I'd like to use a function in some matlab scripts that would do the following:
Pause until user hits any single key
Return the key stroke hit by the user
The pause function doesn't work, because it doesn't return the user keystroke. The input function doesn't work, because it requires the "enter" key to be hit. The keyboard command dumps you into the full command line window which I don't want (although might be useful for future work). Note, there are ways to do this from figures, i.e. if a figure has focus, you can sniff keystrokes using the 'KeyPressFcn' handler. But I want to do this from scripts. Worst case, I can use the input command, but was hoping for something that required fewer keystrokes from the user.
I found this on MathWorks. Does it do what you want: http://www.mathworks.com/matlabcentral/fileexchange/7465-getkey
Related
I wrote a simple script to track keys being pressed and released as shown below:
$j = 0
while($j -lt 10000){
$PressedKey = $Host.UI.RawUI.ReadKey("NoEcho,IncludeKeyDown,IncludeKeyUp")
$PressedKey
continue
}
When I run it and start pressing keys, it works. However when I switch to a different Instance or Window and start pressing keys, it stops giving an output. I assume this is because it stops tracking the keystrokes, can't produce an output, or both. Does anyone know any good alternatives to ReadKey() to how to make it track keystrokes on other Windows and/or Instances
I believe this is PowerShell 7
thx.
The object $Host refers to the current PowerShell console host. Therefore, connecting to the ReadKey() method will only return the current PowerShell host keystrokes, and that is the point of the ReadKey() method, return the current host's keystrokes so that other functions (e.g. PSReadline) can act on them.
If you want to globally respond to keystrokes across applications, I personally recommend AutoHotKey. It is fairly easy to create a script that will detect a key combination and perform an action. It is fast and easy to use and I have dozens of key combinations that I have scripted and use every day.
It is possible to create PowerShell scripts that globally hook into keyboard keystrokes and respond to events, but this is beyond the scope of a SO post.
As stated in MATLAB's FAQ,
1.3.3.1. Why, when I edit a function file in MATLAB, is the change not seen by MATLAB until everything is cleared or MATLAB is restarted?
When you write an M-file in MATLAB, you can either write a script or a
function. The difference is that a script is read from the disk and
parsed line by line each time it is called. A function is loaded into
RAM for execution. Because it is loaded into RAM, when you edit a
function, that change is not loaded into RAM until a call to the new
function is made.
To get MATLAB to recognize your edited function, type
clear functions to clear all functions, or
clear <function name> to clear just your function out of RAM.
This is a major pain when I'm developing a function & editing it repeatedly (I use an external editor most of the time). I was thinking of putting in a final line, at least during debug, like
clear(myfunc)
but I'm concerned about unwanted side effects. Does anyone know if there are any?
Further, I'd rather have a way to configure MATLAB so it doesn't automatically store called functions in RAM once the top-level function (i.e. the one called from the console) terminates. Is that even possible?
EDIT: I should mention that MATLAB's behavior is inconsistent. Sometimes my edits take effect once I save the m-file, other times they don't even if I'm editing with the MATLAB IDE editor window.
In all honesty MATLAB has a very powerful editor so you really should
be using it. It will make you life easier. (just an opinion)
Unless you are running the code by stepping through it no change to code will be run until the code is re-run (preferably with a cleared workspace).
clear(myfunc) will clear the variables created by that function in upto that point. You can add at the end of any function or script clear variableA variableB for all variables you want cleared at the end. This will give you control to only clear what you want. Once variables are cleared the only effect will be that if those variables are called again later in the code an error will occur since they no longer exist.
If your simply testing that particular function and want to save time by not calling inputs each time and want to clear the workspace and command window at the same time. You can add the following code just beneath the function definition.
If you leave the following code and call the function from another function or script, the code will be ignored as long as the inputs are available to it externally. Anything you add to the if statement will only occur when you call the function with no inputs doc nargin. You could add it to the top level function and you would simply press the run button or f5 without having to type in the command window to run the code.
function [ output1, output2 ] = blah( input1, input2 )
if nargin == 0
clc
clear all
%above two lines will clear the workspace and command window when you run
%the function
%define function inputs
%(optionally add the following to behave as if you inserted a breakpoint
%in the location just before the error occurred (great for debugging)
db stop if error
end
*you can also add a short-cut to snippets of code up in the top right of the MATLAB interface to clear the workspace etc when they are clicked.
Hackish* idea for this:
I'd rather have a way to configure MATLAB so it doesn't automatically store called functions in RAM once the top-level function (i.e. the one called from the console) terminates. Is that even possible?
* This is the sort of thing I might use, while advising others on why it is a bad idea, also probably uses undocumented (thus unreliable) things.
Specifically if your using an external editor I guess your going to have to click on the command window to run the function...
commandWindowHandle = ...
handle(com.mathworks.mde.desk.MLDesktop.getInstance.getClient('Command Window'...
.getComponent(0).getComponent(0).getComponent(0),'CallbackProperties');
commandWindowHandle.MouseClickedCallback = 'clear functions'
It doesn't clear the function definitions on exiting a function rather on clicking on the command window
note: the callback will not fire if a function is currently running
For a potentially more reliable but more wasteful version:
commandWindowHandle.KeyPressedCallback= 'clear functions'
will help* ensure definitions are clear, but is wasteful as every keystroke will run 'clear functions'... although after one keystroke this will be quicker as there will be no functions in memory!
* No guarantee I know there are ways in which this could fail... having at least 1 keystroke in the command window after the previous function call has finished would be advisable!
To disable these set the callback to empty string ''
commandWindowHandle.MouseClickedCallback = ''
commandWindowHandle.KeyPressedCallback= ''
In Matlab I can start external .exe files that sometime have a pop up that requires an enter key pressed. For example:
system('C:\Program Files (x86)\WinZip\WINZIP32.EXE')
will start Winzip, and then in order to use it you need to pass the "buy now" pop up window by pressing enter.
Now my problem is not with winzip, I only gave it as an example (i use winrar anyway :).
How can I programmatically press an enter key in Matlab in such cases ? (I use win 7)
Can an event listener be used to solve that?
EDIT: The java.awt.Robot class indeed works on explorer, but not on any software that has a pop up window with an OK button that needs to be pressed. I don't know why it doesn't work for that. I gave the winzip example because I assume everybody has winzip/winrar installed in their machine. The actual software I have is different and irrelevant for the question.
There is a way using Java from Matlab, specifically the java.awt.Robot class. See here.
Apparently there are two types of programs, regarding the way they work when called from Matlab with system('...'):
For some programs, Matlab waits until the program has finished before running the next statement. This happens for example with WinRAR (at least in my Windows 7 machine).
For other programs this doesn't happen, and Matlab proceeds with the next statement right after the external program has been started. An example of this type is explorer (the standard Windows file explorer).
Now, it is possible to return execution to Matlab immediately even for type 1 programs: just add & at the end of the string passed to system. This is standard in Linux Bash shell, and it also works in Windows, as discussed here.
So, you would proceed as follows:
robot = java.awt.Robot;
command = '"C:\Program Files (x86)\WinRAR\WinRAR"'; %// external program; full path
system([command ' &']); %// note: ' &' at the end
pause(5) %// allow some time for the external program to start
robot.keyPress (java.awt.event.KeyEvent.VK_ENTER); %// press "enter" key
robot.keyRelease (java.awt.event.KeyEvent.VK_ENTER); %// release "enter" key
If your applications are only on Windows platform, you can try using .net objects.
The SendWait method of the SendKeys objects allows to send virtually any key, or key combination, to the application which has the focus, including the "modifier" keys like Alt, Shift, Ctrl etc ...
The first thing to do is to import the .net library, then the full syntax to send the ENTER key would be:
NET.addAssembly('System.Windows.Forms');
System.Windows.Forms.SendKeys.SendWait('{ENTER}'); %// send the key "ENTER"
If you only do it once the full syntax is OK. If you plan to make extensive use of the command, you can help yourself with an anonymous helper function.
A little example with notepad
%% // import the .NET assembly and define helper function
NET.addAssembly('System.Windows.Forms');
sendkey = #(strkey) System.Windows.Forms.SendKeys.SendWait(strkey) ;
%% // prepare a few things to send to the notepad
str1 = 'Hello World' ;
str2 = 'OMG ... my notepad is alive' ;
file2save = [pwd '\SelfSaveTest.txt'] ;
if exist(file2save,'file')==2 ; delete(file2save) ; end %// this is just in case you run the test multiple times.
%% // go for it
%// write a few things, save the file then close it.
system('notepad &') ; %// Start notepad, without matlab waiting for the return value
sendkey(str1) %// send a full string to the notepad
sendkey('{ENTER}'); %// send the {ENTER} key
sendkey(str2) %// send another full string to the notepad
sendkey('{! 3}'); %// note how you can REPEAT a key send instruction
sendkey('%(FA)'); %// Send key combination to open the "save as..." dialog
pause(1) %// little pause to make sure your hard drive is ready before continuing
sendkey(file2save); %// Send the name (full path) of the file to save to the dialog
sendkey('{ENTER}'); %// validate
pause(3) %// just wait a bit so you can see you file is now saved (check the titlebar of the notepad)
sendkey('%(FX)'); %// Bye bye ... close the Notepad
As explained in the Microsoft documentation the SendKeys class may have some timing issues sometimes so if you want to do complex manipulations (like Tab multiple times to change the button you actually want to press), you may have to introduce a pause in your Matlab calls to SendKeys.
Try without first, but don't forget you are managing a process from another without any synchronization between them, so timing all that can require a bit of trial and error before you get it right, at least for complex sequences (simple one should be straightforward).
In my case above for example I am running all my data from an external hard drive with an ECO function which puts it into standby, so when I called the "save as..." dialog, it takes time for it to display because the HDD has to wake up. If I didn't introduce the pause(1), sometimes the file path would be imcomplete (the first part of the path was send before the dialog had the focus).
Also, do not forget the & character when you execute the external program. All credit to Luis Mendo for highlighting it. (I tend to forget how important it is because I use it by default. I only omit it if I have to specifically wait for a return value from the program, otherwise I let it run on its own)
The special characters have a special code. Here are a few:
Shift +
Control (Ctrl) ^
Alt %
Tab {TAB}
Backspace {BACKSPACE}, {BS}, or {BKSP}
Validation {ENTER} or ~ (a tilde)
Ins Or Insert {INSERT} or {INS}
Delete {DELETE} or {DEL}
Text Navigation {HOME} {END} {PGDN} {PGUP}
Arrow Keys {UP} {RIGHT} {DOWN} {LEFT}
Escape {ESC}
Function Keys {F1} ... {F16}
Print Screen {PRTSC}
Break {BREAK}
The full list from Microsoft can be found here
There is a small javascript utility that simulates keystrokes like this on the Windows javascript interpreter.
Just create a js file with following code:
var WshShell = WScript.CreateObject("WScript.Shell");
WshShell.SendKeys(WScript.Arguments(0));
then call it from Matlab after the necessary timeout like this:
system('c:\my\js\file\script.js {Enter}');
Can't test here now, but I think this should work...
If you need to run a console-only program in a context that permits full DOS redirection, you can create a file called, say, CR.txt containing a carriage return and use the '<' notation to pipe the value into the program.
This only works if you can provide all the keyboard input can be recorded in the file. It fails dismally if the input has to vary based on responses.
An alternative is to duplicate the input (and possibly output) stream(s) for the program and then pipe data into and out of the program. This is more robust and can permit dynamic responses to the data, but will also likely require substantial effort to implement a robot user to the application.
Rog-O-Matic is an example of a large application completely controlled by a program that monitors screen output and simulates keyboard input to play an early (1980s) ASCII graphic adventure game.
The other responses will be required for GUI-based applications.
Python package pywinauto can wait any dialog and click buttons automatically. But it's capable for native and some .NET applications only. You may have problems with pressing WPF button (maybe QT button is clickable - not checked), but in such case code like app.DialogTitle.wait('ready').set_focus(); app.DialogTitle.type_keys('{ENTER}') may help. Your case is quite simple and probably some tricks with pywinauto are enough. Is your "app with popup" 64-bit or 32-bit?
wait and wait_not functions have timeout parameter. But if you need precisely listener with potentially infinite loop awaiting popups, good direction is global Windows hooks (pyHook can listen mouse and keybd events, but cannot listen dialog opening). I'll try to find my prototype that can detect new windows. It uses UI Automation API event handlers... and... ops... it requires IronPython. I still don't know how to set UI Automation handler with COM interface from standard CPython.
EDIT (2019, January): new module win32hooks was implemented in pywinauto a while ago. Example of usage is here: examples/hook_and_listen.py.
This question already has answers here:
Stop and continue execution from debugger possible?
(6 answers)
Closed 8 years ago.
Strg+C stops and kills a Matlab script (at least sometimes). But is there a way to stop a Matlab, take a look at some variables and continue the calculation?
I am not talking about just setting a breakpoint. I want my script, let’s say run for couple hours come back to it hit some buttons that stops the calculations take a look at some variable and then continue the calculation.
I tried to find out if there is some shortcut key for this – I am quite sure there isn’t.
Now I was thinking about including an if-case that looks if a certain button was pressed by the user. If so there would be a useless k=0 line and a breakpoint on it. And if no one is pressing this button the loop would continue. But this is where my limited Matlab knowledge leaves me. I don’t know if there is a way to ask for a user-button press but don’t wait for a button press like in the function input. Also I just have a running script, I don’t have any GUI.
To drop to the command prompt you need the command keyboard and then type return when you have finished (you don't need a breakpoint). The tricky bit is how to trigger it. There a few options. The easiest is to open a figure window. The following code halts the process when any key is pressed.
keyDownListener=#(src,event) keyboard;
fig = figure;
drawnow
set(fig,'KeyPressFcn',keyDownListener)
for p=1:10000
%do some thing
end
You can modify this to test for a specific key since the keypress is contained within the event struct.
To use no figure gui at all its more of a problem. I'm not aware of a non blocking keyboard input method. A mex file the runs kbhit() in C might do it, but kbhit() is not standard C so it would only work on Windows. An easier option maybe to test for the presence of a file.
for p=1:100000
if exist(fullfile(pwd,'halt.tmp'),'file')
keyboard
end
%do something here
end
This drops to the debug console when halt.tmp is created in the current directory.
Other potential methods could involve using multiple threads to read 'input' (either the Parallel computer toolbox or undocumented Java code), or using http://psychtoolbox.org/ as mentioned by #bdecaf
I have a simple question, although it's harder than it seems; I couldn't find the answer on the interwebs :O
I'm writing a script in Matlab. What I want to do is the following:
When I press the esc key, I want a helpdialogue to pop up, so my script pauses. (So when I press esc, I want to stop the whole script to run so that the car (which im writing the script for) stops driving)
How do I do this? How can I say to Matlab: When I press esc, do this...
Thanks for your time guys!
EDIT: It's no option to implement something which awaits the keypress. Im writing a script for a driving car. It just has to drive around basically, but when I press esc for example, it should stop driving. So the script just has to run, untill I press the esc key; then the script has to pause.
KeyPressFcn is good because it forces you to write event-driven code. Which is generally a good idea! However, if KeyPressFcn doesn't seem right for you, for example if you must keep running in a loop, and you just want to poll whether a key has been pressed, I found this solution buried in the matlab website:
get(gcf,'CurrentCharacter')
Then you could set this property to a blank, and poll it as required.
e.g:
finish=false;
set(gcf,'CurrentCharacter','#'); % set to a dummy character
while ~finish
% do things in loop...
% check for keys
k=get(gcf,'CurrentCharacter');
if k~='#' % has it changed from the dummy character?
set(gcf,'CurrentCharacter','#'); % reset the character
% now process the key as required
if k=='q', finish=true; end
end
end
This worked well for me in 2014b. The downside is that the graphics window needs to be focused to receive the key events.
In a matlab figure you can define a 'KeyPressFcn' that works similar to do what you ask.
If you are in the console you have to work around that matlab is single threaded. Basically you need to halt the program flow to check for key presses.
btw - also when you use 'KeyPressFcn' you will need to make some pauses so that Matlab will check if anything has happened.
btw2 - I should also add during this pauses Matlab will not only read your key presses - but also do some housekeeping such as redrawing its window and stuff.
I frequently ran into similar use cases and typically preferred to react to joystick buttons because of the more convenient interface provided by vrjoystick. However, I recently wrote a library that provides a similar interface for keyboard inputs.
% Pause on ESC
kb = HebiKeyboard();
while true
state = read(kb);
if state.ESC
% PAUSE DRIVING
else
% DRIVE CAR
end
end
It's non-blocking and doesn't require focus on any particular figure.
File Exchange: http://mathworks.com/matlabcentral/fileexchange/61306-hebirobotics-matlabinput
Github: https://github.com/HebiRobotics/MatlabInput
I had a related task once, and i did it with getkey form matlab file exchange.
Basicly you will want to have it listen for ascii 1B (27 decimal)
if getkey does not solve your problem you can still have a look at its code and maybe find the line that will do the trick for you.