如何在 iOS 可达性中检测网络信号强度
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How to detect Network Signal Strength in iOS Reachability
提问by iProgrammed
I am creating a new Traveling Application in iOS, this application is highly dependent on Maps and will include two Maps.
我正在 iOS 中创建一个新的旅行应用程序，这个应用程序高度依赖地图，将包含两个地图。
- My first Map will work when the user has a strong Network Signal (Apple Maps).
- My second Map will be used when their isn't any Network or really Low signal (Offline MapBox).
- 当用户具有强大的网络信号（Apple Maps）时，我的第一个地图将起作用。
- 当它们不是任何网络或真正低信号（离线 MapBox）时，将使用我的第二个地图。
Why do I have two different maps in one Application? My Application is a Direction App, so when the user has really low network or none it will go to the offline Map MapBox. Also the Apple Maps will have Yelp integration and not the offline Map MapBox.
为什么我在一个应用程序中有两个不同的地图？我的应用程序是一个方向应用程序，所以当用户的网络非常低或没有时，它会转到离线地图MapBox。此外，Apple Maps 将集成 Yelp 而不是离线 Map MapBox。
So my Question: How can I detect the network signal in WiFi, 4G Lte, and 3G.
所以我的问题：如何检测 WiFi、4G LTE 和 3G 中的网络信号。
回答by Rob
My original thought was to time the download of a file, and see how long it takes:
我最初的想法是对文件的下载进行计时，看看需要多长时间：
@interface ViewController () <NSURLSessionDelegate, NSURLSessionDataDelegate>
@property (nonatomic) CFAbsoluteTime startTime;
@property (nonatomic) CFAbsoluteTime stopTime;
@property (nonatomic) long long bytesReceived;
@property (nonatomic, copy) void (^speedTestCompletionHandler)(CGFloat megabytesPerSecond, NSError *error);
@end
@implementation ViewController
- (void)viewDidLoad {
[super viewDidLoad];
[self testDownloadSpeedWithTimout:5.0 completionHandler:^(CGFloat megabytesPerSecond, NSError *error) {
NSLog(@"%0.1f; error = %@", megabytesPerSecond, error);
}];
}
/// Test speed of download
///
/// Test the speed of a connection by downloading some predetermined resource. Alternatively, you could add the
/// URL of what to use for testing the connection as a parameter to this method.
///
/// @param timeout The maximum amount of time for the request.
/// @param completionHandler The block to be called when the request finishes (or times out).
/// The error parameter to this closure indicates whether there was an error downloading
/// the resource (other than timeout).
///
/// @note Note, the timeout parameter doesn't have to be enough to download the entire
/// resource, but rather just sufficiently long enough to measure the speed of the download.
- (void)testDownloadSpeedWithTimout:(NSTimeInterval)timeout completionHandler:(nonnull void (^)(CGFloat megabytesPerSecond, NSError * _Nullable error))completionHandler {
NSURL *url = [NSURL URLWithString:@"http://insert.your.site.here/yourfile"];
self.startTime = CFAbsoluteTimeGetCurrent();
self.stopTime = self.startTime;
self.bytesReceived = 0;
self.speedTestCompletionHandler = completionHandler;
NSURLSessionConfiguration *configuration = [NSURLSessionConfiguration ephemeralSessionConfiguration];
configuration.timeoutIntervalForResource = timeout;
NSURLSession *session = [NSURLSession sessionWithConfiguration:configuration delegate:self delegateQueue:nil];
[[session dataTaskWithURL:url] resume];
}
- (void)URLSession:(NSURLSession *)session dataTask:(NSURLSessionDataTask *)dataTask didReceiveData:(NSData *)data {
self.bytesReceived += [data length];
self.stopTime = CFAbsoluteTimeGetCurrent();
}
- (void)URLSession:(NSURLSession *)session task:(NSURLSessionTask *)task didCompleteWithError:(NSError *)error {
CFAbsoluteTime elapsed = self.stopTime - self.startTime;
CGFloat speed = elapsed != 0 ? self.bytesReceived / (CFAbsoluteTimeGetCurrent() - self.startTime) / 1024.0 / 1024.0 : -1;
// treat timeout as no error (as we're testing speed, not worried about whether we got entire resource or not
if (error == nil || ([error.domain isEqualToString:NSURLErrorDomain] && error.code == NSURLErrorTimedOut)) {
self.speedTestCompletionHandler(speed, nil);
} else {
self.speedTestCompletionHandler(speed, error);
}
}
@end
Note, this measures the speed including the latency of starting the connection. You could alternatively initialize startTimein didReceiveResponse, if you wanted to factor out that initial latency.
请注意，这测量的速度包括启动连接的延迟。如果您想排除初始延迟，您也可以初始化startTimein didReceiveResponse。
Having done that, in retrospect, I don't like spending time or bandwidth downloading something that has no practical benefit to the app. So, as an alternative, I might suggest a far more pragmatic approach: Why don't you just try to open a MKMapViewand see how long it takes to finish downloading the map? If it fails or if it takes more than a certain amount of time, then switch to your offline map. Again, there is quite a bit of variability here (not only because network bandwidth and latency, but also because some map images appear to be cached), so make sure to set a kMaximumElapsedTimeto be large enough to handle all the reasonable permutations of a successful connection (i.e., don't be too aggressive in using a low value).
这样做之后，回想起来，我不喜欢花时间或带宽下载对应用程序没有实际好处的东西。因此，作为替代方案，我可能会建议一种更实用的方法：您为什么不尝试打开一个MKMapView并查看完成下载地图需要多长时间？如果失败或花费的时间超过一定时间，则切换到离线地图。同样，这里有相当多的可变性（不仅因为网络带宽和延迟，还因为一些地图图像似乎已被缓存），因此请确保将 a 设置为kMaximumElapsedTime足够大以处理成功的所有合理排列连接（即，不要过于激进地使用低值）。
To do this, just make sure to set your view controller to be the delegateof the MKMapView. And then you can do:
为此，只需确保将您的视图控制器设置delegate为MKMapView. 然后你可以这样做：
@interface ViewController () <MKMapViewDelegate>
@property (nonatomic, strong) NSDate *startDate;
@end
static CGFloat const kMaximumElapsedTime = 5.0;
@implementation ViewController
// insert the rest of your implementation here
#pragma mark - MKMapViewDelegate methods
- (void)mapViewWillStartLoadingMap:(MKMapView *)mapView {
NSDate *localStartDate = [NSDate date];
self.startDate = localStartDate;
double delayInSeconds = kMaximumElapsedTime;
dispatch_time_t popTime = dispatch_time(DISPATCH_TIME_NOW, (int64_t)(delayInSeconds * NSEC_PER_SEC));
dispatch_after(popTime, dispatch_get_main_queue(), ^(void){
// Check to see if either:
// (a) start date property is not nil (because if it is, we
// finished map download); and
// (b) start date property is the same as the value we set
// above, as it's possible this map download is done, but
// we're already in the process of downloading the next
// map.
if (self.startDate && self.startDate == localStartDate)
{
[[[UIAlertView alloc] initWithTitle:nil
message:[NSString stringWithFormat:@"Map timed out after %.1f", delayInSeconds]
delegate:nil
cancelButtonTitle:@"OK"
otherButtonTitles:nil] show];
}
});
}
- (void)mapViewDidFailLoadingMap:(MKMapView *)mapView withError:(NSError *)error {
self.startDate = nil;
[[[UIAlertView alloc] initWithTitle:nil
message:@"Online map failed"
delegate:nil
cancelButtonTitle:@"OK"
otherButtonTitles:nil] show];
}
- (void)mapViewDidFinishLoadingMap:(MKMapView *)mapView
{
NSTimeInterval elapsed = [[NSDate date] timeIntervalSinceDate:self.startDate];
self.startDate = nil;
self.statusLabel.text = [NSString stringWithFormat:@"%.1f seconds", elapsed];
}
回答by p0lAris
I believe a google search will help.
我相信谷歌搜索会有所帮助。
Look out for the following thread on StackOverflow—
在 StackOverflow 上寻找以下线程——
iOS wifi scan, signal strength
So, I don't think you can still do this without using private APIs.
因此，我认为您仍然可以在不使用私有 API 的情况下做到这一点。
回答by Leonif
For Swift
对于斯威夫特
class NetworkSpeedProvider: NSObject {
var startTime = CFAbsoluteTime()
var stopTime = CFAbsoluteTime()
var bytesReceived: CGFloat = 0
var speedTestCompletionHandler: ((_ megabytesPerSecond: CGFloat, _ error: Error?) -> Void)? = nil
func test() {
testDownloadSpeed(withTimout: 5.0, completionHandler: {(_ megabytesPerSecond: CGFloat, _ error: Error?) -> Void in
print("%0.1f; error = \(megabytesPerSecond)")
})
}
}
extension NetworkSpeedProvider: URLSessionDataDelegate, URLSessionDelegate {
func testDownloadSpeed(withTimout timeout: TimeInterval, completionHandler: @escaping (_ megabytesPerSecond: CGFloat, _ error: Error?) -> Void) {
// you set any relevant string with any file
let urlForSpeedTest = URL(string: "https://any.jpg")
startTime = CFAbsoluteTimeGetCurrent()
stopTime = startTime
bytesReceived = 0
speedTestCompletionHandler = completionHandler
let configuration = URLSessionConfiguration.ephemeral
configuration.timeoutIntervalForResource = timeout
let session = URLSession(configuration: configuration, delegate: self, delegateQueue: nil)
guard let checkedUrl = urlForSpeedTest else { return }
session.dataTask(with: checkedUrl).resume()
}
func urlSession(_ session: URLSession, dataTask: URLSessionDataTask, didReceive data: Data) {
bytesReceived += CGFloat(data.count)
stopTime = CFAbsoluteTimeGetCurrent()
}
func urlSession(_ session: URLSession, task: URLSessionTask, didCompleteWithError error: Error?) {
let elapsed = (stopTime - startTime) //as? CFAbsoluteTime
let speed: CGFloat = elapsed != 0 ? bytesReceived / (CGFloat(CFAbsoluteTimeGetCurrent() - startTime)) / 1024.0 / 1024.0 : -1.0
// treat timeout as no error (as we're testing speed, not worried about whether we got entire resource or not
if error == nil || ((((error as NSError?)?.domain) == NSURLErrorDomain) && (error as NSError?)?.code == NSURLErrorTimedOut) {
speedTestCompletionHandler?(speed, nil)
}
else {
speedTestCompletionHandler?(speed, error)
}
}
}
