/*
There are several theories and rumors about UIWebView memory leaks, and how
to properly handle cleaning a UIWebView instance up before deallocation. This
method implements several of those recommendations.
#1: Various developers believe UIWebView may not properly throw away child
objects & views without forcing the UIWebView to load empty content before
dealloc.
Source: http://stackoverflow.com/questions/648396/does-uiwebview-leak-memory
*/
[self loadHTMLString:@"" baseURL:nil];
/*
#2: Others claim that UIWebView's will leak if they are loading content
during dealloc.
Source: http://stackoverflow.com/questions/6124020/uiwebview-leaking
*/
[self stopLoading];
/*
#3: Apple recommends setting the delegate to nil before deallocation:
"Important: Before releasing an instance of UIWebView for which you have set
a delegate, you must first set the UIWebView delegate property to nil before
disposing of the UIWebView instance. This can be done, for example, in the
dealloc method where you dispose of the UIWebView."
Source: UIWebViewDelegate class reference
*/
self.delegate = nil;
/*
#4: If you're creating multiple child views for any given view, and you're
trying to deallocate an old child, that child is pointed to by the parent
view, and won't actually deallocate until that parent view dissapears. This
call below ensures that you are not creating many child views that will hang
around until the parent view is deallocated.
*/
[self removeFromSuperview];
/*
Further Help with UIWebView leak problems:
#1: Consider implementing the following in your UIWebViewDelegate:
- (void) webViewDidFinishLoad:(UIWebView *)webView
{
//source: http://blog.techno-barje.fr/post/2010/10/04/UIWebView-secrets-part1-memory-leaks-on-xmlhttprequest/
[[NSUserDefaults standardUserDefaults] setInteger:0 forKey:@"WebKitCacheModelPreferenceKey"];
}
#2: If you can, avoid returning NO in your UIWebViewDelegate here:
- (BOOL)webView:(UIWebView *)webView shouldStartLoadWithRequest:(NSURLRequest *)request navigationType:(UIWebViewNavigationType)navigationType
{
//this source says don't do this: http://stackoverflow.com/questions/6421813/lots-of-uiwebview-memory-leaks
//return NO;
return YES;
}
#3: Some leaks appear to be fixed in IOS 4.1
Source: http://stackoverflow.com/questions/3857519/memory-leak-while-using-uiwebview-load-request-in-ios4-0
#4: When you create your UIWebImageView, disable link detection if possible:
webView.dataDetectorTypes = UIDataDetectorTypeNone;
(This is also the "Detect Links" checkbox on a UIWebView in Interfacte Builder.)
Sources:
http://www.iphonedevsdk.com/forum/iphone-sdk-development/46260-how-free-memory-after-uiwebview.html
http://blog.techno-barje.fr/post/2010/10/04/UIWebView-secrets-part2-leaks-on-release/
#5: Consider cleaning the NSURLCache every so often:
[[NSURLCache sharedURLCache] removeAllCachedResponses];
[[NSURLCache sharedURLCache] setDiskCapacity:0];
[[NSURLCache sharedURLCache] setMemoryCapacity:0];
Source: http://blog.techno-barje.fr/post/2010/10/04/UIWebView-secrets-part2-leaks-on-release/
Be careful with this, as it may kill cache objects for currently executing URL
requests for your application, if you can't cleanly clear the whole cache in
your app in some place where you expect zero URLRequest to be executing, use
the following instead after you are done with each request (note that you won't
be able to do this w/ UIWebView's internal request objects..):
[[NSURLCache sharedURLCache] removeCachedResponseForRequest:request];
Source: http://stackoverflow.com/questions/6542114/clearing-a-webviews-cache-for-local-files
*/
//其实就4句话
[self loadHTMLString:@"" baseURL:nil];
[self stopLoading];
self.delegate = nil;
[self removeFromSuperview];
self指的是webview