使用这个方法:

 public String getUserEmail() {
    AccountManager manager = AccountManager.get(App.getInstance());
    Account[] accounts = manager.getAccountsByType("com.google");
    List<String> possibleEmails = new LinkedList<>();
    for (Account account : accounts) {
        possibleEmails.add(account.name);
    }
    if (!possibleEmails.isEmpty() && possibleEmails.get(0) != null) {
        return possibleEmails.get(0);
    }
    return "";
}

注意，这需要GET_ACCOUNTS权限:

<uses-permission android:name="android.permission.GET_ACCOUNTS" />

然后:

editTextEmailAddress.setText(getUserEmail());

Android最近锁定了GET_ACCOUNTS，所以一些答案对我不起作用。我得到了这个工作在Android 7.0警告，你的用户必须忍受权限对话框。

AndroidManifest.xml

<uses-permission android:name="android.permission.GET_ACCOUNTS"/>

MainActivity.java

package com.example.patrick.app2;
import android.content.pm.PackageManager;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.accounts.AccountManager;
import android.accounts.Account;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.*;

public class MainActivity extends AppCompatActivity {

    final static int requestcode = 4; //arbitrary constant less than 2^16

    private static String getEmailId(Context context) {
        AccountManager accountManager = AccountManager.get(context);
        Account[] accounts = accountManager.getAccountsByType("com.google");
        Account account;
        if (accounts.length > 0) {
            account = accounts[0];
        } else {
            return "length is zero";
        }
        return account.name;
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case requestcode:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                    String emailAddr = getEmailId(getApplicationContext());
                    ShowMessage(emailAddr);

                } else {
                    ShowMessage("Permission Denied");
                }
        }
    }

    public void ShowMessage(String email)
    {
        AlertDialog alertDialog = new AlertDialog.Builder(MainActivity.this).create();
        alertDialog.setTitle("Alert");
        alertDialog.setMessage(email);
        alertDialog.setButton(AlertDialog.BUTTON_NEUTRAL, "OK",
                new DialogInterface.OnClickListener() {
                    public void onClick(DialogInterface dialog, int which) {
                        dialog.dismiss();
                    }
                });
        alertDialog.show();
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Context context = getApplicationContext();

        if ( ContextCompat.checkSelfPermission( context, android.Manifest.permission.GET_ACCOUNTS )
                != PackageManager.PERMISSION_GRANTED )
        {
            ActivityCompat.requestPermissions( this, new String[]
                            {  android.Manifest.permission.GET_ACCOUNTS  },requestcode );
        }
        else
        {
            String possibleEmail = getEmailId(getApplicationContext());
            ShowMessage(possibleEmail);
        }
    }
}

Android 8及以上-

步骤1 -在“AndroidManifest.xml -”中添加如下代码

<uses-permission android:name="android.permission.GET_ACCOUNTS" />
<uses-permission android:name="android.permission.READ_CONTACTS" />

步骤2 -在运行时请求权限的活动中添加以下代码。

if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            if ((ActivityCompat.checkSelfPermission(this, Manifest.permission.GET_ACCOUNTS) == PackageManager.PERMISSION_GRANTED) && (ActivityCompat.checkSelfPermission(this, Manifest.permission.READ_CONTACTS) == PackageManager.PERMISSION_GRANTED)) {
                getGoogleAccounts();
            }

            else {
                ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.GET_ACCOUNTS, Manifest.permission.READ_CONTACTS}, 1);
                //return false;
            }
        }

步骤3 -为onRequestPermissionsResult -添加代码

 @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if(grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED){

            getGoogleAccounts();
        }
    }

步骤4 -最后添加代码以使用AccountManager检索帐户

private void getGoogleAccounts(){

   AccountManager am = AccountManager.get(this); // "this" references the current Context
    Account[] accounts = am.getAccountsByType("com.google");

    for (Account acc : accounts){
        System.out.println("http accounts " + acc);
    }
}

请参考以下链接的变化在安卓8 - https://developer.android.com/about/versions/oreo/android-8.0-changes#aaad

有一个Android api，允许用户选择他们的电子邮件地址，而不需要许可。来看看:https://developers.google.com/identity/smartlock-passwords/android/retrieve-hints

HintRequest hintRequest = new HintRequest.Builder()
        .setHintPickerConfig(new CredentialPickerConfig.Builder()
                .setShowCancelButton(true)
                .build())
        .setEmailAddressIdentifierSupported(true)
        .setAccountTypes(IdentityProviders.GOOGLE)
        .build();

PendingIntent intent = mCredentialsClient.getHintPickerIntent(hintRequest);
try {
    startIntentSenderForResult(intent.getIntentSender(), RC_HINT, null, 0, 0, 0);
} catch (IntentSender.SendIntentException e) {
    Log.e(TAG, "Could not start hint picker Intent", e);
}

这将显示一个选择器，用户可以在其中选择电子邮件地址。结果将在onActivityResult()中传递

在清单中添加这一行(获得许可)

< uses-permission android: name = " android.permission。GET_ACCOUNTS " / >

然后将此代码粘贴到您的活动中

private ArrayList<String> getPrimaryMailId() {
    ArrayList<String> accountsList = new ArrayList<String>();
    try {
        Account[] accounts = AccountManager.get(this).getAccountsByType("com.google");
        for (Account account : accounts) {
            accountsList.add(account.name);
            Log.e("GetPrimaryMailId ", account.name);
        }
    } catch (Exception e) {
        Log.e("GetPrimaryMailId", " Exception : " + e);
    }
    return accountsList;
}

这可能对其他人有用:

使用AccountPicker在没有任何全局权限的情况下获取用户的电子邮件地址，并允许用户知道并授权或取消该过程。