java - 数据库到游标，游标到数组列表和数组列表到名称值对的字符串。

Question

我有一个包含八列的数据库表，其中包含以下字段:

|_id|flag|HVID|Vname|Vdate|Vtime|Vcost|Vmedicine|

我正在查询此数据库以提取属于某个“HVID”的所有记录:

public Cursor fetchAllVac(String ID) {

        String Key = ID;
        Cursor mCursor = mDb.query(DATABASE_TABLE1, new String[] { IDx, FLAG,
                HVID1, Vname1, VDate1, Vtime1, Vcost1, Vmedicine1 }, "HVID=?",
                new String[] { Key }, null, null, null, null);
        if (mCursor != null) {
            mCursor.moveToFirst();
        }
        return mCursor;
    }

在 Activity 中，我从游标中获取值并将它们存储在数组列表中:

public void Vacforshare() {
    String B = null;
    ArrayList<String> mArrayList = new ArrayList<String>();
    mCursor = DBHelper.fetchAllVac(IDB);
    if (mCursor.moveToFirst()) {
        do {
            try {
                mArrayList.add(mCursor.getString(mCursor
                        .getColumnIndex("_id")));
                mArrayList.add(mCursor.getString(mCursor
                        .getColumnIndex("flag")));
                mArrayList.add(mCursor.getString(mCursor
                        .getColumnIndex("HVID")));
                mArrayList.add(mCursor.getString(mCursor
                        .getColumnIndex("Vname")));
                mArrayList.add(mCursor.getString(mCursor
                        .getColumnIndex("Vdate")));
                mArrayList.add(mCursor.getString(mCursor
                        .getColumnIndex("Vtime")));
                mArrayList.add(mCursor.getString(mCursor
                        .getColumnIndex("Vcost")));
                mArrayList.add(mCursor.getString(mCursor
                        .getColumnIndex("Vmedicine")));
            } catch (Exception h) {

            }

        } while (mCursor.moveToNext());

    }
    for (int i = 0; i < mArrayList.size(); i++) {
        String G = (mArrayList.get(i));
        B = B + G;
    }
    System.out.println("" + B);

}

我在 B 中得到的是一个冗余的(所有行)值字符串(我的记录可以是多行)我想将这些值分成名称-值对，我对如何实现这一点感到困惑。

Answer 1

您可以引入一个新类，它只包含一条记录的值列表，如下所示:

public class Record {
    List<String> values = new ArrayList<String>();

    public List<String> getValues() {
        return values;
    }
}

然后在循环中填写记录列表:

ArrayList<Record> mArrayList = new ArrayList<Record>();
do {
    try {
        Record record = new Record();
        List<String> values = record.getValues();

        values.add(mCursor.getString(mCursor.getColumnIndex("_id")));
        ...
        mArrayList.add(record);
    } catch (Exception h) {

    }
}

现在您可以遍历字段名称和每条记录的值来创建您想要的输出:

String[] names = new String[] {"_id", "flag", ....};
for (int i = 0; i < mArrayList.size(); i++) {
    Record record = mArrayList.get(i);

    String current = "";
    List<String> values = record.getValues();
    for (int j = 0; j < values.size(); j++) {
        String fieldName = names[j];
        String s = values.get(j);
        current += " " + fieldName + "=" + s;
    }
    B = B + "[" + current.trim() + "]";
}
System.out.println(B); // will print: [_id=value1 flag=value2 ...][_id=value1 flag=value2 ...] etc