Detect file change using FileObserver on Android

FileObserver on Android

    private class PathFileObserver extends FileObserver{
        static final String TAG="FILEOBSERVER";
        /**
         * should be end with File.separator
         */
    	String rootPath;
    	static final int mask = (FileObserver.CREATE | 
    			FileObserver.DELETE | 
    			FileObserver.DELETE_SELF |
    			FileObserver.MODIFY |
    			FileObserver.MOVED_FROM |
    			FileObserver.MOVED_TO |
    			FileObserver.MOVE_SELF); 
    	
    	public PathFileObserver(String root){
    		super(root, mask);

    		if (! root.endsWith(File.separator)){
    			root += File.separator;
    		}
    		rootPath = root;
    	}

    	public void onEvent(int event, String path) {
    		
    		switch(event){
    		case FileObserver.CREATE:
    			Log.d(TAG, "CREATE:" + rootPath + path);
    			break;
    		case FileObserver.DELETE:
    			Log.d(TAG, "DELETE:" + rootPath + path);
    			break;
    		case FileObserver.DELETE_SELF:
    			Log.d(TAG, "DELETE_SELF:" + rootPath + path);
    			break;
    		case FileObserver.MODIFY:
    			Log.d(TAG, "MODIFY:" + rootPath + path);
    			break;
    		case FileObserver.MOVED_FROM:
    			Log.d(TAG, "MOVED_FROM:" + rootPath + path);
    			break;
    		case FileObserver.MOVED_TO:
    			Log.d(TAG, "MOVED_TO:" + path);
    			break;
    		case FileObserver.MOVE_SELF:
    			Log.d(TAG, "MOVE_SELF:" + path);
    			break;
    		default:
    			// just ignore
    			break;
    		}
    	}

    	public void close(){
    		super.finalize();
    	}
    }

Change to switch(event & FileObserver.ALL_EVENTS).

@twlkyao check http://www.java2s.com/Open-Source/Android_Free_Code/Example/course/com_toraleap_collimator_utilRecursiveFileObserver_java.htm for RecursiveFileObserver

Instead of using Log.d to log an event,I would like to write all events to a file. Please help.

This has issue on Marshmallow and forward https://issuetracker.google.com/issues/37065227
But the developer team said it has fixed and will be available in a future build, although it's not clear when

The event in onEvent() doesn't returns exact the number as doc, you need to wrap as below

public void onEvent(int event, String path) {

        if ((FileObserver.CREATE & event)!=0) {
            PUtils.log("CREATE: " + rootPath + path);
        } else if ((FileObserver.MODIFY & event)!=0) {
            PUtils.log("MODIFY: " + rootPath + path);
        } else if ((FileObserver.DELETE & event)!=0) {
            PUtils.log("DELETE: " + rootPath + path);
        } else if ((FileObserver.DELETE_SELF & event)!=0) {
            PUtils.log("DELETE_SELF: " + rootPath + path);
        } else if ((FileObserver.MOVED_FROM & event)!=0) {
            PUtils.log("MOVED_FROM: " + rootPath + path);
        } else if ((FileObserver.MOVED_TO & event)!=0) {
            PUtils.log("MOVED_TO: " + rootPath + path);
        } else if ((FileObserver.MOVE_SELF & event)!=0) {
            PUtils.log("MOVE_SELF: " + rootPath + path);
        } else {
            PUtils.log("Unhandled event " + event + rootPath + path);
        }

Getting this error in logcat
java.lang.NoSuchMethodError: No direct method (Ljava/io/File;I)V in class Landroid/os/FileObserver; or its super classes (declaration of 'android.os.FileObserver' appears in /system/framework/framework.jar)
Can anyone help

Getting this error in logcat
java.lang.NoSuchMethodError: No direct method (Ljava/io/File;I)V in class Landroid/os/FileObserver; or its super classes (declaration of 'android.os.FileObserver' appears in /system/framework/framework.jar)
Can anyone help

I run into the same. Did you solved it ?

Getting this error in logcat
java.lang.NoSuchMethodError: No direct method (Ljava/io/File;I)V in class Landroid/os/FileObserver; or its super classes (declaration of 'android.os.FileObserver' appears in /system/framework/framework.jar)
Can anyone help

I run into the same. Did you solved it ?

I saw that message (or something like that) when i was trying to use constructor FileObserver(File). Use of deprecated FileObserver(String) solved my problem. Don't know why...
And for a while look at FixedFileObserver. It's in russian, but code is "in" java. Original FileObserver has bugs.