Android实现简单的答题系统

本文实例为大家分享了Android实现答题系统的具体代码，供大家参考，具体内容如下

Question：

package com.example.lenovo.exam; 

/**
 * Created by lenovo on 2017/12/4.
 */
//保存从数据库中读取的记录
public class Question {
 public String question;
 public String answerA;
 public String answerB;
 public String answerC;
 public String answerD;
 public int answer;
 public String explaination;
 public int ID ;
 //用户选择的答案
 public int selectedAnswer;
}

DBService:

使用android自带数据库，下载SQLite Database Browser对数据库进行操作
src main文件夹下创建assests文件夹（此文件夹下的内容在应用被打包成apk时不会被压缩）（存放试题数据库）

在数据库启动时，将该数据库文件复制到数据库目录下

package com.example.lenovo.exam; 

import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase; 

import java.util.ArrayList;
import java.util.List; 

/**
 * Created by lenovo on 2017/12/4.
 */
//连接数据库，并从数据库中获取所需数据
public class DBService {
 private SQLiteDatabase db;
 //在构造函数中打开指定数据库，并把它的引用指向db
 public DBService(){
  db=SQLiteDatabase.openDatabase("/data/data/com.example.lenovo.exam/databases/question.db" +
    "",null,SQLiteDatabase.OPEN_READWRITE);
 }
 //获取数据库中的问题
 public List<Question> getQuestion(){
  List<Question> list=new ArrayList<Question>();
  /*
    Cursor是结果集游标，用于对结果集进行随机访问,其实Cursor与JDBC中的ResultSet作用很相似。
    rawQuery()方法的第一个参数为select语句；第二个参数为select语句中占位符参数的值，如果select语句没有使用占位符，该参数可以设置为null。*/
  Cursor cursor =db.rawQuery("select * from question",null);
  if(cursor.getCount()>0){
   cursor.moveToFirst();//将cursor移动到第一个光标上
   int count=cursor.getCount();
   //将cursor中的每一条记录生成一个question对象，并将该question对象添加到list中
   for(int i=0;i<count;i++){
    cursor.moveToPosition(i);
    Question question =new Question();
    question.ID=cursor.getInt(cursor.getColumnIndex("ID"));
    question.question=cursor.getString(cursor.getColumnIndex("question"));
    question.answerA=cursor.getString(cursor.getColumnIndex("answerA"));
    question.answerB=cursor.getString(cursor.getColumnIndex("answerB"));
    question.answerC=cursor.getString(cursor.getColumnIndex("answerC"));
    question.answerD=cursor.getString(cursor.getColumnIndex("answerD"));
    question.answer=cursor.getInt(cursor.getColumnIndex("answer")); 

    question.explaination=cursor.getString(cursor.getColumnIndex("explanation"));
    //表示没有选择任何选项
    question.selectedAnswer=-1;
    list.add(question);
   }
  }
  return list;
 } 

}

ExamActivity:

package com.example.lenovo.exam; 

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.TextView; 

import java.util.ArrayList;
import java.util.List; 

/**
 * Created by lenovo on 2017/12/4.
 */ 

public class ExamActivity extends Activity { 

 private int count;
 private int current;
 private boolean wrongMode;//标志变量，判断是否进入错题模式 

 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_exam); 

  DBService dbService = new DBService();
  final List<Question> list = dbService.getQuestion(); 

  count = list.size();
  current = 0;
  wrongMode=false;//默认情况 

  final TextView tv_question = findViewById(R.id.question);
  final RadioButton[] radioButtons = new RadioButton[4];
  radioButtons[0] = findViewById(R.id.answerA);
  radioButtons[1] = findViewById(R.id.answerB);
  radioButtons[2] = findViewById(R.id.answerC);
  radioButtons[3] = findViewById(R.id.answerD);
  Button btn_previous = findViewById(R.id.btn_previous);
  Button btn_next = findViewById(R.id.btn_next);
  final TextView tv_explaination = findViewById(R.id.explaination);
  final RadioGroup radioGroup = findViewById(R.id.radioGroup);
  //为控件赋值
  Question q = list.get(0);
  tv_question.setText(q.question);
  tv_explaination.setText(q.explaination);
  radioButtons[0].setText(q.answerA);
  radioButtons[1].setText(q.answerB);
  radioButtons[2].setText(q.answerC);
  radioButtons[3].setText(q.answerD); 

  btn_next.setOnClickListener(new View.OnClickListener() { 

   @Override
   public void onClick(View view) {
    if (current < count - 1) {//若当前题目不为最后一题，点击next按钮跳转到下一题；否则不响应
     current++;
     //更新题目
     Question q = list.get(current);
     tv_question.setText(q.question);
     radioButtons[0].setText(q.answerA);
     radioButtons[1].setText(q.answerB);
     radioButtons[2].setText(q.answerC);
     radioButtons[3].setText(q.answerD);
     tv_explaination.setText(q.explaination); 

     //若之前已经选择过，则应记录选择
     radioGroup.clearCheck();
     if (q.selectedAnswer != -1) {
      radioButtons[q.selectedAnswer].setChecked(true);
     } 

    }
    //错题模式的最后一题
    else if(current==count-1&& wrongMode==true){
     new AlertDialog.Builder(ExamActivity.this)
       .setTitle("提示")
       .setMessage("已经到达最后一题，是否退出？")
       .setPositiveButton("确定", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialogInterface, int i) {
         ExamActivity.this.finish();
        }
       })
       .setNegativeButton("取消",null)
       .show(); 

    }
    else{
     //当前题目为最后一题时，告知用户作答正确的数量和作答错误的数量，并询问用户是否要查看错题
     final List<Integer> wrongList=checkAnswer(list);
     //作对所有题目
     if(wrongList.size()==0){
      new AlertDialog.Builder(ExamActivity.this)
        .setTitle("提示")
        .setMessage("恭喜你全部回答正确！")
        .setPositiveButton("确定", new DialogInterface.OnClickListener() {
         @Override
         public void onClick(DialogInterface dialogInterface, int i) {
          ExamActivity.this.finish();
         }
        }).show(); 

     }
     else
      new AlertDialog.Builder(ExamActivity.this)
        .setTitle("提示")
        .setMessage("您答对了"+(list.size()-wrongList.size())+
          "道题目；答错了"+wrongList.size()+"道题目。是否查看错题？")
        .setPositiveButton("确定", new DialogInterface.OnClickListener() {
         @Override
         public void onClick(DialogInterface dialogInterface, int which) { 

          //判断进入错题模式
          wrongMode=true;
          List<Question> newList=new ArrayList<Question>();
          //将错误题目复制到newList中
          for(int i=0;i< wrongList.size();i++){
           newList.add(list.get(wrongList.get(i)));
          }
          //将原来的list清空
          list.clear();
          //将错误题目添加到原来的list中
          for(int i=0;i<newList.size();i++){
           list.add(newList.get(i));
          }
          current=0;
          count=list.size();
          //更新显示时的内容
          Question q = list.get(current);
          tv_question.setText(q.question);
          radioButtons[0].setText(q.answerA);
          radioButtons[1].setText(q.answerB);
          radioButtons[2].setText(q.answerC);
          radioButtons[3].setText(q.answerD);
          tv_explaination.setText(q.explaination);
          //显示解析
          tv_explaination.setVisibility(View.VISIBLE);
         }
        })
        .setNegativeButton("取消", new DialogInterface.OnClickListener() {
         @Override
         public void onClick(DialogInterface dialogInterface, int which) {
//点击取消时，关闭当前activity
          ExamActivity.this.finish();
         }
        }).show();
    }
   }
  });
  btn_previous.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View view) {
    if (current > 0)//若当前题目不为第一题，点击previous按钮跳转到上一题；否则不响应
    {
     current--;
     Question q = list.get(current);
     tv_question.setText(q.question);
     radioButtons[0].setText(q.answerA);
     radioButtons[1].setText(q.answerB);
     radioButtons[2].setText(q.answerC);
     radioButtons[3].setText(q.answerD);
     tv_explaination.setText(q.explaination); 

     //若之前已经选择过，则应记录选择
     radioGroup.clearCheck();
     if (q.selectedAnswer != -1) {
      radioButtons[q.selectedAnswer].setChecked(true);
     } 

    } 

   }
  });
  //选择选项时更新选择
  radioGroup.setOnCheckedChangeListener(new RadioGroup.OnCheckedChangeListener() {
   @Override
   public void onCheckedChanged(RadioGroup radioGroup, int checkedId) {
    for (int i = 0; i < 4; i++) {
     if (radioButtons[i].isChecked() == true) {
      list.get(current).selectedAnswer = i;
      break;
     }
    } 

   }
  });
 } 

 /*
判断用户作答是否正确，并将作答错误题目的下标生成list,返回给调用者
 */
 private List<Integer> checkAnswer(List<Question> list) {
  List<Integer> wrongList = new ArrayList<Integer>();
  for(int i=0;i<list.size();i++)
  {
   if(list.get(i).answer!=list.get(i).selectedAnswer){
    wrongList.add(i);
   }
  }
  return wrongList;
 }
}

MainActivity:

package com.example.lenovo.exam; 

import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button; 

import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream; 

public class MainActivity extends AppCompatActivity { 

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  String DB_PATH = "/data/data/com.example.lenovo.exam/databases/";
  String DB_NAME = "question.db";
  //应用启动时，判断数据库是否存在，不存在则将提前打包好的数据库文件复制到数据库目录下
  //数据库目录不存在时，创建数据库目录
  if ((new File(DB_PATH + DB_NAME).exists()) == false) {
   File dir = new File(DB_PATH);
   if (!dir.exists()) {
    dir.mkdir();
   }
  }
//定义输入输出流，用于复制文件
  try {
   InputStream is = getBaseContext().getAssets().open(DB_NAME);
   OutputStream os = new FileOutputStream(DB_PATH + DB_NAME);
   byte[] buffer = new byte[1024];
   int length;
   while ((length = is.read(buffer)) > 0) {
    os.write(buffer, 0, length);
   }
   //刷新输出流，关闭输入输出流
   os.flush();
   os.close();
   os.close(); 

  } catch (IOException e) {
   e.printStackTrace();
  } 

  Button btn = findViewById(R.id.button);
  btn.setOnClickListener(new View.OnClickListener() 

  {
   public void onClick(View v) {
    Intent intent = new Intent(MainActivity.this, ExamActivity.class);
    startActivity(intent); 

   }
  }); 

 }
}

运行截图

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