HttpURLConnection打开跟踪文件时出错：没有这样的文件或目录

Question

I am trying to connect to an url to get geopoints to draw a route in a mapview for my android app. However I get this error when I try to connect to the url to get the points.

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");

I have the following in my manifest

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

I am running this in eclipse 4.2.2 on Mac OSX Lion using the emulator.

Thanks for your help!

EDIT

Sorry, I left out some important info, here are all my permissions in my manifest

<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" />

EDIT 2

here is the full error

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

As you are trying to access Internet on the main Application thread, you are getting this exception. You need to do all network activity in a different thread. You can use AsyncTask to accomplish this.

This is done so the the application will stay responsive even if there are blocking calls to the network. You may also want to read further here .