引起：android.os.NetworkOnMainThreadException

Question

大家好所有觀衆和讀者，我使用link。每當我在單獨的包中運行此代碼時，它工作正常，但每當我試圖將此示例嵌入到我的應用程序中，只有當我點擊選項卡調用它時，纔會收到不幸的應用程序停止，並且Logcat說： -

Caused by: android.os.NetworkOnMainThreadException 
10-30 15:07:35.341: E/AndroidRuntime(732): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117), 

請告訴我我需要做什麼使它對我有用，除了這個特殊的標籤整個應用程序工作正常。

10-30 15:07:26.770: D/dalvikvm(732): GC_FOR_ALLOC freed 61K, 3% free 8035K/8259K, paused 39ms, total 46ms 
    10-30 15:07:26.781: I/dalvikvm-heap(732): Grow heap (frag case) to 8.481MB for 614416-byte allocation 
    10-30 15:07:26.850: D/dalvikvm(732): GC_CONCURRENT freed 1K, 4% free 8634K/8903K, paused 27ms+13ms, total 71ms 
    10-30 15:07:26.881: D/dalvikvm(732): GC_FOR_ALLOC freed 0K, 4% free 8634K/8903K, paused 28ms, total 28ms 
    10-30 15:07:26.900: I/dalvikvm-heap(732): Grow heap (frag case) to 9.798MB for 1382416-byte allocation 
    10-30 15:07:26.970: D/dalvikvm(732): GC_CONCURRENT freed 0K, 4% free 9984K/10311K, paused 28ms+5ms, total 72ms 
    10-30 15:07:27.110: D/gralloc_goldfish(732): Emulator without GPU emulation detected. 
    10-30 15:07:30.591: D/dalvikvm(732): GC_FOR_ALLOC freed 675K, 8% free 9875K/10695K, paused 33ms, total 62ms 
    10-30 15:07:30.671: D/dalvikvm(732): GC_FOR_ALLOC freed 519K, 9% free 9806K/10695K, paused 30ms, total 31ms 
    10-30 15:07:30.740: D/dalvikvm(732): GC_FOR_ALLOC freed 310K, 10% free 9713K/10695K, paused 28ms, total 29ms 
    10-30 15:07:30.751: I/dalvikvm-heap(732): Grow heap (frag case) to 10.488MB for 1000016-byte allocation 
    10-30 15:07:30.820: D/dalvikvm(732): GC_CONCURRENT freed <1K, 9% free 10690K/11719K, paused 25ms+5ms, total 74ms 
    10-30 15:07:30.911: D/dalvikvm(732): GC_FOR_ALLOC freed 0K, 9% free 10690K/11719K, paused 36ms, total 36ms 
    10-30 15:07:30.931: I/dalvikvm-heap(732): Grow heap (frag case) to 12.633MB for 2250016-byte allocation 
    10-30 15:07:31.030: D/dalvikvm(732): GC_CONCURRENT freed 0K, 8% free 12887K/13959K, paused 32ms+16ms, total 93ms 
    10-30 15:07:31.211: D/dalvikvm(732): GC_FOR_ALLOC freed 3683K, 30% free 10314K/14599K, paused 35ms, total 38ms 
    10-30 15:07:31.211: I/dalvikvm-heap(732): Grow heap (frag case) to 11.439MB for 1382416-byte allocation 
    10-30 15:07:31.360: D/dalvikvm(732): GC_CONCURRENT freed <1K, 21% free 11663K/14599K, paused 81ms+5ms, total 144ms 
    10-30 15:07:31.551: D/dalvikvm(732): GC_FOR_ALLOC freed 2555K, 32% free 9936K/14599K, paused 32ms, total 38ms 
    10-30 15:07:31.561: I/dalvikvm-heap(732): Grow heap (frag case) to 10.706MB for 1000016-byte allocation 
    10-30 15:07:31.701: D/dalvikvm(732): GC_CONCURRENT freed 1K, 26% free 10912K/14599K, paused 78ms+16ms, total 139ms 
    10-30 15:07:31.770: D/dalvikvm(732): GC_FOR_ALLOC freed 0K, 26% free 10912K/14599K, paused 31ms, total 31ms 
    10-30 15:07:31.770: I/dalvikvm-heap(732): Grow heap (frag case) to 12.850MB for 2250016-byte allocation 
    10-30 15:07:31.871: D/dalvikvm(732): GC_CONCURRENT freed 0K, 11% free 13109K/14599K, paused 29ms+6ms, total 91ms 
    10-30 15:07:32.060: D/dalvikvm(732): GC_FOR_ALLOC freed 1134K, 11% free 13102K/14599K, paused 35ms, total 39ms 
    10-30 15:07:32.070: I/dalvikvm-heap(732): Grow heap (frag case) to 14.162MB for 1382416-byte allocation 
    10-30 15:07:32.150: D/dalvikvm(732): GC_FOR_ALLOC freed <1K, 10% free 14451K/16007K, paused 36ms, total 36ms 
    10-30 15:07:32.161: I/Choreographer(732): Skipped 460 frames! The application may be doing too much work on its main thread. 
    10-30 15:07:35.280: D/AndroidRuntime(732): Shutting down VM 
    10-30 15:07:35.280: W/dalvikvm(732): threadid=1: thread exiting with uncaught exception (group=0x40a13300) 
    10-30 15:07:35.341: E/AndroidRuntime(732): FATAL EXCEPTION: main 
    10-30 15:07:35.341: E/AndroidRuntime(732): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.erachnida.restaurant.versionoct/com.erachnida.restaurant.versionoct.CustomizedListView}: android.os.NetworkOnMainThreadException 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2059) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.app.ActivityThread.startActivityNow(ActivityThread.java:1900) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.app.LocalActivityManager.moveToState(LocalActivityManager.java:135) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.app.LocalActivityManager.startActivity(LocalActivityManager.java:347) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.widget.TabHost$IntentContentStrategy.getContentView(TabHost.java:694) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.widget.TabHost.setCurrentTab(TabHost.java:358) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.widget.TabHost$2.onTabSelectionChanged(TabHost.java:150) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.widget.TabWidget$TabClickListener.onClick(TabWidget.java:546) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.view.View.performClick(View.java:4084) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.view.View$PerformClick.run(View.java:16966) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.os.Handler.handleCallback(Handler.java:615) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.os.Handler.dispatchMessage(Handler.java:92) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.os.Looper.loop(Looper.java:137) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.app.ActivityThread.main(ActivityThread.java:4745) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at java.lang.reflect.Method.invokeNative(Native Method) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at java.lang.reflect.Method.invoke(Method.java:511) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at dalvik.system.NativeStart.main(Native Method) 
    10-30 15:07:35.341: E/AndroidRuntime(732): Caused by: android.os.NetworkOnMainThreadException 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at java.net.InetAddress.lookupHostByName(InetAddress.java:385) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at java.net.InetAddress.getAllByName(InetAddress.java:214) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at com.erachnida.restaurant.versionoct.XMLParser.getXmlFromUrl(XMLParser.java:45) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at com.erachnida.restaurant.versionoct.CustomizedListView.onCreate(CustomizedListView.java:42) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.app.Activity.performCreate(Activity.java:5008) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1079) 
    10-30 15:07:35.341: E/AndroidRuntime(732): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2023) 
    10-30 15:07:35.341: E/AndroidRuntime(732): ... 18 more 
    10-30 15:07:42.250: I/Process(732): Sending signal. PID: 732 SIG: 9 

Answer 1

這個問題有兩個解決方案。

1）不要在主UI線程中使用異步任務編寫網絡調用。

2）在setContentView（R.layout.activity_main）之後將代碼寫入MainActivity文件中;

if (android.os.Build.VERSION.SDK_INT > 9) { 
    StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build(); 
    StrictMode.setThreadPolicy(policy); 
} 

和下面的import語句放到你的java文件中。

import android.os.StrictMode;