Firebase-在类上找不到要序列化的属性 [英] Firebase - No properties to serialize found on class

问题描述

我有一个这样的班级:

class dataModel {
    String id, name;
    Integer count;

    dataModel() {}
}

然后我从Firebase添加数据.

And I add data from Firebase.

mDatabase.addValueEventListener(mListener = new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            dataSet.add(dataSnapshot.getValue(dataModel.class));
            //...
        }
});

当我以调试方式运行应用程序时，没有问题.但是发布后，应用程序崩溃并显示错误:

When I run the app as debug, there is no problem. But after it is released, app crashes with the error:

com.google.firebase.database.DatabaseException: No properties to serialize found on class com.my.package.dataModel

我有 minifyEnabled true

I have minifyEnabled true

推荐答案

要解决此问题，您的类需要实现

To solve this, your class needs to implement the Serializable interface:

class dataModel implements Serializable {}

您还需要添加带有三个参数的构造函数.您的课程应如下所示:

You also need to add a contructor with three arguments. Your class should look like this:

class dataModel implements Serializable {
    private String id, name;
    private Integer count;
    @ServerTimestamp
    private Date time;

    dataModel() {}

    dataModel(String id, String name, Integer count) {
        this.id = id;
        this.name = name;
        this.count = count;
    }
}

如果日期为null，它将具有服务器生成的时间戳.因此，您无需为其设置值.另请参阅用于标记Date字段的annotation，该字段将使用服务器时间戳填充.

If the date is null, it will have the server-generated timestamp. So you don't need to do set the value for it. Please also see the annotation used to mark a Date field to be populated with a server timestamp.

同样非常重要，不要忘记添加public getters.

Also very important, don't forget to add public getters.

，另一个要求是在proguard-rules.pro中添加-keepclassmembers class com.yourcompany.models.** { *; }.

and the other requirement will be to add -keepclassmembers class com.yourcompany.models.** { *; } in proguard-rules.pro.

如此处所述.

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