2

次のコードを使用して http リクエストを取得しようとしています。URL は次のとおりです。

文字列 url = " http://vlm1.uta.edu/~zhangzhong/questions.json ";

を呼び出すとInputStream source = retrieveStream(url)、エラーが発生します。ちなみに既に追加済み<uses-permission android:name="android.permission.INTERNET"/> 

   private InputStream retrieveStream(String url) {

        DefaultHttpClient client = new DefaultHttpClient(); 

        HttpGet getRequest = new HttpGet(url);

        try {

           HttpResponse getResponse = client.execute(getRequest);
           final int statusCode = getResponse.getStatusLine().getStatusCode();

           if (statusCode != HttpStatus.SC_OK) { 
              Log.w(getClass().getSimpleName(), "Error " + statusCode + " for URL " + url); 
              return null;
           }

           HttpEntity getResponseEntity = getResponse.getEntity();
           return getResponseEntity.getContent();

        } 
        catch (IOException e) {
           getRequest.abort();
           Log.w(getClass().getSimpleName(), "Error for URL " + url, e);
        }

        return null;   
     }

以下は LogCat です。

04-22 16:36:37.042: D/dalvikvm(3840): デバッガーが切り離されました。オブジェクト レジストリには 427 がありました

entries
04-22 16:36:37.042: I/dalvikvm(3840): ignoring registerObject request in thread=1
04-22 16:36:37.042: I/dalvikvm(3840): ignoring registerObject request in thread=1
04-22 16:36:37.042: D/AndroidRuntime(3840): Shutting down VM
04-22 16:36:37.042: W/dalvikvm(3840): threadid=1: thread exiting with uncaught exception (group=0x41760930)
04-22 16:36:37.072: E/AndroidRuntime(3840): FATAL EXCEPTION: main
04-22 16:36:37.072: E/AndroidRuntime(3840): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.flashcard/com.example.flashcard.MainActivity}: android.os.NetworkOnMainThreadException
04-22 16:36:37.072: E/AndroidRuntime(3840):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at android.os.Looper.loop(Looper.java:137)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at android.app.ActivityThread.main(ActivityThread.java:5041)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at java.lang.reflect.Method.invokeNative(Native Method)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at java.lang.reflect.Method.invoke(Method.java:511)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at dalvik.system.NativeStart.main(Native Method)
04-22 16:36:37.072: E/AndroidRuntime(3840): Caused by: android.os.NetworkOnMainThreadException
04-22 16:36:37.072: E/AndroidRuntime(3840):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at java.net.InetAddress.getAllByName(InetAddress.java:214)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at com.example.flashcard.MainActivity.retrieveStream(MainActivity.java:63)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at com.example.flashcard.MainActivity.onCreate(MainActivity.java:37)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at android.app.Activity.performCreate(Activity.java:5104)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-22 16:36:37.072: E/AndroidRuntime(3840):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-22 16:36:37.072: E/AndroidRuntime(3840):     ... 11 more
04-22 16:36:37.092: I/Process(3840): Sending signal. PID: 3840 SIG: 9
04-22 16:37:37.727: D/AndroidRuntime(3957): Shutting down VM
04-22 16:37:43.443: D/AndroidRuntime(4077): Shutting down VM
04-22 16:37:43.443: W/dalvikvm(4077): threadid=1: thread exiting with uncaught exception (group=0x41760930)
04-22 16:37:43.443: E/AndroidRuntime(4077): FATAL EXCEPTION: main
04-22 16:37:43.443: E/AndroidRuntime(4077): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.flashcard/com.example.flashcard.MainActivity}: android.os.NetworkOnMainThreadException
04-22 16:37:43.443: E/AndroidRuntime(4077):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at android.os.Looper.loop(Looper.java:137)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at android.app.ActivityThread.main(ActivityThread.java:5041)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at java.lang.reflect.Method.invokeNative(Native Method)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at java.lang.reflect.Method.invoke(Method.java:511)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at dalvik.system.NativeStart.main(Native Method)
04-22 16:37:43.443: E/AndroidRuntime(4077): Caused by: android.os.NetworkOnMainThreadException
04-22 16:37:43.443: E/AndroidRuntime(4077):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at java.net.InetAddress.getAllByName(InetAddress.java:214)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:137)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at com.example.flashcard.MainActivity.retrieveStream(MainActivity.java:63)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at com.example.flashcard.MainActivity.onCreate(MainActivity.java:37)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at android.app.Activity.performCreate(Activity.java:5104)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-22 16:37:43.443: E/AndroidRuntime(4077):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-22 16:37:43.443: E/AndroidRuntime(4077):     ... 11 more
04-22 16:37:44.865: I/Process(4077): Sending signal. PID: 4077 SIG: 9
4

1 に答える 1

0

ここで起こっていることはよくあることです。アプリケーションのメインスレッドで長時間実行される操作を実行しようとしています。

つまり、メイン スレッドが UI の更新を担当し、スムーズなエクスペリエンスを実現します。Android が、ブロックされる長時間の操作を行っていることを検出すると、アプリを強制的にシャットダウンして、これは悪いことだと知ってください。

AsynTask や IntentService など、多くの代替ソリューションがあります。

IntentService は、インテントを送信したときに実行されるサービスです。

public class NetworkHandler extends IntentService {
    @Override
    protected void onHandleIntent(Intent intent) {
         //Do your request here
    }
}

IntentService を有効にするには、次のようにします。

Intent intent = new Intent(mContext, NetworkHandler.class);
startService(intent);
于 2013-04-22T21:52:39.857 に答える