0

次のコードがあります。

public String test(){
        URL url = null;
        try {
            url = new URL("http://api.heroesofnewerth.com/player_statistics/ranked/nickname/Hieratic/?token=0CZGH8ZI7UR8J2GN");
        } catch (MalformedURLException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }
        BufferedReader reader = null;
        String x = "";
        try {
            reader = new BufferedReader(new InputStreamReader(url.openStream(), "UTF-8"));
            for (String line; (line = reader.readLine()) != null;) {
                System.out.println(line);
                x = line;
            }
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally{
            if (reader !=null) try{reader.close();} catch (IOException ignore) {
            }{}
        }
        JsonElement root = new JsonParser().parse(x);
        return x;
    }
}

今、テキストを次のtextViewに挿入したいと思います。

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_create_competetion);

    TextView tv = (TextView) findViewById(R.id.competetion_text);
    JsonCollector jc = new JsonCollector();

    tv.setText(jc.test());

しかし、私はそれを実行しようとすると。次のエラーが表示されます。

FATAL EXCEPTION: main
 E/AndroidRuntime(1800): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.konkurrencesigner/com.example.konkurrencesigner.CreateCompetetion}: android.os.NetworkOnMainThreadException
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
 E/AndroidRuntime(1800):    at android.app.ActivityThread.access$600(ActivityThread.java:141)
 E/AndroidRuntime(1800):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
 E/AndroidRuntime(1800):    at android.os.Handler.dispatchMessage(Handler.java:99)
  E/AndroidRuntime(1800):   at android.os.Looper.loop(Looper.java:137)
    E/AndroidRuntime(1800):     at android.app.ActivityThread.main(ActivityThread.java:5039)
    E/AndroidRuntime(1800):     at java.lang.reflect.Method.invokeNative(Native Method)
    E/AndroidRuntime(1800):     at java.lang.reflect.Method.invoke(Method.java:511)
    E/AndroidRuntime(1800):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
    E/AndroidRuntime(1800):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
    E/AndroidRuntime(1800):     at dalvik.system.NativeStart.main(Native Method)
    E/AndroidRuntime(1800): Caused by: android.os.NetworkOnMainThreadException
    E/AndroidRuntime(1800):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
    E/AndroidRuntime(1800):     at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
     E/AndroidRuntime(1800):    at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
 E/AndroidRuntime(1800):    at java.net.InetAddress.getAllByName(InetAddress.java:214)
 E/AndroidRuntime(1800):    at libcore.net.http.HttpConnection.<init>(HttpConnection.java:70)
 E/AndroidRuntime(1800):    at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
 E/AndroidRuntime(1800):    at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340)
E/AndroidRuntime(1800):     at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87)
 E/AndroidRuntime(1800):    at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
 E/AndroidRuntime(1800):    at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:316)
    E/AndroidRuntime(1800):     at libcore.net.http.HttpEngine.connect(HttpEngine.java:311)
 E/AndroidRuntime(1800):    at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:290)
 E/AndroidRuntime(1800):    at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:240)
 E/AndroidRuntime(1800):    at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:282)

なぜこれが起こっているのか誰にも教えてもらえますか?

Android マニフェストに次の行を既に追加していることに注意してください。

    <uses-permission android:name="android.permission.INTERNET" />
4

2 に答える 2

4

メイン スレッドで HTTP 通信を行っているため、NetworkOnMainThreadException. を使用して別のスレッドで実行するのAsyncTaskが理想的なソリューションです。これを実装する方法の例を次に示します。

private TextView tv;

@Override
protected void onCreate(Bundle savedInstanceState) {

    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_create_competetion);

    tv = (TextView) findViewById(R.id.competetion_text);
    JsonCollector jc = new JsonCollector();

    // Create and execute a new AsyncTask, the TextView will
    // be updated asynchronously when the task has finished.
    updateTextView();
}

private void updateTextView() {
    new AsyncTask<Void, Void, String>() {

        @Override
        /* Runs on a separate thread */
        protected String doInBackground(Void... params) {
            String result = null;
            BufferedReader reader = null;
            try {
                URL url = new URL("http://api.heroesofnewerth.com/player_statistics/ranked/nickname/Hieratic/?token=0CZGH8ZI7UR8J2GN");
                reader = new BufferedReader(new InputStreamReader(url.openStream(), "UTF-8"));
                for (String line; (line = reader.readLine()) != null;) {
                    System.out.println(line);
                    result = line;
                }
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (reader != null) {
                    try {
                        reader.close();
                    } catch (IOException e) {
                        // Ignore
                    }
                }
            }

            return result;  
        }

        @Override
        /* Runs on the UI/Main thread when doInBackground()
         * has finished */
        protected void onPostExecute(String result) {
            if(result != null) {
                // Update the TextView only if we got a result
                // from the HTTP request
                tv.setText(result);
            }
        }

    }.execute();
}
于 2013-05-15T18:21:18.817 に答える