sheishuoAPP/uikit/res/drawable/nim_emoji_item_selector.xml

<?xml version="1.0" encoding="UTF-8"?>
<selector
  xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true" android:drawable="@drawable/nim_emoji_ck_bg" />
    <item android:state_pressed="false" android:drawable="@android:color/transparent" />
</selector>