I have a TFrame on which some TEdits are placed. These edits are
boxes for serial key input, as I'm trying to setup a user experience
where input focus jumps from one edit box to the next, when a certain amount of
characters been entered in each. That is, user do not need to press tab
or click on the next edit in order to advance.
I found an example in the C++ Builder HowTo book (great book) on how to
"simulate" enter press to behave like a tab press in edits and was
trying to employ the same technique. However, something in my app don't
work as in that example.
In the frames KeyPress event, I have the code
void __fastcall TAboutFrame::Edit1KeyPress(TObject *Sender,
System::WideChar &Key)
{
TEdit* theEdit = dynamic_cast<TEdit*>(Sender);
if(!theEdit)
{
return;
}
if(theEdit->Text.Length() >= 6)
{
//jump to next edit
Perform(WM_NEXTDLGCTL, 0, 0);
...
But the 'jump' to next control does not occur.
The main Form, the frames parent, do have key preview == true and I can
set a breakpoint to see that the Perform call is indeed executed.
The tab orders on the edits are 1,2,3,4,5.
I wonder if this has todo with TFrames messaging or?
If the controls you are using descend from TWinControl (Which they should if you are using stock VCL controls), You can also use TWinControl->SetFocus() to explicitly set the focus to the desired control.
Related
In delphi:
How can you respond to a key press when the current focus is on a radiogroup which does not have an onkeypress event. I was hoping to use the forms onkeypress event but it doesnt see to fire.
You can make this possible by setting the form's KeyPreview property to True.
However, I'm not sure you are actually doing things right, since this is a fairly uncommon problem.
You didn't write what keyboard shortcut you want to respond to. But please remember that
Letters are used to navigate the GUI. For instance, pressing A might select the &All radio button or click the &Add push button. Similarly, Alt+A does the same if the current control allows character input, allows you to open the &Add-ons menu item, etc.
If you want to add a proper shortcut like Ctrl+O, it is much better to use a TActionList with an action having this shortcut. This action can be mapped to menu items, buttons, etc., or simply exist in the background not being attached to any visual control. In very simple applications, you might want to use a stand-alone menu item with such a shortcut instead.
I'm writing a small pyqt program. I want the main window to to react to arrow movement. I added an event to my MainGui class, keyPressEvent, that handle this. The event work fine as long as I don't press certain buttons such as Key_Up or Key_Down are directed to my (currently only) QComboBox and not to my mainGui. I tried to give the focus to mainGui after each paintEvent but then I need to double click on buttons/comboBox.
Then I tried to use the MousePressEvent to check if a certain element is under the mouse. This work fine with the comboBox, but not with the button.
So, how can I direct key events to the mainGui or give the focus to QButtons?
I used eventFilter to identify when the mouse enter the QPushButton and give it focus:
def eventFilter(self,source,event):
if event.type() == QtCore.QEvent.HoverMove:
if self.execButton.underMouse():
self.execButton.setFocus()
self.keepFocus=False
else :
self.keepFocus=True
keepFocus is a flag I initialized in the __init__ function of the class. I added this part at the paintEvent function
if self.keepFocus:
self.setFocus()
else:
self.keepFocus = True
Now, I keep the focus at the MainGui and I only give it to the button when the mouse hove over it. If I do another action (like pressing a mouse button or a keyboard key) the focus is given back to the MainGui. This will create some buggy filling (For example, I need to press twice a keyboard key before the first response) but this is workable.
i wanna make a windows database application with c++ builder. The idea is to have a static menu of 6 icons at the top (i need this to be constant in every screen) while the rest of the screen will host all user interactions and data regarding with the selected menu item. I have a litte experiece with SDI apps and as far as i know there is no way the whole application to be in a single screen / form. Should i build this like an MDI app or is there any other way to maintain a fixed icon based menu at top while the rest screen data to change for every different menu item? I dont want to be in a single window with no overlaping forms while user navigates through the application.
Although an MDI application is definitely possible, the interaction between the different forms sometimes is a little cumbersome. A tabbed page is easier to handle since everything then resides within the same TForm class.
If you want to change the appearance of the individual tabs you can overload the 'PageControlDrawTab' Just add an event handler, get a handle to the Canvas of the tab itself and you are free to draw is as you want. See the example below:
void __fastcall TMainForm::PageControlDrawTab(TCustomTabControl *Control,
int TabIndex, const TRect &Rect, bool Active)
{
/* OnDraw handler to change the appearance of the Tabs.
Change it to blue text on white background.
*/
String s;
TRect r;
TTabControl * tTab = (TTabControl *)Control; // Get a pointer to the tab itself
s = tTab->Tabs->Strings[TabIndex]; // Retrieve the text of this tab
Control->Canvas->Brush->Color = clWhite; // Use the Canvas to draw
Control->Canvas->Font->Color = clBlue; // .. whatever you like
Control->Canvas->FillRect(Rect);
Control->Canvas->TextRect(Rect,Rect.Left+4,Rect.Top+2,s);
}
You will probably have to do it in a MDI format. I do not know of any way to share the menu across forms. The other option you could use though is to use a page control and have all the other "forms" live in a tab so the menu is the same all the time. The menu items could respond differently if you would like them to when the user is on a different tab, or they could do the same thing no matter what tab you are on. Sorry this is the form of an answer, I don't have comment rights yet.
I have two 100% overlapping panels with different contents on a form.
The first (static display of information) should be visible by default, but the other (user interaction) should replace it if the user moves the mouse near the two - and if the mouse moves away, it should switch back.
Something like this:
if (*the mouse is near*) then
begin
Panel1.Hide;
Panel2.Show;
end
else
begin
Panel2.Hide;
Panel1.Show;
end;
My problem is: where to capture mouse movement?
Each component has its own OnMouseMove handler - of course I could forward each of them to the forms handler, but I'd rather have something a bit more elegant (and easier to maintain).
The perfect solution would be something like Form1.MousePreview := true;.
Another solution would be assigning a generic handler that translates coordinates and calls the forms handler; The assigning could be done in FormCreate.
But that's not as easy as it seems, because one TImage already has its own mouse event handlers.
I have tried OnMouseEnter and OnMouseLeave of the two panels but it didn't work; #1 disappeared, but #2 did not appear. I guess that's because if the mouse leaves Panel2, it should disappear - but it also leaves it if it enters a button on it.
That's why I'd like to use a coordinate based approach to make the check more reliable.
Maybe the two panel method is completely wrong?
Update: Yes, it is, as Remy said.
I am now using a TJVPageList because a TPageControl has visual tabs.
The OnMouseEnter handler of the PageList sets one page, the OnMouseLeave sets the other; But once the mouse moves over the PageList, both pages start flickering.
I have tried adding the event handlers to each page, too, but that made no difference.
Should I check all OnMouseEnter / Leave events to filter out the PageList, the two pages and all components sitting on the pages?
Another update: I am using a TPageControl now, but the behaviour is similar.
It doesn't flicker, but if I move the mouse ontop the TPageControl, no TTabSheet is displayed at all.
Only if I press down the left mousebutton, the UI sheet is displayed. The other sheet is displayed normally if I move away the mouse. (The TJVPageList displays the UI page if I press the left mousebutton, too.)
I have used the mouse event handlers (enter/leave) of the TPageControl and both TTabSheets.
Update 3:
Done it.
The static Panel / TabSheet / JvStandardPage (#1) must not trigger the OnMouseLeave handler.
What you describe might be better served using a single TPageControl instead of two TPanel controls. Use the TPageControl's own OnMouseEnter/Leave events (or intercept the CM_MOUSEENTER/LEAVE messages) to switch the TPageControl.ActivePage as needed.
I'm using Delphi7 and I'd like to have a ComboBox with separator items (Just like in popup menus).
I've seen this beautifully implemented in Mozilla Sunbird (I know, it's not Delphi...) the following way:
The separator item is a simple gray line
drawn in the center of the item
If you hover over the separator with
the mouse, the selection doesn't
appear
If the user clicks the separator,
it's not selected either AND the
combobox doesn't closeup.
No. 1 could be implemented using DrawItem. I could live without No. 2 because I have no idea about that.
For No. 3 I'm asking for your help. I've figured out that straight after closing up a CBN_CLOSEUP message is sent to the combobox.
I thought about hooking the window proc and if CBN_CLOSEUP is sent to a certain combobox then countering it. But I'm unsure if this is the best solution, or maybe there are other, more elegant ways?
Whatever the solution is, I'd like to have a standard ComboBox which supports WinXP/Vista/7 theming properly.
Thanks!
Edit: For a working component please see this thread:
Can you help translating this very small C++ component to Delphi?
I played around with making unclickable separator items (as described in this answer) and ran into several UI glitches. The problem is that combo boxes have several aspects to their behavior that can be hard to get exactly right:
Pressing the up and down arrow keys navigates the list while the list is dropped down.
Pressing Enter closes the dropped down list, selecting the current item.
Pressing Escape closes the dropped down list, selecting the current item (if the current item was chosen with the up and down arrow keys) or the last selected item.
If the combo box has the focus, then pressing the up and down arrow keys to changes the current selection without displaying the list.
If the combo box has the focus, then typing anything selects the combo box item matching whatever is typing.
If the combo box has the focus, then pressing F4 drops down the combo box list, which can then be controlled by keyboard or mouse.
Ensuring that disabled separator items don't respond to any of these events (plus any other events which I may be missing, e.g., screen readers?) seems fraught with error.
Instead, the approach I'm using is to draw the separator as part of the item:
Use a variable height owner draw combo box.
Add 3 pixels to the height for any items that need separators.
Draw a horizontal line at the top of each item needing a separator.
Here's some C++Builder code to accomplish this; translating it to Delphi should be easy enough.
void __fastcall TForm1::ComboBox1DrawItem(TWinControl *Control,
int Index, TRect &Rect, TOwnerDrawState State)
{
bool draw_separator = NeedsSeparator(Index) &&
!State.Contains(odComboBoxEdit);
TCanvas *canvas = dynamic_cast<TCustomCombo*>(Control)->Canvas;
canvas->FillRect(Rect);
TRect text_rect = Rect;
// Add space for separator if needed.
if (draw_separator) {
text_rect.Top += 3;
}
canvas->TextOut(text_rect.Left + 3,
(text_rect.Top + text_rect.Bottom) / 2 -
canvas->TextHeight(ComboBox1->Items->Strings[Index]) / 2),
ComboBox1->Items->Strings[Index]);
// Draw a separator line above the item if needed.
if (draw_separator) {
canvas->Pen->Color = canvas->Font->Color;
canvas->MoveTo(Rect.Left, Rect.Top + 1);
canvas->LineTo(Rect.Right, Rect.Top + 1);
}
}
void __fastcall TForm1::ComboBox1MeasureItem(
TWinControl * /* Control */, int Index, int &Height)
{
Height = ComboBox1->ItemHeight;
// Add space for the separator if needed.
if (Index != -1 && NeedsSeparator(Index)) {
Height += 3;
}
}
What you want is an owner-drawn combobox. See this: http://delphi.about.com/od/vclusing/a/drawincombobox.htm
Also, this seems to solve making the item unclicable:
http://borland.newsgroups.archived.at/public.delphi.vcl.components.using.win32/200708/0708225320.html
As far as I know there is no VCL way of doing that, so you'll have to subclass the combobox. It would be nice to create component encapsulating those functionalities so you can reuse them easily.
God bless
If you want your controls to look good use the free SpTBXLib. It supports combo style components which popup a popup menu with lines.