Question

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

对于如何使用SQLiteDatabase可以找到答案：

1）Android ExpandableListView and SQLite Database

2）Android ExpandableListView From Database

使用Room Database是否可以实现相同的目的？

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*/
}

带有Room数据库的Android ExpandableListview

1 个答案: