How to make text in uicontrol object disappear when user starts typing?

Question

KAE 2017-6-21

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/345751-how-to-make-text-in-uicontrol-object-disappear-when-user-starts-typing

评论： KAE 2017-6-27

I have a question about the following editable text box,

f = figure; % Make example figure
peaks; % Plot peaks data that comes preloaded with Matlab
S.ed = uicontrol('style','edit',... % Make editable text box
    'units','pixels', ...
    'position',[10 100 200 30],...
    'fontsize',11,...
    'string','Enter a Word');

How do I implement the following?

When the user starts to type, the text 'Enter a Word' disappears from the text box
When the user presses enter at the end of a character sequence, the entry is "done" and no more characters are accepted, similar to a carriage return?

As a user, this is how I expect text boxes to work, but I don't know how to implement it.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Walter Roberson 2017-6-21

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/345751-how-to-make-text-in-uicontrol-object-disappear-when-user-starts-typing#answer_271502

In order to do that, you have to implement a KeyPressedFcn callback for the uicontrol, and you have to manage all of the text yourself, including deletions. This gets trickier because when you are in a KeyPressedFcn callback for a text box, as you set() the String property, the display will not be updated (unless they changed that in R2014b and later), so you have to keep track of all of the text yourself.