Question

我试图从登录按钮获取facebook测试用户的生日，然后将其传递给firestore文档。所以，我创建了一个UserInfo类，它将生日和id都保存为字符串，这样我就可以随时获取和设置它们的值。然而，当我从facebook JSON获取生日值并将其设置为userinfo时，它可以工作，但是当我尝试从getter获取此值时，我得到一个null对象。我的代码：注意，我已经初始化了用户信息onStar。这是我的代码：

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UserInfo.class

package com.example.saif.dammi;

import android.content.Intent;
import android.net.Uri;
import android.support.annotation.NonNull;
import android.support.design.widget.TextInputLayout;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.RadioButton;
import android.widget.RadioGroup;
import android.widget.Toast;

import com.facebook.AccessToken;
import com.facebook.GraphRequest;
import com.facebook.GraphResponse;
import com.facebook.HttpMethod;
import com.google.android.gms.tasks.OnFailureListener;
import com.google.firebase.auth.FirebaseAuth;
//import com.google.firebase.database.DatabaseReference;
//import com.google.firebase.database.FirebaseDatabase;
import com.google.firebase.firestore.FirebaseFirestore;

import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;

import java.net.URI;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.HashMap;
import java.util.Map;

public class SignupActivity extends AppCompatActivity {

    private TextInputLayout mFullName;
    private RadioGroup mRadioButton;
    private Button mRegister;
    private FirebaseAuth mAuth;
    private UserInfo userInfo;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_signup);
        // Access a Cloud Firestore instance from your Activity
       final FirebaseFirestore db = FirebaseFirestore.getInstance();
//        final String[] bD = new String[1];
        userInfo = new UserInfo();
        mAuth = FirebaseAuth.getInstance();
        mFullName = (TextInputLayout)findViewById(R.id.name_edittext);
        mRadioButton = (RadioGroup) findViewById(R.id.bloodGroup);
        mRegister = (Button)findViewById(R.id.register_btn);
        mRegister.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                int selectedId = mRadioButton.getCheckedRadioButtonId();
                final RadioButton mBloodGroup = (RadioButton)findViewById(selectedId);
                if(mBloodGroup.getText() == null){
                    Toast.makeText(SignupActivity.this, "Please select your Blood Group!", Toast.LENGTH_SHORT).show();
                    return;
                }

               final String name = mFullName.getEditText().getText().toString();
                if (mAuth.getCurrentUser().getUid()!=null) {
                    String userId = mAuth.getCurrentUser().getUid();
                    String userEmail = mAuth.getCurrentUser().getEmail();
                    Uri userPid = mAuth.getCurrentUser().getPhotoUrl();

                    /* make the API call */

                    GraphRequest request = GraphRequest.newMeRequest(
                            AccessToken.getCurrentAccessToken(),
                            new GraphRequest.GraphJSONObjectCallback() {
                                public void onCompleted(JSONObject object,GraphResponse response) {
                                    /* handle the result */
                                    try{
                                        userInfo.setBirthday(object.getString("birthday"));
//                                        bD[0] = object.getString("birthday");
                                        Log.d("Birthday", ""+ userInfo.getBirthday());
//
                                    }catch (JSONException e){
                                        e.printStackTrace();
                                    };
                                }
                            }
                    );
                    Bundle parameters = new Bundle();
                    parameters.putString("fields","id,email,friends,birthday");
                    request.setParameters(parameters);
                    request.executeAsync();

                    Log.d("Birthday1", ""+ userInfo.getBirthday());
                    final Map<String, Object> dataToAdd = new HashMap<>();
//                    dataToAdd.put("Birthday", bD[0]);
                    dataToAdd.put("name", name);
                    dataToAdd.put("id", userId);
                    dataToAdd.put("Pid", userPid.toString());
                    dataToAdd.put("email", userEmail);
                    dataToAdd.put("bloodGroup", mBloodGroup.getText().toString());
                    dataToAdd.put("registered", true);
                    db.collection("Users").document(mAuth.getCurrentUser().getUid()).set(dataToAdd).addOnFailureListener(new OnFailureListener() {
                        @Override
                        public void onFailure(@NonNull Exception e) {
                            Toast.makeText(SignupActivity.this, e.getMessage(), Toast.LENGTH_SHORT).show();
                        }
                    });

//                    DatabaseReference currentUserId = FirebaseDatabase.getInstance().getReference().child("Users").child(mBloodGroup.getText().toString()).child(userId).child("Name").child("Registred");
//                    currentUserId.setValue(name);
//                    currentUserId.child("Registred").setValue(true);
                    Intent startIntent = new Intent(SignupActivity.this, MainActivity.class);
                    startActivity(startIntent);
                    finish();
                }
            }
        });
    }
}

日志： Logs

Answer 1

首先，您需要将no-argument constructor添加到模型类中，如下所示：

public UserInfo() {}

所有JavaBean类型对象都应该有一个，因此可以使用反射来创建它的实例，而不必猜测如何正确地将参数传递给它。

其次，您不能将UserInfo类型的变量声明为全局变量，只需在onCompleted()方法之外使用它。发生这种情况是因为此方法具有异步行为，这意味着甚至在从数据库获取数据之前就会调用此方法。快速解决方法是仅在UserInfo方法中使用onCompleted()对象，或者如果您想在外面使用它，请使用此 post的答案的最后一部分即可。您还可以查看 video 。

getter和setter无法将值设置为firestore

1 个答案: