LogCat问题[重复]

Question

这个问题已经在这里有了答案：

• 如何修复“ android.os.NetworkOnMainThreadException”？ 55个答案
• NetworkOnMainThreadException 5个答案

我正在阅读Professional Android 2 Application Development，并制作了一个站立在那里的应用程序。 但是，当我启动avd并运行avd时，会弹出：不幸的是，地震已经停止。 在日食中，logcat弹出，我得到以下错误消息：

 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

问题是什么

Answer 1

看来这本书是为旧版本的Android编写的。 现在默认情况下禁止在主线程上执行网络任务。 可以通过在应用程序的开头调用以下命令来恢复旧版Android的策略：

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

StrictMode.setThreadPolicy(policy); 

请注意，通常应使用后台线程进行联网。

Answer 2

logcat的第一行...

您不能在需要异步处理的主线程上包含网络内容