如何为Firebase数据库异常添加内置类的无参数构造函数？ [英] How to add no-argument constructor of inbuilt class for Firebase-database exception?

问题描述

我正在尝试从Android中的Firebase Realtime
数据库中获取FirebaseLocationData对象。

I am trying to fetch the FirebaseLocationData object from Firebase Realtime Database in Android.

根据Docs，该类应该没有参数构造函数，已完成
public FirebaseLocationData（）{} ，但仍显示错误

According to Docs, the class should have no arguments constructor which i have done as public FirebaseLocationData() {} but it is still showing error

com.google.firebase.database.DatabaseException：android.location.Location类未定义无参数构造函数。如果您使用的是ProGuard，请确保没有剥离这些构造函数。

我应该如何制作一个无参数的构造函数的 android.location.Location 类？

How am i supposed to make a no-argument constructor of android.location.Location class?

此行产生错误 FirebaseLocationData fld = dataSnapshot .getValue（FirebaseLocationData.class）;

代码：

 public void onChildAdded(DataSnapshot dataSnapshot, String previousChildName) {
            Log.d(TAG, "onChildAdded:" + dataSnapshot.getKey());

            FirebaseLocationData fld = dataSnapshot.getValue(FirebaseLocationData.class);
            Toast.makeText(MainActivity.this, fld.getEmail()+" added", Toast.LENGTH_SHORT).show();

        }

FirebaseLocationData类：

public class FirebaseLocationData {
String email;
Location location;
String time;

public FirebaseLocationData() {
}

public FirebaseLocationData(Location location, String email, String time) {
    this.location = location;
    this.email = email;
    this.time = time;
}

public String getEmail() {
    return email;
}

public void setEmail(String email) {
    this.email = email;
}

public String getTime() {
    return time;
}

public void setTime(String time) {
    this.time = time;
}

public Location getLocation() {
    return location;
}

public void setLocation(Location location) {
    this.location = location;
}

}

推荐答案

您正在尝试编写一个 android.location.Location 对象和 类没有的对象一个无参数的公共构造函数。许多Android库类无法满足Firebase的要求，因此您必须编写自己的序列化/反序列化才能与数据库交换必要的信息。

You're trying to write a android.location.Location object and that class doesn't have a public, no-argument constructor. Many Android library classes will not meet the requirements from Firebase, and you'll have to write your own serialization/deserialization to exchange the necessary information with the database.

另请参见：类android.location。Location未定义一个无参数的构造函数

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