I am not very experienced with Qt and I have trouble doing what I want.
In my application, I search for archive files with password on a disk (that part works) and I want to ask the user for the password each time I find one new encrypted archive.
If I find multiple files while user hasn't given any password, I want the dialog for the first password to stay visible until that password is given and then the dialog for the next password can show and so on.
I use some sort of queue to remember which archives need a password, and I am trying to show and hide an unique dialog (actually a Popup) with the info of each archive and get the password from a TextField inside. In the meantime my application is doing other stuff in the c++ code like searching for archives and extracting them when a given password is OK.
My problem is that it is not really working. The dialog shows the first time, I get the first password but then the dialog doesn't show for the next password. Sometimes I can see the dialog a second time, for a few milliseconds, before it disappears without user interaction. My application is blocked because it cannot go on without the unasked passwords.
I get that I am doing something wrong but I don't get what exactly.
Can anyone help ?
I don't know if I was very clear, English is (obviously) not my mother tongue.
I found my mistake.
I did a component based on a Popup.
Inside the onClicked function of the Check or Skip buttons I was doing two things: send accepted() or refused() to trigger custom actions and then close the dialog.
I was doing that in that order, so the accepted or refused action, which among others things triggered the visibility for the "next" password dialog, occurred before the close event, which was setting the dialog visibility to false.
I switched the order and it's way better.
I feel a little silly now but at least I found it.
Related
I've been following YouTube tutorials most of the day now and I think I've got the basic hang of forms. I'm aiming to create something like this below, which checks a users password and shows how strong it is:
This is what I have at the moment:
I'd like to know the basic theory behind how the top form works, specifically how I can take the user input of password in my form and just get it to print and update in realtime underneath below. I'm not quite sure what tool is used to do that, or for that matter what tool is used to create the colour changing box.
Any help or direction is appreciated, thanks!
Add a keyboardListener to your jtextfield. When a key is pressed get the text and do your stuff(figure out the strength, number of Uppercase etc)
Is this win32 or mfc forms, or some other tech like Qt or wxWidgets?
In both cases you will want to handle messages from the edit field as text is changed in it. This message is the EN_CHANGE message. Handle that message and you can get the text from the edit field and send messages to the strength form to tell it to change its color and text.
Add a System::Windows::Forms::KeyPressEventHandler (or similar) to the TextBox. When raised, do whatever analysis you need to do on the string and update the table below. The color changing box can be one of many implementations. It can be something as simple as a panel that changes its background with a System::Windows::Forms::Label positioned on top of it. It actually looks like that, as the text is not centered.
I'm building a VCL c++ builder application. I would like to see if anyone knows of a component that can load data in the lookup upon drop down only after a user has typed a few letters to limit the rows queried? Preferably after pressing Tab, or Enter.
What I would like best is to get a behaviour similar to what Linux command line has, but that might be wishful thinking. The way it would work is to drop down the combo list after user presses tab only if there is multiple options available, and to fill in additional text till the point where characters are not the same anymore, then if user presses tab again, drop down list.
The next best would be if the drop down would only allow drop down if user has typed a few letters, then pressing a specific button opens the dataset with the parameter of the typed text so far, then drops down the combo.
Does a component like this exist?
You can check out TMS Software. I'm not sure if it has something exactly for you, but their components are quite flexible. And you can send a feature request to them - to consider for next update. If you are lucky they might add it to next release.
When the user clicks the OK or APPLY button on a property sheet and the program determines data on some page is invalid, how can I cause the page containing the error to be displayed along with a message box describing the error?
Currently the procedure doing the validation does the following while processing the PSN_APPLY notification.
MessageBox (hDlg, "Data must be positive!", "Error", MB_OK);
SetWindowLong (hDlg, DWL_MSGRESULT, PSNRET_INVALID);
This works ok if the page doing the validation (A) is currently displayed but if some other page (B) is being displayed, the message box appears with that page (B) being displayed, then when the message box is answered, the page with the validation error (A) is displayed. I thought about setting some flag so that when that page (A) gets the PSN_SETACTIVE notification it displays the message box but that seems kind of hokey.
Win32 API in c++, no MFC, no NET, nothing fancy.
I think the problem is in the design of your validation and it's presentation.
Am I right in thinking that you iterate through your property sheets, validate them and display a message box if something is awry? Because of course, what you have witnessed will happen, if I am on property page 3 and I wrote crap in to a field on property page 1.
The easiest solution is, when validating, note which property page the field in question is, and set that one active if the user has written crap in to one of your fields. This seems the fastest way possible.
Also, rather than spring up an annoying message box, reserve some room beneath the property pages to display a textual (red or otherwise) warning as to why, and then change to the appropriate property page, and highlight the offending control. Your validation routine can do this nice and easily as it loops through.
Even better, don't stop at the first error. One thing I HATE is correcting one field that I think is the only issue, only to be told every time I hit "OK" or "SUBMIT" that there's something else I missed.
I seriously think you should consider going the extra mile here... loop through ALL controls, and add all invalid ones to a list. Then change each offending control's background colour, tab colour etc... Then the user can work through and correct, no matter how many errors he or she made.
My first question was: should I use dom, sax, or sqlite to save the data the user is inputting into my application. The answer I am going with is to use DOM.
My second question is: How should I load the contents of the file into the application when the user decides to open the file? Should it go through the whole file and distribute all the data to the correct spots in the GUI once the user clicks "open" on the file? Or should it only open the stuff up as the user clicks on certain areas?
My third question is: How does qt handle knowing when things have changed? How would i know when the user has changed something and ask them to save the file?
If you do not understand, please let me know and I will try to explain again.
Example:
I am not only reading gui locations.
But the contents of those. For
instance. The user is able to create
tabs that contain edit text boxes. And
those tabs are associated with items
that are in a list. When the user
clicks on an item in the list the user
will be presented with a whole set of
new tabs. And each tab has some
editing forms. The file will need to
contain what is in the list, what tabs
the user has created under each item
in that list and the contents of each
tab associated with the tab of each
item in the list.
Sorry that I posted another question that is similar to my last, but the other question was answered and now I need a new post.
Question 2: This very much depends on how much data you're dealing with. It will be much easier to load everything in one step. If you are expecting complex documents, it might be better to do it incrementally, but I would strongly recommend starting with the simpler approach.
Question 3: Qt does not handle this, except in as far as widgets will fire signals when they are modified. You need to do it, using a model of some sort. You could just use the DOM document directly as the model, although it may help maintainability to abstract the save format. Each change the user makes would cause a change in the model. You will need to detect when e.g. the user edits some text, update your model appropriately and keep track of whether it has changed since the last save.
What do you want to achieve with your solution? If you want to simply set Configuration why not using a simple Ini file (QSettings Class).
I don't know your application, but you should be able to recognise changes (lets say, if the user changed a QLineEdit or hit a radioButton).
There would be also a "sync" method for QSettings, which "rereads" the file you are working with. Qt won't recognise changes itself, you have to do that on your own.
I find this situation comes up from time to time, and I never seem to have a really robust generic solution to it.
I have a control - in this example an EDIT control on a dialog. I want to take certain actions in response to the user - and only the user - modifying the contents of the edit control.
The edit control can be set programmatically - e.g. when the dialog is being setup, there may be an initial value placed into the edit field. Or when the user selects an item from a listview, that selection's text may well be what's placed into the edit field.
But when the user modifies the contents of the edit field, I need to know that, and respond (in this scenario, I want to clear the selection from the corresponding listview).
I am currently looking at what control has focus, and only considering EN_CHANGE's to be "from the user" if the edit control has focus.
This works beautifully under Windows 7. This fails under XP (I haven't tested Vista yet).
In XP, if the edit field has the focus, but the user clicks on the list view, and the list view tells the edit control to set its contents, then I get a notification from the edit control which claims to still have focus (::GetFocus() == HWND of edit control). But this incorrect state doesn't occur in Win7.
This is a layered interface, so I cannot modify the list-view notification handler. It gets a selection change, and updates the edit field without my involvement or ability to really intervene other than to get notifications from both of them.
Any thoughts on how to generically, permanently solve the "Is this control notification really from the user" conundrum?
You can always track LVM_ITEMCHANGING, LVM_ITEMCHANGED, and EN_MSGFILTER messages. If the edit box is modified between LVM_ITEMCHANGING and LVM_ITEMCHANGED without an EN_MSGFILTER in between then you can probably assume the user did not modify the item. Or just check to see if there are any items selected when EN_CHANGE fires and if not or the text doesn't match the selected item, assume it is a user edit.
Or use ES_MULTILINE (from EN_CHANGE documentation):
The EN_CHANGE notification is not sent
when the ES_MULTILINE style is used
and the text is sent through
WM_SETTEXT.
I'd suggest using the right message. EN_CHANGE is too generic, you want to know if the user typed or pasted text. So why not subclass the control and watch for WM_KEYPRESS messages?
Alternatively, you can set a flag in your other code that sets the edit control content. You might be able to assume that anything that makes your wndproc re-entrant represents a programmatic change.
You aren't looking for something actually secure, are you? If you just want to exclude set content calls that's fairly straightforward. If you want to differentiate between user action and programmatic simulation of user keypresses, that's a much harder problem.