带有Room数据库的Android ExpandableListview

Question

我需要填充一个ExpandableListView其数据是从Room数据库中获取的。

有关于如何使用SQLiteDatabase做到这一点的答案：

1） Android ExpandableListView和SQLite数据库

2） Android ExpandableListView从数据库

使用Room Database可以达到相同的目的吗？

我有两个表：a）GroupHeader b）GroupContent

@Entity
public class GroupHeader implements Serializable {
    @PrimaryKey(autoGenerate = true)
    private int groupId;
    private String groupName;
    private String otherProperty1;
    private String otherProperty2;
    /* getters and setters */
}

@Entity
public class GroupContent implements Serializable {
    @PrimaryKey(autoGenerate = true)
    private int contentId;
    private int groupId;
    private String contentName;
    private String otherProperty3;
    private String otherProperty4;    
    /* getters and setters */
}

有什么建议吗？

Answer 1

使用@Relation找到了解决方案。

参考： https : //developer.android.com/reference/android/arch/persistence/room/Relation

@Entity
public class GroupHeader implements Serializable {
    @PrimaryKey(autoGenerate = true)
    private int groupId;
    private String groupName;
    private String otherProperty1;
    private String otherProperty2;
    /* getters and setters */
}

@Entity
public class GroupContent implements Serializable {
    @PrimaryKey(autoGenerate = true)
    private int contentId;
    private int groupId;
    private String contentName;
    private String otherProperty3;
    private String otherProperty4;    
    /* getters and setters */
}

public class Wrapper {
    @Embedded
    private GroupHeader header;
    @Relation(parentColumn="groupId", entityColumn="groupId", entity=GroupContent.class)
    private List<GroupContent> contents;
    /*getters & setters*/
}