目前我感到非常沮丧。我已经研究了几天,甚至无法分离出光标问题以外的任何东西。我正在扩展ListActivity,并在OnCreate方法中使用startManagingCursor(newcursor)。以下是代码(数据库已经填充),当按下主页按钮时运行并崩溃:
private void loadAlbums() {
try {
newcursor = mDbHelper.getAlbumTitlesCursor();
dbalbumadapter = new AlbumListCursorAdapter(this, newcursor);
setListAdapter(dbalbumadapter);
}
catch (SQLiteException s) {
newcursor = null;
fetchalbums = new FetchAlbumsTask().execute();
}
current_view = ALBUMTITLE_VIEW;
}
以下是错误日志:
02-03 13:41:42.379: WARN/dalvikvm(340): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
02-03 13:41:42.389: ERROR/AndroidRuntime(340): Uncaught handler: thread main exiting due to uncaught exception
02-03 13:41:42.590: ERROR/AndroidRuntime(340): java.lang.RuntimeException: Unable to stop activity {com.skip.ngRCv2/com.skip.ngRCv2.ngRC}: java.lang.RuntimeException: Unable to stop activity {com.skip.ngRCv2/com.skip.ngRCv2.MusicLibraryActivity}: java.lang.NullPointerException
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3227)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.ActivityThread.handleStopActivity(ActivityThread.java:3272)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.ActivityThread.access$2500(ActivityThread.java:119)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1880)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.os.Handler.dispatchMessage(Handler.java:99)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.os.Looper.loop(Looper.java:123)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.ActivityThread.main(ActivityThread.java:4363)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at java.lang.reflect.Method.invokeNative(Native Method)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at java.lang.reflect.Method.invoke(Method.java:521)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at dalvik.system.NativeStart.main(Native Method) 02-03 13:41:42.590: ERROR/AndroidRuntime(340):
Caused by: java.lang.RuntimeException: Unable to stop activity {com.skip.ngRCv2/com.skip.ngRCv2.MusicLibraryActivity}: java.lang.NullPointerException
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3227)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.ActivityThread.performStopActivity(ActivityThread.java:3174)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:176)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.LocalActivityManager.dispatchStop(LocalActivityManager.java:572)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.ActivityGroup.onStop(ActivityGroup.java:79)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.Instrumentation.callActivityOnStop(Instrumentation.java:1169)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.Activity.performStop(Activity.java:3797)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3224)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): ... 11 more
02-03 13:41:42.590: ERROR/AndroidRuntime(340):
Caused by: java.lang.NullPointerException
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.Activity.performStop(Activity.java:3808)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): at android.app.ActivityThread.performStopActivityInner(ActivityThread.java:3224)
02-03 13:41:42.590: ERROR/AndroidRuntime(340): ... 18 more
在Activity.performStop(Activity.java:3808)发生了NullPointerException,虽然我无法通过行号交叉验证,但似乎是来自Activity.java中的这个方法:
final void performStop() {
if (!mStopped) {
if (mWindow != null) {
mWindow.closeAllPanels();
}
mCalled = false;
mInstrumentation.callActivityOnStop(this);
if (!mCalled) {
throw new SuperNotCalledException(
"Activity " + mComponent.toShortString() +
" did not call through to super.onStop()");
}
synchronized (mManagedCursors) {
final int N = mManagedCursors.size();
for (int i=; i<N; i++) {
ManagedCursor mc = mManagedCursors.get(i);
if (!mc.mReleased) {
mc.mCursor.deactivate();
mc.mReleased = true;
}
}
}
mStopped = true;
}
mResumed = false;
}
我已经尝试在OnStop方法中关闭和停用光标,以及将列表适配器设置为null。我认为当让活动管理光标时,这些操作都是不必要的。我将光标传递给自定义适配器,但我找到的所有示例都没有在适配器内执行任何管理操作。
如果您能帮我缩小引发此异常的范围,我将不胜感激!