1
我有這個xml文件，我想獲取href字符串。從xml文件獲取鏈接
<asx version = "3.0">
<Title>TITLE</Title>
<Author>http://www.domain.com</Author>
<Copyright>Copyright</Copyright>
<PARAM name="HTMLView" value="http://www.domain.com" />
<MoreInfo href="http://www.domain.com" />
<entry>
<ref href="http://145.765.343.09:8180" />
<Title>Tile</Title>
<Author>http://www.domain.com</Author>
</entry>
</asx>
我已經創建了一個適配器，但我得到Nullpointer ...我在這裏做錯了什麼？
這是代碼：
basefeedparser.class
public class BaseFeedParser {
static String feedUrlString = "http://www.domain.com/listen.asx";
// names of the XML tags
static final String ASX = "asx";
static final String ENTRY = "entry";
static final String REF = "ref";
private final URL feedUrl;
protected BaseFeedParser(){
try {
this.feedUrl = new URL(feedUrlString);
} catch (MalformedURLException e) {
throw new RuntimeException(e);
}
}
protected InputStream getInputStream() {
try {
return feedUrl.openConnection().getInputStream();
} catch (IOException e) {
throw new RuntimeException(e);
}
}
public List<Message> parse() {
final Message currentMessage = new Message();
RootElement root = new RootElement(ASX);
final List<Message> messages = new ArrayList<Message>();
Element itemlist = root.getChild(ENTRY);
//Element item = itemlist.getChild(ENTRY);
itemlist.setEndElementListener(new EndElementListener(){
public void end() {
messages.add(currentMessage.copy());
}
});
itemlist.getChild(REF).setEndTextElementListener(new EndTextElementListener(){
public void end(String body) {
currentMessage.setEntry(body);
}
});
try {
Xml.parse(this.getInputStream(), Xml.Encoding.UTF_8, root.getContentHandler());
} catch (Exception e) {
throw new RuntimeException(e);
}
return messages;
}
}
message.class
公共類消息實現在可比{
private String entry;
private String Link;
public String getEntry() {
return entry;
}
public void setEntry(String entry) {
String imgg = entry.substring(entry.indexOf("<ref href="));
String cleanUp = imgg.substring(0, imgg.indexOf(">")+1);//deixnei apo pou ksekina to keimeno
imgg = imgg.substring(imgg.indexOf("href=") + 5);
int indexOf = imgg.indexOf("\"");
if (indexOf==-1){
indexOf = imgg.indexOf("\"");
}
imgg = imgg.substring(0, indexOf);
setLink(imgg);
this.entry = this.entry.replace(cleanUp, ""); }
public void setLink(String Link) {
this.Link = Link;
}
/**
* @return the Link
*/
public String getLink() {
return Link;
}
public Message copy(){
Message copy = new Message();
copy.entry = entry;
copy.Link=Link;
return copy;
}
@Override
public String toString() {
StringBuilder sb = new StringBuilder();
sb.append("Entry: ");
sb.append(entry);
sb.append('\n');
sb.append("Link: ");
sb.append(Link);
return sb.toString();
}
@Override
public int hashCode() {
final int prime = 31;
int result = 1;
result = prime * result
+ ((entry == null) ? 0 : entry.hashCode());
result = prime * result
+ ((Link == null) ? 0 : Link.hashCode());
return result;
}
@Override
public boolean equals(Object obj) {
if (this == obj)
return true;
if (obj == null)
return false;
if (getClass() != obj.getClass())
return false;
Message other = (Message) obj;
if (entry == null) {
if (other.entry != null)
return false;
} else if (!entry.equals(other.entry))
return false;
if (Link == null) {
if (other.Link != null)
return false;
} else if (!Link.equals(other.Link))
return false;
return true;
}
public int compareTo(Message another) {
if (another == null) return 1;
// sort descending, most recent first
return 0;
}
} 然後即時打印我的主類是ref標籤的鏈接：
for (Message msg : messages){
au.add(msg.getLink());
String print=au.toString();
Toast.makeText(main.this, print, Toast.LENGTH_LONG).show();
}
的logcat：
03-12 09:01:27.164: E/AndroidRuntime(7231): FATAL EXCEPTION: main
03-12 09:01:27.164: E/AndroidRuntime(7231): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.app/com.example.app.main}: java.lang.NullPointerException
03-12 09:01:27.164: E/AndroidRuntime(7231): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
03-12 09:01:27.164: E/AndroidRuntime(7231): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
03-12 09:01:27.164: E/AndroidRuntime(7231): at android.app.ActivityThread.access$600(ActivityThread.java:123)
03-12 09:01:27.164: E/AndroidRuntime(7231): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
03-12 09:01:27.164: E/AndroidRuntime(7231): at android.os.Handler.dispatchMessage(Handler.java:99)
03-12 09:01:27.164: E/AndroidRuntime(7231): at android.os.Looper.loop(Looper.java:137)
03-12 09:01:27.164: E/AndroidRuntime(7231): at android.app.ActivityThread.main(ActivityThread.java:4424)
03-12 09:01:27.164: E/AndroidRuntime(7231): at java.lang.reflect.Method.invokeNative(Native Method)
03-12 09:01:27.164: E/AndroidRuntime(7231): at java.lang.reflect.Method.invoke(Method.java:511)
03-12 09:01:27.164: E/AndroidRuntime(7231): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:787)
03-12 09:01:27.164: E/AndroidRuntime(7231): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:554)
03-12 09:01:27.164: E/AndroidRuntime(7231): at dalvik.system.NativeStart.main(Native Method)
03-12 09:01:27.164: E/AndroidRuntime(7231): Caused by: java.lang.NullPointerException
03-12 09:01:27.164: E/AndroidRuntime(7231): at com.example.app.main.onCreate(main.java:24)
03-12 09:01:27.164: E/AndroidRuntime(7231): at android.app.Activity.performCreate(Activity.java:4465)
03-12 09:01:27.164: E/AndroidRuntime(7231): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
03-12 09:01:27.164: E/AndroidRuntime(7231): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)
03-12 09:01:27.164: E/AndroidRuntime(7231): ... 11 more
線24：
for (Message msg : messages)
發佈您的logcat ... – 2012-03-12 07:07:02
@Samir logcat發佈 – 2012-03-12 07:20:47
您是否初始化消息？ – 2012-03-12 07:22:24