我正在编写一个需要显示计时器的Android测验应用。实现计时器的最佳方法是什么？ 我是android的新手，这是我的第一个应用程序。我尝试过使用Handler。这有效，但似乎没有效率。
public class PertanyaanActivity extends Activity
{
private Handler progressBarHandler = new Handler();
ProgressBar progressBar;
TextView progressText;
PertanyaanData mQuestionData;
JawabanData mAnswerData;
private int mCategoryId;
private Map<Integer, Pertanyaan> mQuestions;
private Map<Integer, Jawaban> mAnswers;
private List<Integer> mQuestionIndexList;
private int mNextQuestionIndex = 0;
private int mTotalQuestions = 0;
private int mQuestionsAnswered = 0;
private int mCorrectAnswers = 0;
private Pertanyaan mCurrentQuestion;
private List<Button> answerButtons;
private LinearLayout.LayoutParams mAnswerButtonLayout;
// private TextView mViewHeader;
private ScrollView mQuestionScrollView;
private TextView mQuestionText;
private LinearLayout mAnswersFrame;
private TextView mQuestionDescriptionText;
// private Button mNextQuestionButton;
// private Button mCompleteButton;
private int max_salah = 0;
private int progressBarStatus = 0;
private long fileSize = 0;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.question);
mCategoryId = getIntent().getIntExtra("categoryId", 0);
Log.i(Constants.APP_LOG_NAME, "Getting question for category ID " + mCategoryId);
mAnswerButtonLayout = new LinearLayout.LayoutParams(
LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);
mAnswerButtonLayout.setMargins(30, 20, 30, 0);
// mViewHeader = (TextView)findViewById(R.id.viewHeader);
mQuestionScrollView = (ScrollView)findViewById(R.id.questionScrollView);
mQuestionText = (TextView)findViewById(R.id.questionText);
mAnswersFrame = (LinearLayout)findViewById(R.id.answersFrame);
progressText=(TextView)findViewById(R.id.progressText);
progressBar= (ProgressBar) findViewById(R.id.ProgressBar01);
// progressBar.setProgress(0);
//progressBar.setMax(100);
waktu();
//mQuestionDescriptionText = (TextView)findViewById(R.id.questionDescriptionText);
// mNextQuestionButton = (Button)findViewById(R.id.nextQuestionButton);
//mCompleteButton = (Button)findViewById(R.id.completeButton);
mQuestionData = new PertanyaanData(this);
mAnswerData = new JawabanData(this);
mQuestions = mQuestionData.getQuestionsByCategoryId(mCategoryId);
mQuestionIndexList = new ArrayList<Integer>();
for (int questionId : mQuestions.keySet())
{
mQuestionIndexList.add(questionId);
}
Collections.shuffle(mQuestionIndexList);
if (mQuestionIndexList.size() > (Constants.MAX_QUESTIONS_PER_ROUND))
{
mQuestionIndexList = mQuestionIndexList.subList(0, Constants.MAX_QUESTIONS_PER_ROUND);
}
mTotalQuestions = mQuestionIndexList.size();
Log.i(Constants.APP_LOG_NAME, "Total questions: " + mTotalQuestions);
if (mTotalQuestions > 0)
{
displayNextQuestion();
}
else
{
Log.e(Constants.APP_LOG_NAME, "No questions found for category ID " + mCategoryId);
}
setVolumeControlStream(AudioManager.STREAM_MUSIC);
}
@Override
public void onDestroy()
{
super.onDestroy();
if (mQuestionData != null)
{
mQuestionData.close();
}
if (mAnswerData != null)
{
mAnswerData.close();
}
}
/**
* Displays the next available question in the current trivia round.
*/
public void displayNextQuestion()
{
// Reset ScrollView position.
mQuestionScrollView.scrollTo(0, 0);
waktu();
mCurrentQuestion = getNextQuestion();
String headerText = getString(R.string.question)
+ " " + mNextQuestionIndex
+ " " + getString(R.string.of)
+ " " + mTotalQuestions;
//mViewHeader.setText(headerText);
//nyalakanWaktu();
//waktu();
displayQuestion(mCurrentQuestion);
// mQuestionDescriptionText.setVisibility(View.GONE);
// mNextQuestionButton.setVisibility(View.GONE);
}
/**
* Gets the next available question in the current trivia round.
*
* @return Question - The instance of the next available question.
*/
private Pertanyaan getNextQuestion()
{
int nextQuestionId = mQuestionIndexList.get(mNextQuestionIndex);
Log.i(Constants.APP_LOG_NAME, "Got next question ID " + nextQuestionId);
Pertanyaan question = mQuestions.get(nextQuestionId);
if (question == null)
{
Log.w(Constants.APP_LOG_NAME, "Next question is null.");
}
mNextQuestionIndex++;
return question;
}
/**
* Displays a question on the screen.
*
* @param Question question - The question instance to display.
*/
private void displayQuestion(Pertanyaan question)
{
if (question != null)
{
mAnswers = mAnswerData.getAnswersByQuestionId(question.getPertanyaanId());
List<Integer> answerIndexList = new ArrayList<Integer>();
for (int answerId : mAnswers.keySet())
{
answerIndexList.add(answerId);
}
Collections.shuffle(answerIndexList);
mAnswersFrame.removeAllViews();
mQuestionText.setText(question.getText());
if (mAnswers != null)
{
answerButtons = new ArrayList<Button>();
Jawaban answer = null;
for (int answerId : answerIndexList)
{
Log.i(Constants.APP_LOG_NAME, "Adding answer ID " + answerId);
answer = mAnswers.get(answerId);
Button answerButton = new Button(this);
answerButton.setId(answer.getJawabanId());
answerButton.setText(answer.getText());
answerButton.setBackgroundResource(R.drawable.button_normal);
answerButton.setOnClickListener(new View.OnClickListener()
{
public void onClick(View v)
{
disableAnswerButtons();
answerButtonClickHandler(v);
}
});
answerButtons.add(answerButton);
mAnswersFrame.addView(answerButton, mAnswerButtonLayout);
}
}
}
else
{
// TODO: Need to handle this in a more user-friendly way.
mQuestionText.setText("Null question.");
}
}
/**
* Click handler for answer option buttons.
* Determines the result of the user selecting an answer.
*
* @param View v - The current view.
*/
public void answerButtonClickHandler(View v)
{
Jawaban answer = mAnswers.get(v.getId());
if (answer != null)
{
mQuestionsAnswered++;
if (answer.isCorrect())
{
mCorrectAnswers++;
v.setBackgroundResource(R.drawable.answer_button_correct);
Suara.playButtonClickSuccess();
}
else
{
max_salah++;
v.setBackgroundResource(R.drawable.answer_button_incorrect);
Suara.playButtonClickFailure();
}
// mQuestionDescriptionText.setText(mCurrentQuestion.getDescription());
//mQuestionDescriptionText.setVisibility(View.VISIBLE);
if (mNextQuestionIndex < mQuestionIndexList.size() && max_salah < 3)
{
//mNextQuestionButton.setVisibility(View.VISIBLE);
//nyalakanWaktu();
waktu();
displayNextQuestion();
}
else
{
Intent i = new Intent(this, SummaryActivity.class);
i.putExtra("categoryId", mCategoryId);
i.putExtra("questionsAnswered", mQuestionsAnswered);
i.putExtra("correctAnswers", mCorrectAnswers);
startActivity(i);
//mCompleteButton.setVisibility(View.VISIBLE);
}
}
}
/**
* Click handler for the next question button.
* Displays the next available question after current question is answered.
*
* @param View v - The current view.
*/
public void nextQuestionButtonClickHandler(View v)
{
displayNextQuestion();
Suara.playButtonClick();
}
/**
* Click handler for the trivia round completion button.
* Displays the round summary screen when clicked.
*
* @param View v - The current view.
*/
public void completeButtonClickHandler(View v)
{
Intent i = new Intent(this, SummaryActivity.class);
i.putExtra("categoryId", mCategoryId);
i.putExtra("questionsAnswered", mQuestionsAnswered);
i.putExtra("correctAnswers", mCorrectAnswers);
startActivity(i);
}
/**
* Disables all answer buttons.
* Used after an answer is selected.
*/
private void disableAnswerButtons()
{
Button answerButton = null;
for (int i = 0; i < answerButtons.size(); i++)
{
answerButton = answerButtons.get(i);
answerButton.setEnabled(false);
}
}
public void nyalakanWaktu(){
final Handler handler = new Handler();
Timer timer = new Timer();
TimerTask doAsynchronousTask = new TimerTask() {
@Override
public void run() {
handler.post(new Runnable() {
public void run() {
try {
progressBar.incrementProgressBy(1);
int stringProgress=progressBar.getProgress();
progressText.setText(stringProgress+"");
} catch (Exception e) {
}
}
});
}
};timer.schedule(doAsynchronousTask, 0, 200);
//audioBackground.stop();
}
答案 0 :(得分：1)
您可以使用CountDownTimer
new CountDownTimer(30000, 1000) {
public void onTick(long millisUntilFinished) {
mTextField.setText("seconds remaining: " + millisUntilFinished / 1000);
}
public void onFinish() {
mTextField.setText("done!");
}
}.start();
我认为在有时间限制时最好使用CountDownTimer。在上面的示例中，30000是时间限制并且具有1000毫秒的间隔。 30分钟后，onfinish()将被调用。你可以在onTick()上花费时间编写你的逻辑。
更好地解释here