Android: How to prevent a Wifi disconnect on DHCP renewal?

Question

We are developing software on a custom Android platform and we begin to receive complaints from customers about the state of the Wifi connection. It seems that once in a while, they loose their Wifi connection for 1-2 seconds and then it comes back automatically. They can notice this from a small GUI feedback or from a disconnect/reconnect event issued from an XMPP client.

After investigation, we found from the log in adb logcat that the Wifi is changing its state from CONNECTED to CONNECTING every time there is a DHCP renewal. As we currently have a DHCP lease time of 1 hour, our platform tries to renew its address every 29 minutes. Here is a log excerpt from a DHCP renewal :

[ 11-24 10:10:11.751  2629: 3350 D/DhcpStateMachine ]
DHCP renewal on wlan0

[ 11-24 10:10:12.351  2629: 3350 D/DhcpStateMachine ]
DHCP succeeded on wlan0

[ 11-24 10:10:12.361  2877: 2877 D/DCT      ]
onReceive: action=android.net.wifi.STATE_CHANGE

[ 11-24 10:10:12.361  2877: 2877 D/DCT      ]
NETWORK_STATE_CHANGED_ACTION: mIsWifiConnected=false

[ 11-24 10:10:12.361  2877: 2877 D/DCT      ]
NETWORK_STATE_CHANGED_ACTION: networkInfo=NetworkInfo: type: WIFI[], state: CONNECTING/VERIFYING_POOR_LINK, reason: (unspecified), extra: "XXX", roaming: false, failover: false, isAvailable: true

[ 11-24 10:10:12.371  2877: 2877 D/DCT      ]
onReceive: action=android.net.wifi.STATE_CHANGE

[ 11-24 10:10:12.371  2877: 2877 D/DCT      ]
NETWORK_STATE_CHANGED_ACTION: mIsWifiConnected=false

[ 11-24 10:10:12.371  2877: 2877 D/DCT      ]
NETWORK_STATE_CHANGED_ACTION: networkInfo=NetworkInfo: type: WIFI[], state: CONNECTING/CAPTIVE_PORTAL_CHECK, reason: (unspecified), extra: "XXX", roaming: false, failover: false, isAvailable: true

[ 11-24 10:10:12.381  2877: 2877 D/DCT      ]
onReceive: action=android.net.wifi.STATE_CHANGE

[ 11-24 10:10:12.381  2877: 2877 D/DCT      ]
NETWORK_STATE_CHANGED_ACTION: mIsWifiConnected=true

[ 11-24 10:10:12.381  2877: 2877 D/DCT      ]
NETWORK_STATE_CHANGED_ACTION: networkInfo=NetworkInfo: type: WIFI[], state: CONNECTED/CONNECTED, reason: (unspecified), extra: "XXX", roaming: false, failover: false, isAvailable: true

How could I prevent the connection state to change from CONNECTED to CONNECTING while using DHCP ? Can I change a setting somewhere to change this behaviour ?

Answer 1

I don't think the DISCONNECTING can be really avoided. The only way to deal with this issue is ignoring the DISCONNECTING state on a Wifi change state and to use the isConnectedOrConnecting method from Network instead of isConnected to verify if we are connected or not.