def state(self):
        """Compute and return the device state.

        :returns: Device state.
        """
        # Check if device is disconnected.
        if not self.available:
            return STATE_UNKNOWN
        # Check if device is off.
        if not self.screen_on:
            return STATE_OFF
        # Check if screen saver is on.
        if not self.awake:
            return STATE_IDLE
        # Check if the launcher is active.
        if self.launcher or self.settings:
            return STATE_STANDBY
        # Check for a wake lock (device is playing).
        if self.wake_lock:
            return STATE_PLAYING
        # Otherwise, device is paused.
        return STATE_PAUSED
Compute and return the device state.

        :returns: Device state.