Android Galaxy S4 — Activity that is visible over lock screen

Question

A few years ago, I wrote an alarm app that worked on Android 2, and I\'m now trying to upgrade it to work on Android 4. Specifically, on the Samsung Galaxy S4.

On A

Answer 1

In Kotlin,

For Api level 28 or less, you can simply add below method in your activity that needs to be opened:

override fun onAttachedToWindow() {
    super.onAttachedToWindow()
    toBeShownOnLockScreen()
}

private fun toBeShownOnLockScreen() {
    window.addFlags(
        WindowManager.LayoutParams.FLAG_DISMISS_KEYGUARD
                or WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
    )
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O_MR1) {
        setTurnScreenOn(true)
        setShowWhenLocked(true)
    } else {
        window.addFlags(
            WindowManager.LayoutParams.FLAG_TURN_SCREEN_ON
                    or WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED
        )
    }
}

And to make it work on Android Pie and above, in additional to above step, we need to set in AndroidManifest as well:

I have tested this code from Api level 21 to 29, and works like charm!