Question

我正在使用xCode中的简单webview制作应用程序。如果没有可用的互联网连接，我希望通知用户。当没有互联网连接时，会弹出一个告诉你“没有可用的互联网连接”和两个选项 - 再试一次，然后取消。我该怎么做呢？我是初学者所以请解释一下。

ViewController.m

#import "ViewController.h"

@interface ViewController () <UIWebViewDelegate>

@end

@implementation ViewController

@synthesize webView;

- (void)viewDidLoad
{

NSURL *url = [NSURL URLWithString:@"http://MyWebPage.com"];
NSURLRequest *requestURL = [NSURLRequest requestWithURL:url];
webView.delegate = self;
[webView loadRequest:requestURL];

[super viewDidLoad];
// Do any additional setup after loading the view, typically from a nib.
}

- (void)didReceiveMemoryWarning
{
[super didReceiveMemoryWarning];
// Dispose of any resources that can be recreated.
}

@end

Answer 1

我同意Leo，但我会做一个简短的尝试来解释它：

从apple或github获取类Reachability：
- 这是一个允许您检查互联网的课程/看看是否可以到达特定主机/ ....

在加载网站之前检查可达性。 - 也许在viewWillAppear

- (void)viewWillAppear:(BOOL)animated {
        [super viewWillAppear:animated];        
        _reachability = [Reachability reachabilityForInternetConnection];
        [self handleReachability];

        //optional monitor
        [[NSNotificationCenter defaultCenter] addObserver:self
                                                 selector:@selector(handleReachability: )
                                                     name:@"kReachabilityChangedNotification" object:nil];

        [_reachability startNotifier]; //! don't forget to remove the notification in viewWillDisappear  

    }

实现句柄方法，例如显示一个简单的UIAlertView：

-(void)handleReachability:(NSNotificationCenter*)notification{
    NetworkStatus netStatus = [reach currentReachabilityStatus];

    if(netStatus == NotReachable) {
        [self setNoInternet:YES];
        // what happens when network/server down: 
        if([webView isLoading]) {
            [UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
            [webView stopLoading];
            hasLoaded = NO;
        }

    }else {
        [self setNoInternet:NO];
        if(![webView isLoading] && !hasLoaded) {
            hasLoaded = NO;
            [self load];
        }
    }
}

如果webview中没有互联网连接，iOS会显示警报

1 个答案: