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rob michael

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since May 22, 2011
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Recent posts by rob michael

One of the best ways to get a leg up in terms of starting to build up freelance clients is by ensuring you have a good web presence and a good portfolio.

Even without clients yet, you should try and build up a portfolio of apps you have made that are in the market (do apps for free for friends/family, offer to do work for free) - This will mean potential clients will be able to come and see your work immediately, and will hold much more sway if you have decent apps they can see, using different technologies etc. Obviously, similar to web design work, a large part of mobile programming is about the design aspect, the aesthetics etc, and clients will want to know that not only can you deliver the functionality they require, but also you can make it look good.
10 years ago
well, this is a tricky one - there are several professional standard frameworks in java that you could use. The choice will be down to specific requirements, experience, IDE and just general preference.

Spring offers a very popular framework which is pretty comprehensive (and just my personal preference ;) so you could look at their "petclinic" example for getting started:

Spring also has a product called Spring Roo, which brings Rapid Application Development to the party and give you increased initial productivity pretty quickly (although, if you are new to Spring, I would recommend you spending time understanding what is going on behind the scenes and how all the parts of the application are being wired together)

Other than that, check out Struts, Vaadin, GAE, Play
11 years ago
just realised that I just replied to another of your posts on this topic in another thread - but in response to your earlier question, I have done a tutorial on how to create a Twitter app using OAuth and Twitter4J which covers callbacks etc. and includes the complete app source code.
11 years ago
Hey Sherif,

any reason you are not using callbacks to return and write the pin to the sharedPrefs?

11 years ago
the guys are right - to be making money is very tough as its a super competitive market and the standard for apps is pretty high.

There was a really interesting thread on HN a while ago about developers making money - its quite an inspiring read to see what people have done/tried to make additional income (some of which work, some fail), but difficult not to get carried away thinking that you could start making money in an instant
11 years ago
For sure, if you can come up with a catchy game then that will do well for you - although the market is hotting up more and more in that section, so another alternative would be to find a niche that you know about and try and fill that.

If you want to go down the games path then there are loads of great libraries out there that you can try out:
11 years ago
I have just done some recommendations for learning Android on my blog here:

But personally, I quite liked Hello, Android as a book to get started!
11 years ago
If you dont want to code it yourself and have no aversion to existing libraries you can use the MultiMap implementation in Google's Collections library (now called guava):
11 years ago
Ok, heres the problem:

in your main class on line 30 (original post line 30) you call the StataColumn constructor as follows:

tokens is initialised as an array of strings, so you are calling the following constructor in your StataColumn class:

instead of calling one of the other constructors that intialises your arrayList

That finally means you get an NPE when your main class calls the StataColumn.add() method on line 47 as it tries to perform this:

and values is not initialised.

To fix this, either call the constructor passing in a MyString object, or change the String constructor to initialise that arrayList.

Hope that helps!
11 years ago
From your stack trace snippet posted in your above system.out example, we see that:

You can see that the exception is on line 61 of your main method (i assume this is the same as line 47 - but has just been increased because of the newly added system.outs) - and then that then is being thrown on StataColumn.add (line 32 of the StataColumn class) - which makes sense as line 47 calls the stataColumn.add() method on line 47:

Can you show us what is happening in the add method for StataColumn?

11 years ago
Whilst LSP is often debated and adopted within OO circles - it is often argued that Java does not obey LSP - as I think was demo'd by your second example.

Google Java and LSP and you will get the idea:

This is worth a look:

include sdetails of UI tools, as well as other handy resources such as wireframing tools, icons, etc
11 years ago
Depending on your preferences, it might be worth looking into Twitter4J - Twitter4J is a Java library that provides a standard API around the Twitter user web services and provides all the objects you need to tweet, re-tweet, view users timelines, profiles etc.

Twitter authentication is done using OAuth, so you need to register for your application details on the Twitter site.

There is an example (plus source code) of very basic twitter functionality here: although it doesn't include the OAuth or updating stuff, it should give you an idea of how the Twitter4J API looks and how easy it sits with Android.

If you prefer to work with WebServices/JSON then you can just use the direct Twitter Web Services.

When developing the app, you will need to take care to optimize the caching etc, as Twitter limits the number of requests that can be made per hour, and if you dont manage the requests properly you can quite quickly hit the limit.
11 years ago
The problem is you dont have org.codehaus.plexus:plexus-utils:jar in your local repository and maven is unable to download it.

Here are some pointers to how to resolve this:

1. Check the maven central repository online to see if this JAR is part of the core library.
- If it is, and your local maven cannot download it then it may be something to do with your web connection, and you may need to setup a proxy in your settings.xml
- If it isn't, google it to see if it is in another repository - if it is in another repository, then you will need to configure your project POM with the new repo details
- If it isn't in any maven repository, then you will need to download the JAR manually and explicitly install it in to your repo using the following command:

In this instance, having checked you can see that it is in the maven repository, which suggests your local setup is having some problem downloading the JAR - so check your proxy settings.
11 years ago