Networkonmainthreadexception in Android Development

It is said that a newly developed small application is just running on android2.3. After switching to a 4.0 system, the program crash is dumpfounded. ADB logcat reads a string of common information, as follows:

E/AndroidRuntime( 3454): FATAL EXCEPTION: mainE/AndroidRuntime( 3454): android.os.NetworkOnMainThreadExceptionE/AndroidRuntime( 3454): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)E/AndroidRuntime( 3454): at libcore.io.BlockGuardOs.recvfrom(BlockGuardOs.java:163)E/AndroidRuntime( 3454): at libcore.io.IoBridge.recvfrom(IoBridge.java:503)E/AndroidRuntime( 3454): at java.net.PlainSocketImpl.read(PlainSocketImpl.java:488)E/AndroidRuntime( 3454): at java.net.PlainSocketImpl.access$000(PlainSocketImpl.java:46)E/AndroidRuntime( 3454): at java.net.PlainSocketImpl$PlainSocketInputStream.read(PlainSocketImpl.java:240)E/AndroidRuntime( 3454): at java.io.BufferedInputStream.fillbuf(BufferedInputStream.java:168)E/AndroidRuntime( 3454): at java.io.BufferedInputStream.read(BufferedInputStream.java:227)E/AndroidRuntime( 3454): at libcore.net.http.HttpConnection.isStale(HttpConnection.java:256)E/AndroidRuntime( 3454): at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:71)E/AndroidRuntime( 3454): at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)E/AndroidRuntime( 3454): at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:308)E/AndroidRuntime( 3454): at libcore.net.http.HttpEngine.connect(HttpEngine.java:303)E/AndroidRuntime( 3454): at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:282)E/AndroidRuntime( 3454): at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:232)E/AndroidRuntime( 3454): at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:273)E/AndroidRuntime( 3454): at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:168)E/AndroidRuntime( 3454): at com.raycommtech.ipcam.Util.httpGet(Util.java:60)E/AndroidRuntime( 3454): at com.raycommtech.ipcam.Util.getVideoInfoByDDNS(Util.java:209)E/AndroidRuntime( 3454): at com.raycommtech.ipcam.VideoInfo.refresh(VideoInfo.java:49)E/AndroidRuntime( 3454): at com.raycommtech.ipcam.imp.p2p.MediaFetchRayCommP2P.<init>(MediaFetchRayCommP2P.java:54)E/AndroidRuntime( 3454): at com.raycommtech.ipcam.MediaFetchFactory.makeMeidaFetch(MediaFetchFactory.java:33)E/AndroidRuntime( 3454): at com.raycommtech.rayfastcfg.service.RayFastcfgService.getMediaFetch(RayFastcfgService.java:88)E/AndroidRuntime( 3454): at com.raycommtech.rayfastcfg.wlan.WifiConfigActivity$1.onServiceConnected(WifiConfigActivity.java:132)E/AndroidRuntime( 3454): at android.app.LoadedApk$ServiceDispatcher.doConnected(LoadedApk.java:1068)E/AndroidRuntime( 3454): at android.app.LoadedApk$ServiceDispatcher$RunConnection.run(LoadedApk.java:1085)E/AndroidRuntime( 3454): at android.os.Handler.handleCallback(Handler.java:605)E/AndroidRuntime( 3454): at android.os.Handler.dispatchMessage(Handler.java:92)E/AndroidRuntime( 3454): at android.os.Looper.loop(Looper.java:137)E/AndroidRuntime( 3454): at android.app.ActivityThread.main(ActivityThread.java:4444)E/AndroidRuntime( 3454): at java.lang.reflect.Method.invokeNative(Native Method)E/AndroidRuntime( 3454): at java.lang.reflect.Method.invoke(Method.java:511)E/AndroidRuntime( 3454): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:787)E/AndroidRuntime( 3454): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:554)E/AndroidRuntime( 3454): at dalvik.system.NativeStart.main(Native Method)E/hubo_EventLog(  309): OnException
The prompt is displayed because the exception is thrown during the httpget () operation, and the Exception name is displayed as a network exception in the main thread. Why is that? I have asked for help from the Google gods. Only with the help of others can I know that the android4.0 system strictly limits the time-consuming operations in the UI main thread, such as network I/O, otherwise, you will be killed.
Solution: use multiple threads or backend services to perform time-consuming operations.
Refer to blog:
Http://www.cnblogs.com/freexiaoyu/archive/2012/04/13/2445707.html