Question

我一直在尝试更新sqLite数据库中的数据，但是当我点击更新按钮时，它只会返回到上一页，并且没有任何变化，我的代码中的数据没有错误。请检查我的代码谢谢

DatabaseHelper类：

public void updateData(long rowId, String new_question, String new_ans1, String new_ans2, String new_ans3, String new_ans4, SQLiteDatabase sqLiteDatabase )
    {
    ContentValues contentValues = new ContentValues();

        contentValues.put(AdminContact.Question.COLUMN_QUESTION, new_question);
        contentValues.put(AdminContact.Question.COLUMN_ANSWER1, new_ans1);
        contentValues.put(AdminContact.Question.COLUMN_ANSWER2, new_ans2);
        contentValues.put(AdminContact.Question.COLUMN_ANSWER3, new_ans3);
        contentValues.put(AdminContact.Question.COLUMN_ANSWER4, new_ans4);

       // String selection = AdminContact.Question.TABLE_QUIZ + " LIKE ?";
        //String[] selection_arg = {new_question};
       sqLiteDatabase.update(AdminContact.Question.TABLE_QUIZ, contentValues, AdminContact.Question.ID + "=" + rowId, null);


    }

my Update class:

 public void updateData(View view)
    {
    helper = new DatabaseHelper(this);
        sqLiteDatabase = helper.getWritableDatabase();

        String question, ans1, ans2, ans3, ans4;

        question = New_Question.getText().toString();
        ans1 = New_Ans1.getText().toString();
        ans2 = New_Ans2.getText().toString();
        ans3 = New_Ans3.getText().toString();
        ans4 = New_Ans4.getText().toString();
long rowId = 0;
        helper.updateData(rowId,question,ans1,ans2,ans3,ans4,sqLiteDatabase);
        Toast.makeText(getApplicationContext()," Successfully Updated", Toast.LENGTH_LONG).show();
        finish();

    }

Answer 1

我不知道long，但我用这段代码来更新String值，在DatabaseHelper类中尝试此代码：
sqLiteDatabase.update(AdminContact.Question.TABLE_QUIZ, contentValues, AdminContact.Question.ID + "=" + rowId, null);
而不是：
datetime.date

Answer 2

我在更新db表的值时遇到了同样的问题。然后我尝试下面的代码。这对我来说可以试试这段代码。

DatabaseHelper类

public class DatabaseHelper extends SQLiteOpenHelper{
Context context;

// change your database details here;

String db_name = "Database name";
String db_version = "Databse version";
String tbl_name = "Table name";
int col_row_id = "row id col";
String col_question = "Question col name";
String col_ans_1 = "answer 1 col";
String col_ans_2 = "answer 2 col";
String col_ans_3 = "answer 3 col";
String col_ans_4 = "answer 4 col";

    public DatabaseHelper(Context context) {
        super(context, db_name, null, db_version);

        this.context = context;

    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String query = "create table " + tbl_name+ "(" +
                int_col_row+ " integer primary key autoincrement, " +
                col_question+ " text, "+
                col_ans_1+ " text, "+
                col_ans_2+ " text, "+
                col_ans_3+ " text, "+
                col_ans_4+ " text, "+
                ");";

        db.execSQL(query);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {

        String query = "drop table if exists "+tbl_name;
        db.execSQL(query);
        onCreate(db);
    }

    public void updateData(int rowId, String new_question, String new_ans1, String new_ans2, String new_ans3, String new_ans4) {
        String query = "update "+tbl_name+ " set "+
        col_question+"=\""+new_question+"\","+
        col_answer1+"=\""+answer1+"\","+
        col_answer2+"=\""+answer2+"\","+
        col_answer3+"=\""+answer3+"\","+
        col_answer4+"=\""+answer4+"\""+
        " where "+col_row_id+"=\""+rowId+"\"";

        SQLiteDatabase db = getWritableDatabase();
        db.execSQL(query);

        db.close();
    }
}

更新课程

public class update{

 // initialise New_Question, New_Ans1, New_Ans2, New_Ans3, New_Ans4 as final variables. Also set onclick function of buttion to updateData

public void updateData(View view){
      helper = new DatabaseHelper(view.getContext());

      String question, ans1, ans2, ans3, ans4;

       question = New_Question.getText().toString();
        ans1 = New_Ans1.getText().toString();
        ans2 = New_Ans2.getText().toString();
        ans3 = New_Ans3.getText().toString();
        ans4 = New_Ans4.getText().toString();
       int rowId = 0;

       helper.updateData(rowId,question,ans1,ans2,ans3,ans4);
}

}

android：更新Sqlite数据库中的数据

2 个答案: