClickListener{

    private Question currentQ;
    private GamePlay currentGame;



    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.question);
        /**
         * Configure current game and get question
         */
        currentGame = ((ChuckApplication)getApplication()).getCurrentGame();
        currentQ = currentGame.getNextQuestion();



        Button nextBtn = (Button) findViewById(R.id.nextBtn);
        nextBtn.setOnClickListener(this);

        /**
         * Update the question and answer options..
         */
        setQuestions();

    }


    /**
     * Method to set the text for the question and answers from the current games
     * current question
     */
    private void setQuestions() {
        //set the question text from current question
        String question = Utility.capitalise(currentQ.getQuestion());
        TextView qText = (TextView) findViewById(R.id.question);
        qText.setText(question);

        //set the available options
        List<String> answers = currentQ.getQuestionOptions();
        TextView option1 = (TextView) findViewById(R.id.answer1);
        option1.setText(Utility.capitalise(answers.get(0)));

        TextView option2 = (TextView) findViewById(R.id.answer2);
        option2.setText(Utility.capitalise(answers.get(1)));

        TextView option3 = (TextView) findViewById(R.id.answer3);
        option3.setText(Utility.capitalise(answers.get(2)));

        TextView option4 = (TextView) findViewById(R.id.answer4);
        option4.setText(Utility.capitalise(answers.get(3)));


        // below is the question counter which displays the current question number is the left corner.
        // it also displays the number of questions in the test.
        int total =currentGame.getNumRounds();
        int to = currentGame.getRound();
        TextView questionNum = (TextView) findViewById(R.id.textView1);
        questionNum.setText("Question " + to +"/" + total);
    }


    @Override
    public void onClick(View arg0) {
        //Log.d("Questions", "Moving to next question");

        /**
         * validate a checkbox has been selected
         */
        if (!checkAnswer()) return;


        /**
         * check if end of game
         */
        if (currentGame.isGameOver()){
            //Log.d("Questions", "End of game! lets add up the scores..");
            //Log.d("Questions", "Questions Correct: " + currentGame.getRight());
            //Log.d("Questions", "Questions Wrong: " + currentGame.getWrong());
            Intent i = new Intent(this, EndgameActivity.class);
            startActivity(i);
            finish();
        }
        else{
            Intent i = new Intent(this, QuestionActivity.class);
            startActivity(i);
            finish();
        }
    }


    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event)
    {
        switch (keyCode)
        {
        case KeyEvent.KEYCODE_BACK :
            return true;
        }

        return super.onKeyDown(keyCode, event);
    }


    /**
     * Check if a checkbox has been selected, and if it
     * has then check if its correct and update gamescore
     */
    private boolean checkAnswer() {
        String answer = getSelectedAnswer();
        if (answer==null){
            //Log.d("Questions", "No Checkbox selection made - returning");
            return false;
        }
        else {
            //Log.d("Questions", "Valid Checkbox selection made - check if correct");
            if (currentQ.getAnswer().equalsIgnoreCase(answer))
            {
                //Log.d("Questions", "Correct Answer!");
                currentGame.incrementRightAnswers();
            }
            else{
                //Log.d("Questions", "Incorrect Answer!");
                currentGame.incrementWrongAnswers();


            }
            return true;
        }
    }


    /**
     * 
     */
    private String getSelectedAnswer() {
        RadioButton c1 = (RadioButton)findViewById(R.id.answer1);
        RadioButton c2 = (RadioButton)findViewById(R.id.answer2);
        RadioButton c3 = (RadioButton)findViewById(R.id.answer3);
        RadioButton c4 = (RadioButton)findViewById(R.id.answer4);
        if (c1.isChecked())
        {
            return c1.getText().toString();
        }
        if (c2.isChecked())
        {
            return c2.getText().toString();
        }
        if (c3.isChecked())
        {
            return c3.getText().toString();
        }
        if (c4.isChecked())
        {
            return c4.getText().toString();
        }

        return null;
    }

}

Answer 1

您应该可以通过覆盖onBackPressed（）http://developer.android.com/reference/android/app/Activity.html#onBackPressed%28%29来实现这一点 - 这意味着您可以删除onKeyDown方法的覆盖

例如：

@Override
onBackPressed() {
   if (currentGame.hasPreviousQuestion()) {
      currentGame.loadPreviousQuestion();
      setQuestions();
   } else {
      // pass call back to super class to be handled
      super.onBackPressed();
   }
}

如何在测验应用中创建后退按钮

1 个答案: