我正在开发android应用程序来控制plc在tcp/ip modbus的帮助下,任何人都有很好的教程吗？
Modbus协议逃脱线程(Android,Jamod)
我是Android新手.我收到错误java.lang.NullPointerException,java.lang.RuntimeException申请人关闭.
10-18 06:04:12.676: E/AndroidRuntime(340): FATAL EXCEPTION: main
10-18 06:04:12.676: E/AndroidRuntime(340): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.md.ExpertRemote/com.md.ExpertRemote.first.ExpertRemote}: java.lang.NullPointerException
10-18 06:04:12.676: E/AndroidRuntime(340): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2663)
10-18 06:04:12.676: E/AndroidRuntime(340): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
10-18 06:04:12.676: E/AndroidRuntime(340): at android.app.ActivityThread.access$2300(ActivityThread.java:125)
10-18 06:04:12.676: E/AndroidRuntime(340): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
10-18 06:04:12.676: E/AndroidRuntime(340): at android.os.Handler.dispatchMessage(Handler.java:99)
10-18 06:04:12.676: E/AndroidRuntime(340): at android.os.Looper.loop(Looper.java:123)
10-18 06:04:12.676: E/AndroidRuntime(340): at android.app.ActivityThread.main(ActivityThread.java:4627)
10-18 06:04:12.676: E/AndroidRuntime(340): at java.lang.reflect.Method.invokeNative(Native Method)
10-18 06:04:12.676: E/AndroidRuntime(340): at java.lang.reflect.Method.invoke(Method.java:521)
10-18 06:04:12.676: E/AndroidRuntime(340): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
10-18 06:04:12.676: E/AndroidRuntime(340): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
10-18 06:04:12.676: E/AndroidRuntime(340): …