Although networks cell phones already offer coverage in places where the signal was rather poor, the Wi-Fi networks do not cease to be the main choice for Smartphone users. Depending on the proximity to the access point, the signal may be weak or strong. Of nothing serves connect to a bad connection Wi-Fi if the experience will be quite limited.
It is possible to avoid bad signal Wi-Fi connections in Android and here you say how to achieve it.
Go to the ‘settings’ on your mobile device and select “Wi-Fi” option of the “Wireless & networks” section.
Then open the menu by pressing the button with three dots vertically and select the “Advanced settings” option.
In the screen following seeks the option “avoid bad connections”, which will prevent that you connect to a network Wi-Fi unless you have good signal.