Programming Handheld and Mobile devices 1 Programming of Handheld and Mobile Devices Lecture 19 Microsoft’s Approach 1 –.NET Mobile Framework part 2 Rob Pooley

Programming Handheld and Mobile devices 2 Simple C# examples for.NET Class Form1 { static void Main() { Application.Run(new Form1()); } private void menuItem2_Click(object sender, System.EventArgs e) { Application.Exit(); }

Programming Handheld and Mobile devices 3 A second form MyNewForm mynewformForm = new MyNewForm (); mynewformForm.ShowDialog();

Programming Handheld and Mobile devices 4 Passing Values to Controls in Other Forms Let's demonstrate setting a control's value by altering a text label. The sequence of events is: 1.Create a new instance of the Form that contains the control (but don't display it). 2.Change the property corresponding to the text label of the control. 3.Display the Form. Assume we have added a text label called label1 to the new Form, and we can do all that with some code like this: MyNewForm mynewformForm = new MyNewForm(); mynewformForm.label1.Text = "Hello World"; mynewformForm.ShowDialog(); The only thing to remember is that the label1 property, by default, will be private so the code for the main Form won't be able to see it. You get around this by setting it to Public

Programming Handheld and Mobile devices 5 What you see Note The size of the Form is not important as the Pocket PC will always expand it to fill the screen.

Programming Handheld and Mobile devices 6 Adding a button If you are creating a new Form that acts as a dialog box, you should also add some way for the user to close it, such as a new button with code like the following attached: private void button1_Click(object sender, System.EventArgs e) { this.Close(); } The new Form will have a close button in the top right for the user to click

Programming Handheld and Mobile devices 7

8 Adding tabs tabs provide access to multiple pages all stored on one dialog. These can be very useful if your application has a lot of settings for the user to work through. Use the TabPage Collection to add and rename new tab pages. Each page is a like a blank form to which you add controls. Treat each tab page as a Form, and place the controls on it as you see fit. The Pocket PC will look after displaying the pages and controls

Programming Handheld and Mobile devices 9 Namespaces supported in.NET Framework and.NET Compact Framework

Programming Handheld and Mobile devices 10 Windows Forms All the common features Windows Forms in the.NET Framework are present in.NET Compact Framework. These features are differently implemented in a separate manner to make them more efficient for size and performance. Supported are: Common controls such as: –Buttons –Listboxes –Tree-views –Listviews –Combo boxes –Textboxes –Picture boxes –Scroll bars –Labels Bitmaps Pens Brushes Colors Drawing Fonts Support for Forms

Programming Handheld and Mobile devices 11 Networking with TCP etc. The System.Net.Sockets namespace is used to provide an interface to access the transport layer of protocol stacks. Multiple protocols can be exposed through this class. In addition,.NET Compact Framework provides additional classes that simplify common developer tasks encapsulating much of the necessary code that is common across all TCP client/server applications. Some of these are: –TCPListener –TCPClient –UDPClient

Programming Handheld and Mobile devices 12 HTTP HttpWebRequest and HttpWebResponse classes provide a rich HTTP client. These classes also support many of the standard mechanisms for encryption and authentication such as SSL/TLS and basic HTTP authentication. Other Web requests can be implemented using other protocols such as: –WebRequest interface –WebResponse interface –IwebRequestCreate interface

Programming Handheld and Mobile devices 13 System.Threading Namespace The System.Threading namespace provides classes and interfaces that enable multithreaded programming. In addition to classes for synchronizing thread activities and access to data (Mutex, Monitor, Interlocked, AutoResetEvent, and so on), this namespace includes aMutexMonitorInterlocked AutoResetEvent –ThreadPool class that allows you to use a pool of system-supplied threads, and aThreadPool –Timer class that executes callback methods on thread pool threads.Timer

Programming Handheld and Mobile devices 14 Threading using System; using System.Threading; // Simple threading scenario: Start a static method running // on a second thread. public class ThreadExample { // The ThreadProc method is called when the thread starts. // It loops ten times, writing to the console and yielding // the rest of its time slice each time, and then ends. public static void ThreadProc() { for (int i = 0; i < 10; i++) { Console.WriteLine("ThreadProc: {0}", i); // Yield the rest of the time slice. Thread.Sleep(0); } public static void Main() { Console.WriteLine("Main thread: Start a second thread."); // The constructor for the Thread class requires a ThreadStart // delegate that represents the method to be executed on the // thread. C# simplifies the creation of this delegate. Thread t = new Thread(new ThreadStart(ThreadProc)); // Start ThreadProc. On uniprocessor, thread does not get // any processor time until the main thread yields. //Uncomment // Thread.Sleep that follows t.Start() to see the difference. t.Start(); //Thread.Sleep(0); for (int i = 0; i < 4; i++) { Console.WriteLine("Main thread: Do some work."); Thread.Sleep(0); } Console.WriteLine("Main thread: Call Join(), to wait until ThreadProc ends."); t.Join(); Console.WriteLine("Main thread: ThreadProc.Join has returned. Press Enter to end program."); Console.ReadLine(); }

Programming Handheld and Mobile devices 15.NET vs J2ME vs Palm OS Problems –Palm OS is the most cumbersome to program –Palm OS uses C/C++ –Palm OS and.NET Compact are both specific to certain kinds of device –J2ME requires a JVM (KVM or CVM) –J2ME is not really compatible with J2SE Benefits –Palm OS is available for many PDAs –J2ME is the most portable –J2ME has wireless features as standard –J2ME uses Java –.NET is higher level –.NET supports XML –.NET supports several languages