使用虚拟表和虚拟树的确可以很大程度地提供UI界面的性能,尤其是在大数据量的情况下,对于TableViewer使用虚拟表很简单,只要在创建TableViewer的时候指定SWT.VIRTUAL即可
tableViewer = new TableViewer(container, SWT.FULL_SELECTION | SWT.BORDER | SWT.HIDE_SELECTION|SWT.VIRTUAL);
在以前的版本,TableViewer要使用virtual table的时候,需要实现ILazyContentProvider接口,但是目前好像是不用了,下面附上两个eclipse社区提供的例子
Snippet030VirtualLazyTableViewer.java,使用的是实现ILazyContentProvider接口
import org.eclipse.jface.viewers.ILazyContentProvider; import org.eclipse.jface.viewers.IStructuredContentProvider; import org.eclipse.jface.viewers.LabelProvider; import org.eclipse.jface.viewers.TableViewer; import org.eclipse.jface.viewers.Viewer; import org.eclipse.swt.SWT; import org.eclipse.swt.layout.FillLayout; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; /** * A simple TableViewer to demonstrate usage of an ILazyContentProvider. You can compare this snippet to the Snippet029VirtualTableViewer * to see the small but needed difference. * * @author Tom Schindl <[email protected]> * */ public class Snippet030VirtualLazyTableViewer { private class MyContentProvider implements IStructuredContentProvider, ILazyContentProvider { private TableViewer viewer; private MyModel[] elements; public MyContentProvider(TableViewer viewer) { this.viewer = viewer; } /* (non-Javadoc) * @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object) */ public Object[] getElements(Object inputElement) { return elements; } /* (non-Javadoc) * @see org.eclipse.jface.viewers.IContentProvider#dispose() */ public void dispose() { } /* (non-Javadoc) * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer, java.lang.Object, java.lang.Object) */ public void inputChanged(Viewer viewer, Object oldInput, Object newInput) { this.elements = (MyModel[])newInput; } public void updateElement(int index) { viewer.replace(elements[index], index); } } public class MyModel { public int counter; public MyModel(int counter) { this.counter = counter; } public String toString() { return "Item " + this.counter; } } public Snippet030VirtualLazyTableViewer(Shell shell) { final TableViewer v = new TableViewer(shell,SWT.VIRTUAL); v.setLabelProvider(new LabelProvider()); v.setContentProvider(new MyContentProvider(v)); v.setUseHashlookup(true); MyModel[] model = createModel(); v.setInput(model); v.setItemCount(model.length); // This is the difference when using a ILazyContentProvider v.getTable().setLinesVisible(true); } private MyModel[] createModel() { MyModel[] elements = new MyModel[10000]; for( int i = 0; i < 10000; i++ ) { elements[i] = new MyModel(i); } return elements; } /** * @param args */ public static void main(String[] args) { Display display = new Display (); Shell shell = new Shell(display); shell.setLayout(new FillLayout()); new Snippet030VirtualLazyTableViewer(shell); shell.open (); while (!shell.isDisposed ()) { if (!display.readAndDispatch ()) display.sleep (); } display.dispose (); } }
Snippet029VirtualTableViewer.java 更加方便,直接指定SWT.VIRTUAL即可
import org.eclipse.jface.viewers.IStructuredContentProvider; import org.eclipse.jface.viewers.LabelProvider; import org.eclipse.jface.viewers.TableViewer; import org.eclipse.jface.viewers.Viewer; import org.eclipse.swt.SWT; import org.eclipse.swt.layout.FillLayout; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; /** * A simple TableViewer to demonstrate the usage of a standard content provider * with a virtual table * * @author Tom Schindl <[email protected]> * */ public class Snippet029VirtualTableViewer { private class MyContentProvider implements IStructuredContentProvider { private MyModel[] elements; /* * (non-Javadoc) * * @see org.eclipse.jface.viewers.IStructuredContentProvider#getElements(java.lang.Object) */ public Object[] getElements(Object inputElement) { return elements; } /* * (non-Javadoc) * * @see org.eclipse.jface.viewers.IContentProvider#dispose() */ public void dispose() { } /* * (non-Javadoc) * * @see org.eclipse.jface.viewers.IContentProvider#inputChanged(org.eclipse.jface.viewers.Viewer, * java.lang.Object, java.lang.Object) */ public void inputChanged(Viewer viewer, Object oldInput, Object newInput) { this.elements = (MyModel[]) newInput; } } public class MyModel { public int counter; public MyModel(int counter) { this.counter = counter; } public String toString() { return "Item " + this.counter; } } public Snippet029VirtualTableViewer(Shell shell) { long time1=System.currentTimeMillis(); final TableViewer v = new TableViewer(shell,SWT.VIRTUAL); v.setLabelProvider(new LabelProvider()); v.setContentProvider(new MyContentProvider()); v.setUseHashlookup(true); MyModel[] model = createModel(); v.setInput(model); v.getTable().setLinesVisible(true); System.out.println(System.currentTimeMillis()-time1); } private MyModel[] createModel() { MyModel[] elements = new MyModel[10000]; for (int i = 0; i < 10000; i++) { elements[i] = new MyModel(i); } return elements; } /** * @param args */ public static void main(String[] args) { Display display = new Display(); Shell shell = new Shell(display); shell.setLayout(new FillLayout()); new Snippet029VirtualTableViewer(shell); shell.open(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) display.sleep(); } display.dispose(); } }
来源网址:http://www.blogjava.net/cherishchen/archive/2007/06/26/126271.aspx