java - 如何在从第一个 Activity 收到的 sqlite 查询中传递整数变量？

Question

我是 Android 设备编程新手。我有两个 Activity ，在第一个 Activity 中，我将一个整数值从第一个 Activity 发送到第二个 Activity 。

如何在我从第一个 Activity 收到的 sqlite 查询中添加此变量？

我想在查询中写入 b=1 的位置添加书号，我想用书号替换 1

private void setData() {

    Intent mIntent = getIntent();
    int booknumber= mIntent.getIntExtra("booknumber", 0);

    stringArrayList = new ArrayList<>();

    mDBHelper = new DatabaseHelper(this);
    mDb = mDBHelper.getReadableDatabase();

    Cursor cursor = mDb.rawQuery("select DISTINCT c from t_asv where b=1", new String[]{});

    if(cursor!=null && cursor.getCount() > 0)
    {
        if (cursor.moveToFirst())
        {
            do {
                stringArrayList.add(cursor.getString(0));
            } while (cursor.moveToNext());
        }
    }

Answer 1

只需将 int 书号连接到您的查询，如下所示:

int booknumber= mIntent.getIntExtra("booknumber", 0);
...
Cursor cursor = mDb.rawQuery("select DISTINCT c from t_asv where b=" + booknumber, new String[]{});

更新:最好使用 PreparedStatement/how to use正如@patrick-hollweck提到的

Writing code like this leaves your app wide open to a sql injection vulnerability and is generally considered a very bad practice