so in appdesigner im building a list box to turn the image to (red ,blue ,green) this is my code for it bout it wont run

value = app.ListBox.Value;

if value== 'Red'

a=(app.Image);

red=a;

red(:,:,2:3)=0

setappdata(0,'filename',red);

setappdata(0,'imrotation',red);

I=imshow(red,'parent',app.UIAxes2,...

'XData',[1 app.UIAxes2.Position(3)],...

'YData',[1 app.UIAxes2.Position(4)]);

app.UIAxes2.XLim=[0 I.XData(2)];

app.UIAxes2.YLim=[0 I.YData(2)];

else if value== 'Blue'

Agray=im2gray(app.Image);

zerochan = zeros(size(Agray),class(Agray));

blue = cat(3,zerochan,zerochan,Agray);

setappdata(0,'filename', blue);

setappdata(0,'imrotation', blue);

I=imshow(blue,'parent',app.UIAxes2,...

'XData',[1 app.UIAxes2.Position(3)],...

'YData',[1 app.UIAxes2.Position(4)]);

app.UIAxes2.XLim=[0 I.XData(2)];

app.UIAxes2.YLim=[0 I.YData(2)];

else

Agray=im2gray(app.Image);

zerochan = zeros(size(Agray),class(Agray));

green = cat(3,zerochan,Agray,zerochan);

setappdata(0,'filename',green);

setappdata(0,'imrotation',green);

I=imshow(green,'parent',app.UIAxes2,...

'XData',[1 app.UIAxes2.Position(3)],...

'YData',[1 app.UIAxes2.Position(4)]);

app.UIAxes2.XLim=[0 I.XData(2)];

app.UIAxes2.YLim=[0 I.YData(2)];

end

end

end

[Jan]

Please do not post code as screenshots, but as text. Then it can be used to create an answer with copy&paste.

This is not twitter: No # before the tags. Thanks.

Answer 1

[Kevin Holly]

Based on the red squiggly line under Methods in your screenshot, you may have an extra "end" in your code.

[jana]

i fixedit but then this popped up

[Kevin Holly]

Use strings instead of character arrays for your if conditions

if value == "Red"

The size was causing issues. See difference of size between character and string arrays below.

Character array:

    size('Red')

ans = 1×2

1 3

String array:

    size("Red")

ans = 1×2

1 1