如何在Matlab中检测键盘空格键按下情况? [英] How to detect keyboard spacebar press in matlab？

问题描述

我想检测用户在5秒钟内单击空格键的次数

I want to detect how many times the user click spacebar in 5 seconds

是否有解决此问题的好方法?
谢谢

Is there any good way to fix this problem?
Thanks

推荐答案

一种轻松从键盘读取用户输入的方法是创建一个新图形并指定一个KeyPressFcn回调函数，如果有任何键被按下，该函数将自动执行.按下.

One way to easily read user inputs from the keyboard is to create a new figure and specify a KeyPressFcn callback function, which is executed automatically if any key is pressed.

让我们从创建一个新人物开始.因为我们不需要该图来显示任何东西，所以让它尽可能的小(即1乘1像素)并将其放置在显示器的下角:

Lets start off by creating a new figure. As we don't need the figure to display anything, let's make it as small as possible (i.e. 1 by 1 pixel) and place it at the lower corner of the display:

f = figure('Position',[0,0,1,1]);

现在，我们将图形的UserData属性(将用作计数器)设置为零:

Now we'll set the UserData property of the figure - which we will use as counter - to zero:

set(f,'UserData',0);

现在让我们看看按下键时的操作:我们可以创建一个小的回调函数，该函数检查被按下的按钮是否为空格，如果是这种情况，则增加UserData计数器.我们将其称为isspace:

Now let's see what to do when a key is pressed: We can create a small callback function which checks if the pressed button was a space and increases the UserData counter if that was the case. We'll call that function isspace:

function isspace(hObject,callbackData)
    if get(hObject,'CurrentCharacter') == ' '
        set(hObject,'UserData',get(hObject,'UserData')+1);
    end
end

现在只需设置图形即可将此功能用作KeyPressFcn，

Now simply set up the figure to use this function as KeyPressFcn by

set(f,'KeyPressFcn',@isspace);

这已经计算了按下空格的次数.计数器的当前值由

This already counts the number of times space is pressed. The current value of the counter is read by

get(f,'UserData');

现在我们需要时间测量.这可以使用timer完成.我们将其配置为在5秒钟后熄灭，然后在基本工作区中添加一个新值.为此，我们需要一个回调函数timerCallback.m

Now we need the time measurement. This can be done using a timer. We'll configure it to go off after 5 seconds and then assing a new value in the base workspace. For that we need a callback function timerCallback.m

function timerCallback(hObj,eventData)
    assignin('base','nSpace',get(gcf,'UserData'));
    delete(gcf);
    stop(hObj);
    delete(hObj);
end

t = timer('StartDelay',5,'TimerFcn',@timerCallback);
start(t);

就是这样:首先创建图形，创建计时器，然后在5秒钟后在工作区的变量nSpace中获得按键次数，并且窗口关闭.

And that's it: First create the figure, create the timer and after 5 seconds you get the number of key presses in the variable nSpace in your workspace and the window is closed.

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