Question

It take about 10s to loadHTMLString in my APP, who can point out what’s the problem?

- (void)viewDidLoad {
    [super viewDidLoad];
    webView = [[UIWebView alloc]initWithFrame:CGRectMake(10, 10, SCREEN_WIDTH, 480)];
    [webView setBackgroundColor:[UIColor clearColor]];
    [webView setOpaque:NO];
    webView.delegate = self;
    [scrollView addSubview:webView];
}

After enter the view, If I receive message:

- (void)updateJournalView:(NSArray *)journals {
    NSString *descHtml = [self getHtmlDesc:journals];
    [webView loadHTMLString:descHtml baseURL:nil];
 }

getHtmlDesc method will return the html string quickly.

from load log, you can see it take about 5s to load.

2012-11-26 20:34:35.322 test[8456:c07] ====start load 2012-11-26 12:34:35 +0000:

2012-11-26 20:34:39.890 test[8456:c07] ====finish load 2012-11-26 12:34:39 +0000:

Following is UIWebViewDelegate method:

- (void)webViewDidFinishLoad:(UIWebView *)aWebView {
 CGRect frame = aWebView.frame;
 frame.size.height = 1;
 aWebView.frame = frame;
 CGSize fittingSize = [aWebView sizeThatFits:CGSizeZero];
 frame.size = fittingSize;
 aWebView.frame = frame;
 scrollView.contentSize = CGSizeMake(SCREEN_WIDTH, fittingSize.height);
 NSLog(@"====finish load %@:", [NSDate date]);
}

  - (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest    *)request
navigationType:(UIWebViewNavigationType)navigationType {
  NSURL *url = [request URL];
  if ([[url scheme] isEqualToString:@"redirect"] &&
  [[url host] isEqualToString:@"opp_detail"]) {
  NSString *oppIdStr = [[url path] stringByReplacingOccurrencesOfString:@"/player_id=" withString:@""];
  if (oppIdStr && [oppIdStr length]) {
    NSNumber *oppId = [NSNumber numberWithInt:[oppIdStr intValue]];
    if ([oppId intValue] != gcontext.me.id) {
      [screenNav gotoOppDetailScreen:[oppId intValue]];
    }
  }
 }
 return YES;
}

- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request
navigationType:(UIWebViewNavigationType)navigationType {
 NSURL *url = [request URL];
 if ([[url scheme] isEqualToString:@"redirect"] &&
  [[url host] isEqualToString:@"opp_detail"]) {
  NSString *oppIdStr = [[url path] stringByReplacingOccurrencesOfString:@"/player_id="   withString:@""];
 if (oppIdStr && [oppIdStr length]) {
  NSNumber *oppId = [NSNumber numberWithInt:[oppIdStr intValue]];
  if ([oppId intValue] != gcontext.me.id) {
    [screenNav gotoOppDetailScreen:[oppId intValue]];
  }
}
}
return YES;
}

- (void)webViewDidStartLoad:(UIWebView *)webView{
  NSLog(@"====start load %@:", [NSDate date]);
}

Please give me a hand, why it is so slow when loadHTMLString with UIWebView?

Answer 1

If there is nothing heavy to render, then it’s possible that all about slow disk operations, that are performing when you’re reading your html string.

https://stackoverflow.com/a/3400892/1851930