Plugin objects in WebView getting destroyed? - objective-c

Question

Here's my situation:
I've written a simple web browser. Tabbed browsing was easy enough to get working once I wrapped my head around the concepts and figured how to perform operations on specific tabs. It works well and is pretty reliable under most circumstances.
A problem has plagued me, however, and I cannot figure out its cause.
Let's say I open a new tab and navigate to YouTube. I click on a video and the flash player loads. The video plays and all works fine. I now create another new tab and navigate to some site. The audio from the youtube player stops completely.
When I switch back to the youtube tab, the page will all still be there just as it was except the player has to reload completely, as if I had just reloaded the page. This seems to apply to other plugin types as well.
What's causing this?
Garbage collection is not enabled and as far as I know I'm creating the web views properly. Is there some silly, simple little thing that I missed somewhere along the line?

Answer 1

The - (void)setHostWindow:(NSWindow *)hostWindow method on WebView is probably what you're looking for.
I had the same problem with the flash in a WebView reloading whenever the syle mask of the enclosing window was changed. Wrapping the call to setStyleMask fixed the problem, as follows:
NSWindow *hostWindow = [[NSWindow alloc] init];
[self.webView setHostWindow:hostWindow];
[[self windowForSheet] setStyleMask:styleMask];
[self.webView setHostWindow:nil];
[hostWindow release];
The documentation for the method isn't stellar, but it does explicitly state a having a WebView inside a NSTabView as one of the use cases:
This method sets the receiver’s host window to hostWindow. Your application should only use this method if a web view is going to be removed from its window temporarily, and you want the web view to continue operating (for example, you don’t want to interrupt a load in progress). Since the receiver retains hostWindow, it is your responsibility to set the host window to nil before closing the window to avoid a retain loop.
For example, you might invoke this method if you attach a web view to an NSTabView object (as in a tabbed browser implementation). The NSTabView object takes views out of the window when they are not in the active tab, so you need to invoke this method before the web view is removed from its window. If you don't invoke this method, plug-ins will stop operating when the web view is removed from its window.

Answer 2

I had a similar problem but with a window with a webView that is closed and restored. Unfortunately the solution by #mlwelles did not solve the problem alone.
What did solve however is removing the webView from the window before it closes (proper "timing" is important). What I came up with is something like this:
id contentView;
id tmpHostWindow;
[window setDelegate:self];
- (BOOL)windowShouldClose:(NSNotification *)notification
{
// set temporary hostWindow on WebView and remove it from
// the closed window to prevent stopping flash plugin
// (windowWillClose would be better but that doesn't always work)
tmpHostWindow = [[NSWindow alloc] init];
[webView setHostWindow:tmpHostWindow];
[window setContentView:nil];
[contentView removeFromSuperview];
return TRUE;
}
- (void)windowDidBecomeKey:(NSNotification *)notification
{
// restore "hidden" webview
// (would be better to do it in applicationShouldHandleReopen
// but that seems to be too early (has no effect)
if ([window contentView] != contentView) {
[window setContentView:contentView];
[webView setHostWindow:nil];
tmpHostWindow = nil;
}
}