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

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。

在棉花糖操作系统中工作

    btn_click=(Button) findViewById(R.id.btn_click);

    btn_click.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View arg0)
        {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M)
            {
                int permissionCheck = ContextCompat.checkSelfPermission(PermissionActivity.this,
                        android.Manifest.permission.CAMERA);
                if (permissionCheck == PackageManager.PERMISSION_GRANTED)
                {
                    //showing dialog to select image
                    String possibleEmail=null;

                     Pattern emailPattern = Patterns.EMAIL_ADDRESS; // API level 8+
                     Account[] accounts = AccountManager.get(PermissionActivity.this).getAccounts();
                     for (Account account : accounts) {
                         if (emailPattern.matcher(account.name).matches()) {
                             possibleEmail = account.name;
                             Log.e("keshav","possibleEmail"+possibleEmail);
                         }
                     }

                    Log.e("keshav","possibleEmail gjhh->"+possibleEmail);
                    Log.e("permission", "granted Marshmallow O/S");

                } else {                        ActivityCompat.requestPermissions(PermissionActivity.this,
                            new String[]{android.Manifest.permission.READ_EXTERNAL_STORAGE,
                                    android.Manifest.permission.READ_PHONE_STATE,
                                    Manifest.permission.GET_ACCOUNTS,
                                    android.Manifest.permission.CAMERA}, 1);
                }
            } else {
// Lower then Marshmallow

                    String possibleEmail=null;

                     Pattern emailPattern = Patterns.EMAIL_ADDRESS; // API level 8+
                     Account[] accounts = AccountManager.get(PermissionActivity.this).getAccounts();
                     for (Account account : accounts) {
                         if (emailPattern.matcher(account.name).matches()) {
                             possibleEmail = account.name;
                             Log.e("keshav","possibleEmail"+possibleEmail);
                     }

                    Log.e("keshav","possibleEmail gjhh->"+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

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;
}

public String getUsername() {
    AccountManager manager = AccountManager.get(this);
    Account[] accounts = manager.getAccountsByType("com.google");
    List<String> possibleEmails = new LinkedList<String>();

    for (Account account : accounts) {
        // TODO: Check possibleEmail against an email regex or treat
        // account.name as an email address only for certain account.type values.
        possibleEmails.add(account.name);
    }

    if (!possibleEmails.isEmpty() && possibleEmails.get(0) != null) {
        String email = possibleEmails.get(0);
        String[] parts = email.split("@");

        if (parts.length > 1)
            return parts[0];
    }
    return null;
}