Java SWT 拖动对话框导致应用程序崩溃

Question

我有一个对话框，单击按钮时会加载图像。本质上，当单击按钮时，它会打开按钮上显示的图像的更大版本。对话框打开并显示图像效果很好，但是当我移动对话框时，它会留下痕迹，然后应用程序崩溃。我认为这与使用 SWTResourceManager 有关，因为只有在将新图像加载到应用程序中时才会出现此问题，而不是在已经存在图像时才出现此问题。

这是崩溃时给出的异常

java.lang.IllegalArgumentException: Argument not valid
at org.eclipse.swt.SWT.error(SWT.java:4263)
at org.eclipse.swt.SWT.error(SWT.java:4197)
at org.eclipse.swt.SWT.error(SWT.java:4168)
at org.eclipse.swt.graphics.GC.setFont(GC.java:4405)
at org.eclipse.swt.widgets.Composite.WM_PAINT(Composite.java:1514)
at org.eclipse.swt.widgets.Control.windowProc(Control.java:4585)
at org.eclipse.swt.widgets.Canvas.windowProc(Canvas.java:341)
at org.eclipse.swt.widgets.Display.windowProc(Display.java:4985)
at org.eclipse.swt.internal.win32.OS.DispatchMessageW(Native Method)
at org.eclipse.swt.internal.win32.OS.DispatchMessage(OS.java:2531)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3752)
at hm_Forms.Dialog_Animal_Photo.open(Dialog_Animal_Photo.java:43)
at hm_Forms.Frm_Animal$2.widgetSelected(Frm_Animal.java:145)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:240)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4165)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3754)
at hm_Forms.Frm_Animal.open(Frm_Animal.java:71)
at hm_Composites.Comp_Animal_List$3$1.widgetSelected(Comp_Animal_List.java:118)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:240)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:4165)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3754)
at hm_Forms.Frm_Main.open(Frm_Main.java:76)
at hm_Forms.Frm_Main.main(Frm_Main.java:60)

---将图像保存到应用程序的代码---

btnSave.addSelectionListener(new SelectionAdapter() {
        @Override
        public void widgetSelected(SelectionEvent e) {
            String path = txtPhotoPath.getText();
            if (CC_Files.fileExists(path)) {
                ArrayList<String> picTypes = new ArrayList<String>();
                picTypes.add(".jpg");
                picTypes.add(".png");
                picTypes.add(".gif");
                int t = 0;

                for(int i = 0; i < picTypes.size(); i++){
                    String s = picTypes.get(i);
                    if(path.contains(s.toUpperCase())){
                        t++;
                    }
                    if(path.contains(s.toLowerCase())){
                        t++;
                    }
                }
                if (t > 0) {
                    SWTResourceManager.dispose();
                    Image image = (Image) SWTResourceManager.getImage(path);
                    ImageData imgData = image.getImageData();
                    ImageLoader imageLoader = new ImageLoader();
                    imageLoader.data = new ImageData[] { imgData };
                    imageLoader.save(Variables.getStrResources()
                            + "Pics\\" + a.getHerd_id() + "a.jpg",
                            SWT.IMAGE_JPEG);

                    int intH = image.getBounds().height;
                    int intW = image.getBounds().width;
                    int h = (150 * intH) / intW;
                    int w = 150;
                    if (h > 150){
                        h = 150;
                        w = (150 * intW) / intH;
                    }
                    imgData = imgData.scaledTo(w, h);
                    imageLoader.data = new ImageData[] { imgData };
                    imageLoader.save(Variables.getStrResources()
                            + "Pics\\" + a.getHerd_id() + ".jpg",
                            SWT.IMAGE_JPEG);
                    image.dispose();

                    try {
                        Frm_Animal.setAnimalEditSC(Frm_Animal
                                .createAnimalComp(a));
                    } catch (Exception e1) {
                        // TODO Auto-generated catch block
                        e1.printStackTrace();
                    }
                }
            }
        }
    });

---Dialog_Animal_Photo 代码---

package hm_Forms;

import hm.Animal;
import hm.Variables;

import org.eclipse.swt.SWT;
import org.eclipse.swt.custom.CLabel;
import org.eclipse.swt.graphics.Image;
import org.eclipse.swt.layout.GridData;
import org.eclipse.swt.layout.GridLayout;
import org.eclipse.swt.widgets.Dialog;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.wb.swt.SWTResourceManager;

import CC_Library.CC_Files;

public class Dialog_Animal_Photo extends Dialog {

protected Object result;
protected Shell shell;

/**
 * Create the dialog.
 * @param parent
 * @param style
 */
public Dialog_Animal_Photo(Shell parent, int style, Animal a) {
    super(parent, SWT.DIALOG_TRIM);
    setText(a.getTag());
}

/**
 * Open the dialog.
 * @return the result
 */
public Object open(Animal a) {
    createContents(a);
    shell.open();
    shell.layout();
    Display display = getParent().getDisplay();
    while (!shell.isDisposed()) {
        if (!display.readAndDispatch()) {
            display.sleep();
        }
    }
    return result;
}

/**
 * Create contents of the dialog.
 */
private void createContents(Animal a) {
    shell = new Shell(getParent(), SWT.SHELL_TRIM | SWT.BORDER |     SWT.APPLICATION_MODAL);

    shell.setText(getText());
    shell.setLayout(new GridLayout(1, false));

    CLabel lblPic = new CLabel(shell, SWT.NONE);
    lblPic.setLayoutData(new GridData(SWT.CENTER, SWT.FILL, true, true, 1, 1));
    lblPic.setText("");

    Image image = null;

    String strPic = Variables.getStrResources() + "Pics\\" + a.getHerd_id()
            + "a.jpg";
    //SWTResourceManager.dispose();
    if (CC_Files.fileExists(strPic)) {
        image = (Image) SWTResourceManager.getImage(strPic);
    } else {
        image = (Image) SWTResourceManager.getImage(Variables
                .getStrResources() + "black_cow.png");
    }
    //shell.setSize(500,500);
    shell.setSize(image.getBounds().width + 25,image.getBounds().height + 50);
    lblPic.setImage(image);
}
}

---打开对话框的按钮代码---

Dialog_Animal_Photo dap = new Dialog_Animal_Photo(shell, SWT.NONE, a);
            dap.open(a);

Answer 1

由于您正在使用 SWTResourceManager 并调用 dispose()，其定义为:

public static void dispose() {
    disposeColors();
    disposeImages();
    disposeFonts();
    disposeCursors();
}

这也会处理所有缓存的Font。

为了防止出现异常，请不要调用 dispose()，而是调用 disposeImages()。