SWT(JFace)体验之多线程问题

测试代码如下：

SyncExecExample.java

 

package swt_jface.demo; import org.eclipse.swt.SWT; import org.eclipse.swt.events.SelectionEvent; import org.eclipse.swt.events.SelectionListener; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; public class SyncExecExample { public static void main(String[] args) { final Display display = new Display(); Shell shell = new Shell(display); final Runnable print = new Runnable() { public void run() { System.out.println("Print from thread: /t" + Thread.currentThread().getName()); } }; final Thread applicationThread = new Thread("applicationThread") { public void run() { System.out.println("Hello from thread: /t" + Thread.currentThread().getName()); display.syncExec(print); System.out.println("Bye from thread: /t" + Thread.currentThread().getName()); } }; shell.setText("syncExec Example"); shell.setSize(300, 100); Button button = new Button(shell, SWT.CENTER); button.setText("Click to start"); button.setBounds(shell.getClientArea()); button.addSelectionListener(new SelectionListener() { public void widgetDefaultSelected(SelectionEvent e) { } public void widgetSelected(SelectionEvent e) { applicationThread.start(); } }); shell.open(); while(! shell.isDisposed()) { if(! display.readAndDispatch()) { display.sleep(); } } display.dispose(); } }

 

 

再来一个例子：

PICalculator.java

package swt_jface.demo; import org.eclipse.swt.SWT; import org.eclipse.swt.events.SelectionEvent; import org.eclipse.swt.events.SelectionListener; import org.eclipse.swt.graphics.Rectangle; import org.eclipse.swt.widgets.Button; import org.eclipse.swt.widgets.Display; import org.eclipse.swt.widgets.Shell; public class PICalculator { Display display = new Display(); Shell shell = new Shell(display); Button buttonThread = new Button(shell, SWT.PUSH); Button buttonAsyncExec = new Button(shell, SWT.PUSH); public PICalculator() { shell.setText("PI Calculator"); shell.setSize(400, 80); Rectangle clientArea = shell.getClientArea(); buttonThread.setText("Click here to calculate PI [Non-UI thread UI Update]"); buttonThread.setBounds( clientArea.x, clientArea.y, clientArea.width, clientArea.height / 2); buttonThread.addSelectionListener(new SelectionListener() { public void widgetDefaultSelected(SelectionEvent e) { } public void widgetSelected(SelectionEvent e) { buttonThread.setText("Calculation in progress ..."); getTask(buttonThread).start(); } }); buttonAsyncExec.setText("Click here to calculate PI [asynExec method UI Update]"); buttonAsyncExec.setBounds( clientArea.x, clientArea.y + clientArea.height / 2, clientArea.width, clientArea.height / 2); buttonAsyncExec.addSelectionListener(new SelectionListener() { public void widgetDefaultSelected(SelectionEvent e) { } public void widgetSelected(SelectionEvent e) { buttonAsyncExec.setText("Calculation in progress ..."); getTask2(buttonAsyncExec).start(); } }); shell.open(); while (!shell.isDisposed()) { if (!display.readAndDispatch()) { display.sleep(); } } display.dispose(); } public Thread getTask(Button button) { final Button theButton = button; return new Thread() { public void run() { double pi = calculatePI(9999999); theButton.setText("PI = " + pi); } }; } public Thread getTask2(Button button) { final Button theButton = button; return new Thread() { public void run() { final double pi = calculatePI(9999999); display.asyncExec(new Runnable() { public void run() { theButton.setText("PI = " + pi); } }); } }; } public static double calculatePI(int nestedLevel) { double product = 1; double lastSqrtValue = 0; for (int i = 0; i < nestedLevel; i++) { double sqrt = getNextSqrtValue(lastSqrtValue); product *= 0.5 * sqrt; lastSqrtValue = sqrt; } return 2 / product; } public static double getNextSqrtValue(double lastValue) { return Math.sqrt(2 + lastValue); } public static void main(String[] args) { new PICalculator(); } }