Question

我的应用程序包含所有Web视图的标签。我正在使用UIWebViewDelegate，以便在设备无法访问互联网时出现错误。我还使用Reachability类来跟踪连接状态的任何变化。

问题在于：

我去了第一个标签
杀死我的网络连接（我收到消息说我丢失了网络连接）
我转到第二部分（互联网连接不见了）
我通过UIWebViewDelegate方法在tab 2中收到错误消息didFailLoadWithError
我重新连接互联网
我点击了我创建的刷新按钮，但我什么都没得到。这就是问题
如果我返回选项卡一个或任何其他选项卡，它可以正常工作

我敢肯定，一旦UIWebView出错，我需要重新初始化一些东西，但我不知道是什么??????

以下是标签的代码。

#import "MINWebTab2Controller.h"

@implementation MINWebTab2Controller
@synthesize webView;
@synthesize timer;
@synthesize progressIndicator;

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
if (self) {
    // Custom initialization
}
return self;
}

- (void)didReceiveMemoryWarning
{
// Releases the view if it doesn't have a superview.
[super didReceiveMemoryWarning];

// Release any cached data, images, etc that aren't in use.
}

#pragma mark - View lifecycle

- (void)viewDidLoad
{
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.

// Set up progress indicator for web page load
//timer = [NSTimer scheduledTimerWithTimeInterval:0.5 target:self            selector:@selector(webViewLoading) userInfo:nil repeats:YES];
//[progressIndicator startAnimating];

webView.delegate = self;
webView.scalesPageToFit = YES;

NSString *urlAddress = @"http://www.mobilityinitiative-synergy.com/index.php/presentations";

//Create a URL object.
NSURL *url = [NSURL URLWithString:urlAddress];

//URL Requst Object
NSURLRequest *requestObj = [NSURLRequest requestWithURL:url];

//Load the request in the UIWebView.
[webView loadRequest:requestObj];

}

- (void)viewDidUnload
{
[super viewDidUnload];
// Release any retained subviews of the main view.
// e.g. self.myOutlet = nil;
}

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation
{
// Return YES for supported orientations
return YES;
}

#pragma mark UIWebViewDelegate methods
- (void)webViewDidStartLoad:(UIWebView *)thisWebView
{
[progressIndicator startAnimating];
}

- (void)webViewDidFinishLoad:(UIWebView *)thisWebView
{    
//stop the activity indicator when done loading
[progressIndicator stopAnimating]; 
}

-(void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {
NSLog(@"Error for WEBVIEW: %@", [error description]);
[progressIndicator stopAnimating];
}

@end

这是主委托类的代码。如您所见，我正在使用Apple提供的Reachability类（衍生版）。

#import "MINAppDelegate.h"
#import "Reachability.h"

@implementation MINAppDelegate

@synthesize window = _window;
@synthesize rootController;
@synthesize connectedToInternet;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
self.window = [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
// Override point for customization after application launch.
connectedToInternet = YES;

// Set up Root Controller
[[NSBundle mainBundle] loadNibNamed:@"TabBarController" owner:self options:nil];
[self.window addSubview:rootController.view];

// Observe the kNetworkReachabilityChangedNotification. When that notification is posted, the
// method "reachabilityChanged" will be called. 
[[NSNotificationCenter defaultCenter] addObserver: self selector: @selector(reachabilityChanged:) name: kReachabilityChangedNotification object: nil];

// allocate a reachability object
Reachability* reach = [Reachability reachabilityWithHostname:@"www.google.com"];

// here we set up a NSNotification observer. The Reachability that caused the notification
// is passed in the object parameter
[[NSNotificationCenter defaultCenter] addObserver:self 
                                         selector:@selector(reachabilityChanged:) 
                                             name:kReachabilityChangedNotification 
                                           object:nil];

[reach startNotifier];


self.window.backgroundColor = [UIColor whiteColor];
[self.window makeKeyAndVisible];
return YES;
}

//Called by Reachability whenever status changes.
- (void) reachabilityChanged: (NSNotification* )note
{        
Reachability * reach = [note object];

if([reach isReachable])
{
    if(connectedToInternet == NO)
    {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Network Change Detected" 
                                                        message:@"You are now connected to the internet and can continue to use application." 
                                                       delegate:nil 
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
        [alert show];
    }
    connectedToInternet = YES;
}
else
{
    if(connectedToInternet == YES)
    {
        UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Network Change Detected" 
                                                        message:@"You must be connected to the internet to use this app.  Please connect to internet and reload the application." 
                                                       delegate:nil 
                                              cancelButtonTitle:@"OK"
                                              otherButtonTitles:nil];
        [alert show];
        //exit(0);
    }
    connectedToInternet = NO;
}    
}

- (void)applicationWillResignActive:(UIApplication *)application
{
/*
 Sent when the application is about to move from active to inactive state. This can occur for certain types of temporary interruptions (such as an incoming phone call or SMS message) or when the user quits the application and it begins the transition to the background state.
 Use this method to pause ongoing tasks, disable timers, and throttle down OpenGL ES frame rates. Games should use this method to pause the game.
 */
}

- (void)applicationDidEnterBackground:(UIApplication *)application
{
/*
 Use this method to release shared resources, save user data, invalidate timers, and store enough application state information to restore your application to its current state in case it is terminated later. 
 If your application supports background execution, this method is called instead of applicationWillTerminate: when the user quits.
 */
}

- (void)applicationWillEnterForeground:(UIApplication *)application
{
/*
 Called as part of the transition from the background to the inactive state; here you can undo many of the changes made on entering the background.
 */
}

- (void)applicationDidBecomeActive:(UIApplication *)application
{
/*
 Restart any tasks that were paused (or not yet started) while the application was inactive. If the application was previously in the background, optionally refresh the user interface.
 */
}

- (void)applicationWillTerminate:(UIApplication *)application
{
/*
 Called when the application is about to terminate.
 Save data if appropriate.
 See also applicationDidEnterBackground:.
 */
}

@end

Answer 1

我不确定这是最好的解决方案，但这就是我所做的。

我移动代码以从viewDidLoad启动webview到viewDidAppear。当我转到选项卡时，会调用viewDidAppear方法。在该方法中，我调用适当的代码行来重新启动webview（[webview loadRequest：URL];）

我还为bPageLoaded添加了一个标志，并将其设置为false，因为加载网页时出错。我在viewDidAppear方法中检查该标志，这样我就不会重绘页面，除非出现错误。

重新连接到Internet后，WebView无法恢复

1 个答案: