Dec/083
Update Delayed on Mysql and PHP
Wouldn’t it be nice if we could use UPDATE DELAYED in mysql just like we do use INSERT DELAYED? Unfortunately, the work around mysql created for this is to insert a record into the events table in order to separate UPDATE statement into another thread. There is a large overhead to inserting to then execute an update.
If you are using PHP with mysql, there is another work around. PHP has a function called, register_shutdown_function, which will execute a function during the shutdown of processing a script file. So if we add an UPDATE LOW_PRIORITY sql statement wrapped in a function that is passed to register_shutdown_function, we can allow the user to receive the page without delay while the UPDATE statement waits until all locks on the table has been release before proceeding.
function update_delayed()
{
$sql = "UPDATE LOW_PRIORITY table_name SET col1 = 'something'";
mysql_query($sql, $conn);
}
register_shutdown_function('update_delayed');
I wonder if there are even better ways to handle this problem.
Dec/081
Second Android phone, Agora, follows G1
It has been less than two months after G1, the first Android phone, was launch that the second one is announced by Kogan. It is the Agora, a phone looking more like a Blackberry than an iPhone. The great thing about this new phone is that it is not locked. However, it does not have as many features as the G1.
Here is what Howard Wong has to say about the Agora vs G1.
This is more blackberry-ish in style, slimmer and so in a way its a bit more “humble” and makes you wanna compare it to a blackberry.. which sort of allows Agora to scale back on memory features (256 meg, 128 meg flash, no WIFI). Also I think they were smarter about battery life by supplying a 1300mAh battery as opposed to G1′s 1150mAh.. G1 most prolly uses more power anyway. Clearly Agora’s niche is to bridge mainstream PDA users to Android.. a very smart move because quite frankly, most people don’t know or care about where mobile applications come from. I believe this phone to be a much more humbler/accessible stage to feature android apps.
Looking back, I think Tmobile should’ve released something like this and steared clear of IPhone envy. One of the first things I said to myself when I first played with the G1 was, “I can’t believe google allowed this to be the first phone.”
I still think the 4 buttons should be electro-sensitive like the touchscreen. For such mainstay controls, they deserve to be on par with the touchscreen. At least with this new Agora phone I won’t complain because interaction through the touchscreen seems more like a bonus whereas on the G1, it seems required.
Nov/081
Where to install Eclipse on Ubuntu
If you’re like me, accustomed to installing most packages via Ubuntu’s package manager, you might be a bit confused as to where to install Eclipse since it should be in a place thats accessible by every user on your system. Sure you can install it in your user home directory but that wouldn’t be very tidy.
I extracted part of these instructions from: http://flurdy.com/docs/eclipse/install.html
These instructions assume you’ve downloaded and extracted the Eclipse tarball:
sudo mv eclipse /opt/eclipse cd /opt sudo chown -R root:root eclipse
sudo mv eclipse /opt/eclipse cd /opt sudo chown -R root:root eclipse
sudo chmod -R +r eclipse
sudo chmod +x `sudo find eclipse -type d`Then create an eclipse executable in your path
sudo touch /usr/bin/eclipse
sudo chmod 755 /usr/bin/eclipsesudoedit /usr/bin/eclipse
With these contents:
#!/bin/sh
export ECLIPSE_HOME=”/opt/eclipse”
$ECLIPSE_HOME/eclipse $*
Now you can execute Eclipse from anywhere in your bash shell. Check out the original article for generating a desktop icon. In the tarball I downloaded, it didn’t come with the icon.xpm that contains the Eclipse icon but no worries for me.
The take-home lesson here is that /opt is meant as a place to install application software packages. The topic is Filesystem Heirarchy Standard (FHS) .. these folks seem to be the standard authority on it:
http://www.pathname.com/fhs/pub/fhs-2.3.html#OPTADDONAPPLICATIONSOFTWAREPACKAGES
However it’s not to say that this standard is the most progressive one we have today. I found GoboLinux to be particularly interesting: http://en.wikipedia.org/wiki/GoboLinux#The_GoboLinux_hierarchy
Nov/089
Installing Eclipse IDE and Android SDK on Ubuntu 8.10
This blog gives pointers on getting the Android development environment working on a base Ubuntu 8.10 installation.
This assumes you’re familiar with google’s installation instructions (see http://code.google.com/android/intro/installing.html) and might still be having some problems.
This also assumes you’ve installed Sun JDK 1.6.
So here are some tips and gotcha’s:
- Don’t install Eclipse with Ubuntu’s package manager. At time of writing, Eclipse 3.2.2.2 is in the distro. Make you sure have the latest Eclipse version by downloading directly from Eclipse’s site. See http://www.eclipse.org/downloads/
- With most (if not all) base Ubuntu installations, java-6-openjdk or java-gcj is used, not Sun’s JDK. You don’t want to uninstall java-6-openjdk either because other apps in your system will be uninstalled along with it. In your Ubuntu filesystem, JVM tools (e.g. javac, javah, javadoc, java) are actually symlinks to the actual JDK. So what you want to do is update these symbolic links. There are at least 2 tools I’ve come across to help do this. I found the following:
- sudo update-alternatives –config java
- sudo galternatives
- In Eclipse, for some reason I’ve not been able to add the ADT plugin via add site. I had to download the SDK zip file and install as a local archive.
- If you don’t know where to install Eclipse, check out my post on where to install eclipse since we’re not using the comfy package manager to take care of things for us.
That’s it for now.
Nov/0812
Getting Android emulator working with Google Maps API Key
I was trying to get an Android app that uses Google Maps API to display a MapView running on the emulator. It took quite a bit of hair pulling to finally get it working.
First, I tried using a self-signed keystore instead of the the debug.keystore provided through the Android SDK. I created my keystore using keytool -genkey from JDK. Then I switch the app from using the default, debug.keystore, to my-new-self-signed.keystore. Using keytool -list, I got the MD5 of the certificate that is needed to obtain a Google Map API key. Then the API key was put into the MapView android:apikey attribute. When I brought up the app in the emulator, I got a blank map grid screen. The reason I wanted to use the self-signed keystore instead of the debug keystore is so I don’t have to obtain a new Map API key and change the code to reflect this upon releasing the app.
So, I decided to go with the debug.keystore and that worked fine. Here is what I had to do.
-
$ keytool -list -alias androiddebugkey -keystore <path_to_debug_keystore>.keystore -storepass android -keypass android
- Copy that MD5 and goto http://code.google.com/android/maps-api-signup.html
- Signup for an API key
- In my xml file that has the views for the activity, add
<com.google.android.maps.MapView android:layout_width="fill_parent" android:layout_height="fill_parent" android:enabled="true" android:clickable="true" android:apiKey="example_Maps_ApiKey_String" />
- In the Manifest.xml file, add the permissions needed
<uses-permission android:name=”android.permission.INTERNET”></uses-permission>
<uses-permission android:name=”android.permission.ACCESS_FINE_LOCATION”></uses-permission> - In the Manifest.xml file, add the maps library
<uses-library android:name=”com.google.android.maps” />
within the application tag - The entire Manifest.xml looks like this
<?xml version=”1.0″ encoding=”utf-8″?>
<manifest xmlns:android=”http://schemas.android.com/apk/res/android”
package=”com.informationideas.mapapp”
android:versionCode=”1″
android:versionName=”1.0.0″>
<uses-permission android:name=”android.permission.INTERNET”></uses-permission>
<uses-permission android:name=”android.permission.ACCESS_FINE_LOCATION”></uses-permission>
<application android:icon=”@drawable/icon” android:label=”@string/app_name”>
<uses-library android:name=”com.google.android.maps” />
<activity android:name=”.ShowDesktop”
android:label=”@string/app_name”>
<intent-filter>
<action android:name=”android.intent.action.MAIN” />
<category android:name=”android.intent.category.LAUNCHER” />
</intent-filter>
</activity>
</application>
</manifest> - The default activity file should look like this
package com.informationideas.mapapp;
import android.os.Bundle;
import com.google.android.maps.MapActivity;public class ShowDesktop extends MapActivity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
}
Now off to building cool things with the map!
Oct/080
G1 Android Phone
I just received my G1 phone in the mail as it is spectacular. The touch screen works very well and the built-in GPS, wi-fi, and 3G network/ functionalities will allow developers build some very exciting new applications for these phones. It also has a compass that is demonstrated using the Street View of Google Maps. When viewing Street View, if you start spinning in one spot the image will rotate according to the direction the back of the phone is facing. It probably has a built-in level also that allows the Street View to pan up to the sky or down to the ground when the phone is moved in those directions.
The Android Market is where users can download application that runs on the phone built by developers (Google and other developers). It currently has about 50 applications from their Android Developer Challenge. On October 27, 2008, they will open up the Android Market to all developers to submit their applications. Currently, all applications in the market must be free of charge, but in the first quarter 2009 they will allow applications that charge a fee. It is interesting that Google has made the Android Market totally open and policed/ ranked by users. They will not require approval for any application and anyone can put applications on the market. That is very different form Apple’s iPhone App Store where they are gatekeepers to every application sold to iPhone users by using a review process. We will see how this pans out, but so far it seems promising.
Well, I’m going to start building Android Apps so that’s it for now.
Jul/080
.NET formview edit mode problem
I encountered problem with the formview not switching to edit mode using the standard commandname=”Edit” for a linkbutton. It turns out the problem was with the way I bind the data source to the formview through code behind. I changed that to defining the formview tag with the attribute of datasource while defining the data source on the page code and everything worked just fine. Go figure.
Jul/081
PHP header redirect
Something to remember when using header location to redirect a page from a server-side script. The output is redirected to the new page, but the logic on the original file will continue to execute. Therefore, if there are database calls the changes to the data will still be made even though a header redirect was issued.
To solve the problem, make sure to issue an exit() command after a header location command.
Jul/080
Information Ideas built Google Maps for Terradex to receive award
We have been building a few applications for Terradex over the past year that have received Environmental Achievement Awards using Google Maps API. The service pulls environmental contamination data from various environmental agencies and uses Google Maps to display their locations. The interface uses a non-page refresh AJAX technique to dynamically pull data as the visitor navigates through the map.
Jul/080
Apple’s new iPhone causing lines to form by chance?
I was speaking with a friend this weekend about the new iPhone and he was surprised that Apple with all its technical abilities could not setup a better system for all their fans to get a hold of the new iPhone than to have everyone stand in line for five hours to purchase one. Well, that was not by chance. Steve Jobs wanted the launch to be so inefficient. There are lots of benefits to having people wait five hours to buy one.
First and most important of all is PR. Every newspaper I read had an article about the iPhone craze. All the people walking by the line will certainly notice the launch. The bragging that happens after a fan has stood in line for five hours to obtain one is going to be more than five months of non-stop blabbing (probably through his new iPhone).
Secondly when someone exerts so much effort to getting his hands on the device, he will love it more than life itself for a certain duration of time. That love for the new iPhone will translate to an irrational love for Apple and resulting in Apple sell more products to these iPhone owners.
The launch was very well orchestrated. Well done, Steve!