Qt for android: change the application icon
You should create an Android manifest file and edit it in Qt Creator. Go to Projects > Build Android APK > Details
Now Select Create Templates to create the manifest file and to open it in editor :
As shown in the picture, you can set three versions of icons for your application with low, medium, and high DPI values, from left to right.
This new way of making an android manifest file is available since Qt 5.4 along Qt Creator 3.3. There used to be a Create AndroidManifest.xml button in Projects->Run->Deploy in previous versions.
Open Run settings of your project and select Create AndroidManifest.xml, then you'll be able to modify the manifest which should include stuff like the icon.
Refer to this:http://qt-project.org/doc/qtcreator-3.2/creator-deploying-android.html
Look at the this article about anatomy of a Qt 5 for Android application. You should attach to your project file AndroidManifest.xml, where you can define icon of application.