Question

我有一个测验测试，为此，我为我的所有问题制作了数据库助手。我有不同的单位，每个单位有10个问题。显示错误答案我使用此代码：

     public static String getAnswers(List<Question> queslist) {
    StringBuffer sb = new StringBuffer();
    int question = 1;
    for (Question currentQ : queslist) {
        if (!currentQ.isAnsweredCorrectly()) {
            sb.append("Q").append(question).append(") ").append(currentQ.getQUESTION()).append("? \n");
            sb.append("Answer: ").append(currentQ.getANSWER()).append("\n\n");
            question++;
        }
    }
    return sb.toString();
}

它工作正常，它给我错误的答案。重点是：queslist从我的db helper中读取所有问题。我如何改变它以向我展示我单位的每个问题和答案。

这是我的db helper＆amp;我的桌子：

   package com.example.triviality;
import java.util.ArrayList;
import java.util.List;
   import android.content.ContentValues;
   import android.content.Context;
   import android.database.Cursor;
  import android.database.sqlite.SQLiteDatabase;
  import android.database.sqlite.SQLiteOpenHelper;
  public class DbHelper extends SQLiteOpenHelper {
private static final int DATABASE_VERSION = 1;
// Database Name
private static final String DATABASE_NAME = "triviaQuiz";
// tasks table name
private static final String TABLE_QUEST = "quest";
// tasks Table Columns names
private static final String KEY_ID = "id";
private static final String KEY_QUES = "question";
private static final String KEY_ANSWER = "answer"; //correct option
private static final String KEY_OPTA= "opta"; //option a
private static final String KEY_OPTB= "optb"; //option b
private static final String KEY_OPTC= "optc"; //option c
private SQLiteDatabase dbase;
public DbHelper(Context context) {
    super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
    dbase=db;
    String sql = "CREATE TABLE IF NOT EXISTS " + TABLE_QUEST + " ( "
            + KEY_ID + " INTEGER PRIMARY KEY AUTOINCREMENT, " + KEY_QUES
            + " TEXT, " + KEY_ANSWER+ " TEXT, "+KEY_OPTA +" TEXT, "
            +KEY_OPTB +" TEXT, "+KEY_OPTC+" TEXT)";
    db.execSQL(sql);        
    addQuestions();
    //db.close();
}
private void addQuestions()
{
    Question q1=new Question("Which company is the largest manufacturer" +
            " of network equipment?","HP", "IBM", "CISCO", "CISCO");
    this.addQuestion(q1);
    Question q2=new Question("Which of the following is NOT " +
            "an operating system?", "SuSe", "BIOS", "DOS", "BIOS");
    this.addQuestion(q2);
    Question q3=new Question("Which of the following is the fastest" +
            " writable memory?","RAM", "FLASH","Register","Register");
    this.addQuestion(q3);
    Question q4=new Question("Which of the following device" +
            " regulates internet traffic?", "Router", "Bridge", "Hub","Router");
    this.addQuestion(q4);
    Question q5=new Question("Which of the following is NOT an" +
            " interpreted language?","Ruby","Python","BASIC","BASIC");
    this.addQuestion(q5);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldV, int newV) {
    // Drop older table if existed
    db.execSQL("DROP TABLE IF EXISTS " + TABLE_QUEST);
    // Create tables again
    onCreate(db);
}
// Adding new question
public void addQuestion(Question quest) {
    //SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put(KEY_QUES, quest.getQUESTION()); 
    values.put(KEY_ANSWER, quest.getANSWER());
    values.put(KEY_OPTA, quest.getOPTA());
    values.put(KEY_OPTB, quest.getOPTB());
    values.put(KEY_OPTC, quest.getOPTC());
    // Inserting Row
    dbase.insert(TABLE_QUEST, null, values);        
}
public List<Question> getAllQuestions() {
    List<Question> quesList = new ArrayList<Question>();
    // Select All Query
    String selectQuery = "SELECT  * FROM " + TABLE_QUEST;
    dbase=this.getReadableDatabase();
    Cursor cursor = dbase.rawQuery(selectQuery, null);
    // looping through all rows and adding to list
    if (cursor.moveToFirst()) {
        do {
            Question quest = new Question();
            quest.setID(cursor.getInt(0));
            quest.setQUESTION(cursor.getString(1));
            quest.setANSWER(cursor.getString(2));
            quest.setOPTA(cursor.getString(3));
            quest.setOPTB(cursor.getString(4));
            quest.setOPTC(cursor.getString(5));
            quesList.add(quest);
        } while (cursor.moveToNext());
    }
    // return quest list
    return quesList;
}
public int rowcount()
{
    int row=0;
    String selectQuery = "SELECT  * FROM " + TABLE_QUEST;
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor cursor = db.rawQuery(selectQuery, null);
    row=cursor.getCount();
    return row;
}

}

Answer 1

满足您要求的最小变化是：在您的数据库中添加另一列以标识给定问题属于哪个单位。完成后，创建一个方法，返回该单元的问题列表，例如：

public List<Question> getQuestionsForUnit(String unit) {
    List<Question> quesList = new ArrayList<Question>();
    // Select All Query
    String selectQuery = "SELECT  * FROM " + TABLE_QUEST + "WHERE UNIT = '" + unit "'";
    ....

总的来说，我认为您可能想重新考虑您的架构;存储问题，用户在一个表中给出的可能答案和答案似乎有点混乱。

如何从我的db帮助器中读取？

1 个答案: