Hot answers tagged wi-fi
On Android 4.4, there is an option "Avoid poor connections" under Settings->Wi-Fi->Advanced(perhaps under the menu). You want to set this option on. This option is not present in Android 6. I'm not sure whether it's present in Android 5.1.
This shell command works on marshmallow: type su to enter superuser mode. Then type the following command: settings put global captive_portal_detection_enabled 0 ^^ it disables the "drop wifi if no internet connection" functionality.
I have the same problem. Recently started though after my phone did a software update. I've had it for almost a year and it used to Autoconnect no problem. It's definitely not the Wifi because it happens everywhere work, home, or any connection.
You can try opera max. It is VPN service that having app management features. There you can manage which app to allow network connections. And then only allowed apps would be able to access network bandwidth.
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