系统存在多用户，很多应用无法遍历

Android系统存在多用户时，很多应用无法遍历，提示no activities found to run，相关代码如下：
for (int i = 0; i < N; i++) {
Intent intent = new Intent(Intent.ACTION_MAIN);
String category = mMainCategories.get(i);
if (category.length() > 0) {
intent.addCategory(category);
}
List mainApps = APIAdapter.queryIntentActivities(packageManager, intent);

if (mainApps == null || mainApps.size() == 0) {
Logger.warningPrintln("// Warning: no activities found for category " + category);
continue;
}
if (mVerbose >= 2) { // very verbose
Logger.println("// Selecting main activities from category " + category);
}
final int NA = mainApps.size();
for (int a = 0; a < NA; a++) {
ResolveInfo r = mainApps.get(a);
String packageName = r.activityInfo.applicationInfo.packageName;
if (MonkeyUtils.getPackageFilter().checkEnteringPackage(packageName)) {
if (mVerbose >= 2) { // very verbose
Logger.println("// + Using main activity " + r.activityInfo.name + " (from package "
+ packageName + ")");
}
mMainApps.add(new ComponentName(packageName, r.activityInfo.name));
} else {
if (mVerbose >= 2) { // very very verbose
Logger.println("// - NOT USING main activity " + r.activityInfo.name
+ " (from package " + packageName + ")");
}
}
}
}