How to clear CurrentCharacter

I am trying to cycle through a few different figures within the same figure window. I have a few while and if loops with counters and flags. I current waits for the first key press to switch to the next figure, then after a key has been pressed, it just cycles through the figures forever. I stepped through my code and believe the issue is due to the CurrentCharacter object/veriable not resting after a key is pressed.

I tried setting it to zero, but after the first keypress, it always contains something, causing isempty to always return 1, thus causing the loop to switch to the other figure.

Z = 1;
ZZ = 1;
forever = 1; 
while forever
      
     while Z == 1
         if ZZ == 1
            %figure('units','normalized','outerposition',[0 0 1 1]);
            figure(10),clf;
            hold on;
            h = figure(10);  

            plot(waveform.XData,waveform.YData);
            set(gca,'XTick',(min(waveform.XData):waveform.SecPerDiv:max(waveform.XData)))
            hold off;
            drawnow
            ZZ = 0;
        end
        pause(0.1);  
        isKeyPressed = ~isempty(get(h,'CurrentCharacter'));
        if isKeyPressed
            Z = Z+1;
            ZZ = 1;
            isKeyPressed = 0;
            CurrentCharacter = '';
        end           
    end

    while Z == 2
        if ZZ == 1
            %figure('units','normalized','outerposition',[0 0 1 1]);
            figure(10),clf;
            hold on;
            plot(H,AllFFT_mean,'DisplayName','Oscilloscope Measured Signal'); hold on;
            stem(X2,triH,':^m','BaseValue',-140); hold on;
            stem(X2,sqrH,':sr','BaseValue',-140); hold on;
            grid minor;
            xlim([0 2020]);
            hold off;
            drawnow
            ZZ = 0;
        end
          
        isKeyPressed = ~isempty(get(h,'CurrentCharacter'));
        if isKeyPressed
            Z = Z-1;
            ZZ = 1;
            CurrentCharacter = '';
        end     
            
    end
end 

I need to set [get(h,'CurrentCharacter')] to nothing.

I tried set(h,'CurrentCharacter',' ') to manually change the object properties. This does allow me to change the value in the keypress array but does not allow me to set it to '' or clear it.

I'm trying to have my code switch between multiple different figures with a single switch from a single keypress. Anyother methods to achive this would help.

Thanks

Answer 1

[Mohith Kulkarni]

You can use a temporary figure to check for key press. Refer to the code below for a workaround

if Z == 1    
    if ZZ == 1
        tempf = figure('Visible','off');
        loop = true;
        while loop
            figure(tempf);
            pause % wait for a keypress
            isKeyPressed = ~isempty(get(tempf,'CurrentCharacter'));
            if isKeyPressed
                loop = false;
                Z = Z+1;
                ZZ = 1;
            end
        end
        delete(tempf);    
    end
end

Also, do notice that i have taken the while loop to check for key press inside the if condition, instead of while Z == 1 i have used if Z == 1 and pushed the while loop inside.

Or you can use a KeyPressFunction Callback. Refer to the code below:

forever = 1; 

XData = [1 2 3 4];
YData = [3 5 7 9];

XData2 = [5 6 7 8];
YData2 = [3 5 7 9];

h = figure(10);
data.A = [1,1];
%data.ZZ = 1;
guidata(h,data);
set(h,'KeyPressFcn', {@key_pressed_fcn});

while forever
      
     if data.A(1) == 1
         if data.A(2) == 1
            %figure('units','normalized','outerposition',[0 0 1 1]);
            figure(10),clf;
            hold on;
            h = figure(10);  
            plot(XData,YData);
            %set(gca,'XTick',(minXData):waveform.SecPerDiv:max(waveform.XData)))
            hold off;
            drawnow
            data.A(2) = 0;
            guidata(h,data);
         end
         
         while data.A(1) == 1
           data = guidata(h);
           pause(0.5);
         end
     end
        
     if data.A(1) == 2
        if data.A(2) == 1
            %figure('units','normalized','outerposition',[0 0 1 1]);
            figure(10),clf;
            hold on;
            %plot(H,AllFFT_mean,'DisplayName','Oscilloscope Measured Signal'); hold on;
            plot(XData2,YData2);
            %stem(X2,triH,':^m','BaseValue',-140); hold on;
            %stem(X2,sqrH,':sr','BaseValue',-140); hold on;
            grid minor;
            %xlim([0 2020]);
            hold off;
            drawnow
            data.A(2) = 0;
            guidata(h,data);
        end
        while data.A(1) == 2
            data = guidata(h);
            pause(0.5)
        end   
     end 
end 
set(h,'KeyPressFcn', 'remove');


function key_pressed_fcn(h,~)
    disp('pressed')
    data = guidata(h);
    if data.A(1) == 1
        disp('Z=1')
        data.A(1) = data.A(1)+1;
    elseif data.A(1) == 2
        disp('Z=2')
        data.A(1) = data.A(1)-1;
    end
    data.A(2) = 1;

    guidata(h,data);
    
end

Make sure to revert back the minor changes I made because I do not have the data for plotting, i used dummy data instead.

[Michael Andersson]

Yes, I changed a few things and it seems to be working a bit better for now. Will see if I can get it fully working when I get to it. Thanks