When I click on a Java button object in MATLAB, why does it not evaluate its callback?

Question

MathWorks Support Team 2009-6-27

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/101390-when-i-click-on-a-java-button-object-in-matlab-why-does-it-not-evaluate-its-callback

采纳的回答： MathWorks Support Team

The callback function for my Java button object is not responding to the button click.

What is the correct way to implement this?

I am using the following code:

function my_java_test()
import java.awt.*
import java.awt.event.*
import javax.swing.*;
f = JFrame(sprintf('Houston... we have a problem'));              
f.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
b = JButton('Hello');
set(b,'ActionPerformedCallback', {@doHelloButtonClicked});
f.getContentPane.add(b)
f.pack
f.show
function doHelloButtonClicked(src, data)
     src.setLabel(sprintf('Roger that... pizza has been ordered'));

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Answer 1

MathWorks Support Team 2009-6-27

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/101390-when-i-click-on-a-java-button-object-in-matlab-why-does-it-not-evaluate-its-callback#answer_110738

This issue can be resolved by explicitly passing the handle of the JButton object to the callback function. This will be the callback function's third input argument.

This is illustrated below:

function my_java_test()
import java.awt.*
import java.awt.event.*
import javax.swing.*;
f = JFrame(sprintf('Houston... we have a problem'));              
f.setDefaultCloseOperation(WindowConstants.DISPOSE_ON_CLOSE);
b = JButton('Hello');
%  set(b,'ActionPerformedCallback', {@doHelloButtonClicked});
set(b,'ActionPerformedCallback', {@doHelloButtonClicked, b}); % Here, b is passed as an argument
f.getContentPane.add(b)
f.pack
f.show
function doHelloButtonClicked(src, data, b )  % Now, b is the third argument to the callback function
     b.setLabel(sprintf('Roger that... pizza has been ordered'));