我想创建一个简单的 RSS 阅读器，这是我的实际代码：
public class MainActivity extends ListActivity {
List headlines;
List links;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Initializing instance variables
headlines = new ArrayList();
links = new ArrayList();
try {
URL url = new URL(
"http://www.radiojudaicastrasbourg.fr/category/podcasts/linvite-de-la-redaction/feed/");
XmlPullParserFactory factory = XmlPullParserFactory.newInstance();
factory.setNamespaceAware(false);
XmlPullParser xpp = factory.newPullParser();
// We will get the XML from an input stream
xpp.setInput(getInputStream(url), "UTF_8");
/*
* We will parse the XML content looking for the "<title>" tag which
* appears inside the "<item>" tag. However, we should take in
* consideration that the rss feed name also is enclosed in a
* "<title>" tag. As we know, every feed begins with these lines:
* "<channel><title>Feed_Name</title>...." so we should skip the
* "<title>" tag which is a child of "<channel>" tag, and take in
* consideration only "<title>" tag which is a child of "<item>"
*
* In order to achieve this, we will make use of a boolean variable.
*/
boolean insideItem = false;
// Returns the type of current event: START_TAG, END_TAG, etc..
int eventType = xpp.getEventType();
while (eventType != XmlPullParser.END_DOCUMENT) {
if (eventType == XmlPullParser.START_TAG) {
if (xpp.getName().equalsIgnoreCase("item")) {
insideItem = true;
} else if (xpp.getName().equalsIgnoreCase("title")) {
if (insideItem)
headlines.add(xpp.nextText()); // extract the
// headline
} else if (xpp.getName().equalsIgnoreCase("enclosure")) {
if (insideItem)
links.add(xpp.getAttributeValue(null, "url")); // extract
// the
// link
// of
// article
}
} else if (eventType == XmlPullParser.END_TAG
&& xpp.getName().equalsIgnoreCase("item")) {
insideItem = false;
}
eventType = xpp.next(); // move to next element
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (XmlPullParserException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
// Binding data
ArrayAdapter adapter = new ArrayAdapter(this,
android.R.layout.simple_list_item_1, headlines);
setListAdapter(adapter);
}
public InputStream getInputStream(URL url) {
try {
return url.openConnection().getInputStream();
} catch (IOException e) {
return null;
}
}
@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
Uri uri = Uri.parse((String) links.get(position));
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
startActivity(intent);
}
}
当我启动应用程序时，它会立即关闭，我不知道为什么。这是日志猫：
>09-12 17:09:06.065: E/AndroidRuntime(11394): FATAL EXCEPTION: main
09-12 17:09:06.065: E/AndroidRuntime(11394): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.parserxml/com.example.parserxml.MainActivity}: android.os.NetworkOnMainThreadException
09-12 17:09:06.065: E/AndroidRuntime(11394): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2339)
09-12 17:09:06.065: E/AndroidRuntime(11394): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2389)
09-12 17:09:06.065: E/AndroidRuntime(11394): at android.app.ActivityThread.access$600(ActivityThread.java:153)
09-12 17:09:06.065: E/AndroidRuntime(11394): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1269)
09-12 17:09:06.065: E/AndroidRuntime(11394): at android.os.Handler.dispatchMessage(Handler.java:99)
09-12 17:09:06.065: E/AndroidRuntime(11394): at android.os.Looper.loop(Looper.java:137)
09-12 17:09:06.065: E/AndroidRuntime(11394): at android.app.ActivityThread.main(ActivityThread.java:5287)
09-12 17:09:06.065: E/AndroidRuntime(11394): at java.lang.reflect.Method.invokeNative(Native Method)
09-12 17:09:06.065: E/AndroidRuntime(11394): at java.lang.reflect.Method.invoke(Method.java:525)
09-12 17:09:06.065: E/AndroidRuntime(11394): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:738)
09-12 17:09:06.065: E/AndroidRuntime(11394): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:554)
09-12 17:09:06.065: E/AndroidRuntime(11394): at dalvik.system.NativeStart.main(Native Method)
09-12 17:09:06.065: E/AndroidRuntime(11394): Caused by: android.os.NetworkOnMainThreadException
09-12 17:09:06.065: E/AndroidRuntime(11394): at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1133)
09-12 17:09:06.065: E/AndroidRuntime(11394): at java.net.InetAddress.lookupHostByName(InetAddress.java:385)
09-12 17:09:06.065: E/AndroidRuntime(11394): at java.net.InetAddress.getAllByNameImpl(InetAddress.java:236)
09-12 17:09:06.065: E/AndroidRuntime(11394): at java.net.InetAddress.getAllByName(InetAddress.java:214)
09-12 17:09:06.065: E/AndroidRuntime(11394): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:70)
09-12 17:09:06.065: E/AndroidRuntime(11394): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
09-12 17:09:06.065: E/AndroidRuntime(11394): at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340)
09-12 17:09:06.065: E/AndroidRuntime(11394): at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87)
09-12 17:09:06.065: E/AndroidRuntime(11394): at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
09-12 17:09:06.065: E/AndroidRuntime(11394): at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:316)
09-12 17:09:06.065: E/AndroidRuntime(11394): at libcore.net.http.HttpEngine.connect(HttpEngine.java:311)
09-12 17:09:06.065: E/AndroidRuntime(11394): at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:290)
09-12 17:09:06.065: E/AndroidRuntime(11394): at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:240)
09-12 17:09:06.065: E/AndroidRuntime(11394): at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:282)
09-12 17:09:06.065: E/AndroidRuntime(11394): at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:177)
09-12 17:09:06.065: E/AndroidRuntime(11394): at com.example.parserxml.MainActivity.getInputStream(MainActivity.java:95)
09-12 17:09:06.065: E/AndroidRuntime(11394): at com.example.parserxml.MainActivity.onCreate(MainActivity.java:44)
09-12 17:09:06.065: E/AndroidRuntime(11394): at android.app.Activity.performCreate(Activity.java:5201)
09-12 17:09:06.065: E/AndroidRuntime(11394): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
09-12 17:09:06.065: E/AndroidRuntime(11394): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2293)
09-12 17:09:06.065: E/AndroidRuntime(11394): ... 11 more