How to solve this EXC_BAD_ACCESS(code=EXC_i386_GPFLT )in swift programming

Question

this is my code.getting this EXC_BAD_ACCESS(code=EXC_i386_GPFLT).I don\'n know how to find and solve plz help me ...application getting crash when get longitude

Answer 1

Your problem here is that most of the operations you are performing can return nil, which will crash Swift if you try and use it as a non-nil value. You need to be explicit about testing for nil. The sledgehammer way of doing it would be

let mapAddress = "Hyderabad,india"

let url = NSURL.URLWithString("http://maps.googleapis.com/maps/api/geocode/json?address=\(mapAddress)")

let jsonData = NSData(contentsOfURL:url)

var latitude = NSNumber(double: 0.0)
var longitude = NSNumber(double: 0.0)
var success = false

if jsonData != nil {
    if let result = NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.MutableContainers, error: nil) as? NSDictionary {
        if let mapServerResultArray = result.valueForKey("results") as? NSArray {
            if let geometry = mapServerResultArray[0].valueForKey("geometry") as? NSDictionary {
                if let location = geometry.valueForKey("location") as? NSDictionary {
                    if let lat = location.valueForKey("lat") as? Float {
                        latitude = lat
                        if let lng = location.valueForKey("lng") as? Float {
                            longitude = lng
                            success = true
                        }
                    }
                }
            }
        }
    }
}
if success {
    println("Latitude = \(latitude), longitude=\(longitude)")
} else {
    println("Failed")
}

... however that is ugly. As this routine may or may not find any of the keys, at the end you may or may not have a valid pair of coordinates. This is exactly what Optionals are for. Consider rewriting it as a function that returns an optional:

struct Coordinate { // Or use any of Cocoa's similar structs
    var latitude: Double
    var longitude: Double
}

func getCoordsOf(#address: String) -> Coordinate? {
    let url = NSURL.URLWithString("http://maps.googleapis.com/maps/api/geocode/json?address=\(address)")
    let jsonData = NSData(contentsOfURL:url)
    if jsonData == nil { return nil }

    let result = NSJSONSerialization.JSONObjectWithData(jsonData, options: NSJSONReadingOptions.MutableContainers, error: nil) as NSDictionary
    if result == nil { return nil }

    if let geometry = result.valueForKey("results").valueForKey("geometry") as? NSArray {
        if geometry.count > 0 {
            let lat = geometry[0].valueForKey("location")?.valueForKey("lat")?.doubleValue
            let lng = geometry[0].valueForKey("location")?.valueForKey("lng")?.doubleValue

            if (lat != nil) && (lng != nil) {
                return Coordinate(latitude: lat!, longitude: lng!)
            }
        }
    }
    return nil
}

if let coord = getCoordsOf(address: "Hyderabad,india") {
    // ... do something
}

This uses Optional Chaining (?) to lessen the testing, but we have to break it at geometry because we need that to be an array, as we need to access a specific element of it (and, of course, should test that it isn't an empty array!)

p.s. - ironically, your test on error != nil does nothing, as you did not send error to the JSONObjectWithData routine.