Eclipse 4 RCP窗口居中-使用LifeCycleHandler

最近几年随着互联网技术的发展，特别是出现React等前端组件化技术后，网页开发越来越方便，使用Eclipse RCP技术的开发人员也越来越少了。原本觉得Eclipse RCP (Rich Client Platform) - Tutorial已经有较详细的文档说明了，更把以前的Eclipse RCP抛掉，没想到这个网站把以前很多高级技术部分的文档改为收费了。最近想学习一下Eclipse 4 RCP，遇到窗口居中的问题，值得记录下来。

1、在plugin.xml文件的product扩展点增加lifeCycleURI内容如下：

<xml version="1.0" encoding="UTF-8">
<eclipse version="3.4">
<plugin>
   <extension
         id="product"
         point="org.eclipse.core.runtime.products">
      <product
            application="org.eclipse.e4.ui.workbench.swt.E4Application"
            name="tech.scut.e4.rcp">
         <property
               name="lifeCycleURI"
               value="bundleclass://tech.scut.e4.rcp/tech.scut.e4.rcp.E4LifeCycle">
         </property>
         <property
               name="applicationCSS"
               value="platform:/plugin/tech.scut.e4.rcp/css/default.css">
         </property>
         <property
               name="appName"
               value="tech.scut.e4.rcp">
         </property>
      </product>
   </extension>
</plugin>

2、E4LifeCycle类内容如下，其中MWINDOW_ID为Application.e4xmi里的Trimmed Window的ID：

package tech.scut.e4.rcp;
 
import org.eclipse.e4.core.contexts.IEclipseContext;
import org.eclipse.e4.ui.model.application.MApplication;
import org.eclipse.e4.ui.model.application.ui.basic.MTrimmedWindow;
import org.eclipse.e4.ui.model.application.ui.basic.MWindow;
import org.eclipse.e4.ui.workbench.lifecycle.PostContextCreate;
import org.eclipse.e4.ui.workbench.lifecycle.PreSave;
import org.eclipse.e4.ui.workbench.lifecycle.ProcessAdditions;
import org.eclipse.e4.ui.workbench.lifecycle.ProcessRemovals;
import org.eclipse.e4.ui.workbench.modeling.EModelService;
import org.eclipse.swt.graphics.Rectangle;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Monitor;
 
/**
 * This is a stub implementation containing e4 LifeCycle annotated
 * methods.

 * There is a corresponding entry in plugin.xml (under the
 * org.eclipse.core.runtime.products' extension point) that references
 * this class.
 **/
public class E4LifeCycle {
    public static final String MWINDOW_ID="tech.scut.e4.rcp.window.main";
 
    @PostContextCreate
    void postContextCreate(IEclipseContext workbenchContext) {
    }
 
    @PreSave
    void preSave(IEclipseContext workbenchContext) {
    }
 
    @ProcessAdditions
    void processAdditions(MApplication app, EModelService modelService) {
MTrimmedWindow window=(MTrimmedWindow)modelService.find(MWINDOW_ID, app);
 
        // 窗口居中
        Display display = Display.getDefault();
        this.setLocation(display, window);
    }
 
    /**
     * 窗口居中
     * 
     * @param display
     * @param window
     */
    private void setLocation(Display display, MWindow window) {
        Monitor monitor = display.getPrimaryMonitor();
        Rectangle monitorRect = monitor.getBounds();
        int x=monitorRect.x+(monitorRect.width-window.getWidth())/2;
        int y=monitorRect.y+(monitorRect.height-window.getHeight())/2;
        window.setX(x);
        window.setY(y);
    }
 
    @ProcessRemovals
    void processRemovals(IEclipseContext workbenchContext) {
    }
}

至此，完成E4 RCP的窗口居中。