Question

我有一个以网格布局显示的项目列表。每行都有几个图像按钮。当行数超过1000时，我得到org.eclipse.swt.SWTError: No more handles例外。

我使用Sleak.java并发现内存中有许多图像。是否有可能以某种方式重复使用这些按钮？

以下是Sleak的统计信息。

颜色：8 游标：6 字体：19 图片：1317

代码：

private void looper(List<File> dicomFiles, int start, int stop, int toShow){
        for(int i=start; i<stop; i++){
            File dicomFile = dicomFiles.get(i);
            Composite rowComposite = new Composite(dicomFilecomposite, SWT.None);
            rowComposite.setLayout(configRowCompositeLayout());
            rowComposite.setLayoutData(getRowCompositeGridData());
            rowComposite.setBackground(Colors.CELL_BG_COLOR);
            Label dicomFIleLabel = new Label(rowComposite, SWT.NULL);
            dicomFIleLabel.setLayoutData(new GridData());
            dicomFIleLabel.setText(dicomFile.getName());
            dicomFIleLabel.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
            dicomFIleLabel.setFont(FONT_10);
            Label fileSizeLabel = new Label(rowComposite, SWT.None);
            fileSizeLabel.setText((dicomFile.length() / 1000)+" "+Const.KB_LABEL);
            fileSizeLabel.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
            Composite progBarLabelComposite = new Composite(rowComposite, SWT.None);
            progBarLabelComposite.setLayout(new RowLayout());
            ProgressBar progressBar = new ProgressBar(progBarLabelComposite, SWT.HORIZONTAL | SWT.SMOOTH);
            progressBar.setVisible(true);
            Label progressPercentageLabel = new Label(progBarLabelComposite, SWT.None);
            progressPercentageLabel.setText(Const.INITIAL_PROGBAR_PERCENTAGE);
            progressPercentageLabel.setForeground(display.getSystemColor(SWT.COLOR_WHITE));
            Composite btnWrapperComposite = new Composite(rowComposite, SWT.None);
            btnWrapperComposite.setLayout(configZeroMarginLayout(true));
            GridData btnWrapperCompositeGridData = new GridData();
            btnWrapperCompositeGridData.horizontalAlignment = GridData.END;
            btnWrapperCompositeGridData.grabExcessHorizontalSpace = true;
            btnWrapperComposite.setLayoutData(btnWrapperCompositeGridData);
            Composite uploadCancelBtnComposite = new Composite(btnWrapperComposite, SWT.None);
            uploadCancelBtnComposite.setLayout(new RowLayout());
            Composite uploadBtnComposite = new Composite(uploadCancelBtnComposite, SWT.NULL);
            uploadBtnComposite.setLayout(configZeroMarginLayout(false));
            ImageButton uploadButton = new ImageButton(uploadBtnComposite, SWT.PUSH);
            uploadButton.setImage(Const.UPLOAD_BTN_BG_IMAGE);
            uploadButton.setListener(MainShell.this);
            uploadButton.setCursor(HAND_CURSOR);
            uploadButton.setToolTipText(Const.UPLOAD_LABEL);
            ImageButton cancelButton = new ImageButton(uploadCancelBtnComposite, SWT.PUSH);
            cancelButton.setImage(Const.DELETE_BTN_BG_IMAGE);
            cancelButton.setListener(MainShell.this);
            cancelButton.setCursor(HAND_CURSOR);
            cancelButton.setToolTipText(Const.DELETE_LABEL);
            FileUploadData fileUploadData = loadFileUploadData(progBarLabelComposite, dicomFilecomposite, dicomFile, progressBar, progressPercentageLabel);
            uploadButton.setData(fileUploadData);
            uploadButton.setData(IMG_BTN_DATA_KEY, Const.UPLOAD_LABEL);
            uploadButtons.add(uploadButton);
            fileUploadDatas.add(fileUploadData);
            cancelButton.setData(fileUploadData);
            cancelButton.setData(IMG_BTN_DATA_KEY, Const.DELETE_LABEL);
            loadSeparatorField(rowComposite);
        }
    }

这两行是我理解中出现问题的地方。

ImageButton uploadButton = new ImageButton(uploadBtnComposite, SWT.PUSH);
    ImageButton cancelButton = new ImageButton(uploadCancelBtnComposite, SWT.PUSH);

Answer 1

在SWT中，您无法重复使用按钮，但可以重复使用图像。写一个单例类说ImageCache并缓存其中的所有图像，并在需要的地方从该类中获取图像。我遇到了同样的问题并以这种方式解决了。还要在UI组件中创建自定义配置方法并自行配置UI组件，因为在大多数情况下，SWT不会正确处理它们并且资源会泄漏。

SWT最佳实践说“必须缓存所有资源”，因此必须在相应的ItemRenderer中缓存和使用您的字体，颜色，图像。

如何在SWT中重用图像

1 个答案: