Checking the network availability before making service calls

Mobile users often work at places with low or missing network connectivity. To avoid problems when calling back-end services, you can put conditions into your action sequences to make sure that mobile devices have the necessary network connectivity.

In order to do this, the PROCE55 Mobile run-time environment offers the following system variables:

 


SYS_NETWORK (value '1' means that the device is connected to a data network, e.g. a 4G/LTE or a wireless LAN)

SYS_MOBILE_DATA ('1' means that the device currently uses a mobile data network, e.g. 4G/LTE)

SYS_WIFI ('1' means that the device is currently using a wireless LAN)

SYS_WIFI_SSID (contains either an empty string, or the name of currently connected wireless LAN)

SYS_FAST_CONNECTION ('1' means that the current connection's speed is above 1 Megabit)

 

All of the above variables except for the SYS_WIFI_SSID can have values of either 0 or 1. To read their values you need to put them into curly brackets like this: ${SYS_WIFI_SSID}

This way you can formulate a condition to check if a device currently uses the wireless network with a specific SSID:

 


'${SYS_WIFI}' == '1' && '${SYS_WIFI_SSID}' == 'WLAN01'

 

You can also use variables instead of explicitly specifying the WLAN name:

 


'${SYS_WIFI}' == '1' && '${SYS_WIFI_SSID}' == '${s1_i2}'

 

It is also possible to react on network connectivity changes using a JavaScript event handler function, which is called automatically every time a device connects or disconnects from a network:

 


function onNetworkChanged(CurrentScreen, isNetwork, isMobileData, isWifi, SSID, isFastConnection) {

if (CurrentScreen === 's1') {
var status1 = 'Network available: ' + isNetwork + '\r\n' + 'on mobile data: ' + isMobileData + '\r\n' + 'SSID: ' + SSID + '\r\n' + 'Fast connection: ' + isFastConnection;
document.getElementById('s1_i1').value = status1;

var element1 = PROCE55_GetElementByName('s1_i1');
element1.ElementValue = status1;
}
}

 

The above parameters coming to the function (isNetwork, isMobileData, isWifi, SSID, isFastConnection) correspond to the system variables mentioned at the top of this page.

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