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());

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);
    }
}

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;
}

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

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);


            }
        }
    });

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