Get label name of item in dropdown menu

조회 수: 22 (최근 30일)
John F
John F 2022년 4월 8일
댓글: John F 2022년 4월 14일
I have 2 dropdown menus that allow the user to select which variables to plot on a figure. I would like to also update the labels of the plot according to the label name of the selected item. Is there a way to access the label name without passing an object to ItemsData (e.g. {["var1",1],["var2",2], ...})?
data = ones(1,length(table_cols)-1); % Dummy data
eng_perf = uitab(PlotTabGroup,'Title','Engine Perf.');
perf_plot = uiaxes(eng_perf,"Units","normalized","Position",[0 0.05 1 0.95]);
% table_cols contains the names of the items
xdrop = uidropdown(eng_perf,"Position",[10 5 100 20],'Items',table_cols(2:end),...
ydrop = uidropdown(eng_perf,"Position",[120 5 100 20],'Items',table_cols(2:end),...
xdrop.ValueChangedFcn = @(xdrop,event) update_perf_plot(xdrop,ydrop,perf_plot);
ydrop.ValueChangedFcn = @(ydrop,event) update_perf_plot(xdrop,ydrop,perf_plot);
function update_perf_plot(xdrop,ydrop,perf_plot)
perf_plot.XLabel.String = xdropSelectedName; % Replace this line
perf_plot.YLabel.String = xdropSelectedName; % Replace this line

답변 (1개)

Geoff Hayes
Geoff Hayes 2022년 4월 12일
@John F - since you are passing the drop down objects into the callback, I think you could just do
function update_perf_plot(xdrop,ydrop,perf_plot)
perf_plot.XLabel.String = xdrop.Value;
perf_plot.YLabel.String = ydrop.Value;
% !! Not sure what the next line is supposed to do !!
% plot(perf_plot,xdrop.Value,ydrop.Value)
That would allow you to set the current selection from each drop down to the appropriate label. As mentioned in the above code, it isn't clear to me how these same two values (strings) are supposed to be used in your call to plot.
There may also be alternatives to passing the drop down objects into this callback. If you have nested your callback within the main code that creates the drop downs, then you can access them directly. For example,
function nestedFunctionExample
eng_perf = uifigure;
xdrop = uidropdown(eng_perf,"Position",[10 5 100 20],'Items',{'abc' 'def' 'ghi'},...
ydrop = uidropdown(eng_perf,"Position",[120 5 100 20],'Items',{'abcd' 'defd' 'ghid'},...
xdrop.ValueChangedFcn = @(xdrop,event) update_perf_plot;
ydrop.ValueChangedFcn = @(ydrop,event) update_perf_plot;
function update_perf_plot()
fprintf('xdrop=%s\n', xdrop.Value);
fprintf('ydrop=%s\n', ydrop.Value);
  댓글 수: 5
Geoff Hayes
Geoff Hayes 2022년 4월 12일
@John F - perhaps since you are mapping strings to numbers, then maybe you should try using a map object. For example,
>> myMap = containers.Map(["a","b","cd"],[1,2,3]);
>> myMap("cd")
ans =
You could then create two map objects, one for the x drop down and one for the y drop down. You would then do something like
perf_plot.XLabel.String = xdrop.Value;
perf_plot.YLabel.String = ydrop.Value;
where xDropMap and yDropMap are the containers that map the drop down elements to the appropriate value.
John F
John F 2022년 4월 14일
@Geoff Hayes This does work but since I need to update the data contained in the map, I would also have to pass the keys around in my app. So I will keep my solution as is. I appreciate the help though and I hope someone else finds it useful in the future!

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