how to cause a change in the colour of a push button every time it is pressed ?

Question

Dany Majed 2019-2-26

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评论： Robin Stengl 2019-12-9

how to insert a pushbutton in GUI that can change its color everytime the pushbutton is pressed. I need it to switch its color to another color

so for example: I need in first push change to green in second push into orange and after 6 colors have been placed i need it to repeat the same series of color back again after all 6 colors specified has been displayed then need to save its state. so how can i do that please ? .Thanks in advance.

% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)

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Answer 1

Kevin Phung 2019-2-26

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https://ww2.mathworks.cn/matlabcentral/answers/447166-how-to-cause-a-change-in-the-colour-of-a-push-button-every-time-it-is-pressed#answer_362866

编辑：Kevin Phung 2019-2-26

在 MATLAB Online 中打开

function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
colors = [ 1 0 0; 0 1 0; 0 0 1]  %this will be your array of colors
if hObject.UserData == size(colors,1)
    hObject.UserData = 0 %if it reaches the end, reset
end
hObject.UserData = hObject.UserData + 1; %stores this data within the button itself
state = hObject.UserData;
hObject.BackgroundColor = colors(state,:);
%note: ForegroundColor is the color of the string, BackgroundColor is the color of the button 

make sure you set the 'UserData property of your button to 0 for its initial state, example :

button = uicontrol('style','pushbutton',...
    'callback',@pushbutton1_Callback,...
    'UserData',0)

In this example, button will turn from red, green, blue, then the cycle repeats.

Can you be clear as to what you mean by 'saves its state?'

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Dany Majed 2019-2-26

编辑：Dany Majed 2019-2-26

在 MATLAB Online 中打开

% --- Executes on button press in pushbutton1.
function pushbutton1_Callback(hObject, eventdata, handles)
% hObject    handle to pushbutton1 (see GCBO)
% eventdata  reserved - to be defined in a future version of MATLAB
% handles    structure with handles and user data (see GUIDATA)
hObject.UserData = 0
colors = [ 1 0 0; 0 1 0; 0 0 1]  %this will be your array of colors
if hObject.UserData == size(colors,1)
    hObject.UserData = 0 %if it reaches the end, reset
end
hObject.UserData = hObject.UserData + 1; %stores this data within the button itself
state = hObject.UserData;
hObject.BackgroundColor = colors(state,:);
%note: ForegroundColor is the color of the string, BackgroundColor is the color of the button

This is my code exactly when i tried it now it changes color to red only then after further pushes it stays red which is the same

button = uicontrol('style','pushbutton',...
    'callback',@pushbutton1_Callback,...
    'UserData',0)

once i am adding this i am getting an error i don't know specifically why ? .

Thanks in advance. Your help is really appreciated

Kevin Phung 2019-2-27

编辑：Kevin Phung 2019-2-27

在 MATLAB Online 中打开

remove the line

hObject.UserData =0

from your callback function. it stays red because state is always equal to 1 (after 0 has been incremented), which is the row [1 0 0] (RED) in the color matrix.

I would like to emphasize that the 'UserData' should be set to 0 when you create your button:

button = uicontrol('style','pushbutton',...
    'callback',@pushbutton1_Callback,...
    'UserData',0)

When you click the button, it calls out your function (another m file I would assume), pushbutton1_callback.

You can see that the first thing the callback does is check the 'UserData' property. At first, it is 0. Then it increments as 1 and changes the color of the pushbutton to the 1st row of the color array, [1 0 0].

If you click it again, then UserData increments to 2 and grabs the 2nd row, [ 0 1 0], and so on until it reaches the end of the color sequence and gets reset back to 0 on its own.

so to recap,

if you copied the callback function exactly, and ran:

button = uicontrol('style','pushbutton',...
    'callback',@pushbutton1_Callback,...
    'UserData',0)

on its own, you will see that a figure will be created with the button, try pushing it and it should change colors accordingly.

Kevin Phung 2019-2-27

happy to have helped!

Robin Stengl 2019-12-9

Hey guys, i have the same problem with the length of the vector. And I have not got the line : hObject.UserData =0

what should i do now?

And where should i place the button = ... in my gui

Thank you for your help

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Answer 2

Steve Kulakowski 2019-2-26

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/447166-how-to-cause-a-change-in-the-colour-of-a-push-button-every-time-it-is-pressed#answer_362865

编辑：Steve Kulakowski 2019-2-26

在 MATLAB Online 中打开

Hello,

The way in which I know how to do it is as follows. You may have to tweak the code a little before it works properly, but the general idea is that you need a global variable outside of your function call. The if/else statement will toggle everytime the pushbutton is called. Also I'm sure there are other/better ways to do this, but this is the only way I know how.

Best of luck!

global control
control = 1
function pushbutton1_Callback(hObject, eventdata, handles)
global control
if control == 1
    set(handles.pushbutton,'BackgroundColor',[0 1 0]);
    control = 0
   
else
   set(handles.button_connect_s1,'BackgroundColor',[1 0 0]);
   control = 1
end
end

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Stephen23 2019-2-26

It is recommended to use guidata rather than a global variable.

Dany Majed 2019-2-26

编辑：Dany Majed 2019-2-26

i do quiet understand what are you trying to say but if you realize after the first if statement which is (if control == 1) the program will turn the button into the other color and will end the process after that so in the other pushes of the button the button will remain same color and i am still a beginner so can't tweak the code that much so if you could please help me with that.Thanks in Advance.

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