如何从不同的SQLite表获取数据并将其显示在一个SimpleAdapter Android中

Question

我是Android新手，需要在列表视图中显示开始时间，停止时间和名称。为了显示，我使用一个SimpleAdapter。问题是我有两个SQLite表：

上桌时间：启动时间|停工时间|学生证

餐桌学生：学生证|学生姓名

现在，我使用Cursor从数据库中获取开始时间，停止时间和学生ID

 Cursor curm1 = myDb.getAllMonday();
 while (curm1.moveToNext()) {
        final HashMap<String, String> resultMapMonday = new HashMap<>();
        resultMapMonday.put("Start", curm1.getString(3));
        resultMapMonday.put("Stop", curm1.getString(4));
        resultMapMonday.put("Student", curm1.getString(5));
        arrayListStudentsName.add(curm1.getString(5));
        listItemsMo.add(resultMapMonday);
 }

然后显示一个SimpleAdapter：

final SimpleAdapter adaptersimpleMo = new SimpleAdapter(this, listItemsMo, R.layout.timeslots_configurate,
            new String[]{"Start", "Stop", "Student"},
            new int[]{R.id.oneTime_start, R.id.oneTime_stop, R.id.selectedStudent});

但是我想显示名称，而不是ID，这些名称存储在另一个表中。我可以使用另一个光标来获取ID的匹配名称

Cursor curm2 = myDb.getNamesbyIDs(arrayListStudentsName);
while (curm2.moveToNext()) {
        final HashMap<String, String> resultMapNames = new HashMap<>();
        resultMapNames.put("Name", curm2.getString(1));
}

但是我不知道如何在相同的适配器中获取名称，以在与匹配的开始和结束时间相同的列表项中显示名称。

编辑

  public Cursor getAllMonday() {
    SQLiteDatabase db = this.getWritableDatabase();
    Cursor res = db.rawQuery("SELECT * FROM " + TABLE_TIME + " WHERE day = 'Montag' ORDER BY CAST(start as unsigned)", null);
    return res;
}

Answer 1

更改getAllMonday()以使用连接两个表的查询：

public Cursor getAllMonday() {
    SQLiteDatabase db = this.getWritableDatabase();
    String sql = "SELECT t.Start, t.Stop, s.Studentname FROM " + TABLE_TIME + " AS t INNER JOIN " + TABLE_STUDENT + 
                 " AS s ON s.StudentID = t.StudentID WHERE t.day = 'Montag' ORDER BY CAST(t.start as unsigned)"
    Cursor res = db.rawQuery(sql, null);
    return res;
}

将表变量TABLE_STUDENT和我以前使用的列名更改为实际名称。现在，光标包含学生的姓名，而不是ID。接下来将代码更改为：

Cursor curm1 = myDb.getAllMonday();
while (curm1.moveToNext()) {
    final HashMap<String, String> resultMapMonday = new HashMap<>();
    resultMapMonday.put("Start", curm1.getString(curm1.getColumnIndex("Start")));
    resultMapMonday.put("Stop", curm1.getString(curm1.getColumnIndex("Stop")));
    resultMapMonday.put("Student", curm1.getString(curm1.getColumnIndex("Stusentname")));
    arrayListStudentsName.add(curm1.getString(curm1.getColumnIndex("Studentname")));
    listItemsMo.add(resultMapMonday);
}
curm1.close();