MATLAB: How to relate a pushbutton to position

position;pushbutton

Hi! I'm making a piano on matlab & can't figure out how to have matlab recognize if the user pushed on a key based on the position of the key itself. Basically, if the user clicks on the right key I want a "Good Job" message to come up & "Error" message to come up if they click the wrong one. I'm thinking to use an if statement but everything I try isnt working. Here is my code so far:
%Paino Figure w/ pushbuttons
function PianoImage_HBraslawsce()
f=figure();
set(f, 'MenuBar','none'); %Remove menu bar
set(f,'NumberTitle','off');
set(f,'Name', 'Note Learner'); %Change name
%Each key as a pushbutton
KEYC = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized','position',[.15 .15 .1 .45]);
KEYD = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized','position',[.25 .15 .1 .45]);
KEYE = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized','position',[.35 .15 .1 .45]);
KEYF = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized','position',[.45 .15 .1 .45]);
KEYG = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized','position',[.55 .15 .1 .45]);
KEYA = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized','position',[.65 .15 .1 .45]);
KEYB = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized','position',[.75 .15 .1 .45]);
KEYCHI = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized','position',[.85 .15 .1 .45]);
KEYCSH = uicontrol('style','pushbutton','backgroundcolor',[0 0 0],'units','normalized','position',[.20 .3 .08 .3]);
KEYEb=uicontrol('style','pushbutton','backgroundcolor',[0 0 0],'units','normalized','position',[.30 .3 .08 .3]);
KEYFSH=uicontrol('style','pushbutton','backgroundcolor',[0 0 0],'units','normalized','position',[.5 .3 .08 .3]);
KEYAb=uicontrol('style','pushbutton','backgroundcolor',[0 0 0],'units','normalized','position',[.60 .3 .08 .3]);
KEYBb=uicontrol('style','pushbutton','backgroundcolor',[0 0 0],'units','normalized','position',[.70 .3 .08 .3]);
%Keys callback
set(KEYC,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
set(KEYCSH,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
set(KEYD,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
set(KEYE,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
set(KEYEb,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
set(KEYF,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
set(KEYFSH,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
set(KEYG,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
set(KEYAb,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
set(KEYA,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
set(KEYBb,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
set(KEYB,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
set(KEYCHI,'Callback',{@keypressed,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI})
end
function keypressed(x,y,KEYC,KEYCSH,KEYD,KEYE,KEYEb,KEYF,KEYFSH,KEYG,KEYA,KEYAb,KEYB,KEYBb,KEYCHI)
x;
y;
KEYC;
KEYCSH;
KEYD;
KEYE;
KEYEb;
KEYF;
KEYFSH;
KEYG;
KEYA;
KEYAb;
KEYB;
KEYBb;
KEYCHI;
KEYC='C';
KEYCSH='C#';
KEYD='D';
KEYE='E';
KEYEb='Eb';
KEYF='F';
KEYFSH='F#';
KEYG='G';
KEYA='A';
KEYAb='Ab';
KEYB='B';
KEYBb='Bb';
KEYCHI='C(high)';
'C'=='position',[.15 .15 .1 .45];
'C#'=='position',[.20 .3 .08 .3];
'D'=='position',[.25 .15 .1 .45];
'E'=='position',[.35 .15 .1 .45];
'Eb'=='position',[.30 .3 .08 .3];
'F'=='position',[.45 .15 .1 .45];
'F#'=='position',[.5 .3 .08 .3];
'G'=='position',[.55 .15 .1 .45];
'Ab'=='position',[.60 .3 .08 .3];
'A'=='position',[.65 .15 .1 .45];
'Bb'=='position',[.70 .3 .08 .3];
'B'=='position',[.75 .15 .1 .45];
'C(high)'=='position',[.85 .15 .1 .45];
end

Best Answer

Han - try using the UserData property of the pushbutton to store the key that the button represents. That way, when the button is pressed and the callback fires, you can use (get) this property to compare against the letters that have popped up on screen. Your code could look something like
function PianoImage_HBraslawsce()
    f=figure();
    set(f, 'MenuBar','none'); %Remove menu bar
    set(f,'NumberTitle','off');
    set(f,'Name', 'Note Learner'); %Change name
    %Each key as a pushbutton
    KEYC = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized',...
        'position',[.15 .15 .1 .45], 'UserData', 'C','Callback',@keypressed);
    KEYD = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized',...
        'position',[.25 .15 .1 .45], 'UserData', 'D','Callback',@keypressed);
    KEYE = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized',...
        'position',[.35 .15 .1 .45], 'UserData', 'E','Callback',@keypressed);
    KEYF = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized',...
        'position',[.45 .15 .1 .45], 'UserData', 'F','Callback',@keypressed);
    KEYG = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized',...
        'position',[.55 .15 .1 .45], 'UserData', 'G','Callback',@keypressed);
    KEYA = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized','position',[.65 .15 .1 .45], 'UserData', 'A','Callback',@keypressed);
    KEYB = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized',...
        'position',[.75 .15 .1 .45], 'UserData', 'B','Callback',@keypressed);
    KEYCHI = uicontrol('style','pushbutton','backgroundcolor',[1 1 1],'units','normalized',...
        'position',[.85 .15 .1 .45], 'UserData', 'C(high)','Callback',@keypressed);
    KEYCSH = uicontrol('style','pushbutton','backgroundcolor',[0 0 0],'units','normalized',...
        'position',[.20 .3 .08 .3], 'UserData', 'C#','Callback',@keypressed);
    KEYEb=uicontrol('style','pushbutton','backgroundcolor',[0 0 0],'units','normalized',...
        'position',[.30 .3 .08 .3], 'UserData', 'Eb','Callback',@keypressed);
    KEYFSH=uicontrol('style','pushbutton','backgroundcolor',[0 0 0],'units','normalized',...
        'position',[.5 .3 .08 .3], 'UserData', 'F#','Callback',@keypressed);
    KEYAb=uicontrol('style','pushbutton','backgroundcolor',[0 0 0],'units','normalized',...
        'position',[.60 .3 .08 .3], 'UserData', 'Ab','Callback',@keypressed);
    KEYBb=uicontrol('style','pushbutton','backgroundcolor',[0 0 0],'units','normalized',...
        'position',[.70 .3 .08 .3], 'UserData', 'Bb','Callback',@keypressed);
    function keypressed(hObject, eventdata)
        fprintf('You have pressed key %s\n', get(hObject, 'UserData'));
    end
end
I've nested the callback within the main function for convenience but also just in case you need to access those variables declared there. This avoids the need to pass the button handles into the callback function whose signature has now been reduced to simply
function keypressed(hObject, eventdata)
In your callback you were overwriting the pushbutton handle inputs with strings (this isn't something you really want or should do as you are changing the purpose of the variable from a function handle to a string). These strings are now stored in the UserData property for each button. We can then use the get function to retrieve that key string.
Note that when comparing this string against whatever note you've displayed, you will want to use the strcmp function (using == with strings will generally only work if the strings being compared have the same number of characters).
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