In our app we need to check if the data is saved when we are in a particular place before navigating away from it. So the user should be able to negate a browser back button request. But by the time that the history value change event is received the url has already been changed. The History class doesn't seem to have a way to restore the url back. Anybody have any ideas?
In GWT 2.1 you get Activities and Places. And activity has a maystop method, which is exactly what you want, if I understand you correctly.
Use a window.onunload or window.onbeforeunload javascript callback to confrim/save state.
onbeforeunload example
I haven't actually implemented this behavior yet, but here is my plan and maybe it will work for you.
1) Each time you receive an onHistoryChanged event and decide to allow it, save the current historyToken in an instance variable somewhere.
2) Keep track of activity on the page that should block navigation. Use a data structure that can keep track of multiple activities, like multiple file uploads, multiple edits, etc.
3) When you receive a new onHistoryChanged event, if your data structure from #2 indicates that it's not safe to navigate, avoid changing the page and restore the historyToken that you saved in #1. I'm assuming that you can do this either by:
a) Calling History.newItem(oldHistoryToken, false) or
b) Calling History.newItem(oldHistoryToken, true) and keeping a flag to force the next onHistoryChanged to be ignored.
Again, I haven't actually implemented this so let me know how it works out.
If you have links that allow the user to leave the app and you want to prevent that as well, you'll need to also add an onbeforeunload.
Have a look at the PlaceManagerImpl class from the gwt-platform framework. Especially the onValueChange() method and the methods dealing with the onLeaveQuestion field.
Hope that helps.
In this issue report, t.broyer explains in his comment that such behavior was planned during design of Places framework. The most important part is:
mayStop was a mistake, or it should have only been called when unloading the app, not for internal navigation within the app.
So probably it's better to not use it at all...
Related
I use SAP standard library: Inbox.
in library class S3.controller by tap on attachments icon is onTabSelect event executed, witch makes
this.fnDelegateAttachmentsCreation();
this.fnFetchDataOnTabSelect("Attachments");
this.fnHandleAttachmentsCountText("Attachments");
this.fnHandleNoTextCreation("Attachments");
break;
fnFetchDataOnTabSelect makes an asynchronous call. During this call is fnHandleAttachmentsCountText already executed, so the update of attachments count occurs before the request for attachments is ready. As far the request for attachments is ready, there is no update for title executed.
On screenshot is AttachmentCountText „Attachnents (1/1)“, that comes from previously selected item.
It should be „Attachements (2/2)".
Also if response comes too quick, then view changes to loading view after it received the answer from request.
If list of attachments was updated from request callback, then it should not be updated second time.
Here it seems, that there is something on loading, but request is already finished.
How could be Inbox extended, to update the attachment header and content after request is ready?
used SAPUI5-Version: 1.71.4
You are using the standard bsp-application ca_fiori_inbox?
You didn't create an extension project of the application ca_fiori_inbox with custom coding?
If that's the case, it's a bug in an standard application delivered by the SAP. SAP releases so called notes to fix bugs in their standard applications.
You can import notes in your system via the transaction SNOTE. May ask a SAP Basis Administrator from your company for help.
The following notes exactly describe your problem
2873960
2823664
2916255
2901520
If you already extended the SAP standard application(MyInbox) without using ExtensionPoints codechanges in the standard application will not affect your custom extension.
When overriding a controller method, any functionality that was previously provided by it is no longer available. Likewise, any future changes made to the original controller method implementation will not be reflected in the custom controller.
In this case you could still implement the note and check the changes in the standard controller vs. your custom controller on your system and change the respective lines in your custom coding.
Don't fix SAP coding. Report it and get a fix.
The Note 2873960 corrects coding in an abap class, not in the bsp-application(ca_fiori_inbox). So definitly import the note and check if it's fixing your problem.
I actually do not know, how the app works, but I want to give it a try.
Since it is an asynchronous function, you can always also wait for the function until it is done. So in your case, you could try to set an await keyword in front of the function.
await fnFetchDataOnTabSelect("Attachments");
This will now wait on this position until it has finished the function call before it will call the next functions. In addition to that you also need to set the upper function onTabSelect to async. So in the end it should look something like this.
onTabSelect: async function() {
// ...
this.fnDelegateAttachmentsCreation();
await this.fnFetchDataOnTabSelect("Attachments");
this.fnHandleAttachmentsCountText("Attachments");
this.fnHandleNoTextCreation("Attachments");
// ...
}
Although the Web IDE maybe shows you errors, it does work, since it is an official JavaScript API.
I'm trying to learn web development, and I bet that this is a simple problem and that I'm overlooking something obvious.
In my default crud edit controller (generated using the MVC framework) I retrieve my model from a localDB instance using my EntityFramework's dbContext. That is sent to the View. In the debugger just before the controller call to return View(model) I can see that the Id is set to 2.
When the [post] edit controller is fired I see that the identity property is 3. I wanted to figure out why so I changed the View to display my Id property and I see that it is 3 as soon as I render the page. Last time I saw it the property was 2, now it is 3.
I don't know how to hook into any logic that would happen between the time I send off my model and when when the view is rendered.
Can anyone help me learn how to debug this so that I can figure out why my Id property is incremented when I pass the model into the view?
I don't know how EntityFramework works but I have worked with CakePHP. My advice is like this:
Usually PHP frameworks have debug mode which you can set in the configuration file (turn it on or off). Usually stack of operation executed is also displayed in debug mode or there is a simple way to do that. There's also for example in CakePHP exist function debug($yourVariable); try to search for sth. similar
It seams like not the edit happens but new row is inserted to the database. Check your database for this. I recommend to debug the id of the column being passed for edit action and check if there's the same id in the database first of all.
Hope something helps.
I figured it out. Posting here for anyone else that comes across my problem.
I tried dumping the whole model out without using any of the htmlhelper methods. (In my case I am uinging: Html.HiddenFor helper) When I did this I saw that the value in the model was what I expected it to be. So I began investigating why the helper methods might be broken. Google worked for me here :)
Turns out, when the helper methods run they first check the ModelState dictionary for the desired value. In my case I was looking for a value that was in my model object as well as the ModelState dictionary, because the name was very common: Id.
To fix the issue before I call return View(model) I call ModelState.Clear() in order to make sure there are no values in the dictionary that are in conflict. Doing this causes my page to be rendered correctly.
My question is very basic on one hand but on the other hand the general situation is more complex, plus I cannot really get any working sample.
I'm developing/maintaing a web-application which is currently in transition from GWT code base into Ember.js.
Most of the newer code already relies on Ember.js and I think it's really awesome.
The problem is we cannot use Ember Router as all the request are being handled by the GWT.
In order to enabled the application run in this unusual configuration we have special JavaScript files that create our Ember main objects (Controllers & Models) for us.
As you can imagine navigation between tabs is cumbersome and is handled by GWT who creates Ember objects when needed. We are in transit toward a brave new world Ember Router and all.
But in the meantime, this is the problem I'm facing right now.
The user clicks a link which opens a page that contains some Ember based table.
The data is retrieved form the server using some Ajax code. Upon success it spawns a forEach loop which tries to pushObject all the received date into our Ember based components.
My problem happens when the user quickly switches between tabs. In this case the first list of object has not finished rendering yet and suddenly there's a new set of objects to handle. This causes Ember to throw errors like:
"Uncaught Error: Cannot perform operations on a Metamorph that is not in the DOM. "
and
"Uncaught NotFoundError: An attempt was made to reference a Node in a context where it does not exist."
Is it possible to prevent the loop from trying to render?
I've tried checking if the controller in question is already inDOM and it is, is there a way to notify Ember this object is no longer valid?
Sorry for a lengthy question and lack of running sample.
I'd probably modify the switch tab code to only execute afterRender has completed, that way you aren't mucking with ember objects while they are being used.
Ember.run.scheduleOnce('afterRender', this, function(){
// call GWT switch tab routine
});
Thank you Daniel and Márcio Rodrigues Correa Júnior. eventually what I did is to add a patch that would check the current context of the application (in my case the currently selected tab). If upon receiving the AJAX response the application is in the correct context (meaning the user haven't change the tab) go on. Otherwise just ignore the response and do not try to render it.
Now it seems to be working
in my app i have a relative complex activity/place. Resolving the state (from history token to model) on start of activity causes some server interactions.
On user interactions the activity only updates the necessary parts of the model and therefore safes some server interactions - the activity/model has an inner state.
Is there a way to reflect the state in browser history without (re)starting the activity? (History.newItem(token) also causes start of activity)
UPDATE
Chris' solution "nearly" works but another problem rose: in my ui i have a reset-button (a link to the place with empty token). If i click around the ui the token is updated fine but now the reset button doesn't work. gwt thinks it is in the same place and so it ignores the reset click.
Before this the problem was nearly the same: the token and place didn't change and so the reset button didn't work either.
GWT logs this as "Asked to return to the same place"
So is there a way to let gwt restart the activity regardless of place equivalence?
Go to a new place, but have your ActivityMapper return the same activity instance. That way, the activity is not restarted.
You have to find a mean of updating the activity when the place changes from some other mean though (e.g. browser history). See GWT MVP updating Activity state on Place change for instance.
There is a semi-solution, and although I don't want to recommend it, I'd like to add it here - just to warn against the drawbacks of this solution:
You could add tokens to the History without firing an event by calling History.newItem(token, false).
This is a semi-solution, because:
It works correctly (as long as you build your tokens correctly).
A part of the performance problem is also solved: The activity won't be re-started when adding the token to the history.
However, if the user goes back and forward through the history, the performance problem would still be there (because then, the events will be fired again).
Wondering how to name this question. Think this is the best situation possible.
Situation:
I got small app written in KohanaPHP framework. However there's one small bug that makes my crazy.
I got my own Core_Controller that is extended by every controller in this app. In constructor of this controller, I'm checking user profile status. So far so good. Although I'm facing a logical issue. It's called endless redirect loop. If I try to redirect (in Core_Controller constructor) user to Member_Controller it cannot be workig due to endless lopp. I understand why it happen.
Solution:
I'm looking for a solution how to make it flexible. I tried to move this verification to a helper and call it in Core_Controller constructor. However, it can be working correctly.
Question:
Do I have to put verification in constructor of every single controller? IS there any universal method to do it?
Waiting for your thoughts.
M.A.
Just check if user is verified and the current request's action isn't something like member/verification, do the redirect.
And parent::__construct(); will call the parent constructor, so I don't see the problem in that either..
You need a condition where it doesn't redirect (on the page you have redirected to). You'll want some code similar to this.
if not member_controller then
redirect to member_controller
else
do nothing
endif
The else isn't needed, but just added so it's more clear to you.