HttpURLConnection打開跟蹤文件時出錯：沒有這樣的文件或目錄

Question

我正在嘗試連接到網址以獲取地理位置，以便在android應用的mapview中繪制路線。 但是，當我嘗試連接到URL以獲得積分時，出現此錯誤。

URL url = new URL("http://maps.google.com/maps?f=d&hl=en&saddr=59.690289,16.60868&daddr=59.6,16.60868&ie=UTF8&0&om=0&output=kml");
Log.d("log","url: " + url);
HttpURLConnection urlConnection=(HttpURLConnection)url.openConnection();          urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
urlConnection.setDoInput(true);
urlConnection.connect();
Log.d("log","connected");

我的清單中有以下內容

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

我正在使用模擬器在Mac OSX Lion的eclipse 4.2.2中運行它。

謝謝你的幫助！

編輯

抱歉，我遺漏了一些重要信息，這是我清單中的所有權限

<uses-permission android:name="com.vogella.android.locationapi.maps.permission.MAPS_RECEIVE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />

編輯2

這是完整的錯誤

04-07 00:24:46.842: E/AndroidRuntime(7280): FATAL EXCEPTION: main
04-07 00:24:46.842: E/AndroidRuntime(7280): java.lang.RuntimeException: Unable to start activity ComponentInfo{markustenghamn.sfsfum/markustenghamn.sfsfum.MapHandlerActivity}: android.os.NetworkOnMainThreadException
04-07 00:24:46.842: E/AndroidRuntime(7280):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at android.app.ActivityThread.access$600(ActivityThread.java:141)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1234)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at android.os.Handler.dispatchMessage(Handler.java:99)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at android.os.Looper.loop(Looper.java:137)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at android.app.ActivityThread.main(ActivityThread.java:5041)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at java.lang.reflect.Method.invokeNative(Native Method)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at java.lang.reflect.Method.invoke(Method.java:511)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:793)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at dalvik.system.NativeStart.main(Native Method)
04-07 00:24:46.842: E/AndroidRuntime(7280): Caused by: android.os.NetworkOnMainThreadException
04-07 00:24:46.842: E/AndroidRuntime(7280):     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1117)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at java.net.InetAddress.getAllByName(InetAddress.java:214)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at libcore.net.http.HttpConnection.<init>(HttpConnection.java:70)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:316)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at libcore.net.http.HttpEngine.connect(HttpEngine.java:311)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:290)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:240)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at libcore.net.http.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:81)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at markustenghamn.sfsfum.MapHandlerActivity.DrawPath(MapHandlerActivity.java:166)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at markustenghamn.sfsfum.MapHandlerActivity.callMap(MapHandlerActivity.java:126)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at markustenghamn.sfsfum.MapHandlerActivity.onCreate(MapHandlerActivity.java:89)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at android.app.Activity.performCreate(Activity.java:5104)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)
04-07 00:24:46.842: E/AndroidRuntime(7280):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)
04-07 00:24:46.842: E/AndroidRuntime(7280):     ... 11 more
04-07 00:24:49.343: E/Trace(7297): error opening trace file: No such file or directory (2)

Answer 1

當您嘗試在主應用程序線程上訪問Internet時，會遇到此異常。 您需要在不同的線程中進行所有網絡活動。 您可以使用AsyncTask完成此操作。

這樣做是為了即使阻塞了對網絡的呼叫，應用程序也將保持響應。 您可能還想在這里進一步閱讀。