Error in SWT/LogCat? or Android 2.2 AVD

问题:

Based on a tip, I changed the target of my Android app from 2.3 to 2.2.

Out of the frying pan and into the fire!

Now my app won't even open (in the 2.2 emulator) and I get this (seems to be an SWT problem, and then an android/LogCat problem):

eclipse.buildId=M20110909-1335
java.version=1.7.0_01
java.vendor=Oracle Corporation
BootLoader constants: OS=win32, ARCH=x86_64, WS=win32, NL=en_US
Framework arguments:  -product org.eclipse.epp.package.java.product
Command-line arguments:  -os win32 -ws win32 -arch x86_64 -product org.eclipse.epp.package.java.product

Error
Thu Nov 24 16:06:47 CST 2011
Unhandled event loop exception

org.eclipse.swt.SWTException: Failed to execute runnable (java.lang.NullPointerException)
    at org.eclipse.swt.SWT.error(SWT.java:4282)
    at org.eclipse.swt.SWT.error(SWT.java:4197)
    at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:138)
    at org.eclipse.swt.widgets.Display.runAsyncMessages(Display.java:4140)
    at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3757)
    at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2696)
    at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2660)
    at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2494)
    at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:674)
    at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
    at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:667)
    at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
    at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:123)
    at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
    at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:344)
    at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
    at java.lang.reflect.Method.invoke(Unknown Source)
    at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:622)
    at org.eclipse.equinox.launcher.Main.basicRun(Main.java:577)
    at org.eclipse.equinox.launcher.Main.run(Main.java:1410)
    at org.eclipse.equinox.launcher.Main.main(Main.java:1386)
Caused by: java.lang.NullPointerException
    at com.android.ddmuilib.logcat.LogCatReceiverFactory.newReceiver(LogCatReceiverFactory.java:57)
    at com.android.ddmuilib.logcat.LogCatPanel.deviceSelected(LogCatPanel.java:229)
    at com.android.ddmuilib.SelectionDependentPanel.deviceSelected(SelectionDependentPanel.java:52)
    at com.android.ide.eclipse.ddms.views.SelectionDependentViewPart.selectionChanged(SelectionDependentViewPart.java:67)
    at com.android.ide.eclipse.ddms.DdmsPlugin$6.run(DdmsPlugin.java:690)
    at org.eclipse.swt.widgets.RunnableLock.run(RunnableLock.java:35)
    at org.eclipse.swt.widgets.Synchronizer.runAsyncMessages(Synchronizer.java:135)
    ... 23 more

-- Configuration Details -- Product: Eclipse 1.4.1.20110909-0613 (org.eclipse.epp.package.java.product)

回答1:

http://www.vogella.de/articles/SWT/article.html seems to be a solid tutorial.

From that tutorial:

import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;

public class FirstSWTApplication {

public static void main(String[] args) {
    Display display = new Display();
    Shell shell = new Shell(display);
    shell.open();
    while (!shell.isDisposed()) {
        if (!display.readAndDispatch())
            display.sleep();
    }
    display.dispose();
}

}

Remember to include org.eclipse.swt in the manifest.