samples/MultiClientInputMethod/res/values/config.xml

<?xml version="1.0" encoding="utf-8"?>
<!--
/*
** Copyright 2019, The Android Open Source Project
**
** Licensed under the Apache License, Version 2.0 (the "License");
** you may not use this file except in compliance with the License.
** You may obtain a copy of the License at
**
**     http://www.apache.org/licenses/LICENSE-2.0
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** distributed under the License is distributed on an "AS IS" BASIS,
** WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
** See the License for the specific language governing permissions and
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-->
<resources xmlns:xliff="urn:oasis:names:tc:xliff:document:1.2">
  <string-array name="config_inputDisplayToImeDisplay">
  <!--
    The MultiClientInputMethod will use the same display for the IME window by default.
    But, if you want to use the separate display for the IME window, consider to define item of
    'config_inputDisplayToImeDisplay'.  The each item is a slash-separated (/) pair of the display
    the uniqueIds.  The first is the uniqueId of the display where the input happens and the second
    is the unqiueId of the display where the IME window will be shown.
    FYI, you can find the uniqueId of displays in "dumpsys display".

    E.g. If you have two displays 19261083906282752, local:19260422155234049 and you want to use
    local:19260422155234049 as the IME window for the input at the display local:19261083906282752,
    then the config item will be:
      <item>local:19261083906282752/local:19260422155234049</item>

    E.g. The display of ActivityView has the unique id of the form of
        'virtual:' + package_name + ',' + ownerUid + ',' + 'ActivityViewVirtualDisplay@'
           + hashCode + ',' + displayIndex.
    We can use the following regular expression to match it:
      <item>virtual:com.android.car.carlauncher,\\d+,ActivityViewVirtualDisplay@\\d+,\\d+/local:19260422155234049</item>
  -->
  </string-array>
</resources>