addrecorddemo_2.java

基于j2me的手机应用程序-电话本

package PhoneBook;
import javax.microedition.lcdui.*;
import javax.microedition.midlet.MIDlet;
import javax.microedition.rms.*;

/**
 * 添加记录，并且把记录遍历出来
 */

public class AddRecordDemo_2 extends MIDlet implements CommandListener {
	//定义按钮
	private final static Command exitCommand = new Command("退出", Command.EXIT,1);

	private final static Command yesCommand = new Command("确定", Command.SCREEN,1);

	private final static Command backCommand = new Command("返回", Command.BACK,1);

	private Display display;

	private List mainList;//列表

	private TextBox tb;//文本框

	private RecordStore rs;

	public AddRecordDemo_2() {
		display = Display.getDisplay(this);
		tb = new TextBox("数据库例子", "List", 1000, 0);
		tb.addCommand(backCommand);
		tb.setCommandListener(this);
	}

	protected void startApp() {

		String[] stringArray = { "添加记录", "读取记录" };
		mainList = new List("数据库例子", Choice.IMPLICIT, stringArray, null);
		mainList.addCommand(exitCommand);
		mainList.setCommandListener(this);
		display.setCurrent(mainList);

		try {
			rs = RecordStore.openRecordStore("Record1", true);
		} catch (Exception e) {
			rs = null;
		}

	}

	protected void destroyApp(boolean unconditional) {

	}

	protected void pauseApp() {
	}

	public void commandAction(Command c, Displayable d) {
		if (d.equals(mainList)) {
			if (c == List.SELECT_COMMAND) {
				if (d.equals(mainList)) {
					switch (((List) d).getSelectedIndex()) {
					case 0:
						//清空屏幕
						tb.setString("");
						tb.addCommand(yesCommand);
						display.setCurrent(tb);

						break;
					//如果选择了读取数据类表		
					case 1:
						String str = "";
						try {
							if (rs.getNumRecords() > 0) {
								RecordEnumeration re = rs.enumerateRecords( null, null, false);
								while (re.hasNextElement()) {
									//把2进制数据转换为字符串
									String temp = new String(re.nextRecord());
									str = temp + "\r\n" + str;
								}
							}
						} catch (Exception e) {
							System.out.println(e);
						}

						tb.setString(str);
						//隐藏确定按钮
						tb.removeCommand(yesCommand);
						display.setCurrent(tb);
						break;

					}
				}
			}
		} else {	
			//如果是【确定】按钮，则添加新记录
			if (c == yesCommand) {
				if (rs != null) {
					byte[] data = tb.getString().getBytes();
					int i = 0;
					try {
						i = rs.addRecord(data, 0, data.length);
					} catch (RecordStoreException e) {
						System.out.println(e);
						e.printStackTrace();
					}
				}
				display.setCurrent(mainList);
			}

			if (c == backCommand) {
				display.setCurrent(mainList);
			}
		}

		if (c == exitCommand) {
			try {
				rs.closeRecordStore();
				rs = null;
			} catch (Exception e) {
			}

			destroyApp(false);
			notifyDestroyed();
		}
	}
}