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[szp895]

有个在天气预报的问题，老是出错，要求只要在模拟器里面显示网上时时更新的预报图片即可。

import java.io.*;
import java.util.*;
import javax.microedition.io.*;
import javax.microedition.midlet.*;
import javax.microedition.lcdui.*;

public class Weather extends MIDlet implements CommandListener, Runnable {

  private Display mDisplay;
  private Command mExitCommand;
  private Command mForecastCommand;
  private Command mWeatherCommand;
  private Image mImage1;
  private Image mImage2;
  private String mUrl1;
  private String mUrl2;
  mUrl1 = "http://www.weatherzone.com.au/wzservlet/wzwoys/button?postcode=2615&locality=FLOREY&type=0";      //weather image
  mUrl2 = "http://www.weatherzone.com.au/wzservlet/wzwoys/button?postcode=2615&locality=FLOREY&type=1";      //forecast image

  private Form mForm;

  public Weather() {
    mForm = new Form("Weather");
    mImage1 = loadImage(mUrl1);
    mImage2 = loadImage(mUrl2);

    mExitCommand = new Command("Exit", Command.EXIT, 0);
    mWeatherCommand = new Command("Weather", Command.SCREEN, 0);
    mForecastCommand = new Command("Forecast", Command.SCREEN, 0);
    mForm.addCommand(mExitCommand);
    mFrom.addCommand(mWeatherCommand);
    mForm.addCommand(mForecastCommand);

    mForm.setCommandListener(this);
  }

  public void startApp() {
    mDisplay = Display.getDisplay(this);
    mForm.append(mImage1);
    mForm.append(mImage2);
    mDisplay.setCurrent(mForm);
  }

  public void pauseApp() {}

  public void destroyApp(boolean unconditional) {}

  public void commandAction(Command c, Displayable s) {
    if (c == mExitCommand) {
      destroyApp(false);
      notifyDestroyed();
    }

    if (c == mWeatherCommand)
    {
      Alert mAlert = new Alert("Alert", "Weather clicked", mImage1, AlertType.INFO);
      mAlert.setTimeout(2000);
      mAlert.setImage(mImage1);
      mDisplay.setCurrent(mAlert, mForm);
    }

    if (c == mForecastCommand) {
	Alert mAlert = new Alert("Alert", "Forecast clicked", mImage2, AlertType.INFO);
      mAlert.setTimeout(2000);
      mAlert.setImage(mImage2);
      mDisplay.setCurrent(mAlert, mForm);
    }
  }

  public void run() {}

  private Image loadImage(URL url) {
    Image image = null;
    try {
      image = Image.createImage(url);
    }
    catch (IOException ioe) {
      System.out.println(ioe);
    }
    return image;
  }
}

这是错误提示。。请问该怎么改？
java.io.IOException
java.io.IOException
startApp threw an Exception
java.lang.NullPointerException
java.lang.NullPointerException
at javax.microedition.lcdui.Form.append(+11)
at Weather.startApp(+19)
at javax.microedition.midlet.MIDletProxy.startApp(+7)
at com.sun.midp.midlet.Scheduler.schedule(+270)
at com.sun.midp.main.Main.runLocalClass(+28)
at com.sun.midp.main.Main.main(+116)

[szp895]

刚刚发错地方了，特转移过来。

[gesanri]

Image.createImage(url);API有这个方法吗?直接把网址传进去就可以？是不是应该先用HttpConnection打开链接再处理