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 aspublic 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:
这篇关于如何为Firebase数据库异常添加内置类的无参数构造函数?的文章就介绍到这了,希望我们推荐的答案对大家有所帮助,也希望大家多多支持!