It is possible to read the following in the apple Documentation:
UIKeyboardFrameBeginUserInfoKey
The key for an NSValue object containing a CGRect that identifies the start frame of the keyboard ……
UIKeyboardFrameEndUserInfoKey
The key for an NSValue object containing a CGRect that identifies the end frame of the keyboard ……
Would that mean that the keyboard has a "start frame" and an "end frame"?
I suppose YES.
But when the keyboard appears I cannot see any frame changing. It just stays the same frome start to end.
So my question is:
What are those "start frame" and "end frame" referring to?
I must be missing something.
Thanks for your help.
The keyboard does indeed have a start and end frame, and the properties do exactly what you suppose they do. They keyboard does not always animate however; sometimes it just appears or changes size. For example, in the case that you are typing on the Japanese keyboard, when the keyboardWillShow fires after the first character is hit. There's no animation, but an additional bar appears above the keyboard, thus changing the size. The properties you listed above tell you how much the keyboard changed size by.
I'm not sure what exactly you're looking at when you say no frames are changing. I suppose it's possible that when you move from one editable text field to another, you get a keyboardWillShow notification, even though nothing on the screen changes.
Related
I am programming a GUI in plain C using X11 library, on Cygwin. When trying to read cursor movements over an open window using XMaskEvent() it works like a charm. It returns an XEvent structure whose coordinates point to the current mouse location and the event_type is a small positive integer number that corresponds to what happened (mouse move, button press, button release etc). So far so good. The problem is that this command blocks (it is supposed to) after each mouse move or button event so my program cannot do anything continuous.
So I tried to replace XMaskEvent() with XCheckMaskEvent() which should read an event, remove it from the queue and continue, so that my program can continue doing something. However, XCheckMaskEvent returns an event with zero coordinates, and constant crazy event_type of minus million-something. Whatever i do with the mouse or keyboard, I am always getting an empty event of a crazy type.
I am using the same event mask for both commands.
What am I doing wrong?
When I start up my PyQt GUI, the focus immediately goes to the text box.
I want there to be no focus on any of the buttons at the start of the program, especially not the text box.
Is there a way to remove the focus entirely or at least move the focus to a button or something?
Thanks
clearFocus() seems to work after a certain amount of delay after the window is visible. I also used setFocus() on the QMainWindow and then the textedit field lost focus.
Create a button with dimensions 0 wide by 0 high.
Set it as the default button and also early in the tab order before the other controlls that except focus; but note that it will be triggered if the user presses ENTER in some edit controls.
Call self.ui.yourbutton.setFocus() if desired for example after restore from minimized
I have a (multiline) text indicator in my program where I display everything that my program does. Every time after adding new string to the indicator, I move the vertical scroll bar to the end to make sure that the user will see the message instantaneously. It works fine.
However, when there is a lot of text in the indicator, the user is unable to move the scroll bar. Also, the scroll bar doesn't move to the bottom of the indicator after adding a new message.
How can I increase the capacity of my text indicator? Is it even possible or do I have to decrease the amount of text I display?
The rest of the program works well, the screen doesn't freeze. The only problem I have is that the vertical scroll bar doesn't work properly.
LabVIEW stores strings as a pointer to a structure containing a 4-byte length value followed by a 1D array of byte integers (8-bit characters). The 4-byte value is the same size as a U32, which has a 2^32 range (0 to 4,294,967,295). So, your string can have up to 4,294,967,295 characters.
About the second part of your question: http://digital.ni.com/public.nsf/allkb/E888D1D6A739A787862571F800586482
Put a gigantic amount of text in your indicator while the VI is in edit mode. Can you move the scrollbar then? If you can, then I suspect the problem is how you're adjusting the scrollbar at run time. Is it possible that you're continuously setting the scroll position to the bottom so your user tries to drag it and fails?
I have a program which displays a ruler on the screen, and with Xlib it polls for the cursor position every 100ms and updates the display. The display consists of numbers/lines etc, in particular a line indicating the position of the cursor (which is why it updates).
The problem is that the old line needs to be erased and the content underneath restored, so I have to redraw the whole window to reflect a change in position. Doing this 10 times a second results in a very flickery program.
I could only redraw the ruler after I have confirmed that the cursor is in a position to change the indicator line (i.e. within the bounds of the ruler), but it would still flicker pretty bad when it was updating.
Sort of a noob to GTK and Xlib and all, any advice would be appreciated.
Code is at https://github.com/zjmichen/zRuler
Well you have arrived at one of the earliest problems faced when cursors were being implemented!! Cursor changes are so frequent that redrawing full window every time just doesn't make any sense! Coming to your problem, look at what is needed & what exactly you are doing. Do you need to update the full window when cursor moves? No. You need to update only a section of the window so don't update the whole window. Off the top, I can think of 2 ways of reducing flicker:
1. Simple way is to make use of GdkCursor. Create a new cursor from the pixmap (Sample provided on the developer page) with the shape of your need, a line in your case. Associate cursor with the GdkWindow of your application's main window. This way you don't have to track cursor & draw the line. The cursor itself will appear as the line (so you don't to bother about clearing & redrawing it). Now in the timer callback where you redraw the complete window, redraw only the component which has to be updated on cursor position change. This should hopefully reduce the flicker as you are not drawing all the components.
2. In case you don't want to use GdkCursor, you could create a separate transparent window on top of application window dedicated to cursor. In this approach you can update only the cursor window & the component in the application window which is to updated on change in cursor position. This way other components in the application window are not redrawn each time & this hopefully should also be able to reduce flicker.
Hope this helps!
Greetings.
I have to make a draggable MFC dialog window, which has a background - used that: http://www.codeproject.com/KB/graphics/picturewindow.aspx - and has several picturebox controls. I have tried two approaches, and while they do work, they have some problems.
First approach is "Manual" - on the LBUTTONDOWN message I check if it;s on a clean area of my window, and set a flag variable. On MOUSEMOVE, the flag is checked and if it's set, a MoveWindow function is called, and then, Invalidate(1). On LBUTTONUP, flag is unset.
This approach works correctly and redraws as needed, but is somehow very slow - if I'm moving the cursor too fast, the window falls behing and isn't dragged, as cursor's not over the window anymore.
The second approach is "Automatic" - I just call
DefWindowProc(WM_SYSCOMMAND, SC_MOVE+2,MAKELPARAM(point.x,point.y));
on LBUTTONDOWN, and it handles the rest, it's quick and never fall behind, but when I drag it over screen's edge ( so that some part of the window gets invisible), when I drag it back, all the controls get invisible and are not refreshed, background is okay. I suppose that's because Invalidate() isn't called during movement that way, as I actually call it after calling DefWindowProc() and so, everything is refreshed properly when I depress the button.
What should I do to improve either of those solutions? I need it both fast and correct. I may have not provided some required information, I'll add it is need arise.
Thanks in advance.
Solved the problem, by modifying the second way. I added a total redraw to the OnPaint(), and to get rid of flicker, I only redraw durng dragging, by using a flag variable.