java登录Firebase时出现了什么问题

Question

  Caused by: com.google.firebase.database.DatabaseException: Failed to get FirebaseDatabase instance: Specify DatabaseURL within FirebaseApp or from your getInstance() call.
        at com.google.firebase.database.FirebaseDatabase.getInstance(com.google.firebase:firebase-database@@16.0.5:114)
        at com.google.firebase.database.FirebaseDatabase.getInstance(com.google.firebase:firebase-database@@16.0.5:71)
        at pl.cyfrogen.budget.FirebaseHandler.onCreate(FirebaseHandler.java:11)
        at 安卓.app.Instrumentation.callApplicationOnCreate(Instrumentation.java:1190)
        at 安卓.app.ActivityThread.handleMakeApplication(ActivityThread.java:7184)
        at 安卓.app.ActivityThread.handleBindApplication(ActivityThread.java:7134) 
        at 安卓.app.ActivityThread.access$1500(ActivityThread.java:274) 
        at 安卓.app.ActivityThread$H.handleMessage(ActivityThread.java:2102) 
        at 安卓.os.Handler.dispatchMessage(Handler.java:107) 
        at 安卓.os.Looper.loop(Looper.java:237) 
        at 安卓.app.ActivityThread.main(ActivityThread.java:8167) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.安卓.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:496) 
        at com.安卓.internal.os.ZygoteInit.main(ZygoteInit.java:1100) 

import 安卓.app.Application;

import com.google.firebase.database.FirebaseDatabase;

public class FirebaseHandler extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
     FirebaseDatabase.getInstance().setPersistenceEnabled(true);
    }
}

Answer 1

根据文档，FirebaseDatabase.getInstance()可以接受URL作为字符串。我希望您需要在这里添加您的项目URL，例如

FirebaseDatabase.getInstance("https://<project-url>.firebaseio.com/")
       .setPersistenceEnabled(true);

Check out the documentation here