android

Last week, O’Reilly started a free training Android course, I had the chance to attend it, all of it, unlike some of my friends who couldn’t stay up till late night

I also had the chance to take notes, .. I will post the notes of the first lecture at the end of this post (its my notes, do not expect to understand everything from it because you did not write it )

the lecture started with the basic principles on how Android works, … you know .. the “useless things that is good to know” sort of things, than some tips on installations and some basic “flash light” program, .. and during that whole thing a lot of questions were made by the people watching the course, .. some questions are really irrelevant and useless, while others were interesting.

Before i post my notes i would like to mention my opinion about the course from the first lecture (this opinion is merely my personal opinion). It is my first time coding Android, .. but it is NOTmy first time coding

My opinion on Tony the lecturer

He seems to know somethings on Android, more than most of us obviously, but i am afraid that I expected the lecture to be more professional, I mean during the lecture, Tony was exploring the code and how things work, i did not find him mastering the language, … but in my opinion as long as he is ahead of us at least one step, than praise him

My humble opinion about the Android programming language

Android relies heavily on user-defined XML tags (or that is what i saw from the first lecture). its not a good or bad thing, .. it is just … different i guess.

It is a very interesting course and i would like to encourage anyone who has the slightest interest in developing mobile applications to attend this course

Anyways .. without further dues, … here are my notes

————————-

linux>Native Libraries > Run time + Dalvik VM > andriod framework (activity manager, content Provider, Location manager, Notification manager,..) > System apps (contacts, Phone Dialer, Email, Web Browser)

app: code + R resources (movie, xml, pic)

Activity: single screen. app have many activities

intent: code to accomplish a verb (call number, open contacts)

——————-

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many companies started using this software either publishing site ( where anouncements & news could be easily shared with employees) , or team sites ( to manage work of small teams and assigning tasks to them) , or document center, or other many things.

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I am used to programe in Java at home and on almost all my personal projects , in my work place i am a C# guy (well in work place they only use .NET ) and this is because in college days all we have been exposed to were OO languages like C++, Java, .NET and that what we are using till now.

As scripting languages, developers around here are far away from them, may be the only scripting language used heavily in this side of the world is PHP, and the most powerfull JavaScript and thats it. I decieded that i want to learn a new programming language and it has to be a scripting language this time, i was looking for Ruby,pearl & python to learn one of them. Finally my choice was python and thats why i hope i will be able to put small tips and tricks of what ever i learn in python here on this blog.

In this blog i am just talking about why i am intrested in learning python , well first since i am used to java and C# and they are statically typed languages I don’t experiance a lot the beauty of dynamically typed language where i dont have to declare variables or specify its type, also in dynamically typed language i will be able to use a variable as integer and after few lines i will use it as string , then again i can use it as an object of my class called money, or what ever else very easily.Another benifit of dynamic typing is that i can have a set, an array that contain compeletly different types of variable that while retriving them i dont have to cast them to their types which really simplifies a lot of rutine work

Other than being dynamically typed language python is very compact compared to java & C#, so typing is less, what ever you type in python will be used to solve your problem not the language problems as in the big OO languages

lets say i want to create a class constractor that meight take a variable or two variable, or three variables.

public class MyclassName{

public MyclassName(String var1)  {      this(var1, 1);  }

  //--------- constructor #2 -------------  public MyclassName(String var1, int var2)  {     this(var1, var2, "single");  }

  //--------- constructor #3 -------------  public MyclassName(String var1,         int var2,         String var3)  {     this.att1= var1;     this.att2= var2;     this.att3= var3;  }

class MyclassName():

  def __init__(self,      var1, var2=1, var3="single"):

      self.att1= var1       self.att2= var2      self.att3= var3

to open file in python 

BufferedReader br=  new BufferedReader(      new FileReader(filename));

fileName = open(filename)

so i think if i master python or any similler language (Ruby, pearl) i will have to type less and be able to concentrate more on solving the problems i am working on.

Another new thing in this kind of language is they support functions as first class entity in the language, so functions could be stored in data structured and passed as arguments to other functions (not as pointers like in C++) Also functions could be created dynamically while the programe is running which i am sure will be very usefull, i have never though of using a dynamically created functions since none of my programe worlds supported that before. if you are new to this like me and need example check this

well i guess after all of these reasons it still didnt come to python, cause these reasons just show i want to learn an scripting language with the mentioned properties that could be any of Perl, Python, PHP, Lua, Tcl/Tk, ECMAScript (JavaScript, ActionScript), Ruby, Io, Scala, or Nemerle. I guess then it is true i wanted to learn python just because it is python  may be another reason is it is very known, supported heavily by Google, in their app engine !

to be honest i was thinking about ruby too. but after some search i found some information that made me like python more that are many blogs says the error messages in ruby compiler are not very much informative compared to python. Another reason is there is a lot of ways of doing the same thing in ruby which is good but can make a new language somewhat confusing. Also the fact that GUI libraries for Ruby they are very limited and in python there are a lot of libraries + default librari that comes with python itself

so i prefered python .so hope fully i will be able to put some small python tips or tutorials as soon as possible.

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for this blog the title actually shouldn’t be SQL tip 3 , it should be MYSQL tip 3, since it is talking about something specific to MYSQL, but since i had two (very old) posts about sql tips SQL tip1 SQL tip2 ,well they were geniral but were demonistrated in MYSQL too.

back to the topic. i needed to know how to get the database schema for a MYSQL DB in one of my projects and knowing the how was not stright forward so thats why i think it will be good and usefull tip.

A very usefull information in this topic is that information on database tables is stored in a system table called “information_schema.tables “.However a better information is writting the query “select * FROM information_schema.tables ” will get you some of the tables that you never had created (system tables) + your tables. to exclude system tables you have to add a where condition

“select * FROM information_schema.tables where version=’10′“ this will show only the tables you have created. version is not related to the version of your MYSQL, but older versions of MYSQL you have to write “select * FROM information_schema.tables where version=’9′“.Another simpller way you can know the table information without taking care of table version is to query based on the database name “select * FROM information_schema.tables where table_schema =’DB_Name’“

ok we have the table information but still we will need column information of these tables. These information could be extracted from another system table called information_schema.`COLUMNS`

a very simple query could give the most important information of your table’s columns is
“SELECT column_name,data_type,column_key FROM information_schema.`COLUMNS` WHERE table_schema=’DB_Name‘ and table_name = ‘your_table_name’;“

hope this very simple tip will be helpful to the readers as an extra knowledge or for those who come to this page searching through google hope this information will aid you

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Well as easy as it may seem, this sometimes proves to be a tedious task to look for. Simply because the legends functionality are not provided on the legend display area. Well enough talk and lets learn how to do that in a few steps

Obviously you are creating a graph (chart of some kind),
* Right click on the Chart Area,
* Chart Expert
* Text Tab
* On the Format Area choose Legend,
* Click the Font button
* Change the font to the your desired display

For MS ACCESS
changing the legend size does not seem to be a problem but the legend caption is.

The Simplest way to change/remove the “Sum of…” text, or any text, in a LEGEND PivotChart.

* Switch from PivotChart View to PivotTable View
* Click once to highlight the field name that reads “Sum of…”
* Go to properties
* Select the “caption” tab
* On the title “caption” type in the new text you would like
* Change the view to pivot chart

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Hello there, well to be honest I am not a fan of Microsoft technologies well any how I cannot live without my XP these days (one of the best things the big M have done), but SharePoint is completely different story. It has a lot of potentials and abilities and once I saw the first time I said to myself this will finish all of my working place’s problems. But I had a feeling something will be wrong in it. To be honest I have faced a lot of challenges many times I was surprised with what SharePoint provides and many many more times I was disappointed with its limitations. But thanks to friends and fellow bloggers who helped a lot out of the problems.

This time I was facing a very strange problem that I am even not sure if it is SharePoint problems or it is just our environment, I was not able to find any similar problem on the net so thought I could document it here.

SharePoint API provides a great API to access list items , search them, add, delete, and update them that save you the effort of reading list information from SharePoint’s database directly, and it is provided in a very nice way. But the updating I have had some strange issue with that I have solved now, but I couldn’t understand why I got it in the first place.

Here I will give you the basics of accessing items from SharePoint Lists and show the issue

To access a list is very simple make a variable and assign it the url where you see the list in the sharepoint

string strDashListRoot = “http://[Servername]/[subsite/subsite]/Lists/[list name]/AllItems.aspx“;// just copy past the link form your browser

Then from the link you can get the site and website and the list easily

using (SPSite site = new SPSite(strDashListRoot))
{

using (SPWeb web = site.OpenWeb())
{
SPList list = web.Lists["listname"]; // do not forget to close the brakets after your code is done } }

Now here you can access the list items easily

String information=Lists.items[2][“fieldname”].toString(); // simply put the index of the item you need and then the field name that you want to show

Now the main thing here is when we want to change field of the list item we could do easily this

Lists.items[2][“fieldname”]= “myvalues”;

Lists.items[2].Update();

but that didn’t worked in our environment while doing the folling code worked !!!

SPListItem item = Lists.items[2];

item[“fieldname”]= “myvalues”;

item.Update();

Well may be that is something related to our environment but hope through this simple blog you know how to access and edit SPList items.

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Once a long time ago (in 80s) I think Assembly was considered the savior for when ever some one need to do some dirty work with their C or whatever language code and its not clear for him how to do it there or few things are not supported assembly comes to give you control on the tiniest transistor on the PC so you can do what ever in your mind (this is not just 80s it is applicable for all times  )

In 90s the days of C++, Visual Basic 6.0, JAVA, PHP,… etc I think the savior was the C language, really when ever there was something you cannot do in any of these languages that you are working on, you would just connect it to a c DLL or any c library file!!, using JNI for Java or active or DLL library for visual basic and similarly for others.

These days (WEB 2.0 days) all of the applications are moving to web using PHP J2EE, .NET 2005/2008, R on R and others. The common factor between them is they all need JavaScript to do the dirty work for them (working on client machines) so as in old days when all programmers needed to know assembly or as in 90s when all programmers needed to know C to do wonders with their softwares, these days developers must know JavaScript; cause it is the language for them all (applicable to any JavaScript framework (jquery, mootool, prototype))!!!

Ok that’s enough chit chat, now why I am talking all about this?? Because jquery enabled me to do something fun with asp.net 2.0’s gridview

I will show you

I have added a jscript folder to my project and in it I have added the jquery and one of its plug-in: datepicker which will show a date picker calendar

Added jquery to my master page code so it will be available to all of my pages in the application that uses this master page

<script type=”text/javascript” src=”Jscript/jquery-1.2.1.min.js”></script>

Now I have a gridview (well for my application need I have a very complex 3 level nested gridview)

Now close date is a template column where I have a textbox I made the cssclass of the text box equals to “datepickerz” <asp:TextBox ID=”TextBox1″ runat=”server” Text=’<%# Bind(“close_date”) %>‘ CssClass=”datepickerz” Width=”89px”></asp:TextBox>

Now I need for each row in this complex gridview the textbox to be a datepicker so simply I wrote the following jquery script

<script type=”text/javascript” src=”Jscript/ui.datepicker.js”></script>

<script type=”text/javascript” >

$(document).ready(function() {

$(‘.datepickerz’).each( function () {

$(this).attachDatepicker();

});

});

</script>

Which is one of the beautiful magic of jquery it allows to pick all controls that have been assigned the class datepickerz and then for each control I just attach it with the datepicker.

The result whenever I click on the textbox in any editable row in the complex gridview I will get a floating calendar to select a date that will be stored in the textbox.

I know I have not discovered the atoms by doing this simple activity, but I wanted to mention it because as I see around me (in Oman) most of .NET developers are not aware of Jquery and other JavaScript frameworks and their features.

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now, i assume that you “developers” did the most efficient way to retrieve the data, but above that there is still a considerable “fetching” time to wait inorder to fully display the records queried, here comes the benefit of adding a splash screen for the user, so he/she doesn’t panic and think that the page is stuck or something.

easy steps to follow inorder to get an attractive waiting screen (see below) while the code is processing and the user is waiting:

first of all you need to add one important line of code to the top of your ASP page, that line is:

<%Response.Buffer = True%>

This line tells the server not to send anything to the client until the page is finished processing or you use “Response.Flush” code in part of your ASP page to send everything fully loaded so far.

now just add the following to javascript functions to your code between “script” tags, those functions are used to “show” and “hide” the splash screen when needed:

function showObj(obj){obj.style.visibility = "visible";}

function hideObj(obj)

{obj.style.visibility = "hidden";}

now after we created the functions we create the part that gonna show as “splash” screen, i created it as “div” as it can contain more then one element inside it not just an animated image or text..

  <div id="splashScreen" style="position:absolute;z-index:5;align:center;">           Searching, please wait .. <br>          <img src="loada.gif"/>

  </div>

its strongly recommended to put this div as close as possible to the nearest element after you invoke a “search” button or a “submit” button so the div would show as soon as the “fetching” face starts

you can put any animated “gif” pic in the img src, i choose to put a loading indicator, you can find a very nice collection of activity indicators from http://www.ajaxload.info/

after you put the div in the right position, you should put the “Response.Flush” code so you tell the browser to show to the user everything loaded so far “including the splash screen” and then do the processing, code executing and searching. after that you do “Response.Flush” again to show the information fetched, and finally you hide the “splash screen” .. so to make it simple, your code would be like the following:

<%..Response.Flush  'this will show everything loaded so far including the splash screen.'... put the searching/fetching code here and show the results ...'... remember that your results wont show until you flush again ....Response.Flush  'this will show everything so far including splash screen AND results

%>

and after we finished from everything we hide the “splash” screen with the following command (put the command in javascript script tag)

var splashsplash = document.getElementById("splashScreen");hideObj(splash);

remember that you can customize the splash to your liking, after all its a div and can be pretty flexible.

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Those days, inorder to increase the websites/intranets features and interactivity it is essential to have a connectivity to a database wither its an oracle database or MS access or other types of databases, .. and with databases comes the issue of performance, so in this article i would like to share some of the things that a developer can do to maintain a reasonable performance and even adding more flexibility to the ASP code dealing with databases that has huge data that needs to be fetched.

in this article am using vbscript as a server-side script.

for convenience i will show the steps on how to connect to MS access database first and after that i will start on the tweaks that developers can do in the coding to enhance performance and adding flexibility

<%

dim conn

set conn=Server.CreateObject(“ADODB.Connection”)

conn.Provider=”Microsoft.Jet.OLEDB.4.0″

conn.Open “c:YOUR_DATABASENAME.mdb”

%>

first of all, after you set up a connectivity to the database, you create a query, for example:

<%

dim rs ‘recored set

set rs=Server.CreateObject(“ADODB.recordset”)

rs.Open “Select * from TABLE_NAME”, conn

%>

at this point not much can be done, connecting to the database and querying to get data is pretty much fixed.

the thing start when manipulating the data we just fetched, most of the people do is manipulating the data like the following code

<%

do while not rs.EOF

‘ manipulate data here, go through the query exucuted, movenext, movelast move previous, etc

response.write(rs(“FIELD_NAME”))

rs.MoveNext

loop

rs.Close

conn.Close

set rs=nothing

set conn=nothing

%>

the above code would work perfectly if you have to deal with one query, relatively small data set in the query, and only small code is used to manipulate the recordset, and as long as you want to deal with the data (in the above code) the recordset should stay open .. what if we wanted to do a new query while we are dealing with the existing one while it is still not closed? .. we would have to create another record set and set it and open connection to it, and this would make a nightmare interms of performance if we have a larg data and multiple quieries to deal with. to avoid this we can copy the query information to a multi-dimensional array and close the recordset so we can use it again while we are working with the existing data. instead of doing the previous code we can do the following code:

<%

dim rsArray

next

conn.Close

set rs=nothing

set conn=nothing

%>

after we fetched the information we needed into “rsArray” we finished from the record set and we closed it “rs.close” so we can use it later while dealing with the existing data without having to create a new recordset. now while we have a multi dimensional array in our hand, we can take advantage of that to our benefit, even we can redim it if we want to add new columns or rows, but when redim-ing the data is lost, so we have to use “preserve” keyword to preserve the data after rediming, for example if we have number of rows and we want to add a new one we do the following code



<%

.

.

.

dim cols

redim preserve rsArray(cols,rows+1) ‘ we have extra row

%>

notice the preserve keyword only works when redim-ing the last dimension, if we want to redim the first one (or the second one or third if we have more then 2) we have to go around it, copying the array to another array and put the dimension we want to change in the last place, and then we can use the “redim preserve” and work with the temp. array.

As a conclusion, using the actual record sets while manipulating data and creating new ones whenever we need is not efficient, on the other hand knowing the features of the arrays we can use it to our advantage so dealing with arrays is more flexible and more efficient then the actual record set.

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Most of the old .NET developer are used to have their web applications deal with post-backs but very few of them really knows how these post-backs do work. well most of the things in .NET application are done depending on client side script (JavaScript).

For that when you have a good amount of JavaScript controlling your application you need to know how to make that JavaScript call an asp function.

Before explaining how to do this first lets see why do we need it ? Well may be you will need to do something with JavaScript before calling server side codes, like validating entered data ( well i know that is a very bad example since in .NET there is a ready validating controles) a better example lets say you have created a web page that allow users to draw for example mind maps, or charts, or mouse gestures so that when user drag his mouse in a specific way there will be a specific response from your web application.

well in all of these examples JavaScript or JavaScript frameworks like jquery will be doing most of the things in the application here the decision to make a server side function call should be given to java script code.

Calling asp.NET function by JavaScript you need to do a simple trick,

Well as i found from some of my tries to get there, that you can not do it having normal form buttons you will need at least one “link button” (sure you can hide it, but NEVER make visible = false because it will be removed from the HTML code; instead apply CSS style on it that make it hidden)

visibility:hidden;

then you need to call the post back function that usually is called if you really do click that link_button and in the asp.NET code do call your asp function in the link_button event handler function.

well thats a lot of blah blah, theoretical talks, well then lets get into action then.

here i will show a very simple example (sorry i am out of creativity by now so the example will be very simple) i created a very simple page with a text box an a link button

<br /> <form id="form1" runat="server">> <div> <asp:textbox id="TextBox1" runat="server"></asp:textbox> </div> <p> <asp:linkbutton style="font-weight: bold;">CssClass=”hdn” ID=”LinkButton1″ runat=”server” onclick=”LinkButton1_Click”>LinkButton</asp:linkbutton> </p> </p></form> <p>

i added a very simple response code to the link button click event in C#
protected void LinkButton1_Click(object sender, EventArgs e) { Response.Write(“yooohooo”); }
well yeah this is our server side function (i told you this week i am out of creativity).

and then i added they style to hide the link button
<br /> <style> .hdn{ visibility:hidden; } </style> <p>
now even in the IDE you just cannot see the link button

now the real thing is in the java script i have done a very simple and a very boring thing witch is on each button press it makes the text in the text box uppercase and if the length of text reaches to 6 it will call the server side function

i have added it just before the end of form tag

<script type="text/javascript"> var t =document.getElementById("TextBox1"); // well you can imagen this function is any thing else may be figuring out how did you made your mouse gesture document.getElementById("TextBox1").onkeydown = function ss(){ t.value= t.value.toUpperCase(); // may be here there is a condition to know if it should call the server side function if(t.value.length >5) { __doPostBack('LinkButton1',''); } } </script>
well you can see the real point is in the function __doPostBack(”,”)
which is created by Visual Studio it self you do not have to program it and it can call server side functions by its own way (well what you do not know that there are a lot of hidden fields in your page that are getting created by visual studio and are used for these kind of stuff)

and the reason i say that we must have a link button is that i found Visual studio do not create this JavaScript function __doPostBack(”,”) if we dont have link button

well thats all for today i think hope this thing (which i had to search and try a lot of things to be able to do) will help you in your projects

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