itemlayoutdemo.java

J2ME MIDP 2.0 无线设备编程的一些源码

//itemLayoutDemo.java file
import javax.microedition.lcdui.*;
import javax.microedition.midlet.*;

public class itemLayoutDemo extends MIDlet implements CommandListener ,ItemCommandListener
{
    private Command exitCommand,layoutCommand, defaultCommand, btnCommand1, btnCommand2;
    private Form form;
    //定义两个输入框
    private TextField tfUserName, tfPassword;
    //定义文字标签和两个用作按钮的文字标签
    private StringItem strTitle, strLogin, strReset;
    public itemLayoutDemo()
    {
        exitCommand =new Command("Exit",Command.EXIT,1);
        btnCommand1 =new Command("Submit",Command.SCREEN,1);
        btnCommand2 =new Command("Reset",Command.SCREEN,1);
        layoutCommand =new Command("setLayout",Command.SCREEN,2);
        defaultCommand =new Command("defaultLayout",Command.SCREEN,2);
        //创建Form对象
        form = new Form("Layout Demo");
        //添加文字标签到Form对象中
        strTitle = new StringItem("","Fill the form and Login");
        form.append(strTitle);
        //添加输入框到Form对象中
        tfUserName = new TextField("Username","",12,TextField.ANY);
        form.append(tfUserName);
        tfPassword = new TextField("Passowrd","",12,TextField.PASSWORD);
        form.append(tfPassword);
        //添加按钮形状的文字标签到Form 对象中
        strLogin = new StringItem("Login", " ", Item.BUTTON);
        form.append(strLogin);
        strReset = new StringItem("Reset", " ", Item.BUTTON);
        form.append(strReset);
        //为了文字标签能够显示为按钮形状，添加命令
        strLogin.addCommand(btnCommand1);
        strReset.addCommand(btnCommand2);
        strLogin.setItemCommandListener(this);
        strReset.setItemCommandListener(this);
        //添加Form 对象的命令
        form.addCommand(exitCommand);
        form.addCommand(layoutCommand);
        form.addCommand(defaultCommand);
        form.setCommandListener(this);
    }

    protected void startApp(  ) throws MIDletStateChangeException
    {
        Display.getDisplay(this).setCurrent(form);
    }

    protected void pauseApp(  )
    {
    }

    protected void destroyApp( boolean p1 )
    {
    }

    public void commandAction(Command c,Displayable d)
    {
        if (c ==exitCommand)
        {
            destroyApp(false);
            notifyDestroyed();
        }
        else if (c ==layoutCommand)
        {//设置每个Item对象的布局方式
            //居中，并且要求下一个对象必须换行
            strTitle.setLayout(Item.LAYOUT_CENTER|Item.LAYOUT_NEWLINE_AFTER|Item.LAYOUT_2);
            //靠左，使用最小宽度
            tfUserName.setLayout(Item.LAYOUT_LEFT|Item.LAYOUT_SHRINK|Item.LAYOUT_2);
            //靠右，使用最小宽度
            tfPassword.setLayout(Item.LAYOUT_RIGHT|Item.LAYOUT_SHRINK|Item.LAYOUT_2);
            //居中，使用最小宽度
            strLogin.setLayout(Item.LAYOUT_CENTER|Item.LAYOUT_SHRINK|Item.LAYOUT_2);
            //居中，使用最小宽度
            strReset.setLayout(Item.LAYOUT_CENTER|Item.LAYOUT_SHRINK|Item.LAYOUT_2);
        }
        else if (c ==defaultCommand)
        {//将每个对象的布局方式恢复到默认状态
            strTitle.setLayout(Item.LAYOUT_DEFAULT);
            strLogin.setLayout(Item.LAYOUT_DEFAULT);
            strReset.setLayout(Item.LAYOUT_DEFAULT);
            tfUserName.setLayout(Item.LAYOUT_DEFAULT);
            tfPassword.setLayout(Item.LAYOUT_DEFAULT);
        }
    }

    public void commandAction(Command c, Item item) 
    {
        if (c == btnCommand1) 
        {
            System.out.println("btnCommand2 Selected");
        }
        else if (c == btnCommand2) 
        {
            System.out.println("btnCommand2 Selected");
        }
    }
}