Sleep command for Android

问题

I am writing a small program to periodically poll the RSSI of the WIFI connection. I am using SystemClock.Sleep(2000) in the program.

The problem, I would like to display the RSSI every 2 seconds. But, currently, even though it polls every 2 seconds, the result is displayed only at the end of the loop.

Here is the code snippet:

for(int i=0;i<10;i++)
        {
            Date dt=new Date();
            WifiInfo info = wifi.getConnectionInfo();
            int rssi = info.getRssi();
            textStatus.append("\n\nRSSI :" +Integer.toString(rssi)); 
            SystemClock.sleep(2000);
        }

Would be glad, if you have some suggestion.

Regards Kiran

回答1:

Don't use sleep in the UI thread.

Do the following instead:

create a MessageHandler (android.os.Handler) that handles messages to be displayed (textStatus.append(...))
create a working thread that runs your loop that contains the sleep
now the working thread can't directly update the textStatus. Instead send a message from the working thread to the message handler.

ADDED:

Here is a useful link that might help you:

See section "Handling Expensive Operations in the UI Thread"

http://developer.android.com/guide/appendix/faq/commontasks.html#threading