Is there a way to set a EditField as ready to accept input in app designer?

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David Rea 2018-5-9

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https://ww2.mathworks.cn/matlabcentral/answers/399946-is-there-a-way-to-set-a-editfield-as-ready-to-accept-input-in-app-designer

回答： Adam Danz 2022-4-5

I am using App Designer to make an EditBox with user text input. I would like to user to be able to select the app and begin typing without the need to select the EditBox. Is there a way to have the code select the EditBox to enable it to be ready for user input?

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Answer 1

Ameer Hamza 2018-5-9

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编辑：Ameer Hamza 2018-5-9

在 MATLAB Online 中打开

sample.zip

It appears that this functionality has still not been added to App Designer. Anyway here is a bodge that can bring an edit field to focus. The idea is to send automatic TAB key presses to the app window. Since you can manually bring an edit field to focus by pressing TAB key several times, you can automate this as follow

import java.awt.*;
import java.awt.event.*;
rob = Robot;
rob.keyPress(KeyEvent.VK_TAB)
rob.keyRelease(KeyEvent.VK_TAB)
rob.keyPress(KeyEvent.VK_TAB)
rob.keyRelease(KeyEvent.VK_TAB)

these line of code will simulate 2 TAB key presses. Since it is a bodge, at the time of coding, you will have to use hit and trial approach to determine how many tab presses are needed to reach a particular edit field. I have attached a sample app. When the app start, it force editfield1 to get focus. After that, whenever button1 is pressed, editfield1 will be focused and button2 will bring editfield2 to focus. You can look at the Code View to get a further idea.

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Ameer Hamza 2018-5-10

sample.mlapp.zip

I also don't know much about java, and how to use it to check if edit box is active. I believe that there must be some elegant way to accomplish this. But since we are talking about bodges, so here is another one. If you click on the gray area of your figure, it will reset the tab sequence and you will get a fixed reference point to reach each element in the figure using TAB presses. So here is what I have done

1) Determine the current position of the mouse pointer on the screen.

2) Move the mouse pointer (programmatically) to the lower left corner of the figure. I just choose lower left an example, an empty area will work.

3) Simulate a left mouse button press. This will reset the tab sequence.

4) Move the mouse back to location noted in step 1.

5) Since the tab sequence is reset, simulate a fixed number of TAB presses to reach a particular field.

See the attached file for the code. The timer will run every 3 seconds and focus the edit field 1, no matter which element in your figure is currently active.

Ameer Hamza 2018-8-7

sampleR17b.mlapp.zip

This file is compatible with 2017b.

Thomas Pallierer 2018-8-7

Thank you very much :-) it works

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Answer 2

Adam Danz 2022-4-5

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Update

Starting in MATLAB R2022a.

Use the new focus(c) function to set focus to a ui component c. This MATLAB release also provides additional resources to control the focus order of ui components in AppDesigner.

More info