you got a lucky day
i hope someone will edit this answer & make it good "i am not good with desg :s"
if you are using to wireless connection with the same name or if you have been connected to a wireless network with the same name
lets check that
search for app name network
wireless => if you find 2 with the same name choose the one that you do not need click on the "==>" button => then click on forget netowrk
elseif you have a 1 ssid with
wireless => select the => click on "==>" button => if you see the strenth = good this is not a dc problem => settings => general => if the checkbox is checked this is not a ubuntu problem
it is your hotspot/rooter problem
here is a solution for that you can make the pc do what you"ve been doing
make a new name it whatever you want .
$ touch filename.conf
$ nano filename.conf
past this
network={
ssid="your wifi name"
key_mgmt=WPA-PSK
proto=WPA
pairwise=TKIP
group=TKIP
psk="your password"
}
do not forget to edit the ssid & the password "psk"
save the file then
$ pwd
$ ifconfig
after you finish that
go to startup applications => add => name whatever you like =>
command
"try this first"
//wpa_supplicant -i "eth card name" -c "the output of $ pwd command & the filename "
the command will be just like this wpa_supplicant -i wlan0 -c /home/username/Desktop/filename.conf => then click on add
try to reboot if that did not workout you should trade the root password with the wireless password
so if when you start your pc will ask you for only the root password this would be just like this
$ sudo apt-get install gksu
then just like we did at the startup application this time it would be just like this
gksu wpa_supplicant -i wlan0 -c /home/username/Desktop/filename.conf
about your android you need to ask this in dev xda forum