效果图

一、配置SDK

插件只能使用IDEA开发，IDEA下载地址：https://www.jetbrains.com/idea/
打开IDEA，选择 File → Project Structure ，在弹出窗口中选择 New → IntelliJ Platform Plugin SDK ，然后点击 OK即可

二、开发插件

1.新建Plugin项目

点击 File → New → Project → IntelliJ Platform Plugin → Next → 输入项目名 → Finish

建好之后会生成一个默认的 plugin.xml 文件，默认代码如下：

<idea-plugin>
  <id>com.your.company.unique.plugin.id</id>
  <name>Plugin display name here</name>
  <version>1.0</version>
  <vendor email="[email protected]" url="http://www.yourcompany.com">YourCompany</vendor>

  <description><![CDATA[
      Enter short description for your plugin here.<br>
      <em>most HTML tags may be used</em>
    ]]></description>

  <change-notes><![CDATA[
      Add change notes here.<br>
      <em>most HTML tags may be used</em>
    ]]>
  </change-notes>

  <!-- please see http://www.jetbrains.org/intellij/sdk/docs/basics/getting_started/build_number_ranges.html for description -->
  <idea-version since-build="173.0"/>

  <!-- please see http://www.jetbrains.org/intellij/sdk/docs/basics/getting_started/plugin_compatibility.html
       on how to target different products -->
  <!-- uncomment to enable plugin in all products
  <depends>com.intellij.modules.lang</depends>
  -->

  <extensions defaultExtensionNs="com.intellij">
    <!-- Add your extensions here -->
  </extensions>

  <actions>
    <!-- Add your actions here -->
  </actions>

</idea-plugin>

2.修改配置

修改配置示例如下，各字段的含义见注释：

<idea-plugin>
  <id>com.your.company.unique.plugin.id</id>
  <!--插件名-->
  <name>MyFirstDemo</name>
  <version>1.0</version>
  <!--开发者信息：邮箱、网站、名称-->
  <vendor email="[email protected]" url="https://github.com/wkxjc">Cassin</vendor>

  <!--插件描述，可以使用html语法-->
  <description><![CDATA[
      Study IDEA Plugin<br>
      It's just for fun. But it has to ask for <em>40</em> characters.
    ]]></description>

  <!--版本变更日志-->
  <change-notes><![CDATA[
      First Version<br>
      It's just for fun. But it has to ask for <em>40</em> characters.
    ]]>
  </change-notes>

  <!-- please see http://www.jetbrains.org/intellij/sdk/docs/basics/getting_started/build_number_ranges.html for description -->
  <idea-version since-build="173.0"/>

  <!-- please see http://www.jetbrains.org/intellij/sdk/docs/basics/getting_started/plugin_compatibility.html
       on how to target different products -->
  <!-- uncomment to enable plugin in all products
  <depends>com.intellij.modules.lang</depends>
  -->

  <extensions defaultExtensionNs="com.intellij">
    <!-- Add your extensions here -->
  </extensions>

  <actions>
    <!-- Add your actions here -->
  </actions>

</idea-plugin>

3.新建Action

注意：必须将类全部放在文件夹下，不能直接放在src目录中，否则打包后运行会报这个错：

java.lang.NullPointerException
	at com.android.tools.idea.diagnostics.AndroidStudioSystemHealthMonitor.getActionName(AndroidStudioSystemHealthMonitor.java:744)
	at com.android.tools.idea.diagnostics.AndroidStudioSystemHealthMonitor.countActionInvocation(AndroidStudioSystemHealthMonitor.java:630)
	at com.android.tools.idea.diagnostics.AndroidStudioSystemHealthMonitor$3.countActionInvocation(AndroidStudioSystemHealthMonitor.java:353)
	at com.intellij.ide.AndroidStudioSystemHealthMonitorAdapter.countActionInvocation(AndroidStudioSystemHealthMonitorAdapter.java:29)
	at com.intellij.openapi.actionSystem.impl.ActionManagerImpl.fireBeforeActionPerformed(ActionManagerImpl.java:1196)
	at com.intellij.openapi.actionSystem.impl.ActionMenuItem$ActionTransmitter.lambda$actionPerformed$0(ActionMenuItem.java:302)
	...

在src下新建一个文件夹，例如com.study.demo。在文件夹下新建一个Action：将光标定位到文件夹上 → File → New → Plugin DevKit → Action

输入Action信息，例如：

需要注意的是，Groups代表该插件安装后显示在哪里。我们选择CodeMenu，代表Code菜单栏下，Anchor表示在Code菜单栏下的第一个位置还是最后一个位置，我们选择Last。
点击 OK 后会自动生成这个我们自定义的MainAction类，同时在plugin.xml中会自动生成以下<action>标签：

<actions>
  <action id="MainAction.ID" class="com.study.demo.MainAction" text="MyPlugin"
      description="This is a demo for study IDEA Plugin.">
    <add-to-group group-id="CodeMenu" anchor="last" />
  </action>
</actions>

当然，我们也可以不使用 Plugin DevKit 快捷方式，改为自己手动创建Action类，并添加类似的<action>标签，效果一样。

4.编写逻辑

修改MainAction代码如下：

public class MainAction extends AnAction {

    @Override
    public void actionPerformed(AnActionEvent e) {
        Project project = e.getData(PlatformDataKeys.PROJECT);
        String text = Messages.showInputDialog(project,
                "What do you want to listen?",
                "I will say it to you",
                Messages.getQuestionIcon());
        Messages.showMessageDialog(project,
                text,
                "Greeting",
                Messages.getInformationIcon());
    }
}