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前言

做IDEA插件，发现一个数据变动好几处需要配合改动。感觉好麻烦，总不能每次改动都在修改数据的地方加上处理吧。想起来有个监听器模式，想必IDEA肯定也是有相应机制的。官网手册➹

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一、IDEA的消息传递简介

事件组成元素:

1. TOPIC:消息主题
2. Listener:消息监听器
   
   消息广播：ProjectBus是ApplicationBus的子集，每个topic都可以有多个监听器；
3. 消息通过ApplicationBus发送到topic1;
4. Handler1收到消息通知;
5. 消息传递给ProjectBus中topic1的订阅者(handler2和handler3);
   

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二、发布消息与处理消息

1. 创建Listener

public interface DateRefreshListener {
    void refresh(String date,Project fireProject);
}
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2. 创建Publisher及其Topic

public class DateRefreshMessagePublisher {

    public static final Topic<DateRefreshListener> TOPIC = new Topic<>("date refresh events", DateRefreshListener.class);

    public static DateRefreshMessagePublisher getInstance(Project project) {
        return (DateRefreshMessagePublisher) project.getPicoContainer().getComponentInstanceOfType(DateRefreshMessagePublisher.class);
    }

    /**
     * 推送刷新事件
     */
    public void fireDateRefreshExecute(String date, Project project) {
        getPublisher(project).refresh(date, project);
    }

    @NotNull
    private static DateRefreshListener getPublisher(Project project) {
        return project.getMessageBus().syncPublisher(TOPIC);
    }
}
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3. 在Plugin.xml注册Service、Listener

public class DateRefreshNotifyListener implements DateRefreshListener {

    @Override
    public void refresh(String date, Project fireProject) {
        Notification notify = NotifyGroupConstants.NOTIFICATION_GROUP
                .createNotification("通过plugin.xml定义的-Listener给" + fireProject.getName() + "发通知" + date, NotificationType.INFORMATION);
        notify.notify(fireProject);
    }
}
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    <extensions defaultExtensionNs="com.intellij">

        <projectService serviceImplementation="org.intellij.sdk.service.DateRefreshNotifyListener"/>
        <projectService serviceImplementation="org.intellij.sdk.listener.DateRefreshMessagePublisher"/>

        <toolWindow id="Sample Calendar" secondary="true" icon="AllIcons.General.Modified" anchor="right"
                    factoryClass="org.intellij.sdk.toolWindow.MyToolWindowFactory"/>
    extensions>

    <projectListeners>
        <listener class="org.intellij.sdk.service.DateRefreshNotifyListener"
                  topic="org.intellij.sdk.listener.DateRefreshListener"/>
    projectListeners>
    <idea-version since-build="193.0"/>
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5. 【演示用】在toolwindow创建时，增加监听方法

public class MyToolWindowFactory implements ToolWindowFactory {
    AtomicBoolean icon = new AtomicBoolean(true);

    @Override
    public void createToolWindowContent(@NotNull Project project, @NotNull ToolWindow toolWindow) {
        MyToolWindow myToolWindow = new MyToolWindow(toolWindow, project);
        ContentFactory contentFactory = ContentFactory.SERVICE.getInstance();
        Content content = contentFactory.createContent(myToolWindow.getContent(), "", false);
        toolWindow.getContentManager().addContent(content);

        project.getMessageBus().connect().subscribe(DateRefreshMessagePublisher.TOPIC, (date, fireProject) -> {
            if (icon.get()) {
                toolWindow.setIcon(AllIcons.Actions.Cancel);
                icon.set(false);
            } else {
                toolWindow.setIcon(AllIcons.Actions.Refresh);
                icon.set(true);
            }

            Notification notify = NotifyGroupConstants.NOTIFICATION_GROUP
                    .createNotification("修改toolWindow图标的同时,给" + fireProject.getName() + "发通知" + date, NotificationType.INFORMATION);
            notify.notify(fireProject);
        });
    }
}
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效果图

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系列文章

第一坑-创建gradle工程编译失败
第二坑-Action的Icon死活加不上去