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

这在Android中是相当棘手的事情，我还没有做过。但也许这些链接可以帮助你:

Android Issue 1073:谷歌认证令牌应该可以通过API访问第三方应用程序 android 2.x+中的SDK API AccountManager

建议的答案将不再有效，因为从android 8开始有新的限制。

更多信息请访问:https://developer.android.com/about/versions/oreo/android-8.0-changes.html#aaad

我会使用Android在ICS中引入的AccountPicker。

Intent googlePicker = AccountPicker.newChooseAccountIntent(null, null, new String[]{GoogleAuthUtil.GOOGLE_ACCOUNT_TYPE}, true, null, null, null, null);
startActivityForResult(googlePicker, REQUEST_CODE);

然后等待结果:

protected void onActivityResult(final int requestCode, final int resultCode,
                                final Intent data) {
    if (requestCode == REQUEST_CODE && resultCode == RESULT_OK) {
        String accountName = data.getStringExtra(AccountManager.KEY_ACCOUNT_NAME);
    }
}

可悲的是，接受的答案并不管用。

我迟到了，但这是内部Android电子邮件应用程序的解决方案，除非内容uri由提供商更改:

Uri EMAIL_ACCOUNTS_DATABASE_CONTENT_URI = 
              Uri.parse("content://com.android.email.provider/account");

public ArrayList<String> GET_EMAIL_ADDRESSES ()
{
    ArrayList<String> names = new ArrayList<String>();
    ContentResolver cr      = m_context.getContentResolver();
    Cursor cursor           = cr.query(EMAIL_ACCOUNTS_DATABASE_CONTENT_URI ,null, 
                             null, null, null);

    if (cursor == null) {
        Log.e("TEST", "Cannot access email accounts database");
        return null;
    }

    if (cursor.getCount() <= 0) {
        Log.e("TEST", "No accounts");
        return null;
    }

    while (cursor.moveToNext()) {
        names.add(cursor.getString(cursor.getColumnIndex("emailAddress")));
        Log.i("TEST", cursor.getString(cursor.getColumnIndex("emailAddress")));
    }
    return names;
}