LogCat问题

Question

我正在阅读专业的Android 2应用程序开发，并创建了一个应用程序站在那里。但是当我开始avd并运行avd时，弹出窗口：不幸的是，地震已经停止。而在Eclipse中logcat中弹出，我得到这个错误信息：

01-26 19:59:11.153: W/dalvikvm(859): threadid=1: thread exiting with uncaught exception (group=0x40a13300) 
01-26 19:59:11.183: E/AndroidRuntime(859): FATAL EXCEPTION: main 
01-26 19:59:11.183: E/AndroidRuntime(859): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.epstudios.earthquake/com.epstudios.earthquake.Earthquake}: android.os.NetworkOnMainThreadException 
01-26 19:59:11.183: E/AndroidRuntime(859): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059) 
01-26 19:59:11.183: E/AndroidRuntime(859): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084) 
01-26 19:59:11.183: E/AndroidRuntime(859): at android.app.ActivityThread.access$600(ActivityThread.java:130) 
01-26 19:59:11.183: E/AndroidRuntime(859): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195) 
01-26 19:59:11.183: E/AndroidRuntime(859): at android.os.Handler.dispatchMessage(Handler.java:99) 
01-26 19:59:11.183: E/AndroidRuntime(859): at android.os.Looper.loop(Looper.java:137) 
01-26 19:59:11.183: E/AndroidRuntime(859): at android.app.ActivityThread.main(ActivityThread.java:4745) 
01-26 19:59:11.183: E/AndroidRuntime(859): at java.lang.reflect.Method.invokeNative(Native Method) 
01-26 19:59:11.183: E/AndroidRuntime(859): at java.lang.reflect.Method.invoke(Method.java:511) 
01-26 19:59:11.183: E/AndroidRuntime(859): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
01-26 19:59:11.183: E/AndroidRuntime(859): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
01-26 19:59:11.183: E/AndroidRuntime(859): at dalvik.system.NativeStart.main(Native Method) 
01-26 19:59:11.183: E/AndroidRuntime(859): Caused by: android.os.NetworkOnMainThreadException 
01-26 19:59:11.183: E/AndroidRuntime(859): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117) 
01-26 19:59:11.183: E/AndroidRuntime(859): at java.net.InetAddress.lookupHostByName(InetAddress.java:385) 
01-26 19:59:11.183: E/AndroidRuntime(859): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236) 
01-26 19:59:11.183: E/AndroidRuntime(859): at java.net.InetAddress.getAllByName(InetAddress.java:214) 
01-26 19:59:11.183: E/AndroidRuntime(859): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:70) 
01-26 19:59:11.183: E/AndroidRuntime(859): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50) 
01-26 19:59:11.183: E/AndroidRuntime(859): at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:341) 
01-26 19:59:11.183: E/AndroidRuntime(859): at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87) 
01-26 19:59:11.183: E/AndroidRuntime(859): at libcore.net.http.HttpConnection.connect(HttpConnection.java:128) 
01-26 19:59:11.183: E/AndroidRuntime(859): at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:315) 
01-26 19:59:11.183: E/AndroidRuntime(859): at libcore.net.http.HttpEngine.connect(HttpEngine.java:310) 
01-26 19:59:11.183: E/AndroidRuntime(859): at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:289) 
01-26 19:59:11.183: E/AndroidRuntime(859): at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:239) 
01-26 19:59:11.183: E/AndroidRuntime(859): at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:273) 
01-26 19:59:11.183: E/AndroidRuntime(859): at libcore.net.http.HttpURLConnectionImpl.getResponseCode(HttpURLConnectionImpl.java:486) 
01-26 19:59:11.183: E/AndroidRuntime(859): at com.epstudios.earthquake.Earthquake.refreshEarthquakes(Earthquake.java:71) 
01-26 19:59:11.183: E/AndroidRuntime(859): at com.epstudios.earthquake.Earthquake.onCreate(Earthquake.java:57) 
01-26 19:59:11.183: E/AndroidRuntime(859): at android.app.Activity.performCreate(Activity.java:5008) 
01-26 19:59:11.183: E/AndroidRuntime(859): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079) 
01-26 19:59:11.183: E/AndroidRuntime(859): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023) 
01-26 19:59:11.183: E/AndroidRuntime(859): ... 11 more 

什么问题

Answer 1

在logcat的第一行....

你不能在主线程上网络的东西你需要asyntask包装它

Answer 2

看来这本书是为较旧版本的Android编写的。现在默认禁止在主线程上执行联网任务。恢复较旧的Android版本的政策可以通过调用这个在您的应用程序的启动来完成：

StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build(); 

StrictMode.setThreadPolicy(policy); 

请注意，你应该使用一个后台线程对于一般的网络。