Android - Kotlin 下使用 Room 遇到 There are multiple good constructors and Room will ... 问题

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问题：

kotlin 更新值 1.2.6 版本时，room 表的实体类就编译不通过了，比如：

@Entity(tableName = "table_hex")
data class HexData constructor(
        @ColumnInfo(name = "id")
        @PrimaryKey(autoGenerate = true)
        var id: Int = 0,
        @ColumnInfo(name = "code")
        var code: String = "",
        @ColumnInfo(name = "datas")
        var datas: String = "") {
    constructor() : this(0)
}

会出现下面警告和异常

Warning:(11, 2) 警告: There are multiple good constructors and Room will pick the no-arg construct

当新增加的字段时，就会编译失败，找不到 setter 方法，其实都是上面警告引起的

解决：

在构造函数上添加 Ignore 注解即可

@Entity(tableName = "table_hex")
data class HexData constructor(
        @ColumnInfo(name = "id")
        @PrimaryKey(autoGenerate = true)
        var id: Int = 0,
        @ColumnInfo(name = "code")
        var code: String = "",
        @ColumnInfo(name = "datas")
        var datas: String = "") {
    @Ignore
    constructor() : this(0)
}