"Introduction to Java Mobile/PDA Programming" Reading notes 3--lcdaui Advanced API list

Notes | program | advanced | design
The screen class has four subclasses: Alert List TextBox Form

List according to the definition of Choice interface, divided into: choice.exclusive (radio) Choice.multiple (multiple selection) choice.implicit (Simple type of radio)

Single selection Image img=image.createimage ("/a.png"); List l=new list ("list Test", choice.exclusive); L.append ("Banana", IMG); L.append ("Apple", null);d isplay.setcurrent (L) ;

Insert () Inserts a new item after a specific item. Set () can reset an item. ...... SYSTEM.OUT.PRINTLN ("You have choice the" +l.getselectedindex () + "item."); System.out.println ("The content is:" +l.getstring (L.getselectedindex ()));

Multi-selection list l=new list ("list Test", choice.multiple) ... int size=l.size (); for (int i=0;i<=size;i++) {if (l.isselected (i)) {SYSTEM.OUT.PRINTLN ("You have selected" +i);}

Getselectedflags () returns a Boolean array to see if that option is selected.

Simple Radio list l=new list ("list Test", choice.implicit) ... public void commandaction (Command c,displayable s) {if (c== List.select_command) {list tmp= (list) S;int i=tmp.getselectedindex (); SYSTEM.OUT.PRINTLN ("You have selected" +i)} ...}

Choice.implicit immediately after the user chooses, the event is raised and List.select_command is passed through the first parameter C of Commandaction (). If you do not want this, you can turn it off Setselectcommand (null), at which point C=null.setselectcommand (x)--x is another command object, and when the list is selected, X acts as the Commandaction ( The first parameter is passed in.

After Setselectcommand (), the command--x is automatically added to the System menu by AddCommand (). Removecommand (c) as follows: Setselectcommand (null); Removecommand (c);

The fitpolicy mechanism provided by the choice interface determines how the text content will be processed when it is too long to automatically wrap choice.text_wrap_off-long text automatically truncated choice.text _wrap_default-according to and different from each other, usually one of the first two