java - 从 SQLite 过滤记录以显示在列表中

Question

我在SQLite数据库中有一些数据，我想在基于小逻辑的List中显示这些数据。

我的表中有三个字段，

first field : id
second field : title
third field : type 

其中类型可以是:每月或每年

这是我的代码:

    // Generate real data for each item
    public List<ReminderItem> generateData(int count) {
        ArrayList<ReminderItem> items = new ArrayList<>();

        // Get all reminders from the database
        List<Reminder> reminders = rb.getAllReminders();

        // Initialize lists
        List<String> Titles = new ArrayList<>();
        List<String> Type = new ArrayList<>();
        List<Integer> IDList= new ArrayList<>();

        // Add details of all reminders in their respective lists
        for (Reminder r : reminders) {
            Titles.add(r.getTitle());
            Type.add(r.getType());
            IDList.add(r.getID());
        }
        return items;
      }

在这种情况下，我需要你们的帮助，正如你们所看到的，我正在显示从数据库到列表的每一条每条记录，无论它所属的类型。

现在，我只想在列表中显示记录，该列表仅属于“每月”类型

那么我到底需要做什么？如何仅在列表中显示“每月”类型的记录

我有一个 String 变量，即 strType = "Monthly";

Answer 1

您有两种选择来执行此操作。

First is directly get only those record from database which reminder type is "Monthly" by execute below sql statement.

SELECT id,title,type FROM table_name WHERE type = "Monthly"

Second is check reminder type is equal to "Monthly" when you add data into List.

for (Reminder r : reminders) {

        String reminderType = r.getType();
        if(reminderType.equalsIgnoreCase(strType)) {

            Titles.add(r.getTitle());
            Type.add(reminderType);
            IDList.add(r.getID());
        }
    }

完整代码

// Generate real data for each item
public List<ReminderItem> generateData(int count) {

    String strType = "Monthly";

    ArrayList<ReminderItem> items = new ArrayList<>();

    // Get all reminders from the database
    List<Reminder> reminders = rb.getAllReminders();

    // Initialize lists
    List<String> Titles = new ArrayList<>();
    List<String> Type = new ArrayList<>();
    List<Integer> IDList= new ArrayList<>();

    // Add details of all reminders which type="Monthly" in their respective lists
    for (Reminder r : reminders) {

        String reminderType = r.getType();
        if(reminderType.equalsIgnoreCase(strType)) {

            Titles.add(r.getTitle());
            Type.add(reminderType);
            IDList.add(r.getID());
        }
    }
    return items;
}