Xmemory

Wireshark - The capture could not be initiated (You don't have permissiont o capture on that device).

2017-01-18T21:05:00.000+11:00

It seems Wireshark installer fails to set up permissions.

To fix it, run this manually:-

chgrp access_bpf /dev/bpf*
chmod g+rw /dev/bpf*

Make sure the user is in the "access_bpf" group.

Refs
https://josephhall.org/nqb2/index.php/wrshrkinstll
http://apple.stackexchange.com/questions/138694/what-is-access-bpf-group

Have fun with cross platform mobile development

2016-02-01T23:41:00.001+11:00

A short presentation about a sample cross platform mobile project called TumChatter for both Android and iOS.

You can find the project on github at the link below:-
https://github.com/have-fun/TumChatter

Programming Language: Kotlin
Frameworks: Java, RoboVM
Dependency Injection: Dagger 2
Json: Gson
REST Client: Retrofit
Reactive Libraries: RxKotlin, RxJava
Unit Testing: Spek (Specification Framework), AssertJ, Mockito
Embedded Server: TumWeb, Nanohttpd
Android UI Binding: KotterKnife, ButterKnife

Create an array

2014-04-01T13:22:00.000+11:00

1	NSArray *array = [NSArray arrayWithObjects:@"One", [NSNumber numberWithInt:1], nil];

Or use literal array expression:-

1	NSArray *array =@[ @"One", [NSNumber numberWithInt:1] ];

Use NSNumber to add boolean or integer values to an array, or prefix a boolean value with ‘@':-

1	NSArray *array = @[ [NSNumber numberWithInt:1], [NSNumber numberWithBool:YES], @NO ];

Otherwise we will get an error like this:-

Collection element of type ‘NSInteger’ (aka ‘int’) is not an Objective-C object

Use NSNull to add a nil equivalent value to an array:-

1	NSArray *array = @[ @"a", [NSNull null], @"b" ];

Refs
http://stackoverflow.com/questions/1602572/how-to-create-an-array-of-strings-in-objective-c-for-iphone
http://clang.llvm.org/docs/ObjectiveCLiterals.html
http://stackoverflow.com/questions/1309535/why-does-nsarray-arraywithobjects-require-a-terminating-nil
http://stackoverflow.com/questions/2057910/how-to-add-nil-to-nsmutablearray

Managed Object ID

2014-03-29T18:10:00.001+11:00

Get the string URL representation from a ManagedObjectID

1 2	NSURL urlID = [objectID URIRepresentation]; NSString strUrlID = [urlID absoluteString];

Get the ManagedObjectID from a URL string

1 2	NSURL urlID = [[NSURL alloc] initWithString:strUrlID]; NSManagedObjectID objectID = [[managedObjectContext persistentStoreCoordinator] managedObjectIDForURIRepresentation:urlID];

Get the ManagedObject by a ManagedObjectID

1 2	NSError error = nil; NSManagedObject managedObject = [moc existingObjectWithID:objectID error:&error];

Check if a ManagedObject is new

1	BOOL isNew = managedObject.objectID.isTemporaryID;

Get the permanent object IDs for the objects in a child context.

  NSError *error = nil;
  [childManagedObjectContext obtainPermanentIDsForObjects:childManagedObjectContext.insertedObjects.allObjects error:&error]);

  // . . . Check for an error . . .

  [childManagedObjectContext save:&error];

  // . . . Check for an error . . .

Refs
http://stackoverflow.com/questions/3519334/how-to-uniquely-identify-nsmangedobject-with-string
http://stackoverflow.com/questions/10811280/how-to-get-the-objectid-from-url
http://stackoverflow.com/questions/3013288/how-to-use-managedobjectid-the-right-way
http://iphonedevelopment.blogspot.com.au/2009/07/core-data-determining-if-managed-object.html
http://stackoverflow.com/questions/11990279/core-data-do-child-contexts-ever-get-permanent-objectids-for-newly-inserted-obj/11996957#11996957

Compare NSDate instances

2014-03-27T17:49:00.001+11:00

  NSComparisonResult result = [date1 compare:date2];  
  if (result == NSOrderedAscending)
  {
    // date1 < date2
  }
  else if (result == NSOrderedDescending)
  {
    // date1 > date2
  }
  else
  {
    // date1 == date2
  }

  if ([date1 timeIntervalSinceReferenceDate] < [date2 timeIntervalSinceReferenceDate])
  {
    // date1 < date2
  }
  else if ([date1 timeIntervalSinceReferenceDate] > [date2 timeIntervalSinceReferenceDate])
  {
    // date1 > date2
  }
  else
  {
    // date1 == date2
  }

Refs
http://stackoverflow.com/questions/5965044/how-to-compare-two-nsdates-which-is-more-recent

lldb Error - no known method '-class'; cast the message send to the method's return type

2014-03-27T16:59:00.001+11:00

p [[navigationController topViewController] class]

returns

error: no known method '-class'; cast the message send to the method's return type

To fix it, cast it first:-

p [(NSObject *) [navigationController topViewController] class]

Refs
http://stackoverflow.com/questions/14007942/lldb-error-property-not-found-on-object-of-type

Start/Stop PostgreSQL on Mac

2013-11-25T17:16:00.000+11:00

Start PostgreSQL:-

sudo -u postgres /Library/PostgreSQL/9.3/bin/pg_ctl -D /Library/PostgreSQL/9.3/data start

Stop PostgreSQL:-

sudo -u postgres /Library/PostgreSQL/9.3/bin/pg_ctl -D /Library/PostgreSQL/9.3/data stop

Stop PostgreSQL from auto-starting on reboot:-

sudo launchctl unload -w /Library/LaunchDaemons/com.edb.launchd.postgresql-9.3.plist

Make PostgreSQL auto-start on reboot:-

sudo launchctl load -w /Library/LaunchDaemons/com.edb.launchd.postgresql-9.3.plist

Refs
http://www.xtuple.org/faq/xtuple-faq/postgresql/how-do-i-stop-postgresql-service-mac
https://gist.github.com/abhishekdev/1960888

Run Tomboy with Mono 3.2 on Mac

2013-08-17T01:16:00.001+10:00

Compiling it from scratch based on http://xmemory.tompium.com/2012/06/running-tomboy-note-taking-app-on-mac.html doesn't work anymore. Here are the additional instructions:-

After getting the latest version of Tomboy (1.15.3), replace "flush(true)" with "flush()" in Note.cs to fix a compile error. Not sure why the compiler complained about this line. Anyway, using just "flush()" fixes the problem but it may not write everything to disk straight away.
After building Tomboy, running it caused an exception:-

Missing method System.Reflection.Assembly::op_Equality(Assembly,Assembly)

To fix it, modify a script file called Tomboy in Tomboy.app -> Contents/MacOS/Tomboy by changing the last line to

exec -a "Tomboy" "$MONO" --runtime=v4.0 --debug $ASSEMBLY $@

Refs
https://bugs.launchpad.net/ubuntu/+source/mono/+bug/882501
http://xmemory.tompium.com/2012/06/running-tomboy-note-taking-app-on-mac.html

Offline Maps on New Google Maps for iOS (v2) and Android (v7)

2013-08-13T10:45:00.001+10:00

To download an area on the map, type

ok maps

in the search box.

To clear the cached map, go to

Settings -> About, terms & privacy -> Terms & privacy

and select

Clear application data

Refs
http://www.idownloadblog.com/2013/07/17/offline-maps-in-google-maps-2/

System.Object is not defined or imported when building PCL project in Xamarin Studio 4.0.12

2013-08-11T10:42:00.000+10:00

There're also a bunch of similar errors:-

: error CS0518: The predefined type `System.Object' is not defined or imported
: error CS0518: The predefined type `System.ValueType' is not defined or imported
: error CS0518: The predefined type `System.Attribute' is not defined or imported
: error CS0518: The predefined type `System.Int32' is not defined or imported
: error CS0518: The predefined type `System.UInt32' is not defined or imported
. . .

To fix this, go to References -> Edit References -> .Net Assembly then add mscorlib.dll from /Library/Frameworks/Mono.framework/Libraries/mono/4.5

Refs
https://bugzilla.xamarin.com/show_bug.cgi?id=12845

Enable Xdebug in MAMP

2013-06-28T12:26:00.000+10:00

Uncomment the zend_extension line and modify the /Applications/MAMP/bin/php/php5.x/conf/php.ini file to look like this:-

[xdebug]
zend_extension="/Applications/MAMP/bin/php/php5.4.10/lib/php/extensions/no-debug-non-zts-20100525/xdebug.so"
xdebug.remote_enable=1
xdebug.remote_host=localhost

; On my machine, the default port 9000 has already been taken by something else.
xdebug.remote_port=9099

; Recommended when using Symfony
xdebug.max_nesting_level=250

Then restart the servers in MAMP.

Refs

http://danpolant.com/want-to-run-xdebug-mamp-is-the-easiest-way/

http://xdebug.org/docs/all_settings

Show print history on Mac

2013-06-28T11:14:00.000+10:00

When I opened the web based CUPS admin interface to show print history:-

http://localhost:631/jobs?which_jobs=completed

I got the "Internal Server Error" message.

To fix it, I used the following commands

sudo cupsctl --debug-logging
sudo cupsctl --no-debug-logging

Refs

http://osxdaily.com/2011/01/20/show-print-history-mac/

https://discussions.apple.com/thread/3510277?start=0&tstart=0

Custom php.ini on shared hosting

2013-06-26T14:06:00.000+10:00

Find the default php.ini path. Mine is /usr/local/lib/php.ini

<?php phpinfo() ?>

Copy the default php.ini to the user's home folder and customise it.

<?php copy("/usr/local/lib/php.ini", "/home/username/php.ini") ?>

Create a .htaccess file in the user's home folder with the following content.

SetEnv PHPRC /home/username/php.ini
# The following lines are important if the php.ini file is put in the document root.
<Files php.ini>
order allow,deny
deny from all
</Files>

Refs

http://php.net/manual/en/function.copy.php

http://jesin.tk/using-custom-php-ini-files-on-shared-hosting/

https://drupal.org/node/290592

List processes and ports on Mac

2013-06-24T01:03:00.000+10:00

Show listening ports

lsof -i -nP | grep LISTEN

or with all processes

sudo lsof -i -nP | grep LISTEN

Show ports with any state, e.g. ESTABLISHED, CLOSE_WAIT, CLOSED, LISTEN

sudo lsof -i -nP | grep TCP

or

sudo lsof -i -nP | grep UDP

Switches
-i select IPv[46] files
-n no host names
-P no port names

Refs
http://hints.macworld.com/article.php?story=20070425165628961

The system is running in low-graphics mode after upgrading the VirtualBox Guest additions to 4.2.12

2013-06-14T18:05:00.000+10:00

I tried switching to use gdm instead of lightdm to see whether it could help but it didn't so I rolled back to v4.2.10 while waiting for v4.2.13 which was reported that this problem has been fixed.

Rebooted the machine in recovery mode in the Grub menu by, while booting:-

Pressing ESC, or
Holding down the Shift key (this works better for me).

Uninstalled the VirtualBox Guest additions

cd /opt/VBoxGuestAdditions-4.2.12
./uninstall.sh
reboot

After reboot, the screen was black. Here is what I did to fix this,

Pressed Cmd + F1 (or Alt + F1, don't know why Ctrl isn't needed on my machine) to switch to tty1.
Made LigthDM the default display manager

sudo dpkg-reconfigure lightdm
sudo reboot

But it didn't work. It turned out that I also had to modify /etc/X11/default-display-manager to have the full path to lightdm like this.

/usr/sbin/lightdm

Then rebooted,

sudo reboot

After that, I could continue installing the VirtualBox Guest additions v4.2.10 and now everything is back to normal.

Refs

https://www.virtualbox.org/ticket/11709

http://ubuntuforums.org/showthread.php?t=1186984

http://askubuntu.com/questions/172319/how-can-i-start-in-safe-mode

https://wiki.ubuntu.com/LightDM

http://askubuntu.com/questions/74551/lightdm-not-starting-on-boot

Install httrack using brew on Mac

2013-06-01T12:43:00.001+10:00

Typed

brew install httrack

Then I got:-

==> Downloading http://download.httrack.com/httrack-3.46.1.tar.gzAlready downloaded: /Library/Caches/Homebrew/httrack-3.46.1.tar.gz
Error: SHA1 mismatch
Expected: be6328d2ff3cbabd21426b7acc54edcf1ebb76e0
Actual: 237fca7a9c5c63b53c5d0134dac6e5714422384c
Archive: /Library/Caches/Homebrew/httrack-3.46.1.tar.gz
(To retry an incomplete download, remove the file above.)

So I did:-

brew update

Then I got:-

error: The following untracked working tree files would be overwritten by merge: Library/Formula/libmusicbrainz.rbPlease move or remove them before you can merge.AbortingError: Failure while executing: git pull -q origin refs/heads/master:refs/remotes/origin/master

To fix it, I did:-

cd /usr/local
git fetch origin
git reset --hard origin/master

After that, I could run "brew update" and "brew install httrack" again with no problem.

Refs

http://forum.httrack.com/readmsg/25812/25794/index.html
http://apple.stackexchange.com/questions/36862/install-homebrew-package-and-ignore-md5-hash
http://stackoverflow.com/questions/10762859/brew-update-the-following-untracked-working-tree-files-would-be-overwritten-by

Reduce memory usage in Chrome by suspending tabs

2013-05-27T20:08:00.000+10:00

Google Chrome seems to use lots of memory especially when there are lots of tabs open at once. It quite often slows down my machine significantly to the point that I have to restart the browser (with all tabs still open after the restart) and then it gradually slows down again. I'm glad I came across The Great Suspender. This extension allows me to suspend any tab manually, or let it suspend idle tabs for me automatically.

Refs

http://lifehacker.com/5982490/the-great-suspender-suspends-memory+hungry-chrome-tabs-you-havent-used-lately
https://chrome.google.com/webstore/detail/the-great-suspender/klbibkeccnjlkjkiokjodocebajanakg?utm_source=chrome-ntp-icon

Convert an object array to a string array in Java

2013-05-24T19:12:00.000+10:00

System.arraycopy(Object src, int srcPos, Object dest, int destPos, int length);
Arrays.asList(Object_Array).toArray(new String[Object_Array.length]);
Java 1.6

String[] stringArray = Arrays.copyOf(objectArray, objectArray.length, String[].class);

Refs

http://stackoverflow.com/questions/1018750/how-to-convert-object-array-to-string-array-in-java

Find which process is using a file on Mac

2013-05-10T21:55:00.001+10:00

Use this command

lsof | grep <filename>

lsof <filepath>

To ignore case, use

lsof | grep -i <filename>

Run it as root if the process is owned by root,

sudo lsof | grep -i <filename>

Refs

Getting the error "oasis-text.icns is in use" when installing LibreOffice on Mac

2013-05-10T21:18:00.000+10:00

The full error message is

The operation can't be completed because the item "oasis-text.icns" is in use.

To fix it, just quit the SystemUIServer process in the Activity Monitor.

Install Force.com IDE on Eclipse 4.2 (Juno)

2013-05-08T20:16:00.000+10:00

Use this Force.com IDE Update site http://www.adnsandbox.com/tools/ide/install/
Copy org.eclipse.update.ui_3.2.300.v20100512.jar to the eclipse/plugins directory. Get this file from the old version of Eclipse or from this site http://www.java2s.com/Code/Jar/o/Downloadorgeclipseupdateui32300v20100512jar.htm. If this file is missing, we will get the following error message:-

Cannot complete the install because one or more required items could not be found.
Software being installed: Force.com IDE 27.0.0.201302151147 (com.salesforce.ide.feature.feature.group 27.0.0.201302151147)
Missing requirement: Force.com IDE 27.0.0.201302151147 (com.salesforce.ide.feature.feature.group 27.0.0.201302151147) requires 'org.eclipse.update.ui 0.0.0' but it could not be found

Refs

Running Tomboy Note-Taking App on Mac

2012-06-15T22:23:00.000+10:00

When running Tomboy 1.10.2 on Mac OS X Lion with Mono 2.10.9 installed, I got this error:-

Unhandled Exception: System.TypeInitializationException: An exception was thrown by the type initializer for IgeMacIntegration.IgeMacDock ---> System.EntryPointNotFoundException: ige_mac_dock_get_type

I found that the ige-mac-integration-sharp.dll library used by Tomboy is not compatible with libigemacintegration.dylib in Mono 2.10.9 (some external functions don't exist any more). I'm new to Mono and this library and I just wanted to get Tomboy to run on Mac and also wanted to keep the latest version of Mono so I did a dirty fix by doing the following:-

Build Tomboy.

git clone git://git.gnome.org/tomboy
xbuild Tomboy-mac.sln
./bundle-mac-app.sh

Copy libigemacintegration.0.0.0.dylib from Mono 2.6.x to Tomboy.app/Contents/MacOS and rename it to libigemacintegration.dylib
Transfer all notes from my Ubuntu machine to Mac.

cp /Volumes/tom-ubuntu/.local/share/tomboy/*.note /Users/tomtanti/Library/Application Support/Tomboy/

Run Tomboy for testing.

open Tomboy.app

Move Tomboy.app to Applications so that I can simply run it from there in the future.

Update (2013-08-17):
New instructions for running Tomboy with Mono 3.2

Refs

Firefox 10 keeps crashing

2012-02-06T14:25:00.000+11:00

After upgrading to Firefox 10, the new version kept crashing every time I opened it. Running it in safe mode (firefox -safe-mode) didn't help.

I ended up creating a new profile to fix this problem using the following command and switch:-

firefox -P

All plugins were gone and needed reinstalling. I could get some data back though from the old profile folder in

/home/tom/.mozilla/firefox/xxxx.default

Refs
http://ubuntuforums.org/showthread.php?p=11595179

Make Eclipse look better on Ubuntu

2012-01-13T21:47:00.001+11:00

Compact the look and fix unreadable selected entry in content assist in some themes (e.g. Ambience) by creating a new text file called "gtkrc" (a stylesheet file for GTK apps) with the following content:-

gtk-color-scheme = "selected_text_color:#000000"
style "compact"
{
GtkButton::default_border={0,0,0,0}
GtkButton::default_outside_border={0,0,0,0}
GtkButtonBox::child_min_width=0
GtkButtonBox::child_min_heigth=0
GtkButtonBox::child_internal_pad_x=0
GtkButtonBox::child_internal_pad_y=0
GtkMenu::vertical-padding=1
GtkMenuBar::internal_padding=1
GtkMenuItem::horizontal_padding=4
GtkToolbar::internal-padding=1
GtkToolbar::space-size=1
GtkOptionMenu::indicator_size=0
GtkOptionMenu::indicator_spacing=0
GtkPaned::handle_size=4
GtkRange::trough_border=0
GtkRange::stepper_spacing=0
GtkScale::value_spacing=0
GtkScrolledWindow::scrollbar_spacing=0
GtkExpander::expander_size=10
GtkExpander::expander_spacing=0
GtkTreeView::vertical-separator=0
GtkTreeView::horizontal-separator=0
GtkTreeView::expander-size=12
GtkTreeView::fixed-height-mode=TRUE
GtkWidget::focus_padding=0

font_name="Liberation Sans,Sans Regular 8"
text[SELECTED] = @selected_text_color
}
class "GtkWidget" style "compact"
style "compact2"
{
xthickness=1
ythickness=1
}
class "GtkButton" style "compact2"
class "GtkToolbar" style "compact2"
class "GtkPaned" style "compact2"

To use the above stylesheet with Eclipse (my version is Indigo - 3.7.1), run Eclipse like this:-

GTK2_RC_FILES=$GTK2_RC_FILES:/somewhere_1/gtkrc /somewhere_2/eclipse

Make tooltip readable by using #000000 as its foreground colour (tooltip_fg_color) and #f5f5b5 as background (tooltip_bg_color) in the following files:-

/usr/share/themes/<your-current-theme>/gtk-3.0/settings.ini
/usr/share/themes/<your-current-theme>/gtk-3.0/gtk.css
/usr/share/themes/<your-current-theme>/gtk-2.0/gtkrc

Install Eclipse theme colour plugin and may want to try my TumCode theme which keeps the number of colours to the minimum.
Replace the default "Monospace" font with "Liberation Mono" and optionally reduce the font size to 8 or 9.

Windows -> Preferences -> General -> Appearance -> Colors and Fonts

(for Java Editor Text Font, Javadoc display font, Properties File Editor Text Font, etc.)

Here is how it looks after the above changes:-

Refs
http://blog.xam.dk/?p=70
http://askubuntu.com/questions/70599/how-to-change-tooltip-background-color-in-unity
http://blog.valotas.com/2010/02/eclipse-on-linux-make-it-look-good.html

Merry Christmas and a Happy New Year

2011-12-25T10:27:00.003+11:00

I would like to wish you all a Merry Christmas and a Prosperous New Year. May the season bring you and your family joy and peace.