mainform.java

Java ME手机应用开发大全一书的配套光盘上的源码

import javax.microedition.lcdui.Form;
import javax.microedition.lcdui.Item;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.MIDlet;
//定义输入收件人和邮件主题的屏幕
public class MainForm extends Form implements CommandListener
{

    private MailClient midlet;
    //声明输入收件人的文本框
    private TextField toField;
    //声明输入邮件主题的文本框
    private TextField subField;
    //声明是否是第一个窗体的标志位
    private boolean first = true;
    public static final Command nextCommand = new Command("NEXT", Command.OK, 1);
    public MainForm(MailClient midlet, String arg0)
    {
        super(arg0);
        this.midlet = midlet;
        if(first)
        {
            first = false;
            init();
        }
        
    }
    //初始化控件并添加到屏幕上
    public void init()
    {
        toField = new TextField("To:", null, 25, TextField.ANY);
        subField = new TextField("Subject:", null, 30, TextField.ANY);
        this.append(toField);
        this.append(subField);
        this.addCommand(nextCommand);
        this.setCommandListener(this);
        
    }
    
    public void commandAction(Command cmd,Displayable disp)
    {
        if(cmd == nextCommand)
        {
            String to = toField.getString();
            String subject = subField.getString();
			//判断输入的收件人或者邮件主题是否为空
            if(to == "" && subject == "")
            {
				//为空，则显示错误对话框
                midlet.displayAlert("Null to or sub",AlertType.WARNING,this);
            }
			//不为空，则显示输入邮件内容的屏幕
            else
            {
                midlet.getMessage().setTo(to);
                midlet.getMessage().setSubject(subject);
                midlet.getDisplay().setCurrent(midlet.getContentForm());
            }
        }
    }

}