public variable in gui

hello,

how can i define variable all the function of gui see it?

[Merged information from duplicate question]

if i have tow func in gui and i have variable x i need x identified from function 1 and function 2

func 1

x=1+y;

func2

z=x+1

Answer 1

[Image Analyst]

See the FAQ: http://matlab.wikia.com/wiki/FAQ#How_can_I_share_data_between_callback_functions_in_my_GUI.28s.29.3F

[mohamed al-asklany]

no benefits

[Walter Roberson]

I count at least 4 solutions to the problem in the reference that IA gave you.

[mohamed al-asklany]

i can not understand the solution which IA say

[Walter Roberson]

The FAQ gives examples for some of the solutions, and you can search the MATLAB documentation for information on the functions mentioned.

You can also ask specific questions about interpretation of the documentation.

[Image Analyst]

What's so hard about adding your variable on to handles as a new member?

Answer 2

[Walter Roberson]

func 1

global x
x=1+y;

func 2

global x
z=x+1

This is not a recommended solution. The solutions in the FAQ that IA pointed you to are better ones.

[Image Analyst]

How is adding onto the handles structure any better than declaring it global? Wouldn't both have the same benefits and drawbacks?

[Walter Roberson]

handles structures are per-figure, not completely global.

[Image Analyst]

Right, but within a figure the argument against globals has been that you can change them, and it's changed everywhere and that's supposedly bad (though you knew and wanted this, so that's why you made them global to begin with), and that's the same thing that would happen if you changed your "handles.myVariable" variable. So why is changing it via handles okay but changing it with global not okay?

[Sean de Wolski]

global could be changed from somewhere completely different having nothing to do with the figure.

[Walter Roberson]

The theory goes that barriers to using a variable as if it is global will introduce reluctance to indeed use it as if it is global.

Using handles introduces notable barriers, such as needing to guidata() in the assigning routine to allow the change to be seen, and needing to guidata() in any calling routine that needs to know the updated value. And for cross-gui work, needing to know the figure number of the other gui in order to be able to access its information. It is common for people to run into difficulties when they do _not_ know these mechanisms, so in one sense the barriers are being effective.

On the other hand, I have the distinct impression that what newcomers tend to learn about handles is that there is a particular _pattern_ to use, and they just go ahead and use that pattern without understanding it. Sort of like people just going ahead and entering their password any time MS Windows or OS-X ask for it. Barriers that become treated by rote become ineffective barriers.