java.lang.ClassCastException: android.graphics.drawable.ColorDrawable
at bv.getView(BackgroundGallery.java:163)
at android.widget.Gallery.makeAndAddView(Gallery.java:748)
at android.widget.Gallery.fillToGalleryRight(Gallery.java:700)
at android.widget.Gallery.layout(Gallery.java:631)
at android.widget.Gallery.onLayout(Gallery.java:339)
at android.view.View.layout(View.java:7228)
at android.widget.FrameLayout.onLayout(FrameLayout.java:338)
at android.view.View.layout(View.java:7228)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1254)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1130)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1047)
at android.view.View.layout(View.java:7228)
at android.widget.FrameLayout.onLayout(FrameLayout.java:338)
at android.view.View.layout(View.java:7228)
at android.view.ViewRoot.performTraversals(ViewRoot.java:1157)
at android.view.ViewRoot.handleMessage(ViewRoot.java:1877)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:130)
at android.app.ActivityThread.main(ActivityThread.java:3687)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:507)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:842)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:600)
at dalvik.system.NativeStart.main(Native Method)

I went back, checked the image and everything seemed to be ok. Getting frustrated I started looking online for answers.
Finally I found a bug report with others having the same issue.
It turns out that on Android versions before 3.0 there is a bug in the OS which causes the first Drawable in the resources folder to be loaded as a ColorDrawable.
Obviously this will cause an error if you’re just trying to load an image.
The solution for me was to create a dummy image named a.png and placing it in res/drawable, making sure to never use it.
After that I was able to use my other images without any issues.
Original bug report

Authorization failed (server replied with a 401).
This can happen if the consumer key was not correct or the signatures did not match.

I checked the consumer key and the signatures and they were ok.
As it turns out, if you want to use the callback mechanism, you have to specify a callback url in the twitter application settings.
To do this go to https://dev.twitter.com and sign in. Under your username click My Applications.
Select the application you’re using and select the Settings tab.
Then enter any callback you want into the callback url setting.

This is a weird quirk, but it was mentioned in the twitter developer forum.
After setting the callback url to something, in my case to http://blog.arextech.net/callback I was able to use the previous calls which didn’t work, unchanged, and they worked.
Source:
Twitter developer discussion

• avahi-daemon (to advertise on the network that we can accept the Apple Filing Protocol, AFP, protocol which is used by Time Machine for backups)
• netatalk (free, open-source implementation of the AppleTalk suite of protocols)

Install netatalk (which is in the Ubuntu repositories):

sudo apt-get install netatalk

Next we’ll configure which folders we want to make available over AFP so edit the file /etc/netatak/AppleVolumes.default

sudo pico /etc/netatak/AppleVolumes.default

I commented out the home directory share and added the last line to specify which folder to use for the backups, the name of the share and the options:

# By default all users have access to their home directories.
#~/                     "Home Directory"
/backup_folder         "TMBackup"       options:tm

Next I edited the /etc/netatalk/afpd.conf file since I wasn’t able to connect to the Time Machine share, I was getting a weird error saying

There was a problem connecting to the server "SERVER".
Check the server name or IP address, and then try again.
If you continue to have problems, contact your system administrator.

I fixed that by add replacing the last configuration line of /etc/netatalk/afpd.conf

sudo pico /etc/netatalk/afpd.conf

with the following line, which removes access by the guest user and adds password authentication for local users:

- -tcp -noddp -uamlist uams_dhx.so,uams_dhx2_passwd.so -nosavepassword

Once that’s done, restart the netatalk service:

sudo service netatalk restart

Install the avahi daemon (if you don’t already have it):

sudo apt-get install avahi-daemon

In previous versions of netatalk, we’d have to provide a configuration file for the AFP service in /etc/avahi/services/afpd.service, but we don’t need to do that anymore since the newer version of netatalk takes care of advertising itself through avahi.
Restart the avahi daemon, just to make sure it’s running:

sudo service avahi-daemon restart

Now on your Mac, if you didn’t enable network backups to devices other than the time capsule from Apple, run the following command in a Terminal window:

sudo defaults write com.apple.systempreferences TMShowUnsupportedNetworkVolumes 1

You should now be able to go into Finder -> Go -> Connect to Server -> Browse, and see your new time machine share. Select it in Time Machine and start backing up.

Notes
You can restrict which users have access to the time machine afp share by modifying the /etc/netatak/AppleVolumes.default config file and adding the “allow:” option with the usernames allowed to access the share:

# By default all users have access to their home directories.
#~/                     "Home Directory"
/backup_folder         "TMBackup"     allow:username       options:tm

Also make sure the folder selected for the backup folder has proper write permissions for the user(s)/group(s) which will make backups to it.

Sources
Michael Koflers Blog
Ubuntu Guide

-dontwarn android.support.v4.**

If you can narrow it down to only a certain package you can ignore just that more specific package, but I would’ve had to make 3 new rules for proguard in my case.

Another way to fix those warnings is to change the API version you’re targeting (if you have that possibility).
API version 11 is Honeycomb so that should have all the missing classes.

<uses-feature android:name="android.hardware.location" android:required="false"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>

And the code to actually get the location is:

LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
Location loc = locationManager.getLastKnownLocation("static");

Source

Some terms in this post:
host – machine on which VirtualBox runs, your “real” server
guest – virtual machine running in VirtualBox, your virtual server

1. Install or Update VirtualBox:
   • Download it from the site: http://www.virtualbox.org/wiki/Downloads
   • For Debian based systems there are detailed instructions on the linux download page: http://www.virtualbox.org/wiki/Linux_Downloads
   • For this post I’m using VirtualBox 3.1.2
2. Create the virtual machine and register it with VBox. The name of the vm is vbuntu.

   user@host:~$ VBoxManage createvm --name vbuntu --ostyle "Ubuntu" --register

3. Create a SATA controller which we will use to control the disk image.

   user@host:~$ VBoxManage storagectl vbuntu --name "SATA Controller" --add sata --controller IntelAhci

4. Create and register the virtual disk image, basically the virtual disk from which the vm runs. Give it a filename and a size in MB, here my virtual disk image is name vbuntu.vdi and it has 30,000 MB.

   user@host:~$ VBoxManage createhd --filename vdesktop.vdi --size 30000 --variant Standard

5. Link the vdi to the vm’s SATA controller we previously created. Connect it to the first port and make it the first device, basically sda1

   user@host:~$ VBoxManage storageattach vbuntu --storagectl "SATA Controller" --port 0 --device 0 --type hdd --medium vdesktop.vdi

6. Create an IDE controller which we will use to control the virtual dvd drive from which we will install the OS.

   user@host:~$ VBoxManage storagectl vbuntu --name "IDE" --add ide

7. Register the install disk image of ubuntu server with VBox and mount the install disk on your vm.

    user@host:~$ VBoxManage storageattach vbuntu --storagectl "IDE" --port 0 --device --0 --type dvddrive --medium /path/to/ubuntu-9.04-server-amd64.iso

8. Modify the boot order for the virtual machine so it boots from the install dvd first.

    user@host:~$ VBoxManage modifyvm vbuntu --boot1 dvd --boot2 disk

9. Modify the default options for the vm. I gave the vm 1GB of ram, turned on ACPI for power control, turned on PAE (ubuntu server requires it, it enabled 32bit hosts to use more than 4GB of ram) and I also turned on Enable VT-x/AMD-V which are the technologies Intel and AMD processors use for hardware virtualization extensions. To use these extensions your host must have a processor supporting them and then enable them from the BIOS.

   user@host:~$ VBoxManage modifyvm vbuntu --memory 1024MB --acpi on --pae on --hwvirtex on

10. For networking I’m using bridged networking. First set the vm nic to bridged mode, then bridge it with one of the host’s nic. Here I bridged it over my host’s eth1 nic.

    user@host:~$ VBoxManage modifyvm vbuntu --nic1 bridged
    user@host:~$ VBoxManage modifyvm vbuntu --bridgeadapter1 eth1

11. I also changed the port for the remote desktop protocol to 33891 because I’m running multiple vm’s, so each vm has its own port.

    user@host:~$ VBoxManage modifyvm vbuntu --vrdpport 33891

12. Start the vm in the background, so remember to add the ampersand at the end of the command. After that you can RDP into the vm by connecting to the IP of your host system on the above set port. Now you can install the guest OS.

    user@host:~$ VBoxHeadless -startvm vbuntu &

13. To shut off the vm use this command.

    user@host:~$ VBoxManage controlvm vbuntu poweroff

14. Once done with the install, you can unregister the install disk and have the vm boot from its own hdd.

    user@host:~$ VBoxManage storageattach vbuntu --storagectl "IDE Controller" --port 0 --device 0 --medium none
    user@host:~$ VBoxManage modifyvm vbuntu --boot1 disk --boot2 none

15. Optionally here are the steps to get rid of the vm and its disk image if you don’t need it anymore.

    user@host:~$ VBoxManage modifyvm vbuntu --boot1 none
    user@host:~$ VBoxManage unregistervm --delete vbuntu
    user@host:~$ VBoxManage unregisterimage disk "vbuntu.vdi"

Let me know if you have any suggestions or comments as to the process I just described.

user@server:~$ sudo apt-get install smartmontools

Once that is installed, you can try the help command to make sure it got installed correctly:

user@server:~$ smartctl -h

If that works correctly, now we’re ready to read some temperatures.
Depending on the series of the 3ware card you have, the care is accessed through either /dev/twa or /dev/twe
Now, to read the temperature of the hdd in slot 1, the command is:

user@server:~$ sudo smartctl -H -d 3ware,0 /dev/twa0

Note that after the comma in 3ware,0 comes the number of the hdd slot you’re trying to read, going from 0 up. For example, for the hdd in the second slot, it would be 3ware,1
Also, I had my 3ware raid card in /dev/twa0, which might not be the case for your setup.
You might also want to look through the smartctl tool’s manual page because it’s quite a powerful tool for monitoring hdd performance and kicking off SMART tests on the hdds.

The scenario is this: you have a fresh install of ubuntu on a VM called vbuntu.
You want to install something on it, but want to create a snapshot in case something goes wrong.

Look at the previous posts to see how to create the initial VM.
Once that is done, this is how you create a snapshot of the original VM called vbuntu, and call the snapshot initial_install

user@server:~$ VBoxManage snapshot vbuntu take initial_install

Then you do your install. If something goes wrong, you want to go back to the initial_install snapshot, here’s how to

user@server:~$ VBoxManage snapshot vbuntu restore initial_install

If your install goes well and want to create another snapshot before you install another program, you should take another snapshot, like above.

For more information about VirtualBox 3.1 snapshots check out the VirtualBox site.

nameserver 192.168.1.1
nameserver 10.0.0.1

Those just examples, but the 192.168.1.1 IP address in my case was my router’s IP address since it acts as a relay for the ISP’s nameservers, the next one is just an example IP. Now try to bring your ethernet interface up, or just reboot your box.

Another annoying problem is that the mysql server would not start on the ubuntu machine. I checked in the dmesg error log and found this weird looking error:

[10360.109659] type=1503 audit(1256893798.480:502): operation=”open” pid=23026 parent=23025 profile=”/usr/sbin/mysqld” requested_mask=”r::” denied_mask=”r::” fsuid=0 ouid=0 name=”/sys/devices/system/cpu/”

After a couple Google searches I found some other people had the same problem and it stemmed from an option in the mysql configuration where it disabled berkley db support.
I went in the mysql configuration file, in ubuntu /etc/mysql/my.cnf and commented out the skip-bdb, just put a # in front of the option:

#skip-bdb

That should do it, now restart mysql and it should work, if it doesn’t try to reboot and see if that does it.
user@host:~$ sudo /etc/init.d/mysqld restart
That’s all for now, let me know if you had any other problems when upgrading.

Some terms in this post:
host – machine on which VirtualBox runs, your “real” server
guest – virtual machine running in VirtualBox, your virtual server

1. Install VirtualBox:
   • Download it from the site: http://www.virtualbox.org/wiki/Downloads
   • For Debian based systems there are detailed instructions on the linux download page: http://www.virtualbox.org/wiki/Linux_Downloads
   • For this post I’m using VirtualBox 3.0
2. Create the virtual machine and register it with VBox. The name of the vm is vbuntu.

   user@host:~$ VBoxManage createvm -name vbuntu -register

3. Change the boot adapter to the virtual dvd drive so we can boot the OS install disk.

   user@host:~$ VBoxManage modifyvm vbuntu --boot1 dvd

4. Create and register the virtual disk image, basically the virtual disk from which the vm runs. Give it a filename and a size in MB, here my virtual disk image is name vbuntu.vdi and it has 30,000 MB.

   user@host:~$ VBoxManage createvdi -filename "vbuntu.vdi" -size 30000 -register

5. Link the vdi to the vm, here hda is the hdd off which the vm boots.

   user@host:~$ VBoxManage modifyvm vbuntu -hda vbuntu.vdi

6. Register the install disk image of ubuntu server with VBox. Then mount the install disk on your vm.

   user@host:~$ VBoxManage registerimage dvd /path/to/ubuntu-9.04-server-amd64.iso
   user@host:~$ VBoxManage modifyvm vbuntu -dvd /path/to/ubuntu-9.04-server-amd64.iso

7. Modify the default options for the vm. I gave the vm 1GB of ram, turned on ACPI for power control, turned on PAE (ubuntu server requires it, it enabled 32bit hosts to use more than 4GB of ram) and I also turned on Enable VT-x/AMD-V which are the technologies Intel and AMD processors use for hardware virtualization extensions. To use these extensions your host must have a processor supporting them and then enable them from the BIOS.

   user@host:~$ VBoxManage modifyvm vbuntu --memory 1024MB --acpi on --pae on --hwvirtex on

8. For networking I’m using bridged networking. First set the vm nic to bridged mode, then bridge it with one of the host’s nic. Here I bridged it over my host’s eth1 nic.

   user@host:~$ VBoxManage modifyvm vbuntu --nic1 bridged
   user@host:~$ VBoxManage modifyvm vbuntu --bridgeadapter1 eth1

9. I also changed the port for the remote desktop protocol to 33891 because I’m running multiple vm’s, so each vm has its own port.

   user@host:~$ VBoxManage modifyvm vbuntu --vrdpport 33891

10. Start the vm in the background, so remember to add the ampersand at the end of the command. After that you can RDP into the vm by connecting to the IP of your host system on the above set port. Now you can install the guest OS.

    user@host:~$ VBoxHeadless -startvm vbuntu &

11. To shut off the vm use this command.

    user@host:~$ VBoxManage controlvm vbuntu poweroff

12. Once done with the install, you can unregister the install disk and have the vm boot from its own hdd.

    user@host:~$ VBoxManage modifyvm vbuntu -dvd none
    user@host:~$ VBoxManage unregisterimage dvd /path/to/ubuntu-9.04-server-amd64.iso
    user@host:~$ VBoxManage modifyvm vbuntu -boot1 hda

13. Optionally here are the steps to get rid of the vm and its disk image if you don’t need it anymore.

    user@host:~$ VBoxManage modifyvm vbuntu --hda none
    user@host:~$ VBoxManage unregistervm --delete vbuntu
    user@host:~$ VBoxManage unregisterimage disk "vbuntu.vdi"

Let me know if you have any suggestions or comments as to the process I just described.