public class FileObserverTest extends Activity{ @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); MyFileObserver mfo = new MyFileObserver(getApplicationContext().getFilesDir() + "/data.txt"); mfo.startWatching();//启动文件监听 //mfo.stopWatching();//取消文件监听 } public class MyFileObserver extends FileObserver { public MyFileObserver(String path) {     super(path); } @Override public void onEvent(int event, String path) {     switch (event) {     case android.os.FileObserver.CREATE:         // 文件被创建         Log.d("FileObserver", "---file create---");         break;     case android.os.FileObserver.OPEN:         // 文件被打开         //Log.d("FileObserver", "---file open---");         break;     case android.os.FileObserver.ACCESS:         // 打开文件后，读文件内容操作         //Log.d("FileObserver", "---file access---");         break;     case android.os.FileObserver.MODIFY:         //文件被修改         Log.d("FileObserver", "---file MODIFY---");         break;     } } } }