当文件插入 sdcard 时，我正在尝试开始一项活动。为此，我想启动一个 helloworld.java 活动（虚拟活动）。我在 startActivity() 方法中收到“未定义”错误。Eclipse 用红色下划线突出显示错误代码代码。我已经在清单文件中注册了这两个类。所以清单文件没有问题。
public class MyFileObserver extends FileObserver {
public static final String PREFS_NAME = "MyPreferencesFile";
public static String absolutePath;
//final adapter info = new adapter(this);
HashSet<ObserverActivity> registeredObservers;
FileEvent fileevent = new FileEvent();
final filehelper f_help = new filehelper(fileevent);
private Context context;
public MyFileObserver(Context context) {
super(absolutePath);
this.context = context;
}
public MyFileObserver(String path) {
super(path, FileObserver.ALL_EVENTS);
//this.fileevent = fileevent;
absolutePath = path;
registeredObservers = new HashSet<ObserverActivity>();
}
public void registerObserver(ObserverActivity toRegister){
registeredObservers.add(toRegister);
}
public void unregisterObserver(ObserverActivity toUnregister){
registeredObservers.remove(toUnregister);
}
@Override
public void onEvent(int event, String path) {
// try{
if (path == null)
{
return;
}
/*for(ObserverActivity o: registeredObservers){
o.onFileObserved(event, path);
}*/
//a new file or subdirectory was created under the monitored directory
if ((FileObserver.CREATE & event)!=0) {
FileAccessLogStatic.accessLogMsg += absolutePath + "/" + path + " is created\n";
Log.v(path+ " in FileObserver of sample_fileobserver ====>>>> ",path);
// setpath(path);
//fileevent.insert(path);
/*for(ObserverActivity o: registeredObservers){
o.onFileObserved(event, path);
}*///try
// {
FileEvent.path2 = path;
Intent i = new Intent("com.example.sample_fileobserver.hello");
startActivity(i);
// startAct();
// fileevent.insert(path);
// }
//catch(Exception e)
//{
// Log.v("Activity cannot be started ====>>>> ",e.toString());
// }
//Intent i=new Intent("com.example.seperate_fileobserver.FileEvent");
// i.putExtra("path", path);
// startActivity(i);
}
//a file or directory was opened
if ((FileObserver.OPEN & event)!=0) {
FileAccessLogStatic.accessLogMsg += path + " is opened\n";
}
//data was read from a file
if ((FileObserver.ACCESS & event)!=0) {
FileAccessLogStatic.accessLogMsg += absolutePath + "/" + path + " is accessed/read\n";
}
//data was written to a file
if ((FileObserver.MODIFY & event)!=0) {
FileAccessLogStatic.accessLogMsg += absolutePath + "/" + path + " is modified\n";
}
//someone has a file or directory open read-only, and closed it
if ((FileObserver.CLOSE_NOWRITE & event)!=0) {
FileAccessLogStatic.accessLogMsg += path + " is closed\n";
}
//someone has a file or directory open for writing, and closed it
if ((FileObserver.CLOSE_WRITE & event)!=0) {
String filename = "";
int numbers = 0;
f_help.insertpic(filename,numbers);
FileAccessLogStatic.accessLogMsg += absolutePath + "/" + path + " is written and closed\n";
}
//[todo: consider combine this one with one below]
//a file was deleted from the monitored directory
if ((FileObserver.DELETE & event)!=0) {
//for testing copy file
// FileUtils.copyFile(absolutePath + "/" + path);
FileAccessLogStatic.accessLogMsg += absolutePath + "/" + path + " is deleted\n";
Log.v("deleting path",path);
// fileevent.delete(path);
//for(ObserverActivity o: registeredObservers){
// o.onFileObserved(event, path);
// }
try{
fileevent.delete(path);
}
catch(Exception e)
{
Log.v("File cannot be deleted ====>>>> ",e.toString());
}
}
//the monitored file or directory was deleted, monitoring effectively stops
if ((FileObserver.DELETE_SELF & event)!=0) {
FileAccessLogStatic.accessLogMsg += absolutePath + "/" + " is deleted\n";
}
//a file or subdirectory was moved from the monitored directory
if ((FileObserver.MOVED_FROM & event)!=0) {
FileAccessLogStatic.accessLogMsg += absolutePath + "/" + path + " is moved to somewhere " + "\n";
}
//a file or subdirectory was moved to the monitored directory
if ((FileObserver.MOVED_TO & event)!=0) {
FileAccessLogStatic.accessLogMsg += "File is moved to " + absolutePath + "/" + path + "\n";
}
//the monitored file or directory was moved; monitoring continues
if ((FileObserver.MOVE_SELF & event)!=0) {
FileAccessLogStatic.accessLogMsg += path + " is moved\n";
}
//Metadata (permissions, owner, timestamp) was changed explicitly
if ((FileObserver.ATTRIB & event)!=0) {
FileAccessLogStatic.accessLogMsg += absolutePath + "/" + path + " is changed (permissions, owner, timestamp)\n";
}
我无法理解为什么它未定义，以及为什么 FileObserver.onEvent() 不支持 startActivity(Intent) 方法。
提前致谢。