我正在做一个需要线程的程序，因为它在GUI开始工作时没有响应。我使用了thread，但我不知道使用它是否正确，我也使用了display.asyncExec每个都给了我错误
这是代码
btnCopyFolder.addSelectionListener(new SelectionAdapter() {
@Override
public void widgetSelected(SelectionEvent arg0) {
display.asyncExec(
new Runnable()
{
public void run(){
File srcFolder = new File(txtSource.getText());
File destFolder = new File(txtDestination.getText());
if(!srcFolder.exists()){
MessageBox msgBox = new MessageBox(shell, SWT.ICON_INFORMATION | SWT.OK);
msgBox.setText("Information");
msgBox.setMessage("Directory does not exist.");
msgBox.open();
txtSource.setText("");
txtSource.setEnabled(false);
txtDestination.setText("");
}else{
if(txtDestination.getText().isEmpty())
{
MessageBox msgBox = new MessageBox(shell, SWT.ICON_WARNING | SWT.OK);
msgBox.setText("WARNING");
msgBox.setMessage("Invalid Path...");
msgBox.open();
txtSource.setText("");
txtSource.setEditable(false);
txtDestination.setText("");
btnCopyFolder.setEnabled(true);
btnCopyFile.setEnabled(true);
}
else
{
try {
tc.copyFolder(srcFolder,destFolder);
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
txtDetails.append("Finished Copying.....\n");
MessageBox msgBox = new MessageBox(shell, SWT.ICON_INFORMATION | SWT.OK);
msgBox.setText("Information");
msgBox.setMessage("Done Copying...");
msgBox.open();
txtSource.setText("");
txtSource.setEditable(false);
txtDestination.setText("");
btnCopyFolder.setEnabled(true);
btnCopyFile.setEnabled(true);
tc1 = new threadclass();
tc = new threadclass();
tc1.start();
tc.start();
}
}
}
});
}
});
错误
java.lang.NullPointerException
at org.eclipse.wb.swt.FortryApplication$5.widgetSelected(FortryApplication.java:303)
at org.eclipse.swt.widgets.TypedListener.handleEvent(Unknown Source)
at org.eclipse.swt.widgets.EventTable.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Widget.sendEvent(Unknown Source)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Unknown Source)
at org.eclipse.swt.widgets.Display.readAndDispatch(Unknown Source)
at org.eclipse.wb.swt.FortryApplication.open(FortryApplication.java:63)
at org.eclipse.wb.swt.FortryApplication.main(FortryApplication.java:486)
for Thread我试过这些
btnCopyFile.addSelectionListener(new SelectionAdapter() {
@Override
public void widgetSelected(SelectionEvent arg0)
{
new Thread(){
public void run()
{
File srcFolder = new File(txtSource.getText());
File destFolder = new File(txtDestination.getText());
if(!srcFolder.exists()){
MessageBox msgBox = new MessageBox(shell, SWT.ICON_INFORMATION | SWT.OK);
msgBox.setText("Information");
msgBox.setMessage("Directory does not exist.");
msgBox.open();
txtSource.setText("");
txtSource.setEditable(false);
txtDestination.setText("");
}else{
if(txtDestination.getText().isEmpty())
{
MessageBox msgBox = new MessageBox(shell, SWT.ICON_WARNING | SWT.OK);
msgBox.setText("Warning");
msgBox.setMessage("Invalid Path..");
msgBox.open();
txtSource.setText("");
txtSource.setEditable(false);
txtDestination.setText("");
btnCopyFolder.setEnabled(true);
btnCopyFile.setEnabled(true);
}
else
{
try {
tc.copyFolder1(srcFolder,destFolder);
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
txtDetails.append("Finished Copying.....\n");
MessageBox msgBox = new MessageBox(shell, SWT.ICON_INFORMATION | SWT.OK);
msgBox.setText("Information");
msgBox.setMessage("Done Copying...");
msgBox.open();
txtSource.setText("");
txtSource.setEditable(false);
txtDestination.setText("");
btnCopyFolder.setEnabled(true);
btnCopyFile.setEnabled(true);
// tc1 = new threadclass();
// tc = new threadclass();
// tc1.start();
// tc.start();
}
}
}
}.start();
}
});
错误显示：
Exception in thread "Thread-2" org.eclipse.swt.SWTException: Invalid thread access
at org.eclipse.swt.SWT.error(Unknown Source)
at org.eclipse.swt.SWT.error(Unknown Source)
at org.eclipse.swt.SWT.error(Unknown Source)
at org.eclipse.swt.widgets.Widget.error(Unknown Source)
at org.eclipse.swt.widgets.Widget.checkWidget(Unknown Source)
at org.eclipse.swt.widgets.Text.getText(Unknown Source)
at org.eclipse.wb.swt.FortryApplication$4$1.run(FortryApplication.java:239)
编辑
完整代码：
ublic class FortryApplication implements Runnable {
static Display display;
static Shell shell;
static Color color;
private static Text txtSource;
private static Text txtDestination;
private static Text txtDetails;
static DateTime dateFrom;
static DateTime dateTo;
Button btnSourceFile, btnSelectFolder;
Button btnBrowseFile;
Button btnCopyFolder;
Button btnCopyFile;
Button btnCancel;
static String text = "" ;
static String text2 = "" ;
threadclass tc = new threadclass();
threadclass tc1 = new threadclass();
// pos x, pos y, width, height
public void open() {
Display display = Display.getDefault();
createContents();
shell.open();
shell.layout();
while (!shell.isDisposed()) {
if (!display.readAndDispatch()) {
display.sleep();
}
}
}
protected void createContents()
{
shell = new Shell();
shell.setSize(600,530);
shell.setText("SWT Shell Demonstration");
shell.setLayout(new GridLayout());
final Group grpInput = new Group(shell, SWT.NONE);
grpInput.setFont(SWTResourceManager.getFont("Segoe UI", 11, SWT.NORMAL));
grpInput.setText("Input File");
GridLayout gl_grpInput = new GridLayout();
gl_grpInput.numColumns = 3;
grpInput.setLayout(gl_grpInput);
GridData gd_grpInput = new GridData(GridData.FILL_HORIZONTAL);
gd_grpInput.widthHint = 419;
gd_grpInput.verticalAlignment = SWT.CENTER;
gd_grpInput.heightHint = 57;
grpInput.setLayoutData(gd_grpInput);
btnSourceFile = new Button(grpInput, SWT.PUSH);
btnSourceFile.addSelectionListener(new SelectionAdapter() {
@Override
public void widgetSelected(SelectionEvent arg0) {
FileDialog fd = new FileDialog(shell, SWT.MULTI);
// Collection files = new ArrayList();
String firstFile = fd.open();
if (firstFile != null) {
txtSource.setText("");
String[] selectedFiles = fd.getFileNames();
File file = new File(firstFile);
for (int ii = 0; ii < selectedFiles.length; ii++ )
{
if (file.isFile())
{
tc.displayFiles(new String[] { file.toString()});
}
else
tc.displayFiles(file.list());
}
}
btnCopyFolder.setEnabled(false);
btnCopyFile.setEnabled(true);
btnCancel.setEnabled(true);
}
});
btnSourceFile.setText("Select File");
btnSelectFolder = new Button(grpInput, SWT.NONE);
btnSelectFolder.addSelectionListener(new SelectionAdapter() {
@Override
public void widgetSelected(SelectionEvent arg0) {
DirectoryDialog dlg = new DirectoryDialog(shell);
dlg.setFilterPath(txtSource.getText());
dlg.setMessage("Select a source file to transfer");
String dir = dlg.open();
if (dir != null) {
txtSource.setText(dir);
btnCopyFile.setEnabled(false);
btnCopyFolder.setEnabled(true);
btnCancel.setEnabled(true);
// txtDetails.setText("Progress " + "\n");
}
}
});
btnSelectFolder.setText("Select Folder");
new Label(grpInput, SWT.NONE);
txtSource = new Text(grpInput, SWT.BORDER);
txtSource.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, true, false, 2, 1));
new Label(grpInput, SWT.NONE);
Group grpDestnationFile = new Group(shell, SWT.NONE);
grpDestnationFile.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false, 1, 1));
grpDestnationFile.setText("Destnation File");
grpDestnationFile.setFont(SWTResourceManager.getFont("Segoe UI", 11, SWT.NORMAL));
GridLayout gl_grpDestnationFile = new GridLayout();
gl_grpDestnationFile.numColumns = 2;
grpDestnationFile.setLayout(gl_grpDestnationFile);
btnBrowseFile = new Button(grpDestnationFile, SWT.NONE);
btnBrowseFile.addSelectionListener(new SelectionAdapter() {
@Override
public void widgetSelected(SelectionEvent arg0) {
DirectoryDialog dialog = new DirectoryDialog(shell, SWT.SAVE);
dialog.setFilterPath(txtDestination.getText());
String dir = dialog.open();
if(dir != null){
txtDestination.setText(dir);
}
}
});
btnBrowseFile.setText("Browse File");
new Label(grpDestnationFile, SWT.NONE);
txtDestination = new Text(grpDestnationFile, SWT.BORDER);
GridData gd_txtDestination = new GridData(SWT.FILL, SWT.CENTER, true, false, 1, 1);
gd_txtDestination.widthHint = 429;
txtDestination.setLayoutData(gd_txtDestination);
new Label(grpDestnationFile, SWT.NONE);
Label label = new Label(grpDestnationFile, SWT.NONE);
GridData gd_label = new GridData(SWT.FILL, SWT.CENTER, true, false, 3, 1);
gd_label.heightHint = -5;
label.setLayoutData(gd_label);
Group grpDateRange = new Group(shell, SWT.NONE);
grpDateRange.setFont(SWTResourceManager.getFont("Segoe UI", 11, SWT.NORMAL));
GridData gd_grpDateRange = new GridData(SWT.FILL, SWT.CENTER, false, false, 1, 1);
gd_grpDateRange.heightHint = 63;
gd_grpDateRange.widthHint = 78;
grpDateRange.setLayoutData(gd_grpDateRange);
grpDateRange.setText("Date Range");
DateTime dateFrom = new DateTime(grpDateRange, SWT.BORDER);
dateFrom.setBounds(111, 40, 122, 24);
Label lblFrom = new Label(grpDateRange, SWT.NONE);
lblFrom.setBounds(153, 19, 55, 15);
lblFrom.setText("From");
DateTime dateTo = new DateTime(grpDateRange, SWT.BORDER);
dateTo.setBounds(352, 40, 122, 24);
Label lblTo = new Label(grpDateRange, SWT.NONE);
lblTo.setText("To");
lblTo.setBounds(397, 19, 55, 15);
Label label_1 = new Label(grpDateRange, SWT.NONE);
label_1.setFont(SWTResourceManager.getFont("Segoe UI", 12, SWT.NORMAL));
label_1.setBounds(293, 40, 20, 24);
label_1.setText(":");
Group grpDetails = new Group(shell, SWT.NONE);
grpDetails.setLayoutData(new GridData(SWT.FILL, SWT.CENTER, false, false, 1, 1));
grpDetails.setText("Details");
grpDetails.setFont(SWTResourceManager.getFont("Segoe UI", 11, SWT.NORMAL));
GridLayout gl_grpDetails = new GridLayout();
gl_grpDetails.numColumns = 2;
grpDetails.setLayout(gl_grpDetails);
txtDetails = new Text(grpDetails, SWT.BORDER | SWT.READ_ONLY | SWT.WRAP | SWT.H_SCROLL | SWT.V_SCROLL | SWT.CANCEL | SWT.MULTI);
GridData gd_txtDetails = new GridData(SWT.FILL, SWT.CENTER, true, false, 1, 1);
gd_txtDetails.widthHint = 460;
gd_txtDetails.heightHint = 66;
txtDetails.setLayoutData(gd_txtDetails);
new Label(grpDetails, SWT.NONE);
Label label_2 = new Label(grpDetails, SWT.NONE);
GridData gd_label_2 = new GridData(SWT.FILL, SWT.CENTER, true, false, 3, 1);
gd_label_2.heightHint = -3;
label_2.setLayoutData(gd_label_2);
Group grpCopyOptions = new Group(shell, SWT.NONE);
grpCopyOptions.setFont(SWTResourceManager.getFont("Segoe UI", 11, SWT.NORMAL));
GridData gd_grpCopyOptions = new GridData(SWT.FILL, SWT.CENTER, false, false, 1, 1);
gd_grpCopyOptions.heightHint = 70;
gd_grpCopyOptions.widthHint = 492;
grpCopyOptions.setLayoutData(gd_grpCopyOptions);
grpCopyOptions.setText("Copy Options");
btnCopyFile = new Button(grpCopyOptions, SWT.NONE);
btnCopyFile.addSelectionListener(new SelectionAdapter() {
@Override
public void widgetSelected(SelectionEvent arg0)
{
Display.getDefault().asyncExec(
new Runnable()
{
public void run()
{
File srcFolder = new File(txtSource.getText());
File destFolder = new File(txtDestination.getText());
if(!srcFolder.exists()){
MessageBox msgBox = new MessageBox(shell, SWT.ICON_INFORMATION | SWT.OK);
msgBox.setText("Information");
msgBox.setMessage("Directory does not exist.");
msgBox.open();
txtSource.setText("");
txtSource.setEditable(false);
txtDestination.setText("");
}else{
if(txtDestination.getText().isEmpty())
{
MessageBox msgBox = new MessageBox(shell, SWT.ICON_WARNING | SWT.OK);
msgBox.setText("Warning");
msgBox.setMessage("Invalid Path..");
msgBox.open();
txtSource.setText("");
txtSource.setEditable(false);
txtDestination.setText("");
btnCopyFolder.setEnabled(true);
btnCopyFile.setEnabled(true);
}
else
{
try {
tc.copyFolder1(srcFolder,destFolder);
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
txtDetails.append("Finished Copying.....\n");
MessageBox msgBox = new MessageBox(shell, SWT.ICON_INFORMATION | SWT.OK);
msgBox.setText("Information");
msgBox.setMessage("Done Copying...");
msgBox.open();
txtSource.setText("");
txtSource.setEditable(false);
txtDestination.setText("");
btnCopyFolder.setEnabled(true);
btnCopyFile.setEnabled(true);
tc1 = new threadclass();
tc = new threadclass();
tc1.start();
tc.start();
}
}
}
});
}
});
btnCopyFile.setBounds(128, 23, 166, 25);
btnCopyFile.setText("Copy File");
btnCopyFolder = new Button(grpCopyOptions, SWT.NONE);
btnCopyFolder.addSelectionListener(new SelectionAdapter() {
@Override
public void widgetSelected(SelectionEvent arg0) {
Display.getDefault().asyncExec(
new Runnable()
{
public void run(){
File srcFolder = new File(txtSource.getText());
File destFolder = new File(txtDestination.getText());
if(!srcFolder.exists()){
MessageBox msgBox = new MessageBox(shell, SWT.ICON_INFORMATION | SWT.OK);
msgBox.setText("Information");
msgBox.setMessage("Directory does not exist.");
msgBox.open();
txtSource.setText("");
txtSource.setEnabled(false);
txtDestination.setText("");
}else{
if(txtDestination.getText().isEmpty())
{
MessageBox msgBox = new MessageBox(shell, SWT.ICON_WARNING | SWT.OK);
msgBox.setText("WARNING");
msgBox.setMessage("Invalid Path...");
msgBox.open();
txtSource.setText("");
txtSource.setEditable(false);
txtDestination.setText("");
btnCopyFolder.setEnabled(true);
btnCopyFile.setEnabled(true);
}
else
{
try {
tc.copyFolder(srcFolder,destFolder);
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
}
txtDetails.append("Finished Copying.....\n");
MessageBox msgBox = new MessageBox(shell, SWT.ICON_INFORMATION | SWT.OK);
msgBox.setText("Information");
msgBox.setMessage("Done Copying...");
msgBox.open();
txtSource.setText("");
txtSource.setEditable(false);
txtDestination.setText("");
btnCopyFolder.setEnabled(true);
btnCopyFile.setEnabled(true);
tc1 = new threadclass();
tc = new threadclass();
tc1.start();
tc.start();
}
}
}
});
}
});
btnCopyFolder.setText("Copy Folder");
btnCopyFolder.setBounds(300, 23, 166, 25);
btnCancel = new Button(grpCopyOptions, SWT.NONE);
btnCancel.setBounds(247, 54, 96, 25);
btnCancel.setText("Cancel");
}
class threadclass extends Thread
{
public void cancel(boolean b) {
tc.interrupt();
}
public void displayFiles(String[] files) {
for (int i = 0; files != null && i < files.length; i++) {
txtSource.append(files[i]);
txtSource.setEditable(false);
}
}
public void copyFolder(File src, File dest)
throws IOException{
if(src.isDirectory()){
if (!dest.exists())
{
dest.mkdir();
txtDetails.append("Directory created : " + dest + "\n");
}
final String files[] = src.list();
for (String file : files)
{
File srcFile = new File(src, file);
File destFile = new File(dest, file);
//Recursive function call
copyFolder(srcFile, destFile);
}
}
else{
// btnCancel.setEnabled(true);
txtDetails.append("");
Files.copy(src.toPath(), dest.toPath(), StandardCopyOption.REPLACE_EXISTING);
txtDetails.append(text + "Copying " + src.getAbsolutePath() + "\n");
//
}
}
public void copyFolder1(File src, File dest)
throws IOException{
// String fileName = new SimpleDateFormat("yyyyMMddHHmm'.txt'").format(new DateTime(ddFrom, 0));
if(src.isDirectory()){
if (!dest.exists())
{
dest.mkdir();
txtDetails.append("Directory created : " + dest + "\n");
}
String files[] = src.list();
for (String file : files)
{
File srcFile = new File(src, file);
File destFile = new File(dest, file);
//Recursive function call
copyFolder1(srcFile, destFile);
}
}
else{
if(dest.isDirectory())
{
// btnCancel.setEnabled(true);
copyFile(src, new File (dest, src.getName()));
txtDetails.append(text + "Copying " + src.getAbsolutePath() + "\n");
}
else
{
copyFile(src, dest);
}
// }
}
}
public void copyFile(File src, File dest) throws IOException
{
InputStream oInStream = new FileInputStream(src);
OutputStream oOutStream = new FileOutputStream(dest);
// Transfer bytes from in to out
byte[] oBytes = new byte[1024];
int nLength;
BufferedInputStream oBuffInputStream = new BufferedInputStream( oInStream );
while ((nLength = oBuffInputStream.read(oBytes)) > 0)
{
oOutStream.write(oBytes, 0, nLength);
}
oInStream.close();
oOutStream.close();
}
public void fileCopy(File sourceDir , File destDir) throws IOException{
// File sDir = new File(sourceDir);
if (!sourceDir.isDirectory()){
// throw error
}
// File dDir = new File(destDir);
if (!destDir.exists()){
destDir.mkdir();
}
File[] files = sourceDir.listFiles();
for (int i = 0; i < files.length; i++) {
File destFile = new File(destDir.getAbsolutePath()+File.separator+files[i].getName().replace(",", "") //remove the commas
.replace("[", "") //remove the right bracket
.replace("]", "")
.replace(" ", ""));
// destFile.createNewFile();
Files.copy(files[i].toPath(), destFile.toPath(), StandardCopyOption.REPLACE_EXISTING);
txtDetails.append(text + " Copying " + files[i].getAbsolutePath() + "\n");
}
}
}
public static void main(String[] args) {
try {
FortryApplication window = new FortryApplication();
window.open();
} catch (Exception e) {
e.printStackTrace();
}
}
@Override
public void run() {
// TODO Auto-generated method stub
}
}
答案 0 :(得分：0)
您不使用asyncExec来运行后台任务，asyncExec始终在UI线程中运行代码。
每次要执行UI操作时，都会在后台线程中使用asyncExec 。 必须使用后台线程执行长时间运行的任务。
因此，当您想要运行长时间运行的任务时，您可以执行以下操作：
Thread background = new Thread() {
@Override
public void run() {
... long running background code
Display.getDefault().asyncExec(new Runnable() {
@Override
public void run() {
.. code accessing user interface objects
}
});
.... more code
}
};
background.start();