java - 如何在 Android Studio 上使用 Gmail API 获取用户的电子邮件？

Question

我多次看到这个问题，但没有一个解决方案对我有用。我已经成功地使用他/她的 Gmail 帐户在我的应用上为用户签名。我还要求额外的范围来阅读用户的消息。但是我没有成功阅读这些消息。下面是我到目前为止工作的代码。如果有人可以帮助我编写应该包含在已经编写的代码中以获取电子邮件的代码，那将是非常友好的。:)

package com.example.eventmanager; 
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import android.widget.Toast;
import com.google.android.gms.auth.api.signin.GoogleSignIn;
import com.google.android.gms.auth.api.signin.GoogleSignInAccount;
import com.google.android.gms.auth.api.signin.GoogleSignInClient;
import com.google.android.gms.auth.api.signin.GoogleSignInOptions;
import com.google.android.gms.common.api.ApiException;
import com.google.android.gms.tasks.OnCompleteListener;
import com.google.android.gms.tasks.Task;
import com.google.android.gms.common.api.Scope;
import com.google.api.client.auth.oauth2.Credential;
import com.google.api.client.extensions.java6.auth.oauth2.AuthorizationCodeInstalledApp;
import com.google.api.client.extensions.jetty.auth.oauth2.LocalServerReceiver;
import com.google.api.client.googleapis.auth.oauth2.GoogleAuthorizationCodeFlow;
import com.google.api.client.googleapis.auth.oauth2.GoogleClientSecrets;
import com.google.api.client.googleapis.batch.BatchRequest;
import com.google.api.client.googleapis.batch.json.JsonBatchCallback;
import com.google.api.client.googleapis.javanet.GoogleNetHttpTransport;
import com.google.api.client.googleapis.json.GoogleJsonError;
import com.google.api.client.http.HttpHeaders;
import com.google.api.client.http.javanet.NetHttpTransport;
import com.google.api.client.json.JsonFactory;
import com.google.api.client.json.jackson2.JacksonFactory;
import com.google.api.client.util.Base64;
import com.google.api.client.util.StringUtils;
import com.google.api.client.util.store.FileDataStoreFactory;
import com.google.api.services.gmail.Gmail;
import com.google.api.services.gmail.GmailScopes;
import com.google.api.services.gmail.model.ListMessagesResponse;
import com.google.api.services.gmail.model.Message;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.security.GeneralSecurityException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;


public class MainActivity extends AppCompatActivity {
    private ImageView imageView,imageView2;
    private static int RC_SIGN_IN = 1;
    GoogleSignInClient mGoogleSignInClient;
    GoogleSignInAccount account;
    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageView = findViewById(R.id.button);
        imageView2 = findViewById(R.id.button2);

        // Removing the Action Bar
        if (getSupportActionBar() != null) {
            getSupportActionBar().hide();
        }

        GoogleSignInOptions gso = new GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_SIGN_IN)
                .requestEmail()
                .requestScopes(new Scope("https://www.googleapis.com/auth/gmail.readonly"))
                .build();

        mGoogleSignInClient = GoogleSignIn.getClient(this, gso);
        account = GoogleSignIn.getLastSignedInAccount(this);
        imageView.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                signIn();
            }
        });
        imageView2.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                signOut();
                Toast.makeText(MainActivity.this, "Successfully signed out ", Toast.LENGTH_SHORT).show();
            }
        });

    }
    private void signIn() {
        Intent signInIntent = mGoogleSignInClient.getSignInIntent();
        startActivityForResult(signInIntent, RC_SIGN_IN);
    }
    private void signOut() {
        mGoogleSignInClient.signOut()
                .addOnCompleteListener(this, new OnCompleteListener<Void>() {
                    @Override
                    public void onComplete(@NonNull Task<Void> task) {
                    }
                });
    }
    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);

        // Result returned from launching the Intent from GoogleSignInClient.getSignInIntent(...);
        if (requestCode == RC_SIGN_IN) {
            // The Task returned from this call is always completed, no need to attach
            // a listener.
            Task<GoogleSignInAccount> task = GoogleSignIn.getSignedInAccountFromIntent(data);
            handleSignInResult(task);
        }
    }
    private void handleSignInResult(Task<GoogleSignInAccount> completedTask) {
        try {
            GoogleSignInAccount account = completedTask.getResult(ApiException.class);
            GoogleSignInAccount acct = GoogleSignIn.getLastSignedInAccount(this);
            if (acct != null) {
                String personName = acct.getDisplayName();
                String personGivenName = acct.getGivenName();
                String personFamilyName = acct.getFamilyName();
                String personEmail = acct.getEmail();
                String personId = acct.getId();
                String sc = acct.getRequestedScopes().toString();
                String re = acct.getGrantedScopes().toString();
                Uri personPhoto = acct.getPhotoUrl();
                //Intent intent = new Intent(MainActivity.this,SecondActivity.class);
                Toast.makeText(this, personName, Toast.LENGTH_SHORT).show();

            }
        } catch (ApiException e) {
            // The ApiException status code indicates the detailed failure reason.
            // Please refer to the GoogleSignInStatusCodes class reference for more information.
            Log.d("status", "signInResult:failed code=" + e.getStatusCode());
        }
    }
}

标签： javaandroidapigmail