我的代码有问题，我希望得到一些帮助。
我首先使用此代码:
new DefaultHttpClient().execute(new HttpGet(linkk)).getEntity().writeTo(
new FileOutputStream(f));
而且它在android 2.3上工作正常，但在4.0上却没有。经过一番研究，我听说使用AndroidHttpClient更好，这样它就可以在4.0和3.1上运行。问题是我不知道我是否正确修改了代码，并且互联网上没有太多有关AndroidhttpClient的示例。
这是我的代码已调整:
AndroidHttpClient client = AndroidHttpClient.newInstance("Android");
HttpGet request = new HttpGet(linkk);
HttpResponse response = client.execute(request); //here is where the exception is thrown
response.getEntity().writeTo(new FileOutputStream(f));
这是logcat显示的内容:
01-03 01:32:11.950: W/dalvikvm(17991): threadid=1: thread exiting with uncaught exception (group=0x40a2e1f8)
01-03 01:32:11.986: E/AndroidRuntime(17991): FATAL EXCEPTION: main
01-03 01:32:11.986: E/AndroidRuntime(17991): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.lacra.fbirthdays/com.lacra.fbirthdays.ListV}: android.os.NetworkOnMainThreadException
01-03 01:32:11.986: E/AndroidRuntime(17991): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
01-03 01:32:11.986: E/AndroidRuntime(17991): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
01-03 01:32:11.986: E/AndroidRuntime(17991): at android.app.ActivityThread.access$600(ActivityThread.java:123)
01-03 01:32:11.986: E/AndroidRuntime(17991): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
01-03 01:32:11.986: E/AndroidRuntime(17991): at android.os.Handler.dispatchMessage(Handler.java:99)
01-03 01:32:11.986: E/AndroidRuntime(17991): at android.os.Looper.loop(Looper.java:137)
01-03 01:32:11.986: E/AndroidRuntime(17991): at android.app.ActivityThread.main(ActivityThread.java:4424)
01-03 01:32:11.986: E/AndroidRuntime(17991): at java.lang.reflect.Method.invokeNative(Native Method)
01-03 01:32:11.986: E/AndroidRuntime(17991): at java.lang.reflect.Method.invoke(Method.java:511)
01-03 01:32:11.986: E/AndroidRuntime(17991): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
01-03 01:32:11.986: E/AndroidRuntime(17991): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
01-03 01:32:11.986: E/AndroidRuntime(17991): at dalvik.system.NativeStart.main(Native Method)
01-03 01:32:11.986: E/AndroidRuntime(17991): Caused by: android.os.NetworkOnMainThreadException
01-03 01:32:11.986: E/AndroidRuntime(17991): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1099)
01-03 01:32:11.986: E/AndroidRuntime(17991): at java.net.InetAddress.lookupHostByName(InetAddress.java:391)
01-03 01:32:11.986: E/AndroidRuntime(17991): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:242)
01-03 01:32:11.986: E/AndroidRuntime(17991): at java.net.InetAddress.getAllByName(InetAddress.java:220)
01-03 01:32:11.986: E/AndroidRuntime(17991): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
01-03 01:32:11.986: E/AndroidRuntime(17991): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
01-03 01:32:11.986: E/AndroidRuntime(17991): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
01-03 01:32:11.986: E/AndroidRuntime(17991): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
01-03 01:32:11.986: E/AndroidRuntime(17991): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
最佳答案
自API级别9引入StrictMode.ThreadPolicy以来，自API级别11以来已更改了默认线程策略，这简而言之，不允许在UI线程上执行网络操作(包括HttpClient和HttpUrlConnection)。如果执行此操作，则会得到NetworkOnMainThreadException。
可以使用以下方式更改此限制:
if (android.os.Build.VERSION.SDK_INT > 9) {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
}
将以上代码添加到您的主要 Activity 的onCreate()方法中。
此外，对于，始终建议将网络操作移出UI线程，例如，使用AsyncTask。
希望对您有所帮助。