Android launcher icon still showing default in Android oreo

You Need Put Round Icon for 8.1

 <application
    android:name=".aaa"
    android:allowBackup="true"
    android:roundIcon="@mipmap/ic_launcher"
    android:icon="@mipmap/ic_launcher"
    android:label="aaa"
    android:theme="@style/AppTheme">

I solved my issue by changing

classpath 'com.android.tools.build:gradle:2.3.3'

to

classpath 'com.android.tools.build:gradle:3.0.1'

in project build-gradle

dependencies {
        //classpath 'com.android.tools.build:gradle:2.3.3'
        classpath 'com.android.tools.build:gradle:3.0.1'
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }

this will cause a flavoring issue ,that can be solved by adding

flavorDimensions "default"

in application build-gradle

android {

...
flavorDimensions "default"
defaultConfig {
}


}

this may help some one with same problem.

Best solution is delete mipmap-anydpi-v26 folder then app will take default icon. In android studio Project mode go to this package

res/mipmap-anydpi-v26

delete it and rebuild and Run program.