java.lang.NullPointerException:尝试调用虚拟方法'java.lang.String com.google.firebase.auth.FirebaseUser.getUid()' [英] java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.google.firebase.auth.FirebaseUser.getUid()'

问题描述

Process: com.example.vicevirus.myapplication, PID: 13471  
    java.lang.NullPointerException: Attempt to invoke virtual method 'java.lang.String com.google.firebase.auth.FirebaseUser.getUid()' on a null object reference
              at com.example.vicevirus.myapplication.RegisterActivity$1.onComplete(RegisterActivity.java:48)
              at com.google.android.gms.tasks.zzc$1.run(Unknown Source)
              at android.os.Handler.handleCallback(Handler.java:751)
              at android.os.Handler.dispatchMessage(Handler.java:95)
              at android.os.Looper.loop(Looper.java:154)
              at android.app.ActivityThread.main(ActivityThread.java:6119)
              at java.lang.reflect.Method.invoke(Native Method)
              at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:886)
              at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:776)

这是在android监视器上.我该如何解决?

This is on android monitor. How do I solve this?

package com.example.vicevirus.myapplication;

import android.app.ProgressDialog;
         import android.support.annotation.NonNull;
         import android.support.v7.app.AppCompatActivity;
         import android.os.Bundle;
         import android.view.View;
         import android.widget.EditText;
         import android.widget.Toast;
         import com.google.android.gms.tasks.OnCompleteListener;
         import com.google.android.gms.tasks.OnSuccessListener;
         import com.google.android.gms.tasks.Task;
         import com.google.firebase.auth.AuthResult;
         import com.google.firebase.auth.FirebaseAuth;
         import com.google.firebase.database.DatabaseReference;
         import com.google.firebase.database.FirebaseDatabase;

public class RegisterActivity extends AppCompatActivity {
    private EditText email,name,password;
    DatabaseReference databaseReference;
    FirebaseAuth mAuth;
    private DatabaseReference userIdRef;
    ProgressDialog registerDialog;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_register);
        email=(EditText)findViewById(R.id.email);
        name=(EditText)findViewById(R.id.name);
        password=(EditText)findViewById(R.id.password);
        databaseReference= FirebaseDatabase.getInstance().getReference().child("chat_users");
        mAuth=FirebaseAuth.getInstance();
        registerDialog=new ProgressDialog(this);
        registerDialog.setMessage("Registering..");
    }
    public void submit(View view) {
        registerDialog.show();
        mAuth.createUserWithEmailAndPassword(email.getText().toString(),password.getText().toString()).addOnCompleteListener(this, new OnCompleteListener<AuthResult>() {
            @Override
            public void onComplete(@NonNull Task<AuthResult> task) {
                if(task.isComplete())
                {
                    registerDialog.dismiss();
                    Toast.makeText(getApplicationContext(),"Registered successfully",Toast.LENGTH_SHORT).show();
                    userIdRef=databaseReference.child(mAuth.getCurrentUser().getUid());
                    userIdRef.child("name").setValue(name.getText().toString());
                    finish();
                }
                registerDialog.dismiss();
            }
        });
    }
}

推荐答案

问题似乎是您的用户尚未登录甚至尚未注册.因此，调用 mAuth.getCurrentUser()返回null.

The problem seems to be that your user is not yet logged in or even registered. So calling mAuth.getCurrentUser() returns null.

有关您需要如何此页的FireBase文档进行用户注册.这可能是失败的.检查 task.isSuccessful()对此很有必要.

Check out this page of the FireBase documentation about how you need to implement the registering of users. It could be that this is failing. The check task.isSuccessful() is necessary to check this.

这篇关于java.lang.NullPointerException:尝试调用虚拟方法'java.lang.String com.google.firebase.auth.FirebaseUser.getUid()'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IT屋！