Receiving Drag events on an NSWindow when the window contains a single WebView view - objective-c

Question

I am new to objective-c and cocoa so please break things down for me. I'm working on a project started by another developer and have only been working in objective-c for 3 days.
I have an NSWindow subclass that contains a WebView view. The WebView content that is loaded is a Silverlight plugin. I registered the NSWindow to receive Drag events. The drag events are being generated but only when the drag occurs within the NSWindow Title Bar. I register for the drag events in the load method.
AdminWindow.mm
#import "AdminWindow.h"
#import "NativeMessageReceiver.h"
extern AdminWindow* adminRiaWindow;
#implementation AdminWindow
#synthesize adminWebView;
BOOL isAdminContentLoaded;
-(void) load
{
if (!isAdminContentLoaded)
{
NSLog(#"loading Admin window");
NSString *curDir = [[NSBundle mainBundle] bundlePath];
NSString* url = [NSString stringWithFormat: #"file://%#/Contents/Resources/RIA/AdminContentMac.html",curDir];
[[adminWebView mainFrame] loadRequest: [NSURLRequest requestWithURL: [NSURL URLWithString: url]]];
[adminWebView setDrawsBackground:NO];
id win = [adminWebView windowScriptObject];
NativeMessageReceiver* receiver = [NativeMessageReceiver getInstance];
[win setValue:receiver forKey:#"NativeMessageReceiver"];
receiver.adminWebView = adminWebView;
isAdminContentLoaded = YES;
}
}
-(void) show
{
[self load];
[self setIsVisible: YES];
[[NSApplication sharedApplication] activateIgnoringOtherApps:YES];
[self makeKeyAndOrderFront: self];
[self makeMainWindow];
[self center];
}
-(void) hide
{
[self setIsVisible: NO];
}
- ( BOOL ) windowShouldClose : ( id ) sender
{
[self setIsVisible: NO];
return NO;
}
- (BOOL) canBecomeKeyWindow
{
return YES;
}
- (BOOL) canBecomeMainWindow
{
return YES;
}
#end
extern "C" void ShowAdminWindow()
{
NSLog(#"showing Admin window");
if (![NSThread isMainThread])
[adminRiaWindow performSelectorOnMainThread:#selector(show) withObject:nil waitUntilDone:YES];
else
{
[adminRiaWindow show];
}
}
extern "C" void HideAdminWindow()
{
if (![NSThread isMainThread])
{
[adminRiaWindow performSelectorOnMainThread:#selector(hide) withObject:nil waitUntilDone:YES];
}
else
{
[adminRiaWindow hide];
}
}
CustomeWebView
#implementation SteamPunkWebView
- (id)initWithFrame:(NSRect)frame
{
self = [super initWithFrame:frame];
if (self)
{
[self registerForDraggedTypes:[NSArray arrayWithObjects: NSFilenamesPboardType, nil]];
NSLog(#"In Custom View Init");
}
return self;
}

Answer 1

I think you're only getting drag events in the title bar because you registered the window to receive the events, not the web view.
Try this instead:
[self.adminWebView registerForDraggedTypes:[NSArray arrayWithObjects: NSFilenamesPboardType, nil]];

Answer 2

WebViews are one of the most complex views in Cocoa and are a special case when it comes to dragging. Instead of implementing the standard NSView dragging behaviour, you need instead to set an object as the web view's WebUIDelegate and implement the following delegate method:
‑webView:dragDestinationActionMaskForDraggingInfo:
You can then control how you want the web view to respond to the drag action. The WebUIDelegate protocol has several other methods to control dragging, so you should read the documentation for more detail.
To actually receive the dragged objects and process them, you will need to subclass WebView and implement ‑draggingEnded:.
You definitely do not need to add any dragging methods to the window itself.