newdisplayable.java

《Java程序设计实践教程》代码

/***************************************************
*  程序文件名称：　newDisplayable.java
*  功能：信息查询模块
***************************************************/
import javax.microedition.lcdui.*;

public class newDisplayable extends Form implements CommandListener {
  private Alert alert2;
  private Command backCommand;
  private Command searchCommand;
  TextField cityName = new TextField("", "", 15, TextField.ANY);
  public newDisplayable() {
    super("信息查询");
    try {
      jbInit();
    }
    catch(Exception e) {
      e.printStackTrace();
    }
    alert2 = new Alert("注意","错误的城市名",null,AlertType.ERROR);
    alert2.setTimeout(Alert.FOREVER);

  }

  private void jbInit() throws Exception {
    // Set up this Displayable to listen to command events
    setCommandListener(this);
    // add the Exit command
    backCommand = new Command("返回", Command.BACK, 1);
    addCommand(backCommand);
    searchCommand = new Command("查询",Command.OK,1);
    addCommand(searchCommand);
    cityName.setLabel("输入城市");
    cityName.setLayout(Item.LAYOUT_NEWLINE_AFTER);
    cityName.setString("泉州");
    this.append(cityName);
  }

  public void commandAction(Command command, Displayable displayable) {
    if(command==backCommand){
      //返回前一画面
      Info_client.instance.display.setCurrent(Info_client.instance.displayable);
    }
    else if(command==searchCommand){
      if (cityName.size()==0){
         //显示提示对话框
        Info_client.instance.display.setCurrent(alert2);
      }else{
        //调用searchCity类，执行查询功能
        new searchCity(cityName.getString());
      }
    }
  }

}