Android Install_packages Permission And Non-playstore Apps

I'm preparing my app for the play store and plan to deliver one component as separate install package (since my customer can't recover the source code, but the app is signed with h

Solution 1:

My needs are just these: Users with "unknown sources" deactivated should be able to install the 2nd app. And: The user should never be redirected to Google Play store.

This combination is impossible, barring a major security flaw in Android and/or the Play Store. The only way to install apps through the Play Store is via the Play Store app.

I would like a solution, where I sent an intent to the PlayStore app and it displayed the app name, permissions and the install button.

That activity is not exported. You are welcome to use a market://Uri to lead the user to the Play Store, where they can review this second app and decide, for themselves, whether or not to download and install it.

since the user already accepted that my app may install packages

Your app cannot install packages directly, unless it is signed with the firmware signing key or is installed on the system partition (e.g., by a rooted device user), as that is the only way that you can hold the INSTALL_PACKAGES permission. Ordinary SDK apps are welcome to create an ACTION_VIEW or ACTION_INSTALL_PACKAGEIntent to request that the app be installed, but the user will need "unknown sources" enabled.