Question

我想在下一个按钮上更新特定列。但是在运行之后，应用程序会双倍地插入一个值。如果该值已经在表中，我该如何更新。谢谢欣赏。

这是我的数据库代码。

public class DatabaseHelper extends SQLiteOpenHelper
{
    SQLiteDatabase sqlDatabase;

        //Database name
       public static final String DATABASE_NAME = "Test.db";

       //Database Version
       static final int DATABASE_VERSION = 2;

       public DatabaseHelper(Context context) {
            super(context, DATABASE_NAME, null, DATABASE_VERSION);
            // TODO Auto-generated constructor stub
             this.sqlDatabase = this.getWritableDatabase();  
        }


       public static final String QUESTION_ANSWERS_TABLE = "question_answers";

        //Table REGISTRATION_TABLE columns Name
       public static final String  Question_Id = "question_id";
       public static final String Question_No = "question_no";
       public static final String Question_Type = "question_type";
       public static final String Question = "question";
       public static final String Answer = "answer";
       public static final String Options_ID = "option";
       public static final String Marks = "mark";

    @Override
       public void onCreate(SQLiteDatabase db)
       {
        // TODO Auto-generated method stub
         String  CREATE_QUESTION_ANSWERS_TABLE = "CREATE TABLE "+ QUESTION_ANSWERS_TABLE + "("
                  + Question_Id + " INTEGER PRIMARY KEY AUTOINCREMENT, " 
                  + Question_No + " TEXT,"
                  + Question_Type + " TEXT, "
                  + Question+ " TEXT, "
                  + Answer + " TEXT, "
                  + Marks + " TEXT, "
                  + Options_ID + " TEXT "+");";
          db.execSQL(CREATE_QUESTION_ANSWERS_TABLE);

      }
    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        // TODO Auto-generated method stub

         db.execSQL("DROP TABLE IF EXISTS " + QUESTION_ANSWERS_TABLE);
         onCreate(db);
    }



    public boolean insertQueDetails(String strQuestionNo , String strQuestionType, String strQuestion, String strAnswer, 
                                    String strMark   , String strOptionId )
       {
          SQLiteDatabase db = this.getWritableDatabase();
          ContentValues contentValues = new ContentValues();
          contentValues.put(Question_No, strQuestionNo);
          contentValues.put(Question_Type, strQuestionType);
          contentValues.put(Question, strQuestion);
          contentValues.put(Answer, strAnswer);
          contentValues.put(Marks, strMark);    
          contentValues.put(Options_ID, strOptionId);

          db.insert(QUESTION_ANSWERS_TABLE, null, contentValues);
          db.close();
          return true;
       }


    public void updateAnswerRow(Integer strQ_Id , String strAnswer)
    {
            SQLiteDatabase db = this.getWritableDatabase();
            ContentValues args = new ContentValues();
            args.put(Answer, strAnswer);

            db.update("question_answers", args, "question_id = ? ", new String[] { Integer.toString(strQ_Id) } );
     }


}

这是我的活动代码。

  public void checkEmptyTable()
    {
        DatabaseHelper databaseHelper = new DatabaseHelper(this.getApplicationContext());
        sqdb = databaseHelper.getWritableDatabase();

        Cursor cur = sqdb.rawQuery("SELECT COUNT(question_id) AS Count_Id FROM question_answers", null);
        if (cur != null) 
        {
            cur.moveToFirst();  
            // Always one row returned.
               int Count_Id = cur.getInt(cur.getColumnIndex("Count_Id"));        
               System.out.println("Count_Id in Table is Empty !!!! i = " + Count_Id);  // Zero count means empty table.

        }cur.close();
    }

    public void storingResult()
    {
            AnswerOptions = (RadioButton) findViewById(Options_RadioGroup.getCheckedRadioButtonId());
            String str_AnswerOptions = AnswerOptions.getText().toString().trim();
            System.out.println("rbVal = " + str_AnswerOptions);
            if (str_AnswerOptions.equals(((Datastructure) Vectore_mquestionDatabaseStructure .get(StaticClass.QuestionNumber)).Answer))
                {
                    if (!StaticClass.isTest)
                    {
                        String str_queNo = button_QuestionLimit.getText().toString().trim();
                        String strstrqueType = txtViewQuestiontype.getText().toString().trim();
                        String str_que = txtViewQuestion.getText().toString().trim();
                        String str_marks = "1";

                        if(Count_Id == 0 )
                        {
                            databaseHelper.insertQueDetails(str_queNo, strstrqueType, str_que, str_AnswerOptions, str_marks  , strOption_Id);
                            System.out.println("str_queNo = " + str_queNo + ", strstrqueType = " + strstrqueType +" , str_que = " + str_que + " , str_AnswerOptions = " + str_AnswerOptions + ", str_marks = " + str_marks + ", strOption_Id = " + strOption_Id);
                            Toast.makeText(this, " Right Answer ", Toast.LENGTH_LONG).show();
                        }
                        else if(Count_Id == convertVector)
                        {
                             databaseHelper.updateAnswerRow(convertVector , str_AnswerOptions);
                             Toast.makeText(this, "Updated SuccesFully", Toast.LENGTH_LONG).show();
                             System.out.println("Answer Updated Successfully !!!");
                        }
                    }

                }

                else
                {
                    if (!StaticClass.isTest)

                    {
                        String str_queNo = button_QuestionLimit.getText()
                                .toString().trim();
                        String strstrqueType = txtViewQuestiontype.getText()
                                .toString().trim();
                        String str_que = txtViewQuestion.getText().toString()
                                .trim();
                        String str_marks = "0";

                        if(Count_Id == 0 )
                        {
                            databaseHelper.insertQueDetails(str_queNo, strstrqueType, str_que, str_AnswerOptions, str_marks  , strOption_Id);
                            System.out.println("str_queNo = " + str_queNo + ", strstrqueType = " + strstrqueType +" , str_que = " + str_que + " , str_AnswerOptions = " + str_AnswerOptions + ", str_marks = " + str_marks + ", strOption_Id = " + strOption_Id);
                            Toast.makeText(this, " Wrong Answer ", Toast.LENGTH_LONG).show();
                        }
                        else if(Count_Id == convertVector)
                        {
                             databaseHelper.updateAnswerRow(convertVector , strtext);
                             Toast.makeText(this, "Wrong Updated SuccesFully", Toast.LENGTH_LONG).show();
                             System.out.println("Wrong Answer Updated Successfully !!!");
                        }
                    }
                }

                if (StaticClass.isTest)
            {
                StaticClass.resultOfTest = 1 + StaticClass.resultOfTest;
                ((Datastructure) Vectore_mquestionDatabaseStructure.elementAt(StaticClass.QuestionNumber)).setResult_Of_Test(true);
                return;
            }
    }

这是我的活动屏幕截图

enter image description here 这是屏幕截图

Answer 1

将要保存到数据库中的所有数据的Getter和setter类生成，并将其用于保存和更新数据。

更改数据库中的更新方法：

public void updateAnswerRow(gettersetterclass classs)
    {
            SQLiteDatabase db = this.getWritableDatabase();
            ContentValues contentValues = new ContentValues();
            contentValues.put(Question_No, classs.getuestionno);
            contentValues.put(Question_Type, classs.getquestiontype);
            contentValues.put(Question, classs.getquestion);
            contentValues.put(Answer, classs.getAnswer);
            contentValues.put(Marks, classs.getmarks);    
            contentValues.put(Options_ID, classs.getoptionid);
            db.update(QUESTION_ANSWERS_TABLE , args, Question_Id +" = ? ", new String[] { Integer.toString(classs.getstrQ_Id) } );
     }

如果您已经制作了gettersetter类，那么请使用它。

如何在Android中更新行？

1 个答案: