I has get the method to resolve the question.
Simply put is modify the app AndroidManifest.xml file like this
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.HOME" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
you apk will become a launcher ,when the android system start,you app become the home.
if you have interest can email me.