Question

我是android.i的新手我正在尝试制作一个有类别的测验应用。我在点击每个类别时传递不同的int值我想在我的Questionactivity类中使用该值，这样当点击第一个按钮时，只会运行前10个问题，点击第二个按钮将运行10到20个问题。

    package com.example.chaitanya.myquiz;

     import java.util.List;
      import java.util.Random;
     import java.util.Timer;
     import java.util.concurrent.TimeUnit;

     import android.annotation.SuppressLint;
     import android.annotation.TargetApi;
     import android.app.Activity;
      import android.content.Intent;
      import android.graphics.Typeface;
      import android.media.MediaPlayer;
      import android.os.Build;
      import android.os.Bundle;
      import android.os.CountDownTimer;
      import android.support.annotation.Nullable;
      import android.util.Log;
      import android.view.View;
      import android.widget.Button;
      import android.widget.TextView;

      import static java.lang.Integer.parseInt;


  public class QuestionActivity extends Activity {
  List<Question> quesList;
  int score = 0;
  Random r = new Random();
  Question currentQ;
  TextView txtQuestion, times, scored;
  Button button1, button2, button3;
  CounterClass timer;


  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    Intent intent2 = getIntent();
    int qid = intent2.getIntExtra("qid",10);
    QuizHelper db = new QuizHelper(this);  // my question bank class
    quesList = db.getAllQuestions();  // this will fetch all quetonall   
    questions
    currentQ = quesList.get(qid); // the current question

    txtQuestion = (TextView) findViewById(R.id.txtQuestion);
    // the textview in which the question will be displayed

    // the three buttons,

    button1 = (Button) findViewById(R.id.button1);
    button2 = (Button) findViewById(R.id.button2);
    button3 = (Button) findViewById(R.id.button3);

    // the textview in which score will be displayed
    scored = (TextView) findViewById(R.id.score);

    // the timer
    times = (TextView) findViewById(R.id.timers);


    // method which will set the things up for our game
    setQuestionView();
    times.setText("00:00:30");

    // A timer of 30 seconds to play for, with an interval of 1 second (1000 milliseconds)
    timer = new CounterClass(30000, 1000);
    timer.start();

    // button click listeners
    button1.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {

            // passing the button text to other method
            // to check whether the anser is correct or not
            // same for all three buttons
            getAnswer(button1.getText().toString());
        }
    });

    button2.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            getAnswer(button2.getText().toString());
        }
    });

    button3.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            getAnswer(button3.getText().toString());
        }
    });
}

public void getAnswer(String AnswerString) {
    Intent intent2 = getIntent();
    int qid = intent2.getIntExtra("qid", 10);
    if (currentQ.getANSWER().equals(AnswerString)) {

        // if conditions matches increase the int (score) by 1
        // and set the text of the score view
        score++;
        scored.setText("Score : " + score);

    } else {

        // if unlucky start activity and finish the game
        timer.cancel();
        Intent intent = new Intent(QuestionActivity.this,
                ResultActivity.class);
        // passing the int value
        Bundle b = new Bundle();
        b.putInt("score", score); // Your score
        intent.putExtras(b); // Put your score to your next
        startActivity(intent);
        finish();
    }

    if (qid < 60) {

        // if questions are not over then do this
        currentQ = quesList.get(qid);
        setQuestionView();
    } else {
        // if over do this
        timer.cancel();
        Intent intent = new Intent(QuestionActivity.this,
                ResultActivity.class);
        Bundle b = new Bundle();
        b.putInt("score", score); // Your score
        intent.putExtras(b); // Put your score to your next
        startActivity(intent);
        finish();
    }


}


@TargetApi(Build.VERSION_CODES.GINGERBREAD)
@SuppressLint("NewApi")
public class CounterClass extends CountDownTimer {

    public CounterClass(long millisInFuture, long countDownInterval) {
        super(millisInFuture, countDownInterval);
        // TODO Auto-generated constructor stub
    }


    @Override
    public void onFinish() {
        times.setText("Time is up");
        Intent intent = new Intent(QuestionActivity.this,
                ResultActivity.class);
        timer.cancel();
        Bundle b = new Bundle();
        b.putInt("score", score); // Your score
        intent.putExtras(b); // Put your score to your next
        startActivity(intent);
        finish();

    }

    @Override
    public void onTick(long millisUntilFinished) {
        // TODO Auto-generated method stub

        long millis = millisUntilFinished;
        String hms = String.format(
                "%02d:%02d:%02d",
                TimeUnit.MILLISECONDS.toHours(millis),
                TimeUnit.MILLISECONDS.toMinutes(millis)
                        - TimeUnit.HOURS.toMinutes(TimeUnit.MILLISECONDS
                        .toHours(millis)),
                TimeUnit.MILLISECONDS.toSeconds(millis)
                        -   
           TimeUnit.MINUTES.toSeconds(TimeUnit.MILLISECONDS
                        .toMinutes(millis)));
        System.out.println(hms);
        times.setText(hms);
    }


}

private void setQuestionView() {
    Random r = new Random();
    Intent intent2 = getIntent();
    int qid = intent2.getIntExtra("qid", 10);
    switch (qid) {
        case 10:
            // the method which will put all things together
            txtQuestion.setText(currentQ.getQUESTION());
            button1.setText(currentQ.getOPTA());
            button2.setText(currentQ.getOPTB());
            button3.setText(currentQ.getOPTC());
            qid = (r.nextInt(10) + 1);
        case 20:
            txtQuestion.setText(currentQ.getQUESTION());
            button1.setText(currentQ.getOPTA());
            button2.setText(currentQ.getOPTB());
            button3.setText(currentQ.getOPTC());
            qid = (r.nextInt(20) + 11);
        case 30:
            txtQuestion.setText(currentQ.getQUESTION());
            button1.setText(currentQ.getOPTA());
            button2.setText(currentQ.getOPTB());
            button3.setText(currentQ.getOPTC());
            qid = (r.nextInt(30) + 21);
        }

          }
        }

Answer 1

您需要Internet权限才能访问网络。

将这些权限添加到AndroidManifest.xml。

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />

详细信息：https://developer.android.com/training/basics/network-ops/connecting.html

Answer 2

从空指针引发异常，您的活动的起始意图没有额外的包

java.lang.NullPointerException: Attempt to     
           invoke virtual method 'double 
        android.os.Bundle.getDouble(java.lang.String)' on a null             
              object reference
              at    
              com.example.chaitanya.calculatornew.
              MainActivity.findtheweather(MainActivity.java:27)

如何通过意图通过一个类获得价值？

2 个答案: