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ticker在screen类中被定义为一个域（Field）它可以被连接到任何screen类的子集中在下面的例子中我们将展示如何将ticker连接到列表(List)和alert对象中 注意以下例子基于MIDP和CLDC 源代码 /* * TickerExamplejava **/ import javaxmicroeditionmidlet*; import javaxmicroeditionlcdui*; public class TickerExample extends MIDlet implements CommandListener { private Display display; // 对显示对象的引用Reference to Display object private List lsProducts; // 主产品列表 private Alert alHelp;// 显现文字和图像的警告板 private Ticker tkSale; // 对现在销售的提示 private Command cmExit;// 退出命令 public TickerExample() { display = DisplaygetDisplay(this); cmExit = new Command(Exit CommandSCREEN ); tkSale = new Ticker(Current Sale: Bobs Pretty Good Laptop only $); lsProducts = new List(Products ChoiceIMPLICIT); lsProductsappend(Laptop null); lsProductsappend(Printer null); lsProductsappend(Help null); lsProductsaddCommand(cmExit); lsProductssetCommandListener(this); lsProductssetTicker(tkSale); } public void startApp() { displaysetCurrent(lsProducts); } public void pauseApp() { } public void destroyApp(boolean unconditional) { } public void showAlert() { try { // Create an image Image im = ImagecreateImage(/helppng); // Create Alert add text and image no sound alHelp = new Alert(Help Information Bobs Pretty Good Productsso much to choose from! im null); alHelpsetTimeout(AlertFOREVER); alHelpsetTicker(tkSale); } catch(Exception e) { Systemoutprintln(Unable to read png image); } // Display the Alert Once dismissed return to product list displaysetCurrent(alHelp lsProducts); } public void commandAction(Command c Displayable s) { if (c == ListSELECT_COMMAND) { switch (lsProductsgetSelectedIndex()) { case : Systemoutprintln(Laptop selected); break; case : Systemoutprintln(Printer selected); break; case : showAlert(); break; } } else if (c == cmExit) { destroyApp(true); notifyDestroyed(); } } } |
