我希望这将是一个简单的。
我重新使用教程中的代码，该代码在列表视图中解析并显示RSS 从代理服务器后面运行代码或没有互联网时，我获得以下崩溃报告：
12-12 09:48:57.372: W/RssApp(1494): Exception while retrieving the input stream
12-12 09:48:57.372: W/RssApp(1494): java.net.ConnectException: failed to connect to gigglepics.co.uk/188.121.41.139 (port 80): connect failed: ETIMEDOUT (Connection timed out)
12-12 09:48:57.372: W/RssApp(1494): at libcore.io.IoBridge.connect(IoBridge.java:114)
12-12 09:48:57.372: W/RssApp(1494): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
12-12 09:48:57.372: W/RssApp(1494): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
12-12 09:48:57.372: W/RssApp(1494): at java.net.Socket.connect(Socket.java:842)
12-12 09:48:57.372: W/RssApp(1494): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:76)
12-12 09:48:57.372: W/RssApp(1494): at libcore.net.http.HttpConnection.<init>(HttpConnection.java:50)
12-12 09:48:57.372: W/RssApp(1494): at libcore.net.http.HttpConnection$Address.connect(HttpConnection.java:340)
12-12 09:48:57.372: W/RssApp(1494): at libcore.net.http.HttpConnectionPool.get(HttpConnectionPool.java:87)
12-12 09:48:57.372: W/RssApp(1494): at libcore.net.http.HttpConnection.connect(HttpConnection.java:128)
12-12 09:48:57.372: W/RssApp(1494): at libcore.net.http.HttpEngine.openSocketConnection(HttpEngine.java:316)
12-12 09:48:57.372: W/RssApp(1494): at libcore.net.http.HttpEngine.connect(HttpEngine.java:311)
12-12 09:48:57.372: W/RssApp(1494): at libcore.net.http.HttpEngine.sendSocketRequest(HttpEngine.java:290)
12-12 09:48:57.372: W/RssApp(1494): at libcore.net.http.HttpEngine.sendRequest(HttpEngine.java:240)
12-12 09:48:57.372: W/RssApp(1494): at libcore.net.http.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:282)
12-12 09:48:57.372: W/RssApp(1494): at libcore.net.http.HttpURLConnectionImpl.getInputStream(HttpURLConnectionImpl.java:177)
12-12 09:48:57.372: W/RssApp(1494): at eu.MasterZangetsu.RssService.getInputStream(RssService.java:48)
12-12 09:48:57.372: W/RssApp(1494): at eu.MasterZangetsu.RssService.onHandleIntent(RssService.java:33)
12-12 09:48:57.372: W/RssApp(1494): at android.app.IntentService$ServiceHandler.handleMessage(IntentService.java:65)
12-12 09:48:57.372: W/RssApp(1494): at android.os.Handler.dispatchMessage(Handler.java:99)
12-12 09:48:57.372: W/RssApp(1494): at android.os.Looper.loop(Looper.java:137)
12-12 09:48:57.372: W/RssApp(1494): at android.os.HandlerThread.run(HandlerThread.java:60)
12-12 09:48:57.372: W/RssApp(1494): Caused by: libcore.io.ErrnoException: connect failed: ETIMEDOUT (Connection timed out)
12-12 09:48:57.372: W/RssApp(1494): at libcore.io.Posix.connect(Native Method)
12-12 09:48:57.372: W/RssApp(1494): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:85)
12-12 09:48:57.372: W/RssApp(1494): at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
12-12 09:48:57.372: W/RssApp(1494): at libcore.io.IoBridge.connect(IoBridge.java:112)
12-12 09:48:57.372: W/RssApp(1494): ... 20 more
12-12 09:48:57.382: W/dalvikvm(1494): threadid=11: thread exiting with uncaught exception (group=0x40a71930)
12-12 09:48:57.402: E/AndroidRuntime(1494): FATAL EXCEPTION: IntentService[RssService]
12-12 09:48:57.402: E/AndroidRuntime(1494): java.lang.NullPointerException
12-12 09:48:57.402: E/AndroidRuntime(1494): at eu.MasterZangetsu.PcWorldRssParser.parse(PcWorldRssParser.java:33)
12-12 09:48:57.402: E/AndroidRuntime(1494): at eu.MasterZangetsu.RssService.onHandleIntent(RssService.java:33)
12-12 09:48:57.402: E/AndroidRuntime(1494): at android.app.IntentService$ServiceHandler.handleMessage(IntentService.java:65)
12-12 09:48:57.402: E/AndroidRuntime(1494): at android.os.Handler.dispatchMessage(Handler.java:99)
12-12 09:48:57.402: E/AndroidRuntime(1494): at android.os.Looper.loop(Looper.java:137)
12-12 09:48:57.402: E/AndroidRuntime(1494): at android.os.HandlerThread.run(HandlerThread.java:60)
这发生在inputStream.close（）;
public List<RssItem> parse(InputStream inputStream)
throws XmlPullParserException, IOException {
try {
XmlPullParser parser = Xml.newPullParser();
parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
parser.setInput(inputStream, null);
parser.nextTag();
return readFeed(parser);
} finally {
inputStream.close();
}
}
我想要做的就是捕获此异常以确保应用程序不会崩溃，而是显示错误消息
我尝试的所有内容似乎仍会崩溃并产生完全不同的错误。我必须遗漏一些非常基本的东西
答案 0 :(得分：4)
代码缺少实际的catch语句：
try {
XmlPullParser parser = Xml.newPullParser();
parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
parser.setInput(inputStream, null);
parser.nextTag();
return readFeed(parser);
}catch(IllegalArgumentException e){ //Replace this with the more specific exception
//do something
}catch(Excpetion e){ //You can have multiple catch blocks from specific to general
//do something
}finally {
inputStream.close();
}
添加此代码后，您仍会收到错误，因为inputStream为空，并在NullPointerException块中抛出finally。有两种方法可以解决这个问题。
首先是简单地抓住NullPointerException区块中的finally：
try {
XmlPullParser parser = Xml.newPullParser();
parser.setFeature(XmlPullParser.FEATURE_PROCESS_NAMESPACES, false);
parser.setInput(inputStream, null);
parser.nextTag();
return readFeed(parser);
}catch(IllegalArgumentException e){ //Replace this with the more specific exception
//do something
}catch(Excpetion e){ //You can have multiple catch blocks from specific to general
//do something
}finally {
try{
inputStream.close();
}catch(Exception e){
//do something
}
}
第二个不是不在方法开头通过添加保护条件接受空InputStream。
public List<RssItem> parse(InputStream inputStream)
throws IllegalArgumentException {
if(inputStream == null){
throw new IllegalArgumentException();
}
}
可以这样称呼：
try{
someObject.parse(null);
}catch(IllegalArgumentException e){
//do something
}
答案 1 :(得分：0)
喜欢这个
try {
}catch(IllegalArgumentException e){ //Added this catch block.
}
finally {
inputStream.close();
}
答案 2 :(得分：0)
只需添加catch块，然后catch特定exception。
try{
// your implementation
}catch(Exception e){
// handle the exception
}finally{
try{
// do what ever the thing should diffidently happens
}catch(Exception e){
}
}