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[Java教程]如何在RCP程序中添加一个banner栏


前言:这段时间还算比较空闲,我准备把过去做过的有些形形色色,甚至有些奇怪的研究总结一下,也许刚好有人用的着也不一定,不枉为之抓耳挠腮的时光和浪费的电力。以前有个客户提出要在RCP程序中添加一个banner栏,研究了很久才搞定。代码是基于eclipse4.3.2的。

先看一下效果预览:

image

 

为了添加一个banner栏,我们必须重写RCP程序最外层的layout类,即TrimmedPartLayout.java。这个layout类是用来控制menu,toolbar等最基本的layout布局的。我们写一个CustomTrimmedPartLayout 类,继承自TrimmedPartLayout:

public class CustomTrimmedPartLayout extends TrimmedPartLayout {  public Composite banner;  /**   * This layout is used to support parts that want trim for their containing   * composites.   *   * @param trimOwner   */  public CustomTrimmedPartLayout(Composite parent) {    super(parent);    banner 
= new Composite(parent, SWT.NONE); GridLayout gridLayout = new GridLayout(1, false); gridLayout.horizontalSpacing=0; gridLayout.verticalSpacing = 0; gridLayout.marginHeight = 0; gridLayout.marginWidth = 0
;    banner.setLayout(gridLayout);    //banner.setLayoutData(new GridData(GridData.FILL_BOTH));  }    protected void layout(Composite composite, boolean flushCache) {    Rectangle ca = composite.getClientArea();    Rectangle caRect = new Rectangle(ca.x, ca.y, ca.width, ca.height);    
// 'banner' spans the entire area if (banner != null && banner.isVisible() ) { Point bannerSize = banner.computeSize(caRect.width, SWT.DEFAULT, true); // Don't layout unless we've changed Rectangle newBounds = new Rectangle(caRect.x, caRect.y, bannerSize.x, bannerSize.y); caRect.y += bannerSize.y; caRect.height -= bannerSize.y; if (!
newBounds.equals(banner.getBounds())) {          banner.setBounds(newBounds);      }    }            // 'Top' spans the entire area         if (top != null && top.isVisible()) {      Point topSize = top.computeSize(caRect.width, SWT.DEFAULT, true);      // Don't layout unless we've changed      Rectangle newBounds = new Rectangle(caRect.x, caRect.y, caRect.width,          topSize.y);      if (!newBounds.equals(top.getBounds())) {        top.setBounds(newBounds);      }            caRect.y += topSize.y;      caRect.height -= topSize.y;    }        // Include the gutter whether there is a top area or not.    caRect.y += gutterTop;    caRect.height -= gutterTop;    // 'Bottom' spans the entire area    if (bottom != null && bottom.isVisible()) {      Point bottomSize = bottom.computeSize(caRect.width, SWT.DEFAULT,          true);      caRect.height -= bottomSize.y;      // Don't layout unless we've changed      Rectangle newBounds = new Rectangle(caRect.x, caRect.y          + caRect.height, caRect.width, bottomSize.y);      if (!newBounds.equals(bottom.getBounds())) {        bottom.setBounds(newBounds);      }    }    caRect.height -= gutterBottom;    // 'Left' spans between 'top' and 'bottom'    if (left != null && left.isVisible()) {      Point leftSize = left.computeSize(SWT.DEFAULT, caRect.height, true);      caRect.x += leftSize.x;      caRect.width -= leftSize.x;      // Don't layout unless we've changed      Rectangle newBounds = new Rectangle(caRect.x - leftSize.x,          caRect.y, leftSize.x, caRect.height);      if (!newBounds.equals(left.getBounds())) {        left.setBounds(newBounds);      }    }    caRect.x += gutterLeft;    caRect.width -= gutterLeft;    // 'Right' spans between 'top' and 'bottom'    if (right != null && right.isVisible()) {      Point rightSize = right.computeSize(SWT.DEFAULT, caRect.height,          true);      caRect.width -= rightSize.x;      // Don't layout unless we've changed      Rectangle newBounds = new Rectangle(caRect.x + caRect.width,          caRect.y, rightSize.x, caRect.height);      if (!newBounds.equals(right.getBounds())) {        right.setBounds(newBounds);      }    }    caRect.width -= gutterRight;    // Don't layout unless we've changed    if (!caRect.equals(clientArea.getBounds())) {      clientArea.setBounds(caRect);    }  }}

 

如果我们希望Banner放在工具栏下面,而不是上面,只要稍微修改一下代码的位置

public class CustomTrimmedPartLayout extends TrimmedPartLayout {public Composite banner;  /**   * This layout is used to support parts that want trim for their containing   * composites.   *   * @param trimOwner   */  public CustomTrimmedPartLayout(Composite parent) {    super(parent);     banner 
= new Composite(parent, SWT.NONE); GridLayout gridLayout = new GridLayout(1, false); gridLayout.horizontalSpacing=0; gridLayout.verticalSpacing = 0; gridLayout.marginHeight = 0; gridLayout.marginWidth = 0
;    banner.setLayout(gridLayout);    //banner.setLayoutData(new GridData(GridData.FILL_BOTH));  }    protected void layout(Composite composite, boolean flushCache) {    Rectangle ca = composite.getClientArea();    Rectangle caRect = new Rectangle(ca.x, ca.y, ca.width, ca.height);            // 'Top' spans the entire area         if (top != null && top.isVisible()) {      Point topSize = top.computeSize(caRect.width, SWT.DEFAULT, true);      // Don't layout unless we've changed      Rectangle newBounds = new Rectangle(caRect.x, caRect.y, caRect.width,          topSize.y);      if (!newBounds.equals(top.getBounds())) {        top.setBounds(newBounds);      }            caRect.y += topSize.y;      caRect.height -= topSize.y;    }        
// 'banner' spans the entire area if (banner != null && banner.isVisible()) { Point bannerSize = banner.computeSize(caRect.width, SWT.DEFAULT, true); // Don't layout unless we've changed Rectangle newBounds = new Rectangle(caRect.x, caRect.y, bannerSize.x, bannerSize.y); caRect.y += bannerSize.y; caRect.height -= bannerSize.y; if (!
newBounds.equals(banner.getBounds())) {            banner.setBounds(newBounds);        }      }        // Include the gutter whether there is a top area or not.    caRect.y += gutterTop;    caRect.height -= gutterTop;    // 'Bottom' spans the entire area    if (bottom != null && bottom.isVisible()) {      Point bottomSize = bottom.computeSize(caRect.width, SWT.DEFAULT,          true);      caRect.height -= bottomSize.y;      // Don't layout unless we've changed      Rectangle newBounds = new Rectangle(caRect.x, caRect.y          + caRect.height, caRect.width, bottomSize.y);      if (!newBounds.equals(bottom.getBounds())) {        bottom.setBounds(newBounds);      }    }    caRect.height -= gutterBottom;    // 'Left' spans between 'top' and 'bottom'    if (left != null && left.isVisible()) {      Point leftSize = left.computeSize(SWT.DEFAULT, caRect.height, true);      caRect.x += leftSize.x;      caRect.width -= leftSize.x;      // Don't layout unless we've changed      Rectangle newBounds = new Rectangle(caRect.x - leftSize.x,          caRect.y, leftSize.x, caRect.height);      if (!newBounds.equals(left.getBounds())) {        left.setBounds(newBounds);      }    }    caRect.x += gutterLeft;    caRect.width -= gutterLeft;    // 'Right' spans between 'top' and 'bottom'    if (right != null && right.isVisible()) {      Point rightSize = right.computeSize(SWT.DEFAULT, caRect.height,          true);      caRect.width -= rightSize.x;      // Don't layout unless we've changed      Rectangle newBounds = new Rectangle(caRect.x + caRect.width,          caRect.y, rightSize.x, caRect.height);      if (!newBounds.equals(right.getBounds())) {        right.setBounds(newBounds);      }    }    caRect.width -= gutterRight;    // Don't layout unless we've changed    if (!caRect.equals(clientArea.getBounds())) {      clientArea.setBounds(caRect);    }  }}

 

最后,我们需要把shell加载的layout从TrimmedPartLayout替换为CustomTrimmedPartLayout。

在ApplicationWorkbenchWindowAdvisor 的preWindowOpen中添加如下代码:

public class ApplicationWorkbenchWindowAdvisor extends WorkbenchWindowAdvisor {...  public void preWindowOpen() {    IWorkbenchWindowConfigurer configurer = getWindowConfigurer();    configurer.setInitialSize(new Point(600, 400));    configurer.setShowCoolBar(true);    configurer.setShowPerspectiveBar(true);    configurer.setShowStatusLine(true);    configurer.setShowProgressIndicator(false);    configurer.setShowFastViewBars(false);        IWorkbenchWindow workbenchWindow= configurer.getWindow();    workbenchWindow= configurer.getWindow();        Shell shell 
= workbenchWindow.getShell(); TrimmedPartLayout layout = (TrimmedPartLayout)shell.getLayout(); CustomTrimmedPartLayout customLayout = new CustomTrimmedPartLayout(layout.clientArea.getParent()); customLayout.clientArea =
 layout.clientArea;    shell.setLayout(customLayout);    Label bannerLabel 
= new Label(customLayout.banner, SWT.SIMPLE|SWT.CENTER); customLayout.banner.setBackground(…); GridData gridData = new GridData(SWT.FILL, SWT.FILL, true, true); bannerLabel.setLayoutData(gridData); Image image =
 Activator.getImageDescriptor(bannerExtensionPoint.getImage()).createImage();    bannerLabel.setImage(image);  }....}

 

其中 ---

标记为绿色的代码是用来替换Layout类的

标记为蓝色的代码是用来在banner中创建一个Label,并加载一张作为banner的图片。