如何知道是否在jtextarea中进行了任何更改? [英] How to know whether any changes in the jtextarea have been made or not?
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问题描述
我创建了一个jtextarea,用户可以在其中修改其内容.我想知道,如果有任何办法,用户在关闭应用程序之前是否已修改其内容.请帮忙.
-预先感谢
I've created a jtextarea where a user can modify its content. I want to know,if there is any way, whether the user has modified its content or not before closing the application. Please help.
-Thanks in advance
推荐答案
您需要添加文档,该文档支持文本区域.
You need to add a DocumentListener to the Document that backs the text area.
然后在侦听器的回调方法(insertUpdate(),removeUpdate(),changedUpdate())中,只需设置一个已更改的标志并在关闭应用程序之前测试该标志
Then in the callback methods (insertUpdate(), removeUpdate(), changedUpdate()) of the listener, simply set a flag that something has changed and test that flag before closing the application
public class MyPanel
implements DocumentListener
{
private boolean changed;
public MyPanel()
{
JTextArea textArea = new JTextArea();
textArea.getDocument().addDocumentListener(this);
.....
}
.....
public void insertUpdate(DocumentEvent e)
{
changed = true;
}
public void removeUpdate(DocumentEvent e)
{
changed = true;
}
public void changedUpdate(DocumentEvent e)
{
changed = true;
}
}
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