I am building a really basic Cocoa application using WebKit, to display a Flash/Silverlight application within it. Very basic, no intentions for it to be a browser itself.
So far I have been able to get it to open basic html links (<a href="..." />) in a new instance of Safari using
[[NSWorkspace sharedWorkspace] openURL:[request URL]];
Now my difficulty is opening a link in a new instance of Safari when window.open() is used in JavaScript. I "think" (and by this, I have been hacking away at the code and am unsure if i actually did or not) I got this kind of working by setting the WebView's policyDelegate and implementing its
-webView:decidePolicyForNavigationAction:request:frame:decisionListener:
delegate method. However this led to some erratic behavior.
So the simple question, what do I need to do so that when window.open() is called, the link is opened in a new instance of Safari.
Thanks
Big point, I am normally a .NET developer, and have only been working with Cocoa/WebKit for a few days.
I made from progress last night and pinned down part of my problem.
I am already using webView:decidePolicyForNewWindowAction:request:newFrameName:decisionListener: and I have gotten it to work with anchor tags, however the method never seems to get called when JavaScript is invoked.
However when window.open() is called webView:createWebViewWithRequest:request is called, I have tried to force the window to open in Safari here, however request is always null. So I can never read the URL out.
I have done some searching around, and this seems to be a known "misfeature" however I have not been able to find a way to work around it.
From what I understand createWebViewWithRequest gives you the ability to create the new webview, the the requested url is then sent to the new webView to be loaded. This is the best explanation I have been able to find so far.
So while many people have pointed out this problem, I have yet to see any solution which fits my needs. I will try to delve a little deeper into the decidePolicyForNewWindowAction again.
Thanks!
Well, I'm handling it by creating a dummy webView, setting it's frameLoad delegate to a custom class that handles
- (void)webView:decidePolicyForNavigationAction:actionInformation :request:frame:decisionListener:
and opens a new window there.
code :
- (WebView *)webView:(WebView *)sender createWebViewWithRequest:(NSURLRequest *)request {
//this is a hack because request URL is null here due to a bug in webkit
return [newWindowHandler webView];
}
and NewWindowHandler :
#implementation NewWindowHandler
-(NewWindowHandler*)initWithWebView:(WebView*)newWebView {
webView = newWebView;
[webView setUIDelegate:self];
[webView setPolicyDelegate:self];
[webView setResourceLoadDelegate:self];
return self;
}
- (void)webView:(WebView *)sender decidePolicyForNavigationAction:(NSDictionary *)actionInformation request:(NSURLRequest *)request frame:(WebFrame *)frame decisionListener:(id<WebPolicyDecisionListener>)listener {
[[NSWorkspace sharedWorkspace] openURL:[actionInformation objectForKey:WebActionOriginalURLKey]];
}
-(WebView*)webView {
return webView;
}
There seems to be a bug with webView:decidePolicyForNewWindowAction:request:newFrameName:decisionListener: in that the request is always nil, but there is a robust solution that works with both normal target="_blank" links as well as javascript ones.
Basically I use another ephemeral WebView to handle the new page load in. Similar to Yoni Shalom but with a little more syntactic sugar.
To use it first set a delegate object for your WebView, in this case I'm setting myself as the delegate:
webView.UIDelegate = self;
Then just implement the webView:createWebViewWithRequest: delegate method and use my block based API to do something when a new page is loaded, in this case I'm opening the page in an external browser:
-(WebView *)webView:(WebView *)sender createWebViewWithRequest:(NSURLRequest *)request {
return [GBWebViewExternalLinkHandler riggedWebViewWithLoadHandler:^(NSURL *url) {
[[NSWorkspace sharedWorkspace] openURL:url];
}];
}
That's pretty much it. Here's the code for my class. Header:
// GBWebViewExternalLinkHandler.h
// TabApp2
//
// Created by Luka Mirosevic on 13/03/2013.
// Copyright (c) 2013 Goonbee. All rights reserved.
//
#import <Foundation/Foundation.h>
#class WebView;
typedef void(^NewWindowCallback)(NSURL *url);
#interface GBWebViewExternalLinkHandler : NSObject
+(WebView *)riggedWebViewWithLoadHandler:(NewWindowCallback)handler;
#end
Implemetation:
// GBWebViewExternalLinkHandler.m
// TabApp2
//
// Created by Luka Mirosevic on 13/03/2013.
// Copyright (c) 2013 Goonbee. All rights reserved.
//
#import "GBWebViewExternalLinkHandler.h"
#import <WebKit/WebKit.h>
#interface GBWebViewExternalLinkHandler ()
#property (strong, nonatomic) WebView *attachedWebView;
#property (strong, nonatomic) GBWebViewExternalLinkHandler *retainedSelf;
#property (copy, nonatomic) NewWindowCallback handler;
#end
#implementation GBWebViewExternalLinkHandler
-(id)init {
if (self = [super init]) {
//create a new webview with self as the policyDelegate, and keep a ref to it
self.attachedWebView = [WebView new];
self.attachedWebView.policyDelegate = self;
}
return self;
}
-(void)webView:(WebView *)sender decidePolicyForNavigationAction:(NSDictionary *)actionInformation request:(NSURLRequest *)request frame:(WebFrame *)frame decisionListener:(id<WebPolicyDecisionListener>)listener {
//execute handler
if (self.handler) {
self.handler(actionInformation[WebActionOriginalURLKey]);
}
//our job is done so safe to unretain yourself
self.retainedSelf = nil;
}
+(WebView *)riggedWebViewWithLoadHandler:(NewWindowCallback)handler {
//create a new handler
GBWebViewExternalLinkHandler *newWindowHandler = [GBWebViewExternalLinkHandler new];
//store the block
newWindowHandler.handler = handler;
//retain yourself so that we persist until the webView:decidePolicyForNavigationAction:request:frame:decisionListener: method has been called
newWindowHandler.retainedSelf = newWindowHandler;
//return the attached webview
return newWindowHandler.attachedWebView;
}
#end
Licensed as Apache 2.
You don't mention what kind of erratic behaviour you are seeing. A quick possibility, is that when implementing the delegate method you forgot to tell the webview you are ignoring the click by calling the ignore method of the WebPolicyDecisionListener that was passed to your delegate, which may have put things into a weird state.
If that is not the issue, then how much control do you have over the content you are displaying? The policy delegate gives you easy mechanisms to filter all resource loads (as you have discovered), and all new window opens via webView:decidePolicyForNewWindowAction:request:newFrameName:decisionListener:. All window.open calls should funnel through that, as will anything else that triggers a new window.
If there are other window opens you want to keep inside your app, you will to do a little more work. One of the arguments passed into the delegate is a dictionary containing information about the event. Insie that dictionary the WebActionElementKey will have a dictionary containing a number of details, including the original dom content of the link. If you want to poke around in there you can grab the actual DOM element, and check the text of the href to see if it starts with window.open. That is a bit heavy weight, but if you want fine grained control it will give it to you.
By reading all posts, i have come up with my simple solution, all funcs are in same class,here it is, opens a link with browser.
- (WebView *)webView:(WebView *)sender createWebViewWithRequest:(NSURLRequest *)request {
return [self externalWebView:sender];
}
- (void)webView:(WebView *)sender decidePolicyForNavigationAction:(NSDictionary *)actionInformation request:(NSURLRequest *)request frame:(WebFrame *)frame decisionListener:(id<WebPolicyDecisionListener>)listener
{
[[NSWorkspace sharedWorkspace] openURL:[actionInformation objectForKey:WebActionOriginalURLKey]];
}
-(WebView*)externalWebView:(WebView*)newWebView
{
WebView *webView = newWebView;
[webView setUIDelegate:self];
[webView setPolicyDelegate:self];
[webView setResourceLoadDelegate:self];
return webView;
}
Explanation:
Windows created from JavaScript via window.open go through createWebViewWithRequest.
All window.open calls result in a createWebViewWithRequest: with a null request, then later a location change on that WebView.
For further information, see this old post on the WebKit mailing list.
An alternative to returning a new WebView and waiting for its loadRequest: method to be called, I ended up overwriting the window.open function in the WebView's JSContext:
First, I set my controller to be the WebFrameLoadDelegate of the WebView:
myWebView.frameLoadDelegate = self;
Then, in the delegate method, I overwrote the window.open function, and I can process the URL there instead.
- (void)webView:(WebView *)webView didCreateJavaScriptContext:(JSContext *)context forFrame:(WebFrame *)frame{
context[#"window"][#"open"] = ^(id url){
NSLog(#"url to load: %#", url);
};
}
This let me handle the request however I needed to without the awkward need to create additional WebViews.
Related
I am attempting to have window.onerror notify my view controller anytime it is called. I am setting a block callback on the JSContext of the web view in question and it does execute, however this only works on the initial page load in the web view. When the page is refreshed, the errors are no longer hitting the controller. Any ideas?
JSContext *ctx = [resultWebView valueForKeyPath:#"documentView.webView.mainFrame.javaScriptContext"];
ctx[#"window"][#"onerror"] = ^(JSValue *message, JSValue *file, JSValue *line) {
NSLog(#"%#", message);
};
The page refresh causes the JSContext to be replaced.
You need to implement a delegate for the frame load and put your window.onerror handler in your implementation of the selector for -webView:didCreateJavaScriptContext:forFrame:
#implementation MyFrameLoadDelegate
- (void)webView:(WebView *)webView didCreateJavaScriptContext:(JSContext *)context forFrame:(WebFrame *)frame
{
context[#"window"][#"onerror"] = ^(JSValue *message, JSValue *file, JSValue *line) {
NSLog(#"%#", message);
};
}
#end
For a great intro to the new features recently introduced in JavaScriptCore.framework, check out the 2013 WWDC introduction "Integrating JavaScript into Native Apps" session on Apple's developer network: https://developer.apple.com/videos/wwdc/2013/?id=615
It does have a brief section towards the end on WebView.
I'm trying to write a simple (toy) program that uses the NSFilePresenter and NSFileCoordinator methods to watch a file for changes.
The program consists of a text view that loads a (hardcoded) text file and a button that will save the file with any changes. The idea is that I have two instances running and saving in one instance will cause the other instance to reload the changed file.
Loading and saving the file works fine but the NSFilePresenter methods are never called. It is all based around a class called FileManager which implements the NSFilePresenter protocol. The code is as follows:
Interface:
#interface FileManager : NSObject <NSFilePresenter>
#property (unsafe_unretained) IBOutlet NSTextView *textView;
- (void) saveFile;
- (void) reloadFile;
#end
Implementation:
#implementation FileManager
{
NSOperationQueue* queue;
NSURL* fileURL;
}
- (id) init {
self = [super init];
if (self) {
self->queue = [NSOperationQueue new];
self->fileURL = [NSURL URLWithString:#"/Users/Jonathan/file.txt"];
[NSFileCoordinator addFilePresenter:self];
}
return self;
}
- (NSURL*) presentedItemURL {
NSLog(#"presentedItemURL");
return self->fileURL;
}
- (NSOperationQueue*) presentedItemOperationQueue {
NSLog(#"presentedItemOperationQueue");
return self->queue;
}
- (void) saveFile {
NSFileCoordinator* coordinator = [[NSFileCoordinator alloc] initWithFilePresenter:self];
NSError* error;
[coordinator coordinateWritingItemAtURL:self->fileURL options:NSFileCoordinatorWritingForMerging error:&error byAccessor:^(NSURL* url) {
NSString* content = [self.textView string];
[content writeToFile:[url path] atomically:YES encoding:NSUTF8StringEncoding error:NULL];
}];
}
- (void) reloadFile {
NSFileManager* fileManager = [NSFileManager defaultManager];
NSFileCoordinator* coordinator = [[NSFileCoordinator alloc] initWithFilePresenter:self];
NSError* error;
__block NSData* content;
[coordinator coordinateReadingItemAtURL:self->fileURL options:0 error:&error byAccessor:^(NSURL* url) {
if ([fileManager fileExistsAtPath:[url path]]) {
content = [fileManager contentsAtPath:[url path]];
}
}];
dispatch_async(dispatch_get_main_queue(), ^{
[self.textView setString:[[NSString alloc] initWithData:content encoding:NSUTF8StringEncoding]];
});
}
// After this I implement *every* method in the NSFilePresenter protocol. Each one
// simply logs its method name (so I can see it has been called) and calls reloadFile
// (not the correct implementation for all of them I know, but good enough for now).
#end
Note, reloadFile is called in applicationDidFinishLaunching and saveFile gets called every time the save button is click (via the app delegate).
The only NSFilePresenter method that ever gets called (going by the logs) is presentedItemURL (which gets called four times when the program starts and loads the file and three times whenever save is clicked. Clicking save in a second instance has no noticeable effect on the first instance.
Can anyone tell me what I'm doing wrong here?
I was struggling with this exact issue for quite a while. For me, the only method that would be called was -presentedSubitemDidChangeAtURL: (I was monitoring a directory rather than a file). I opened a technical support issue with Apple, and their response was that this is a bug, and the only thing we can do right now is to do everything through -presentedSubitemDidChangeAtURL: if you're monitoring a directory. Not sure what can be done when monitoring a file.
I would encourage anyone encountering this issue to file a bug (https://bugreport.apple.com) to encourage Apple to get this problem fixed as soon as possible.
(I realize that this is an old question, but... :) )
First of all, I notice you don't have [NSFileCoordinator removeFilePresenter:self]; anywhere (it should be in dealloc).
Secondly, you wrote:
// After this I implement *every* method in the NSFilePresenter protocol. Each one
// simply logs its method name (so I can see it has been called) and calls reloadFile
// (not the correct implementation for all of them I know, but good enough for now).
You're right: it's the incorrect implementation! And you're wrong: it's not good enough, because it's essential for methods like accommodatePresentedItemDeletionWithCompletionHandler: which take a completion block as a parameter, that you actually call this completion block whenever you implement them, e.g.
- (void) savePresentedItemChangesWithCompletionHandler:(void (^)(NSError * _Nullable))completionHandler
{
// implement your save routine here, but only if you need to!
if ( dataHasChanged ) [self save]; // <-- meta code
//
NSError * err = nil; // <-- = no error, in this simple implementation
completionHandler(err); // <-- essential!
}
I don't know whether this is the reason your protocol methods are not being called, but it's certainly a place to start. Well, assuming you haven't already worked out what was wrong in the past three years! :-)
This is my first app, and actually isn't even fully mine but rather involves re-working an existing app to add functionality.
It involves a JSON feed which I'm successfully reading in and then trying to pass the value of a URL to a view. Here's the code from my app delegate that is successfully fired once the feed is read in:
- (void)JSONFetch:(MYJSONFetch *)fetch gotTheCollection:(id)collection
{
[UIApplication sharedApplication].networkActivityIndicatorVisible = NO;
self.testViewController.feedURL = [NSURL URLWithString:[collection objectForKey:#"Listings"]];
[JSONFetch release];
JSONFetch = nil;
}
Then in my testViewController I have this viewDidLoad method:
- (void)viewDidLoad {
[super viewDidLoad];
if(self.feedURL)
{
[self startDownload];
}
}
Eventhough, when I debug, the gotTheCollection method passes a value to the feedURL of the view, it then fails on the if(self feedURL) check within the view and thus the view never gets populated.
As I'm so new to this code I've no idea if the sequence is wrong, or maybe it's how I'm passing the variable.
I know the description is relatively vague but even on a basic level I don't know if this functionality works in objective C, it doesn't cause any errors though, just sits there not loading because it can't get the data.
UPDATE: Definition of FeedURL follows, in the H file:
NSURL *feedURL;
then
#property (nonatomic, retain) NSURL *feedURL;
then in the M file:
#synthesize feedURL;
Thanks for the help guys, I finally decided to just restart the entire upgrade as the project had become a mess of reworked code and I couldn't be sure what worked and what didn't. As a result there's no clear answer to this but I imagine Franks was probably the closest so I'll mark that as the answer.
The NSURL is being autoreleased, you will need to retain it yourself
Assign the NSURL to feedURL, like so
self.testViewController.feedURL = [[NSURL URLWithString:[collection objectForKey:#"Listings"]] retain];
This will also mean you will have to release it yourself.
On OSX, I am using XCode to make a desktop app with a webview in it. The webview loads ok, and I can dynamically load content into it - but when I click on links inside the webview, they are not followed. They change color, but no new page is loaded. If I code my links with javascript like this - then they work.
link there
Is there an Objective-C one liner that allows links to be followed inside web-views?
Is there another issue I am not aware of here?
The links at the top of Gmail open in a new window. To make them work you have to implement at least the WebUIDelegate methods webView:createWebViewWithRequest: and webViewShow:. If you simply want to open all links in the same web view, you could return it from webView:createWebViewWithRequest: instead of creating a new one.
Turns out it was because I had code I copied form the web with some custom function to ignore WebPolicyDecisionListener...
Sorry for asking question without giving all the details - all this objective-c is new to me, I don't know which bits do what yet. I do some pointing and clicking, and then some coding - I don't know exactly how that all links up. With other languages, you have the whole program in one place - it takes a bit of a learning curve to get used to... but I digress.
I fixed by adding some comments - see code below...
- (void)webView:(WebView *)aWebView
decidePolicyForNavigationAction:(NSDictionary *)actionInformation
request:(NSURLRequest *)request
frame:(WebFrame *)frame
decisionListener:(id < WebPolicyDecisionListener >)listener
{
if ([self requestIsLinkClick:actionInformation]) {
if ([#"method" isEqual:[[request URL] scheme]]) {
SEL selector = NSSelectorFromString([[request URL] resourceSpecifier]);
if ([prototypeDelegate respondsToSelector:selector]) {
[prototypeDelegate performSelector:selector];
}
}
// [listener ignore];
} // else {
[listener use];
//}
}
I set up a simple event handler as mentioned here, but it appears that the selector isn't called. I put the code in my AppDelegate class and wired up the delegate in IB. Tried putting in some NSLog()s and breakpoints in the selector I expect to be called, but none of it is hit. The URL scheme works inasmuch as it launches my app, but it doesn't do anything after that. Can anyone advise how to troubleshoot this? Thanks!
Well, I can't help but notice that you're -init method is mis-declared. If should have return type id and have a return self; at the end.
- (id)init
{
self = [super init];
if (self) {
[[NSAppleEventManager sharedAppleEventManager] setEventHandler:self andSelector:#selector(getUrl:withReplyEvent:) forEventClass:kInternetEventClass andEventID:kAEGetURL];
}
return self;
}
With those fixes, I was able to paste those two routines into a test AppController class and have it print out the URLs (with a custom scheme) that I typed into Safari. I'd put a breakpoint on that -init method and step through it to make absolutely sure that -setEventHandler: method is getting called.
The big question is: Where are you calling NSAppleEventManager's -setEventHandler:...? You need to call this before your app finishes launching if you want to catch a URL that started your app. If your app delegate is created in your MainMenu.nib, then either its -init or -awakeFromNib methods will work, but, for example, -applicationDidFinishLaunching: won't.
Also, make sure that the selector you provide to -setEventHandler: is exactly the same as your method name, paying particular attention to capitalization and the proper number of colons.
Obviously, if you posted your app delegate's relevant code, it would be quite helpful.
Thanks for the suggestions. I double-checked those things. I'm sure it's some newbie mistake, but I'd appreciate anyone looking at the code. (The URL bits are stored in info.plist.) Right now I'm just trying to confirm that it's working before I try to do anything with the URL.
- (void)init{
self = [super init];
if(self){
[[NSAppleEventManager sharedAppleEventManager] setEventHandler:self andSelector:#selector(getUrl:withReplyEvent:) forEventClass:kInternetEventClass andEventID:kAEGetURL];
}
}
- (void)getUrl:(NSAppleEventDescriptor *)event withReplyEvent:(NSAppleEventDescriptor *)replyEvent
{
NSString *url = [[event paramDescriptorForKeyword:keyDirectObject] stringValue];
NSLog(url);
// now you can create an NSURL and grab the necessary parts
}
Newbie mistake #2: Didn't set the class of my app delegate in IB. Fixing this and the init method as above got me going. Grrr...