我正在尝试将一个Android应用转换为codenameone应用，然后再转换为iOS应用。现有的Android应用使用android.utils.Log，它使用两个String变量，而com.codename1.io.Log使用一个String变量和一个int作为日志级别。我没有修改现有代码，而是尝试围绕com.codename1.io.Log编写一个 Package 类W_Log：

import com.codename1.io.Log;

import java.io.IOException;

public class W_Log {
    static Log w_Log;

    public W_Log()  {
        w_Log = Log.getInstance();
    }

    public void d(String a, String b) {
        w_Log.p(a + b, Log.DEBUG);
    }

    public void e(String a, String b) {
        w_Log.p(a + b, Log.ERROR);
    }

    public void e(String a, String b, IOException e) {
        w_Log.p(a + b, Log.ERROR);
        w_Log.e(e);
    }

    public void i(String a, String b) {
        w_Log.p(a + b, Log.INFO);
    }
}

在我现有的代码中，我注解掉了android.utils.Log的导入行，并添加了以下行：

public static W_Log Log = new W_Log();

因此，我不需要更改现有代码中的"Log. d（" blah "，" blah "）"和"Log. e（" blah "，" blah "）"。
将codenameone的jar文件添加到库后，我在Android Studio中运行它时，显示了以下错误：

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: myapp.da, PID: 29854
    java.lang.RuntimeException: Unable to start service com.myapp.myapp.DA_Service@859ad2f with Intent { cmp=myapp.da/com.myapp.myapp.DA_Service (has extras) }: java.lang.NullPointerException: Attempt to invoke virtual method 'java.io.InputStream com.codename1.impl.CodenameOneImplementation.getResourceAsStream(java.lang.Class, java.lang.String)' on a null object reference
        at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:5248)
        at android.app.ActivityThread.-$$Nest$mhandleServiceArgs(Unknown Source:0)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2444)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loopOnce(Looper.java:226)
        at android.os.Looper.loop(Looper.java:313)
        at android.app.ActivityThread.main(ActivityThread.java:8741)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:571)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1067)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'java.io.InputStream com.codename1.impl.CodenameOneImplementation.getResourceAsStream(java.lang.Class, java.lang.String)' on a null object reference
        at com.codename1.ui.Display.getResourceAsStream(Display.java:3104)
        at com.codename1.io.Log.print(Log.java:327)
        at com.codename1.io.Log.p(Log.java:276)
        at com.myapp.myapp.W_Log.i(W_Log.java:29)
        at com.myapp.myapp.DA_Service.onStartCommand(DA_Service.java:207)
        at android.app.ActivityThread.handleServiceArgs(ActivityThread.java:5230)
        at android.app.ActivityThread.-$$Nest$mhandleServiceArgs(Unknown Source:0) 
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2444) 
        at android.os.Handler.dispatchMessage(Handler.java:106) 
        at android.os.Looper.loopOnce(Looper.java:226) 
        at android.os.Looper.loop(Looper.java:313) 
        at android.app.ActivityThread.main(ActivityThread.java:8741) 
        at java.lang.reflect.Method.invoke(Native Method) 
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:571) 
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1067) 

我按照调试步骤深入到codename1类，发现创建的矩形的宽度和高度都为零。
谢谢你的帮助。