MATLAB: Changing color of pushbuttons before pushing them

for loopmatlab gui

I am trying to change the colors of some pushbuttons in mat alb before actually pushing them, but just according to the values in a certain matrix (these values may change). The following code runs but the result is odd. What I am doing wrong with the for loop?

This is an example of matrix:

A = [0 0 3 1 1];

Here I set the screen:

scr = get(0, 'screensize');
f1 = figure(1);
set(f1, 'menubar', 'none');
set(f1, 'position', [scr(1) scr(2) scr(3) scr(4)]);

These are the pushbuttons:

h1 = uicontrol('Style', 'pushbutton',...
'BackgroundColor', '[0.91 0.91 0.91]',...
'Position', [200 200 100 100]);
h2 = uicontrol('Style', 'pushbutton',...
'BackgroundColor', '[0.91 0.91 0.91]',...
'Position', [300 200 100 100]);
h3 = uicontrol('Style', 'pushbutton',...
'BackgroundColor', '[0.91 0.91 0.91]',...
'Position', [400 200 100 100]);
h4 = uicontrol('Style', 'pushbutton',...
'BackgroundColor', '[0.91 0.91 0.91]',...
'Position', [500 200 100 100]);
h5 = uicontrol('Style', 'pushbutton',...
'BackgroundColor', '[0.91 0.91 0.91]',...
'Position', [600 200 100 100]);

I put them together in an array:

L = [h1 h2 h3 h4 h5];

Now I want the pushbuttons to change color according to the values in the matrix. So if the first value in the matrix is zero, the color of the first pushbutton should be white. If the second value in the matrix is zero, the color of the second pushbutton should be white, and so on.

for i = length(A)
if A(i) == 0
    set(L(i),'Backgroundcolor', 'w');
elseif A(i) == 1
    set(L(i),'Backgroundcolor','b');
elseif A(i) == 2
    set(L(i),'Backgroundcolor','y');
elseif A(i) == 3
    set(L(i),'Backgroundcolor','g');
end
end

But in the end I just get the last pushbutton blue, and the others unchanged! They should all be changing color.

Best Answer

I changed the parameter to numeric but that did not solve the problem. I have found out that the for loop only goes over the last index. I also need to change the loop indication to:

for i = 1 : length(A)

and it will iterate correctly.

Related Solutions

MATLAB: How to loop through pushbuttons (=tiles in a maze) with a single callback

Serena - I think that you are missing an end at the end of your first double for loop block that sets the colours of the pushbuttons, and that missing end has been put at the end of the next double for loop block to make some of the pushbuttons visible. This causes two problems since both sets of double for loops use the same indexing variables i and j (as an aside, you may want to consider renaming these to something more meaningful since MATLAB also uses these to represent the imaginary number). This most likely causes a problem with the line

set(L(i,j),'callback',{@my_funct,L,A});

only being assigned to the (5,5) pushbutton control since it occurs outside of the previous double for loop. I suggest that you include this in the first block and end it appropriately as

    for r = 1: size(A,1) % rows
        for c = 1: size(A,2) % columns
            set(L(r,c),'callback',{@my_funct});
            if A(r,c) == 0
                set(L(r,c),'BackgroundColor', 'w')
                set(L(r,c), 'visible', 'off')
            elseif A(r,c) == 1
                set(L(r,c),'BackgroundColor','b')
                set(L(r,c), 'visible', 'off')
            elseif A(r,c) == 2
                set(L(r,c),'BackgroundColor','y')
                set(L(r,c),'String','GOAL')
                set(L(r,c), 'visible', 'on')
            elseif A(r,c) == 3
                set(L(r,c),'BackgroundColor','g')
            end
        end
    end

So now every pushbutton will be assigned the callback. Since the above outer for loop as been terminated with the end then you will have to remove the redundant end from the second block of code.

Note the change to your callback

 set(L(r,c),'callback',{@my_funct});

Since the callback is a nested function within create_maze, you do not need to pass in parameters that are declared or are local to create_maze. The callback will have access to these elements since it is nested. This will require you to change the callback signature to

 function [] = my_funct(source, callbackdata)

So that should get the callback to fire. The next step will be to revisit your callback logic - you probably only want "do" anything if the user is pressing a white pushbutton. You can use the source input along with the property BackgroundColor to retrieve the colour as

 bgColor = get(source,'BackgroundColor');
 if all(bgColor)
     % pushbutton is white
     % do something
 end

Since the bgColor is a 1x3 array indicating the RGB color, if it is all ones then the button background is white.

Now you presumably need to determine the neighbours of this white pushbutton only. How can you do that since all you have is the source (which is the handle to the pushbutton)? Since the handles are of a floating precision (double) data type, you don't want to be looking through each element of L and comparing each to this handle. So how else can you determine where in L (and so A) this handle is? Hint - look back at how you assign the callback to the pushbutton and consider using the r and c as the unique identifier into L and A.

MATLAB: How to use set to change a property of a uicontrol

Change

addstring = {get(texth, 'String')};

addstring = get(texth, 'String');

Best Answer

Related Solutions

MATLAB: How to loop through pushbuttons (=tiles in a maze) with a single callback

MATLAB: How to use set to change a property of a uicontrol

Related Question