blocks|key|4014672|text|我通常会这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4014673|JPanel+panel+=+new+JPanel();
panel.add(new+JButton(new+AbstractAction("name+of+button")+{
++++public+void+actionPerformed(ActionEvent+e)+{
++++++++//do+stuff+here
++++}
}));|code-block|syntax|javascript|4014674|AbstractAction实现了ActionListener，因此这应该可以满足任务。|4014675|将这么多行代码挤在一起可能是一种糟糕的做法，但如果您习惯于阅读它，那么它可能会非常优雅。|4014676|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

I usually go something like this:

<pre><code>JPanel panel = new JPanel();
panel.add(new JButton(new AbstractAction("name of button") {
 public void actionPerformed(ActionEvent e) {
 //do stuff here
 }
}));
</code></pre>

AbstractAction implements ActionListener so this should satisfy the task.

It can be bad practice to squish so many lines of code together, but if you're used to reading it then it can be quite elegant.

blocks|key|1260221|text|我不会在现实世界的程序中做这样的事情，但考虑到你作业中的要求，你很难做得更好。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1260222|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

I would not do something like that in a real-world program, but given the requirements in your assignment, you can hardly do better.

blocks|key|4014766|text|好的，有一种更优雅的方法。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4014767|不幸的是，它不是一种核心Java/Swing方法。|4014768|你可以在Groovy中使用SwingBuilder来达到同样的效果，使用稍微简洁一些的语法，例如psuedo代码：|4014769|button(text:+''+%2B+counter,
+++++++++actionPerformed:+{counter--;+text+=+''+%2B+counter+%2B+''},
+++++++++constraints:BL.SOUTH)|code-block|syntax|javascript|4014770|[http://groovy.codehaus.org/Swing%2BBuilder][1]|offset|length|4014771|我不会在你的作业中使用它，我已经看到学生偏离了标准，并被扣分，但至少你可以把它作为进一步研究的可能途径。|4014772|不过，我认为你目前所拥有的一切都是非常好的。|4014773|entityMap|0|LINK|mutability|MUTABLE|url|http://groovy.codehaus.org/Swing%2BBuilder][1]^0|0|0|0|0|0|19|0|0|0|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|11|8|@]|9|@]|A|$]]|$1|D|3|E|5|6|7|12|8|@]|9|@]|A|$]]|$1|F|3|G|5|H|7|13|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|14|8|@]|9|@$M|15|N|16|1|17]]|A|$]]|$1|O|3|P|5|6|7|18|8|@]|9|@]|A|$]]|$1|Q|3|R|5|6|7|19|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]]|T|$U|$5|V|W|X|A|$Y|Z]]]]

Well there is a much more elegant way to do it.

Unfortunately, it's not a Core Java/Swing approach.

You can use SwingBuilder in Groovy to achieve the same result, using slightly more terse syntax, e.g. psuedo code:

<pre><code>button(text: '' + counter,
 actionPerformed: {counter--; text = '' + counter + ''},
 constraints:BL.SOUTH)
</code></pre>

[<a href="http://groovy.codehaus.org/Swing+Builder][1]" rel="nofollow noreferrer">http://groovy.codehaus.org/Swing+Builder][1]</a>

I wouldn't use this in your assignment though, I've seen students really deviate from the norm and get marked down for it, but at least you can include it as a possible avenue to investigate further. 

I think what you have at present is absolutely fine though.

blocks|key|4014830|text|实现多个类型通常不是一个好主意。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|4014831|很少有必要扩展JComponent类，尽管很多糟糕的软件和教程都是这样做的。最近越来越流行的一个习惯用法是双括号--一个类只是一个子类，目的是给它一个实例初始化器，它的行为就像其他语言的with语句。|offset|length|style|CODE|4014832|在这种情况下，相关代码可以写成：|4014833|JButton+button+=+new+JButton();
button.addActionListener(new+ActionListener()+{
++++int+counter+=+1;
++++{
++++++++updateText();
++++}
++++public+void+actionPerformed(ActionEvent+arg0)+{
++++++++--counter;
++++++++updateText();
++++}
++++private+void+updateText()
++++++++setText(Integer.toString(counter));
++++}
});
f.getContentPane(button);|code-block|syntax|javascript|4014834|如果它变得更加复杂，那么您可能希望创建一个外部类(不实现ActionListener或扩展JButton)来处理数据。|4014835|还要注意，您应该使用EventQueue.invokeLater样板，以确保仅在AWT+EDT上使用Swing组件。|4014836|entityMap^0|0|7|A|2L|4|0|0|0|S|E|19|7|0|A|M|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@$D|W|E|X|F|G]|$D|Y|E|Z|F|G]]|9|@]|A|$]]|$1|H|3|I|5|6|7|10|8|@]|9|@]|A|$]]|$1|J|3|K|5|L|7|11|8|@]|9|@]|A|$M|N]]|$1|O|3|P|5|6|7|12|8|@$D|13|E|14|F|G]|$D|15|E|16|F|G]]|9|@]|A|$]]|$1|Q|3|R|5|6|7|17|8|@$D|18|E|19|F|G]]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1A|8|@]|9|@]|A|$]]]|T|$]]

Implementing multiple types is generally a bad idea.

It is rarely necessary to extend <code>JComponent</code> classes, although a lot of bad software and tutorials do it. An idiom/hack that has been gaining ground recently is Double Brace - a class is only subclasses in order to give it an instance initialiser which acts like a <code>with</code> statement from other languages.

In this case, the relevant code can be written as:

<pre><code>JButton button = new JButton();
button.addActionListener(new ActionListener() {
 int counter = 1;
 {
 updateText();
 }
 public void actionPerformed(ActionEvent arg0) {
 --counter;
 updateText();
 }
 private void updateText()
 setText(Integer.toString(counter));
 }
});
f.getContentPane(button);
</code></pre>

If it gets more complex, then you'll probably want to make an outer class (that does not implement <code>ActionListener</code> or extend <code>JButton</code>) to handle the data.

Also note, you should be using the <code>EventQueue.invokeLater</code> boilerplate to ensure that Swing components are only ever used on the AWT EDT.

blocks|key|795978|text|它非常难看，但您可以使用ActionListener方法和一个匿名类执行以下操作：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|795979|++f.getContentPane().add(new+JButton(new+AbstractAction("name+of+button")+{
++++++private+int+counter+=+0;

++++++public+void+actionPerformed(ActionEvent+e)+{
++++++++++((JButton)+e.getSource()).setText(Integer.toString(counter--));
++++++}
++})+{
++++++{
++++++++++setText("1");
++++++}
++});|code-block|syntax|javascript|795980|为了更容易访问计数器，您可以将它移到类的顶层，并从调用setText的两个位置访问它。|795981|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

It's quite ugly, but you could do the following using the ActionListener method and an anonymous class:

<pre><code> f.getContentPane().add(new JButton(new AbstractAction("name of button") {
 private int counter = 0;

 public void actionPerformed(ActionEvent e) {
 ((JButton) e.getSource()).setText(Integer.toString(counter--));
 }
 }) {
 {
 setText("1");
 }
 });
</code></pre>

To make it easier to access the counter you could move it out to the top level of your class and access it from both places where setText is called.

blocks|key|796048|text|这是只在家庭作业中被迫完成的不良练习任务之一;-)糟糕的事情：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|796049|796050|使用ActionListener而不是本身就不好的操作|unordered-list-item|796051|因此，作用域问题会使|796052|计数器的作用域扩大到超出必要的范围|796053|需要访问actionPerformed内的按钮(通过类型转换或访问周围对象的access|796054|796055|796056|​|796057|796058|unreadable+(也称为:+unmaintainable)+code|796059|796060|但是，然后..。我们无法抗拒，不是吗;-)这是一个使用Action的版本，对于前两个问题是干净的(或者我认为是这样)，像所有其他示例一样不可读(当然，我作弊了:首先实现匿名类，然后让IDE做内联|796061|++++f.add(new+JButton(new+AbstractAction()+{

++++++++int+counter+=+1;
++++++++{+//+constructor+block+of+action
++++++++++++updateName();
++++++++}

++++++++@Override
++++++++public+void+actionPerformed(ActionEvent+e)+{
++++++++++++counter--;
++++++++++++updateName();
++++++++}

++++++++private+void+updateName()+{
++++++++++++putValue(Action.NAME,+""+%2B+counter);
++++++++}

++++})++{+//+subclass+button+
++++++++++{++//+constructor+block+button
++++++++++++setBackground(Color.PINK);
++++++++}}
++++);|code-block|syntax|javascript|796062|entityMap^0|0|0|0|1|1|1|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|12|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|13|8|@]|9|@]|A|$]]|$1|C|3|D|5|E|7|14|8|@]|9|@]|A|$]]|$1|F|3|G|5|E|7|15|8|@]|9|@]|A|$]]|$1|H|3|I|5|E|7|16|8|@]|9|@]|A|$]]|$1|J|3|K|5|E|7|17|8|@]|9|@]|A|$]]|$1|L|3|-4|5|6|7|18|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|19|8|@]|9|@]|A|$]]|$1|N|3|O|5|6|7|1A|8|@]|9|@]|A|$]]|$1|P|3|-4|5|6|7|1B|8|@]|9|@]|A|$]]|$1|Q|3|R|5|E|7|1C|8|@]|9|@]|A|$]]|$1|S|3|-4|5|6|7|1D|8|@]|9|@]|A|$]]|$1|T|3|U|5|6|7|1E|8|@]|9|@]|A|$]]|$1|V|3|W|5|X|7|1F|8|@]|9|@]|A|$Y|Z]]|$1|10|3|-4|5|6|7|1G|8|@]|9|@]|A|$]]]|11|$]]

This is one of bad-practice tasks forced to do in homework only ;-) Bad things:

<ul>
<li>usage of ActionListener instead of Action which is bad in itself</li>
<li>as a consequence, scoping problems bubble up 
<ul>
<li>counter's scope wider than necessary</li>
<li>need access to button inside the actionPerformed (via type-cast or accessing surrounding object's api)</li>
</ul></li>
<li>unreadable (aka: unmaintainable) code</li>
</ul>

But, then .. we cannot resist, can we ;-) Here's a version using Action which is clean (or so I think) as to the first two issue, unreadable as all other examples (and I cheated, of course: first implemented the anonymous classes, then let the IDE do the inline

<pre><code> f.add(new JButton(new AbstractAction() {

 int counter = 1;
 { // constructor block of action
 updateName();
 }

 @Override
 public void actionPerformed(ActionEvent e) {
 counter--;
 updateName();
 }

 private void updateName() {
 putValue(Action.NAME, "" + counter);
 }

 }) { // subclass button 
 { // constructor block button
 setBackground(Color.PINK);
 }}
 );
</code></pre>

I was recently doing a programming assignment that required us to implement in code a program specified by a UML diagram. At one point, the diagram specified that I had to create an anonymous JButton that displayed a count (starting at one) and decremented each time it was clicked. The JButton and its ActionListener both had to be anonymous.

I came up with the following solution:

<pre><code>public static void main(String[] args) {
 JFrame f = new JFrame("frame");
 f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
 f.setSize(400, 400);

 f.getContentPane().add(new JButton() {

 public int counter;

 {
 this.counter = 1;
 this.setBackground(Color.ORANGE);
 this.setText(this.counter + "");

 this.addActionListener(new ActionListener() {
 public void actionPerformed(ActionEvent arg0) {
 counter --;
 setText(counter + "");
 }
 });

 }
 });

 f.setVisible(true);

}</code></pre>

This adds an anonymous JButton, then adds another (inner) anonymous ActionListener to handle events and update the button's text as necessary. Is there a better solution? I'm pretty sure I can't declare an anonymous <code>JButton implements ActionListener ()</code>, but is there another more elegant way to achieve the same result?

Java anonymous class that implements ActionListener?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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我最近做了一个编程任务，要求我们在代码中实现一个由UML图指定的程序。在某一时刻，该图指定我必须创建一个匿名JButton，它显示一个计数(从1开始)，并在每次单击它时递减。JButton及其ActionListener都必须是匿名的。我想出了以下解决方案：public static void main(String[...

问实现ActionListener的Java匿名类？
EN

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问实现ActionListener的Java匿名类？EN