I am writing a Windows C++ app which I would like to have detect a keypress (for this example, using the letter 'S'). When the key is pressed, the program should switch a bool value either on or off (depending on its current state).
I know that in console apps you can use cin.get, but I'm unfamiliar with the Win32 API. I also would like to be sure that when the key is pressed, the event is only registered once, i.e. if the user presses 'S' but holds the key down for a while, the program should detect only 'S'; not 'SSSSSSS'.
So you have a windows message loop going, right? Capture WM_KEYDOWN and check whether it's on autorepeat.
But I'd guess you are actually using a framework, be it MFC, QT or something else. The framework will wrap your windows message loop and allow you to capture key events, but if you want us to tell you how, you'll have to say what framework you're using.
Related
I am writing a win32 application that needs to take hotkeys while not on focus(it runs in the background without drawing a window). I use RegisterHotKey to assing a few keys but that blocks the for every other process. For example I assign the 'c' key and when I press it in notepad nothing happens.
RegisterHotKey() registers global hotkeys. Hotkeys are processed before regular keyboard input processing, meaning that if you register a hotkey successfully, pressing that key will result in you getting your hotkey message rather than the app with focus getting the normal WM_KEYDOWN/WM_CHAR messages. You have effectively blocked other apps from seeing that key press.
This is by design.
Obviously the solution to avoid clashes like you describe is to not register a hotkey that other applications may use. If you register C without any qualifiers as a hotkey, then no other program will see the C key being pressed. Instead you should use qualifiers like Ctrl/Shift/Alt to prevent your hotkey from interfering with the normal use of the keyboard.
There is no way to register a hotkey that's global unless some other program is active. If you want to achieve the situation where, say, your hotkey works while the desktop is active but nothing else is, you could use a message hook to inject code into the desktop's process (via SetWindowsHookEx()) and intercept key presses that way. But you can't do it with RegisterHotKey().
I just tried UnregisterHotKey(), simulated the key with keybd_event(), then RegisterHotKey() again. I don't recommend it as a production code, it's probably better to use hooks for that, but as a quick hack I just wanted to say that it works.
GetAsyncKeyState()
can be used to determine if certain keys are pressed, even when the program is running in the background.
Alright, I want to write a program that intercepts mouse and keyboard events before they are reported to the active window/application, whatever that may be. Based on my program logic I want to be able to send custom key events.
For example: When the mouse button is held down, for any key press, send the next alphabetical letter. So if I hold down the right mouse button and hit 'a', the application sees it as a 'b' keypress.
I have briefly researched hooks and methods of intercepting WinAPI messages, and I'm unclear as to whether this is the solution I am looking for or not. According to what I've read, some of these solutions require you to inject a DLL into the desired application; my program needs to work for any running application.
Also, I have noticed that most of these solutions are in C#. As a matter of personal preference I would like to use C++ to write this program. Is there any reason why I would need to use C#?
Any pointers or advice is appreciated.
I'm writing a console application with Qt Creator and I must know if a key is pressed (or not) and make the true decision, but how could I know?
should i write a function to do this purpose ?
Have a look at QKeyEvent and google for some tutorials like this one.
How to do it depends on the operating system. For example, when you press the P key while playing a video game on your Windows PC, the game pauses. How does the game know to pause? The game is monitoring the state of the P key in a loop. Like all keys, the P key has two states (up or down). When the state changes, the key has been pressed or released. Passive keystroke loggers work this way, except they monitor all the keys, not just one.
Use QShortcut. Refer to the Qt doc for usage
I'm trying to create a simple bot in Qt and need therefor a way of simulating keyboard presses OUTSIDE the Qt application itself.
I've successfully made this possible by using the "old" keybd_event
keybd_event(Qt::Key_A,0,0, 0); // Pressing the 'A-button"
and that works out fine. But i can't make it when i'm trying to execute a 'select all' command which needs two buttons to be pressed at once.
As i researched the problem on Google i was refereed to the 'SendInput' function with the message 'This function (keybd_event) has been superseded. Use SendInput instead.'
The problem now is that I've little knowledge of windows API and especially in the contex of "Qt" and would like guidance on how to get started.
keybd_event is actually not Qt function, but part of Windows Api.
Both keybd_event and SendInput allow you to send press event and release event. If you want to send combination ctrl+A you should send events as follows:
press Ctrl -> press A -> release A -> release Ctrl
If you want to use keybd_event, you need to call it 4 times subsequently, if you want to use SendInput, you can make an array of 4 events.
You should use keyboard codes from Windows API to simulate keyboard events, while Qt's codes may coincide with Microsoft's.
Also you should understand that this solution has nothing to do with Qt, it Windows specified.
You just found all links to docs you would need, I think you should start studing it and ask more concrete questions, if you would have any problems.
The down arrow key of my laptop is very loose and it does not seems to last very long.
Is it possible to write any programm(in any language but especially C++) hat simulates the down arrow key.say I made a programm such that when I press A,B,C on the key board it simulates down arrow key.
If not then,
Is there any software available to do this?
Use the On-screen keyboard
If you want to simulate input, use the SendInput API. This injects input at a fairly low level, windows automatically routes it to the appropriate thread based on who has focus. Call it twice, once to send the key down, and again to send the key up.
Perhaps the easiest thing to do is to write a simple app that calls RegisterHotkey for some combination like ctrl-alt-Z, and then calls SendInput for a keypress then keyrelease of the down arrow key.
You might need to wait a short time after receiving WM_HOTKEY to give you time to release the set of hotkeys so that the down arrow gets processed alone without those modifiers from your hotkey interfering with it. (...otherwise the focused app might think you typed in shift+alt+downarrow instead of plain downarrow!)
if you're using linux, xmodmap: http://www.xfree86.org/4.2.0/xmodmap.1.html
I think that you are actually looking for Sharpkeys www.randyrants.com/sharpkeys/
This works with the windows registry and can be used to change mappings of keys.
You can easily write a program that sends WM_KEYDOWN and WM_KEYUP messages to the window which has the current focus. Once you have this program, bind it to a function key in the properties for the .exe file.