Transparent patches in the main figure, but no transparent patches in the legend

In the following example, how can I have transparent patches in the main figure and No transparent patches in the legend?

N = 100;
x = linspace(0,1,N);
y1 = repmat([-2;2],1,N);
y2 = repmat([-1;1],1,N);
figure; hold on;
h1 = fill([x flip(x)], [y1(1,:) flip(y1(2,:))],'r');
h2 = fill([x flip(x)], [y2(1,:) flip(y2(2,:))],'g');
ylim([-2,2]);
first = legend('area1','area2','NumColumns',2);
PatchInLegend = findobj(first.PlotChildren, 'type', 'patch');
% Here below, FaceAlpha is applied to both patches in the main figure 
% and in the legend - But I would need the transparency only for the main figure's patches
set(PatchInLegend(1), 'FaceAlpha', 0.2); 
set(PatchInLegend(2), 'FaceAlpha', 0.4);

Answer 1

[Simon Chan]

One possible way is to use dummy handles.

N = 100;
x = linspace(0,1,N);
y1 = repmat([-2;2],1,N);
y2 = repmat([-1;1],1,N);
figure; hold on;
h1 = fill([x flip(x)], [y1(1,:) flip(y1(2,:))],'r','FaceAlpha',0.2);
h2 = fill([x flip(x)], [y2(1,:) flip(y2(2,:))],'g','FaceAlpha',0.4);
h3 = fill(NaN,NaN,'r');                                                 % Dummy one for red
h4 = fill(NaN,NaN,'g');                                                 % Dummy one for green
ylim([-2,2]);
legend([h3 h4],{'area1','area2'},'NumColumns',2);

[Sim]

thanks a lot @Simon Chan :-)