Android provides an Application class.

Base class for those who need to maintain global application state.

Here’s how to create such a class in Mono for Android:

[Application]  // <-- Attribute required
class MyApp : Application {
  // Required constructor
  public MyApp(IntPtr javaReference, JniHandleOwnership transfer) 
    : base(javaReference, transfer) { }

  // Test method - not required
  public override void OnCreate() {
    base.OnCreate();
  }
}

Note: There can only be one such class in an Android application.

CodeProject

During my time as a student at the University of Stuttgart we had to learn the programming language Ada. Back then I was swearing about the compiler error message because they were totally meaningless (at least to me).

I am currently working on a C++ project and I have to say that C++ isn’t an inch better than Ada. Consider the following code:

1
2
3
4
5
6
7
8
9
10
11
12
13

#include <Windows.h>
 
namespace Geometry {
  class Polyline { };
}
 
using Geometry::Polyline;
 
namespace OtherNS {
  Polyline* get() {
    return NULL;
  }
}

Trying to compile this code gives you the following error message (on Visual C++ 2010):

using_test.cpp(10): error C2143: syntax error : missing ';' before '*'
using_test.cpp(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int
using_test.cpp(10): error C4430: missing type specifier - int assumed. Note: C++ does not support default-int

What? Syntax error? And then you start looking where you missed a ;.

The problem, however, is completely different. It’s because there is a function called Polyline() defined somewhere in Windows.h and now the compiler tries to use this function as return type instead of the class Polyline (but doesn’t say anything about that). <irony>This, of course, becomes totally clear just by reading this extremely meaningful error message.</irony> *sigh*

GCC isn’t better here (in case you were blindly blaming Microsoft for writing bad error messages):

error: ‘Polyline’ does not name a type

By the way, the problem can be solved by placing the using statement inside the OtherNS namespace.

C makes it easy to shoot yourself in the foot; C++ makes it harder, but when you do, it blows away your whole leg.

— Bjarne Stroustrup, developer of the C++ programming language

Java is open-source, fortunately. Accessing its source code is, unfortunately, not so intuitive on Mac OS X Lion when using Eclipse. This article will guide you through the steps required to be able to view Java’s source code in Eclipse.

Read more →

Assigning a DNS name to a virtual machine can be a convenient thing. Do this is not very complicated, it requires some technical skill though. This tutorial shows how to do this with a Ubuntu 11.10 Linux server running under Parallels Desktop 7 on Mac OS X Lion. The basic principals described in this article work as well for any other combination, but that’s beyond this article (and that’s where your technical skill comes into play).

Read more →