Possible Duplicate:
How to detect whether GPS signal is weak or high?
Is there any possible way to know that the GPS signal is week ?
Such as the user in the building then the GPS may not send data. This is the reason why I want to check the GPS signal.
There is no specific way to do that. I usually follow a time-out approach where you can wait for about 30-45 seconds to get a fix and if you do not get a fix within that time, you can infer that the GPS fix cannot be obtained at the current location of the user.
In case the fix is available and your onLocationChanged() method is getting called, you should use the combination of getAccuracy() and getTime() to accept the fix and infer about the strength of the signal.
The getAccuracy() method of the Location object returned by onLocationChanged provides a good indication of how good the "fix" is.
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How to detect whether GPS signal is weak or high?