如何广播意图中的可包裹物体？

我是Java / Android的新手，正在尝试开发与USB CAN总线适配器通信的adroid应用程序。我通过CANBusController类以字符串形式接收来自适配器的消息，并建立了一个可打包的类CANMessage，该类将收到的字符串转换为我可以使用的形式（int Id，int Length，byte []数据）。现在，我试图显示我收到的消息。我有一个片段，CANBusControlFragment，它声明了BroadcastReceiver。收到消息后，我将构建我的CANMessage，将其及其字符串放入一个包中，将该包放入一个Intent中，然后使用sendBroadcast（intent）：

CANBusController
{
    public void handleMessage(Message msg)
    {
        Bundle bundle = msg.getData();
        CANMessage canMsg = bundle.getParcelable("CAN_MESSAGE");
        if (canMsg != null)
        {
            Intent intent = new Intent();
            intent.setAction(BroadcastActions.CAN_MESSAGE_RECEIVED);
            //intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
            intent.putExtra("CAN_MESSAGE", canMsg);
            intent.putExtra("STRING_MESSAGE", canMsg.toString());
            parentContext.sendBroadcast(intent);
        }
    }
}

CANBusControlFragment extends Fragment
{
    private final BroadcastReceiver canMsgReceiver = new BroadcastReceiver()
    {
        @Override
        public void onReceive(Context context, Intent intent)
        {
            String action = intent.getAction();
            Bundle bundle = intent.getExtras();
            try
            {
                if (BroadcastActions.CAN_MESSAGE_RECEIVED.equals(action))
                {
                    synchronized(this)
                    {
                        String str = bundle.getString("STRING_MESSAGE"); // <-- Crash
                        CANMessage canMsg = bundle.getParcelable("CAN_MESSAGE"); // 
                        Append(str);
                        Append(canMsg.toString();
                    }
                }
            }
            catch (Exception ex)
                print exception
        }
    }
}

如果将CANMessage添加到包中，当我尝试getString或getParcelable时，我的应用程序将在BroadcastReceiver的onReceived方法中崩溃，并出现Null指针异常。如果我不包括CANMessage，则该应用程序将正常运行。我相信CANMessage可以正确实现Parcelable，因为我已经通过执行所有相同的步骤（广播消息除外）对其进行了测试：构建CANMessage，在Bundle中放置putParcelable，在Intent中放置Bundle，从Intent中获取Bundle，从中获取getParcelable束。

感谢您的帮助。谢谢 ：）

编辑-LogCat信息：看来错误在我的包裹方法中。尝试readByteArray（byte []）会使应用程序崩溃。

11-12 09:17:44.568: E/AndroidRuntime(3087): FATAL EXCEPTION: main

11-12 09:17:44.568: E/AndroidRuntime(3087): java.lang.RuntimeException: Error receiving broadcast Intent { act=com.sb2tablet.CAN_MESSAGE_RECEIVED flg=0x10000010 (has extras) } in com.sb2tablet.CANBusControlFragment$1@9e8f6e00
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:768)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.os.Handler.handleCallback(Handler.java:725)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.os.Handler.dispatchMessage(Handler.java:92)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.os.Looper.loop(Looper.java:137)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.app.ActivityThread.main(ActivityThread.java:5041)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at java.lang.reflect.Method.invokeNative(Native Method)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at java.lang.reflect.Method.invoke(Method.java:511)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at dalvik.system.NativeStart.main(Native Method)
11-12 09:17:44.568: E/AndroidRuntime(3087): Caused by: java.lang.NullPointerException
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.os.Parcel.readByteArray(Parcel.java:1594)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at com.sb2tablet.models.CANMessage.<init>(CANMessage.java:93)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at com.sb2tablet.models.CANMessage$1.createFromParcel(CANMessage.java:18)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at com.sb2tablet.models.CANMessage$1.createFromParcel(CANMessage.java:1)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.os.Parcel.readParcelable(Parcel.java:2103)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.os.Parcel.readValue(Parcel.java:1965)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.os.Parcel.readMapInternal(Parcel.java:2226)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.os.Bundle.unparcel(Bundle.java:223)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.os.Bundle.containsKey(Bundle.java:271)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.content.Intent.hasExtra(Intent.java:4121)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at com.sb2tablet.CANBusControlFragment$1.onReceive(CANBusControlFragment.java:51)
11-12 09:17:44.568: E/AndroidRuntime(3087):     at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:758)

编辑-writeToParcel和宗地在：

public void writeToParcel(Parcel out, int flags)
{
    out.writeValue(id);    // int
    out.writeValue(len);   // int
    out.writevalue(data);  // byteArray, the value is not null here
    //out.writeByArray(data);
}

public CANMessage(Parcel in)
{
    id = in.readInt();
    len = in.readInt();
    in.readByteArray(data); // Actual crash is here
}

编辑-测试用例1-似乎额外的数据已添加到我的包裹中，我不确定如何添加。

public void writeToParcel(Parcel out, int flags)
{
    out.writeValue(id);    // int = 256
    out.writeValue(len);   // int = 2, length of byte array
    out.writevalue(data);  // byte array = { 17, 51 }
}

public CANMessage(Parcel in)
{
    len = in.readInt();        // 1
    id = in.readInt();         // 256
    len = in.readInt();        // 1
    len = in.readInt();        // 2
    int i = in.readInt();      // 13
    if (data == null) data = new byte[len];
    in.readByteArray(data);    // data = { 17, 51 }
}

编辑-测试用例2

public void writeToParcel(Parcel out, int flags)
{
    out.writeValue(id);       // int = 256
    out.writeValue(len);      // int = 2, length of byte array
    out.writeByteArray(data); // byte array = { 17, 51 }
}

public CANMessage(Parcel in)
{
    len = in.readInt();        // 1
    id = in.readInt();         // 256
    len = in.readInt();        // 1
    len = in.readInt();        // 2
    len = in.readInt();        // 2
    if (data == null) data = new byte[len];
    // in.readByteArray(data); // Crashes
    int i = in.readInt();      // 13073 = 0x3311 = byte[] { 17, 51 }
}