I have an application that stores data in isolated storage. I have a function to read the data (called in Apps.xaml.cs):
await ReadData();
However, before the data read, OnNavigatedTo is called in MainPage. At that point the buffer holding the data is still null.
How can I prevent MainPage.OnNavigateTo() from being as long as ReadData is not complete?
I tried syncing Apps & MainPage by setting a semaphore in Apps, and WaitOne() in the MainPage constructor. This hang the app on the WaitOne.
Any idea how this timing problem can be solved?
You can't delay the loading of the main page - as if the loading cycle is not executed within a timely fashion the app will be closed by the OS.
The best way around this is to create an interim splash page, which will handle the downloading of data whilst showing UI to the user. Once the data has downloaded you can then redirect to your main application page.
Related
I opened my website in Chrome last night, then closed that tab, but didn't close browser. Today I failed to open my site in a new tab because jQuery(not use CDN) hits a syntax error: unexpected end of input.
My site always hits this error no matter how many times I refresh. But the error didn't happen again after hard refresh.
This problem happens many times in recent months.
I checked Chrome devtool, it says my jquery.min.js is loaded from memory cache. And it is not a whole file, only contains part of jquery library. That's why I got syntax error.
I did some research from google:
The lifetime of memory cache is attach to the lifetime of render process, which roughly corresponds to a tab.
So if I create a new tab to visit my site, stands to reason, jQuery should not be loaded from memory cache.
I expect browser do not load my files from memory again if I visit site in new tab.
Is there anything I can do to locate the problem source and fix it?
EDIT (2019-05-13):
Today hit this error again, but fortunately, I found new point seems helpful to this problem.
This is that request:
See status code is 206 Partial Content (from memory cache).
And I have no idea why my request header contains 'Range' field.
You can't detect newtab in browser and load your jquery.min.js,But you can avoid loading from cache by adding timestamp into suffix of your lib like follows.
http://yoursite.com/lib/js/jquery.min.js?1557301884
You can achieve this in two ways
Case:1 If you are using server side page rendering means(PHP,JSP) just print the timestamp
Case:2 If Client side means some javascript stuff you have to do
I want to unload all used modules when a user logs out of the webside to reset the application. When a new logs into the backendserver with the same running application all lazy loaded modules are still there.
I did some research and seems to me like it isn't possible by now.
Does somebody know a solution or a githublink to the ticket?
I guess unloading my modules was the wrong direction.
Once the chunks are loaded they shouldn't be constructed again.
I register the services in another service. Now when I Logout I call a function which iterates through all the services and calls a function for every service which empties all data by the previous User.
----------EDIT---------
Seeing that this question still get views here is a solution I used for some Apps:
Kudos to user benh80
Resetting the complete App and reloading it:
Resetting Angular 2 App
the whole point of using lazy loading is to load the relevant modules for a component. Once you log out the application it actually loads the modules which need for that component. Hence there is nothing to unload
I have an http handler built and running on my website server. Code in flex generates a http request then navigates to the handler, which generates and streams back file information for the user to download.
Basically the request sends image data and the return result is a pptx stream with the image data in a powerpoint slide.
This worked fantastically this morning until about an hour ago. I have no idea what changed, but every swf I am building which attempts to access this handler is now giving me:
* Security Sandbox Violation *
Connection to https://g1.localhost/Turm/BounceBack.aspx halted - not permitted from https://g1.localhost/Turm/FlashApps/ImageAndExporting.swf?debug=true
I even fully qualified the BounceBack.aspx name (it was a relative url until just now) in case something was confusing the flash player, but as you can see, the url request and the swf are loaded from exactly the same domain (even the same virtual app in the web domain).
I have even added the physical filepath as a 'trusted folder' in my flash player security settings.
What gives? Anyone have any suggestions?
Using the Apache 4.9.1 SDK and latest version of flashplayer.
As mentioned, this worked all day yesterday and this morning. I cannot figure out what has changed, but am having no luck resolving the issue, source code has not changed.
Finally figured out what changed. I move the navigation to my ASPX handler into a seperate method that delays invoation till after a UI update. Becuase I use the same ui components for printing as well as exporting, I tested the updates with the print feature and that worked without error. About an our later, I noticed the handlers were failing. Since the url request is not handled inside a UI interaction event (Like MouseEvent.CLICK) the flash player was preventing the call. Once I moved the navigation back into the event handler, the sandbox violation went away.
If you ask me, not a very good error message due to the actual problem encountered, but ... you learn something every day.
I'm inserting a new file, and using the returned File object to store a thumbnail. Intermittently, getThumbnail() returns null for .pdf files.
I'm guessing that the explanation is the thumbnail is generated asynchronously and there are times when the processing is incomplete before the insert() call returns with anincomplete File object.
Is there any way I can make this behave more deterministically?
Alternatively, anybody know if the subsequent processing of the thumbnail constitutes a "change" that would be returned by a get changes call?
AFAIK yes the thumbnails are calculated asynchronously. The delay can be different based on server loads, file type and file size but in my testing the thumbs for PDF were available very shortly after the file has been created.
Probably at this point the best you could do is try a subsequent request and keep trying until you get a thumbnail but don't forget to use exponential back-off not to overload the server and kill your quota in some case.
I don't think that when the thumbnail is ready this counts as a change in the changes feed in that case.
I am working on an android application that will show an html page that contains only some text on a tablet device. The device will be on and showing this page for long periods of time(several hours). The text on this page will get changed from time to time.
To change the text on the page I've made a separate second page that contains a form to enter the new strings into and a submit button that uses ASP to generate a new version of the first page and save it over top of the original copy. This is set up and working great, but it means that I have to refresh the page very frequently in order to ensure I am always showing the latest message.
I am looking for a way that I could trigger a refresh only when a new message is saved. That way I will not have to refresh the page every minute but the new message will still get shown in a timely manner.
No dice, HTTP is built as a stateless, pull-only (ignoring file uploads) protocol. The server can't push data to the client, the client has to actually poll the server for new information.
However, you can minimize the overhead of this by using an AJAX call with JSON as the transport protocol instead of generating entire web pages and update your page on the client side. The overhead should be minimal for almost any application.
If you were just a web-app, I would suggest looking into the various Comet frameworks.
http://www.google.com/search?q=comet+framework
But, since you have an Android shell around it, you can make a Socket connection back to your server and have the server signal when it's time to refresh. It's essentially the same, but you don't need to code up the push in JavaScript if you're more comfortable in Java.