我在我的项目中使用谷歌地图。我正在计算当前位置的位置距离,并显示这是 TableView。现在有多个地方,我想在 tableView 中显示它。对于每个地方及其与当前位置的距离,我需要调用 google distanceMatrix Api。我能够将 Places 坐标存储在数组中并循环遍历我调用 distance martix api 的数组。
这是代码
func calculateDistance(type : String)
{
let currentLocationCordinate = "\(userCurrentLocation.coordinate.latitude),\(userCurrentLocation.coordinate.longitude)"
var url = String()
var remoteUrl = NSURL()
var request = NSURLRequest()
var session = NSURLSession()
var locatioArrayIndex = 0
//locationArray Stores Cordinate of nearby array
for locatioArrayIndex in 0...locationArray.count-1
{
placeCordinationArray = "\(locationArray[locatioArrayIndex].coordinate.latitude),\(locationArray[locatioArrayIndex].coordinate.longitude)"
url = "https://maps.googleapis.com/maps/api/distancematrix/json?units=imperial&origins=\(currentLocationCordinate)&destinations=\(placeCordinationArray)&key=\(key)"
remoteUrl = NSURL(string: url)!
request = NSURLRequest(URL: remoteUrl)
let config1 = NSURLSessionConfiguration.defaultSessionConfiguration()
session = NSURLSession(configuration: config1)
// Asych start here
let task = session.dataTaskWithRequest(request, completionHandler: {(data, response, error) in
// Convert server json response to NSDictionary
do {
let convertedJsonIntoDict = try NSJSONSerialization.JSONObjectWithData(data!, options: [])
let rows = convertedJsonIntoDict["rows"] as! NSArray
let elements = rows[0]
let element1 = elements["elements"] as! NSArray
let distance = element1[0]
let distanceDictionary = distance["distance"]
let testDistance = distanceDictionary!!["text"] as! String!
self.distanceMeter = testDistance
self.placeDistantArray.append(self.distanceMeter)
if (locatioArrayIndex == 9)
{
dispatch_async(dispatch_get_main_queue(),
{
self.segueCheck = true
self.searchActivityIndicator.stopAnimating()
self.searchActivityIndicator.hidesWhenStopped = true
self.tableView.reloadData()
})
}
//
print("LOCATION ARRAY INDEXINSIDE",locatioArrayIndex)
}
catch let error as NSError
{
print("SOME ERROR ",error.localizedDescription)
}
})
task.resume()
}// For Loop CLosed
}
我将距离存储在 self.placeDistantArray 数组中。然后用它的数据重新加载 tableview。但 self.placeDistantArray 中的值有时会重复。和 tableview 有时会出现数组索引错误
最佳答案
你的代码非常非常不干净而且根本不可读,所以我清理了它:
func calculateDistanceUpdatingUI(type : String)
{
//locationArray Stores Cordinate of nearby array
for (index, location) in locationArray.enumerate()
{
if let remoteUrl = distanceCalculationURLFrom(userCurrentLocation, toDestination: location) {
let request = NSURLRequest(URL: remoteUrl)
let session = NSURLSession(configuration: NSURLSessionConfiguration.defaultSessionConfiguration())
// clear array
self.placeDistantArray.removeAll()
// request distance
let task = session.dataTaskWithRequest(request, completionHandler: {(data, response, error) in
do
{
if let distanceMeter = try self.testDistanceFrom(data) {
self.distanceMeter = distanceMeter
self.placeDistantArray.append(distanceMeter)
}
if (index == 9)
{
self.updateUI()
}
print("LOCATION ARRAY INDEXINSIDE", index)
}
catch let error as NSError
{
print("SOME ERROR ", error.localizedDescription)
}
})
task.resume()
}
}
}
private func updateUI()
{
dispatch_async(dispatch_get_main_queue())
{
self.segueCheck = true
self.searchActivityIndicator.stopAnimating()
self.searchActivityIndicator.hidesWhenStopped = true
self.tableView.reloadData()
}
}
private func distanceCalculationURLFrom(origin: CLLocation, toDestination destination: CLLocation) -> NSURL?
{
var urlString = "https://maps.googleapis.com/maps/api/distancematrix/json?units=imperial&origins="
urlString += "\(origin.coordinate.latitude),\(origin.coordinate.longitude)&destinations="
urlString += "\(destination.coordinate.latitude),\(destination.coordinate.longitude)&key=\(key)"
return NSURL(string: urlString)
}
private func testDistanceFrom(data: NSData?) throws -> String?
{
guard let data = data else {
return nil
}
let convertedJsonIntoDict = try NSJSONSerialization.JSONObjectWithData(data, options: [])
if let rows = convertedJsonIntoDict["rows"] as? NSArray where rows.count > 0,
let element1 = rows[0]["elements"] as? NSArray where element1.count > 0,
let distanceDictionary = element1[0]["distance"] as? NSDictionary,
let testDistance = distanceDictionary["text"] as? String
{
return testDistance
}
return nil
}
这里有一些建议:
- 您不应该轻易使用强制解包。
- 你应该尽量避免使用旧式的 for 循环,尽量使用快速枚举(更具可读性)。
- 你的函数不应该有副作用。如果你调用你的函数
calculateDistance
,它应该这样做,计算距离。不更改placeCordinationArray
等变量或更新 UI。 - 您应该尝试拆分代码并制作更小的函数。如果您必须添加像
//For Loop CLosed
这样的注释,那肯定太大了 - 你不应该初始化你不会使用的对象(如
var request = NSURLRequest()
) - 尝试使用正确的词,例如
coordinate
而不是cordination
或location
而不是locatio
。
正如@Jigar Tarsariya 所说,我还在阵列再次填充之前清理了它。
关于swift - 如何在swift中的for循环中使用异步任务,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/37429062/