Slide 3.11: Line-by-line anatomy of HelloMIDlet.java (cont.)   Slide 3.13: Line-by-line anatomy of HelloMIDlet.java (cont.)   Home

Line-by-line Anatomy of HelloMIDlet.java (Cont.)

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tbxMain = new TextBox("HelloMIDlet", "Hello, World!", 50, 0);
The constructor public javax.microedition.lcdui.TextBox(String title, String text, int maxSize, int constraints) creates a new TextBox object with the following parameters:

• title — The title text is to be shown with the display.


• text — The initial contents of the text editing area. If the text parameter is null, the TextBox is created empty.


• maxSize — The maximum capacity in characters, which must be greater than zero.


• constraints — The different constraints allow the application to request that the user's input be restricted in a variety of ways. Constant 0 is assigned to public static final int ANY, which allows users to enter any text. Other constraints can be found from the Field Summary of input constraints.

tbxMain.addCommand(cmdExit);
The method public void javax.microedition.lcdui.Displayable.addCommand (Command cmd) adds a command to the Displayable. The implementation may choose, for example, to add the command to any of the available soft buttons or place it in a menu.

tbxMain.setCommandListener(this);
The method public void javax.microedition.lcdui.Displayable.setCommandListener (CommandListener l) sets a listener for Commands to this Displayable, replacing any previous CommandListener.

public void startApp( ) {
The MIDlet enters the Active state after the application manager calls startApp( ) via clicking on the button Launch.