Entering a value for 'String'

When 'String','' and enter the value in manually it works. When 'String','100' it does not.

vi = uicontrol('Style','edit','String','100','position',[10 630 100 20],'Callback',(@h_vi));

How do I correct this?

Answer 1

[Image Analyst]

630 is too big - it's off screen, try [10 30 100 20] instead.

Answer 2

[Philosophaie]

This is the error I get. I do use str2double to convert vi and angle.

Error code:

    Undefined function 'mpower' for input arguments of type 'matlab.ui.control.UIControl'.

    Error in ProjectileMotion>Evaluate (line 55)
        maxh = vi^2/(2*9.81)*(sin(angle*pi/180))^2;

Error while evaluating UIControl Callback

Answer 3

[Image Analyst]

You can't raise and edit field itself to a power. You have to get the number out of the edit field first, then raise it to a power.

% Create an edit field.  The "handle" to it is called hEdit.
hEdit = uicontrol('Style','edit','String','100','position',[10 30 100 20],'Callback',(@h_vi));
% Get string out of the edit field and then convert it to a double variable.
vi = str2double(get(hEdit, 'String'));
% Now do the mathematical equation.
maxh = vi^2/(2*9.81)*(sin(angle*pi/180))^2;

Of course vi will be 100 since you gave no time for the user to change it before you pulled out the 100 and used it.

[Image Analyst]

By the way, you can use sind(angle) instead of sin(angle*pi/180).

Answer 4

[Philosophaie]

I did that for both vi and angle.

vi = str2double(get(hEdit, 'String'));