(Objective-c)How to round a number

Here is a solution to round a float number:

NSString *pi = @"3.14159265";
int floatSize = 3;
NSDecimalNumber *numericValue = [NSDecimalNumber decimalNumberWithString:pi];
NSDecimalNumberHandler *roundingStyle = [NSDecimalNumberHandler 

decimalNumberHandlerWithRoundingMode:
NSRoundBankers scale:floatSize raiseOnExactness:NO raiseOnOverflow:NO 

raiseOnUnderflow:NO 
raiseOnDivideByZero:NO];
NSDecimalNumber *roundedNumber = [numericValue 

decimalNumberByRoundingAccordingToBehavior:
roundingStyle];

or

NSString *pi = @"3.14159265";
NSString *roundedNumber = [[NSString alloc] initWithFormat:

@"%.3f",[pi floatValue]];

Result: 3.142

(Eclipse)How to resolve "Initializing Java Tooling"

Just met an initialization error on Eclipse, the error message is:

'Initializing Java Tooling' has encountered a problem. An internal error occurred during: "Initializing Java Tooling".

It's really annoying, after googling several sites, here is a working solution:

Delete the following directory: WORKSPACE_HOME/.metadata/.plugins/org.eclipse.core.resources/.project, and restart Eclipse and problem should be solved.

(Other)The Google Online Marketing Challenge 2008 Campaign Results

I have chosen the course "E-Commerce" in my last semester in the Université de Montpellier 2. Dr. Jean-Yves Delort which is our professor organized 14 student teams participating to The Google Online Challenge 2008. I just get the rating of our team from Dr. Jean-Yves Delort's site. We are "Strong Campaign", it is such a good news, because marketing is not our major, and we really did a good job.

Dr. Jean-Yves Delort's site

2008 Campaign Results

(Objective-c) How to get MD5 hash string of a NSData

- (NSString*)dataMD5:(NSData*)data {
CC_MD5_CTX md5;

CC_MD5_Init(&md5);

CC_MD5_Update(&md5, [data bytes], [data length]);

unsigned char digest[CC_MD5_DIGEST_LENGTH];
CC_MD5_Final(digest, &md5);
NSString* s = [NSString stringWithFormat: 

@"%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
digest[0], digest[1],
digest[2], digest[3],
digest[4], digest[5],
digest[6], digest[7],
digest[8], digest[9],
digest[10], digest[11],
digest[12], digest[13],
digest[14], digest[15]];
return [s uppercaseString];
}

Mark A. Ziesemer: Java: Iterating over XML DOM Nodes

Mark A. Ziesemer: Java: Iterating over XML DOM Nodes

(XCode) How to setup a bracket / brace macro in XCode

Before i used XCode and learned Objective-C, i never thought the bracket is a horrible symbol, there is a solution of creating text macro to insert bracket / brace:

1. Open ObjectiveC.xctxtmacro with an text editor, you can find this file with this path:

/Developer/Applications/Xcode.app/Contents/PlugIns/TextMacros.xctxtmacro/Contents/Resources/ObjectiveC.xctxtmacro 

2.Add follow code in the file:

{
Identifier = objc.bracket;
BasedOn = objc;
IsMenuItem = YES;
Name = "Bracket Expression";
TextString = "[<#!expression!#>]";
CompletionPrefix = bra;
},

This scope create a text macro "bra" to insert "[<#!expression!#>]", you need to type bra in your code and presse "esc" button, there is a window shows "Bracket Expression", press enter "[<#!expression!#>]" will be inserted.

You can create a similar macro for Brace, here is an example:

{
Identifier = objc.brace;
BasedOn = objc;
IsMenuItem = YES;
Name = "Brace Expression";
TextString = "{<#!expression!#>}";
CompletionPrefix = bra;
},

Here you have a same text macro "bra" to choose bracket or brace.

Update: In the XCode 3.2 which is released for Snow Leopard, the above lines wouldn't work until add this line in each section:

OnlyAtBOL = YES;

(Android) First application released

I just released my first application on the Android Market. It is Voice Dictionary which is a very useful tool for translating words or phrases between 17 different languages (Chinese, English, French, German, Italian, Spanish etc), the Voice Dictionary also supports Text-To-Speech to give you a full experience of pronunciation.

It uses Google Translate service API and eyes-free TTS engine for Android.

Here is a web version Android Market which contains this app's information.

(Android) How to write your code with a good style

I saw an excellent article in Android Code Source site, it is a Code Style Guide, which is Google Android team asks their developer to respect. Writing code with a good style helps others to read your code, and developer should have a good habit of writing code too.

Code Style Guide

(Objective-C) How to sort an array

Here is an example to sort an array:

- (NSArray *) sortArray:(NSArray *)array :(BOOL)inAscending {
  if (inAscending) {
      return [array sortedArrayUsingSelector:@selector(compare:)];
  }
  else {
      NSArray *ascendArray = [array sortedArrayUsingSelector:@selector(compare:)];
      return [[ascendArray reverseObjectEnumerator] allObjects];
  }
}