CODEWITHSUNDEEP
iphoneuiwebviewloadios5.1
Paresh Masani
Paresh Masani

Reputation: 7504

iOS: Webview causes flicking while navigating to another controller

I use webview in my UIVIewController and load the local HTML file in it using following method.

[self.webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:filePath]]];

If I put this method in ViewDidLoad, I can see white flicking while navigating to my controller that doesn't look good.

I tried putting this method in ViewWillAppear like below. I am using webViewLoaded flag to make sure that webview has been loaded then only show the current view else it waits but it is going in infinite loop of waiting!

- (void)viewWillAppear:(BOOL)animated {
    webViewLoaded = NO;

    webView.scalesPageToFit = allowZoom;
    webView.dataDetectorTypes = UIDataDetectorTypeNone;
    webView.delegate = self;

   [self.webView loadRequest:[NSURLRequest requestWithURL:[NSURL URLWithString:filePath]]];

   int count = 0;

   while(webViewLoaded == NO) 
   {
        NSLog(@"Waiting...");
        [NSThread sleepForTimeInterval:0.1];
        if(count++ > 10) break;
   }
}

- (void)webViewDidFinishLoad:(UIWebView *)localwebView {
    webViewLoaded = YES;
}

I have also tried the same thing in ViewDidLoad but still its going in infinite loop.

Please note that webViewLoaded is "volatile BOOL" but the webview delegate method is not getting called. Not sure what's going on!

Could anyone please help me to fix this. Thanks.

Upvotes: 0

Views: 930

Answers (3)

Saad
Saad

Reputation: 8947

use Following code for

[self performSelectorInBackground:@selector(webViewLoaded) withObject:nil];

so that it will not affect your UI

Upvotes: 0

epolyakov
epolyakov

Reputation: 75

First : You're blocking your main thread and not giving WebView any chance to finish loading. Never block your main thread.

Second : There are two UIWebView delegate methods : webViewDidFinishLoad and webView:didFailLoadWithError: - make sure to listen to both.

If you're trying to wait until WebView completes loading and only show your controller afterwards - use delegation or blocks. Please note that this is not a proper way of doing things - i'm just modifying your example to make it work :

child controller (with WebView) :

-(void)startLoadingWithParent:(id)_parent {
  self.parent = _parent;
  NSURL * url = [[NSBundle mainBundle] URLForResource:@"resource" withExtension:@"html"];
  [webView loadRequest:[NSURLRequest requestWithURL:url]];
}

-(void)webViewDidFinishLoad:(UIWebView *)webView {
  [parent showMe:self];
}

-(void)webView:(UIWebView *)webView didFailLoadWithError:(NSError *)error {
  [parent showError:error];
}

master controller :

-(void)doSomething {
   SecondController * ctrl; /// secondController should be created AND has its view loaded at this point
   /// ctrl = [SecondController new];
   /// ctrl.view;
   [ctrl startLoadingWithParent:self];
   /// show user that we're doing something - display activity indicator or something
 }

 -(void)showMe:(UIViewController*)me {
    [self.navigationController pushViewControllerAnimated:me];
 }

Upvotes: 3

shabbirv
shabbirv

Reputation: 9098

Try using [NSURL fileURLWithPath:filePath]

Upvotes: 0

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