题
I'm building a RSS/Atom feed reader which check different tag and takes in only the tags that we need.
However, when I execute the code, I'm having an Android RunTime Exception.
https://stackoverflow.com/questions/23372623
italiano
english
français
española
中国
日本の
العربية
Deutsch
한국어
Português
Russian04-29 23:56:20.745: D/ProgressBar(18432): setProgressDrawable mProgressDrawable = null, d = android.graphics.drawable.LayerDrawable@42347548needUpdate = false
04-29 23:56:20.745: D/ProgressBar(18432): setProgressDrawable drawableHeight = 32
04-29 23:56:20.745: D/ProgressBar(18432): setProgress = 0
04-29 23:56:20.745: D/ProgressBar(18432): setProgress = 0, fromUser = false
04-29 23:56:20.745: D/ProgressBar(18432): mProgress = 0mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:20.755: D/ProgressBar(18432): setProgress = 0
04-29 23:56:20.755: D/ProgressBar(18432): setProgress = 0, fromUser = false
04-29 23:56:20.755: D/ProgressBar(18432): mProgress = 0mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:20.865: D/libEGL(18432): loaded /vendor/lib/egl/libEGL_adreno.so
04-29 23:56:20.875: D/libEGL(18432): loaded /vendor/lib/egl/libGLESv1_CM_adreno.so
04-29 23:56:20.885: D/libEGL(18432): loaded /vendor/lib/egl/libGLESv2_adreno.so
04-29 23:56:20.885: I/Adreno-EGL(18432): <qeglDrvAPI_eglInitialize:316>: EGL 1.4 QUALCOMM build: LNXBUILD_AU_LINUX_ANDROID_JB_3.2.4.04.03.00.173.012+PATCH[ES]_msm8226_JB_3.2.4__release_ENGG ()
04-29 23:56:20.885: I/Adreno-EGL(18432): OpenGL ES Shader Compiler Version: 20.00.01
04-29 23:56:20.885: I/Adreno-EGL(18432): Build Date: 02/27/14 Thu
04-29 23:56:20.885: I/Adreno-EGL(18432): Local Branch:
04-29 23:56:20.885: I/Adreno-EGL(18432): Remote Branch: quic/jb_3.2.4
04-29 23:56:20.885: I/Adreno-EGL(18432): Local Patches: 7de55685a2714b78da20f2a126b0dd72b0d2c0c4 Merge "PROFILER: fix default enabled/disabled setting"
04-29 23:56:20.885: I/Adreno-EGL(18432): 75d04ab84c7a68c72d92d59aae1827fcfef44b91 PROFILER: fix default enabled/disabled setting
04-29 23:56:20.885: I/Adreno-EGL(18432): Reconstruct Branch: LOCAL_PATCH[ES]
04-29 23:56:20.925: D/OpenGLRenderer(18432): Enabling debug mode 0
04-29 23:56:20.925: D/ProgressBar(18432): updateDrawableBounds: left = 0
04-29 23:56:20.925: D/ProgressBar(18432): updateDrawableBounds: top = 0
04-29 23:56:20.925: D/ProgressBar(18432): updateDrawableBounds: right = 96
04-29 23:56:20.925: D/ProgressBar(18432): updateDrawableBounds: bottom = 32
04-29 23:56:20.925: D/ProgressBar(18432): updateDrawableBounds: mProgressDrawable.setBounds()
04-29 23:56:21.885: D/ProgressBar(18432): setProgress = 1
04-29 23:56:21.885: D/ProgressBar(18432): setProgress = 1, fromUser = false
04-29 23:56:21.885: D/ProgressBar(18432): mProgress = 0mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:21.895: D/ProgressBar(18432): setProgress = 2
04-29 23:56:21.895: D/ProgressBar(18432): setProgress = 2, fromUser = false
04-29 23:56:21.895: D/ProgressBar(18432): mProgress = 1mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:21.895: D/ProgressBar(18432): setProgress = 3
04-29 23:56:21.895: D/ProgressBar(18432): setProgress = 3, fromUser = false
04-29 23:56:21.895: D/ProgressBar(18432): mProgress = 2mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:21.905: D/ProgressBar(18432): setProgress = 4
04-29 23:56:21.905: D/ProgressBar(18432): setProgress = 4, fromUser = false
04-29 23:56:21.905: D/ProgressBar(18432): mProgress = 3mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:21.945: D/ProgressBar(18432): setProgress = 5
04-29 23:56:21.945: D/ProgressBar(18432): setProgress = 5, fromUser = false
04-29 23:56:21.945: D/ProgressBar(18432): mProgress = 4mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:21.955: D/ProgressBar(18432): setProgress = 6
04-29 23:56:21.955: D/ProgressBar(18432): setProgress = 6, fromUser = false
04-29 23:56:21.955: D/ProgressBar(18432): mProgress = 5mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:21.955: D/ProgressBar(18432): setProgress = 7
04-29 23:56:21.955: D/ProgressBar(18432): setProgress = 7, fromUser = false
04-29 23:56:21.955: D/ProgressBar(18432): mProgress = 6mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:21.965: D/ProgressBar(18432): setProgress = 8
04-29 23:56:21.965: D/ProgressBar(18432): setProgress = 8, fromUser = false
04-29 23:56:21.965: D/ProgressBar(18432): mProgress = 7mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:21.975: D/ProgressBar(18432): setProgress = 9
04-29 23:56:21.975: D/ProgressBar(18432): setProgress = 9, fromUser = false
04-29 23:56:21.975: D/ProgressBar(18432): mProgress = 8mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:21.985: D/ProgressBar(18432): setProgress = 10
04-29 23:56:21.985: D/ProgressBar(18432): setProgress = 10, fromUser = false
04-29 23:56:21.985: D/ProgressBar(18432): mProgress = 9mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:21.985: D/ProgressBar(18432): setProgress = 11
04-29 23:56:21.985: D/ProgressBar(18432): setProgress = 11, fromUser = false
04-29 23:56:21.985: D/ProgressBar(18432): mProgress = 10mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:21.995: D/ProgressBar(18432): setProgress = 12
04-29 23:56:21.995: D/ProgressBar(18432): setProgress = 12, fromUser = false
04-29 23:56:21.995: D/ProgressBar(18432): mProgress = 11mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.015: D/ProgressBar(18432): setProgress = 13
04-29 23:56:22.015: D/ProgressBar(18432): setProgress = 13, fromUser = false
04-29 23:56:22.015: D/ProgressBar(18432): mProgress = 12mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.015: D/ProgressBar(18432): setProgress = 14
04-29 23:56:22.015: D/ProgressBar(18432): setProgress = 14, fromUser = false
04-29 23:56:22.015: D/ProgressBar(18432): mProgress = 13mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.025: D/ProgressBar(18432): setProgress = 15
04-29 23:56:22.025: D/ProgressBar(18432): setProgress = 15, fromUser = false
04-29 23:56:22.025: D/ProgressBar(18432): mProgress = 14mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.035: D/ProgressBar(18432): setProgress = 16
04-29 23:56:22.035: D/ProgressBar(18432): setProgress = 16, fromUser = false
04-29 23:56:22.035: D/ProgressBar(18432): mProgress = 15mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.045: D/ProgressBar(18432): setProgress = 17
04-29 23:56:22.045: D/ProgressBar(18432): setProgress = 17, fromUser = false
04-29 23:56:22.045: D/ProgressBar(18432): mProgress = 16mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.045: D/ProgressBar(18432): setProgress = 18
04-29 23:56:22.045: D/ProgressBar(18432): setProgress = 18, fromUser = false
04-29 23:56:22.045: D/ProgressBar(18432): mProgress = 17mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.065: D/ProgressBar(18432): setProgress = 19
04-29 23:56:22.065: D/ProgressBar(18432): setProgress = 19, fromUser = false
04-29 23:56:22.065: D/ProgressBar(18432): mProgress = 18mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.075: D/ProgressBar(18432): setProgress = 20
04-29 23:56:22.075: D/ProgressBar(18432): setProgress = 20, fromUser = false
04-29 23:56:22.075: D/ProgressBar(18432): mProgress = 19mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.075: D/ProgressBar(18432): setProgress = 21
04-29 23:56:22.075: D/ProgressBar(18432): setProgress = 21, fromUser = false
04-29 23:56:22.075: D/ProgressBar(18432): mProgress = 20mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.085: D/ProgressBar(18432): setProgress = 22
04-29 23:56:22.085: D/ProgressBar(18432): setProgress = 22, fromUser = false
04-29 23:56:22.085: D/ProgressBar(18432): mProgress = 21mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.095: D/ProgressBar(18432): setProgress = 23
04-29 23:56:22.095: D/ProgressBar(18432): setProgress = 23, fromUser = false
04-29 23:56:22.095: D/ProgressBar(18432): mProgress = 22mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.095: D/ProgressBar(18432): setProgress = 24
04-29 23:56:22.095: D/ProgressBar(18432): setProgress = 24, fromUser = false
04-29 23:56:22.095: D/ProgressBar(18432): mProgress = 23mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.105: D/ProgressBar(18432): setProgress = 25
04-29 23:56:22.105: D/ProgressBar(18432): setProgress = 25, fromUser = false
04-29 23:56:22.105: D/ProgressBar(18432): mProgress = 24mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.115: D/ProgressBar(18432): setProgress = 100
04-29 23:56:22.115: D/ProgressBar(18432): setProgress = 100, fromUser = false
04-29 23:56:22.115: D/ProgressBar(18432): mProgress = 25mIndeterminate = false, mMin = 0, mMax = 100
04-29 23:56:22.115: D/AndroidRuntime(18432): Shutting down VM
04-29 23:56:22.115: W/dalvikvm(18432): threadid=1: thread exiting with uncaught exception (group=0x41758898)
04-29 23:56:22.125: E/AndroidRuntime(18432): FATAL EXCEPTION: main
04-29 23:56:22.125: E/AndroidRuntime(18432): java.lang.NullPointerException
04-29 23:56:22.125: E/AndroidRuntime(18432): at com.itcuties.app.SplashActivity$GetRSSDataTask.onPostExecute(SplashActivity.java:81)
04-29 23:56:22.125: E/AndroidRuntime(18432): at com.itcuties.app.SplashActivity$GetRSSDataTask.onPostExecute(SplashActivity.java:1)
04-29 23:56:22.125: E/AndroidRuntime(18432): at android.os.AsyncTask.finish(AsyncTask.java:631)
04-29 23:56:22.125: E/AndroidRuntime(18432): at android.os.AsyncTask.access$600(AsyncTask.java:177)
04-29 23:56:22.125: E/AndroidRuntime(18432): at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:644)
04-29 23:56:22.125: E/AndroidRuntime(18432): at android.os.Handler.dispatchMessage(Handler.java:99)
04-29 23:56:22.125: E/AndroidRuntime(18432): at android.os.Looper.loop(Looper.java:176)
04-29 23:56:22.125: E/AndroidRuntime(18432): at android.app.ActivityThread.main(ActivityThread.java:5493)
04-29 23:56:22.125: E/AndroidRuntime(18432): at java.lang.reflect.Method.invokeNative(Native Method)
04-29 23:56:22.125: E/AndroidRuntime(18432): at java.lang.reflect.Method.invoke(Method.java:525)
04-29 23:56:22.125: E/AndroidRuntime(18432): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1225)
04-29 23:56:22.125: E/AndroidRuntime(18432): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1041)
04-29 23:56:22.125: E/AndroidRuntime(18432): at dalvik.system.NativeStart.main(Native Method)
04-29 23:57:07.065: I/Process(18432): Sending signal. PID: 18432 SIG: 9
Here's my java File which does that,
package com.itcuties.app.util.atom;
import java.text.ParseException;
import java.util.ArrayList;
import java.util.List;
import org.xml.sax.Attributes;
import org.xml.sax.SAXException;
import org.xml.sax.helpers.DefaultHandler;
import android.util.Log;
import android.widget.ProgressBar;
import com.itcuties.app.reader.data.RssAtomItem;
import com.itcuties.app.util.text.TextConverter;
public class RssAtomParseHandler extends DefaultHandler {
private List<RssAtomItem> rssItems;
// Used to reference item while parsing
private RssAtomItem currentItem;
// Parsing title indicator
private boolean parsingTitle;
// Parsing contents indicator
private boolean parsingContents;
// Parsing published date indicator
private boolean parsingPublishedDate;
// A buffer for title contents
private StringBuffer currentTitleSb;
// A buffer for content tag contents
private StringBuffer currentContentSb;
// A buffer for publish date tag contents;
private StringBuffer currentPubishDateSb;
// Parsing published Author name
private boolean parsingAuthorName;
// A buffer for Author Name
private StringBuffer currentAuthorSb;
// This is a ProgressBar reference set by the SplashScreen
// We use it to show the real progress while each item from
// the feed is read.
private ProgressBar progressBar;
public RssAtomParseHandler() {
rssItems = new ArrayList<RssAtomItem>();
}
public List<RssAtomItem> getItems() {
return rssItems;
}
public void setProgressBar(ProgressBar progressBar) {
this.progressBar = progressBar;
}
@Override
public void startElement(String uri, String localName, String qName,
Attributes attributes) throws SAXException {
if ("entry".equals(qName)) {
currentItem = new RssAtomItem();
} else if ("title".equals(qName)) {
parsingTitle = true;
currentTitleSb = new StringBuffer();
} else if ("author".equals(qName)) {
parsingAuthorName = true;
currentAuthorSb = new StringBuffer();
} else if ("content".equals(qName)) {
parsingContents = true;
currentContentSb = new StringBuffer();
} else if ("published".equals(qName)) {
parsingPublishedDate = true;
currentPubishDateSb = new StringBuffer();
} else if ("category".equals(qName)) {
if (currentItem != null && currentItem.getCategory() == null) {
currentItem.setCategory(attributes.getValue("term"));
}
}
}
@Override
public void endElement(String uri, String localName, String qName)
throws SAXException {
if ("entry".equals(qName)) {
rssItems.add(currentItem);
currentItem = null;
} else if ("title".equals(qName)) {
parsingTitle = false;
// There is a title tag for a whole channel present.
// It is being parsed before the entry tag is present,
// so we need to check if item is not null
if (currentItem != null)
// We encode the title so that it can be read by the application
// properly
currentItem.setTitle(TextConverter.convertTitle(currentTitleSb
.toString()));
} else if ("content".equals(qName)) {
parsingContents = false;
if (currentItem != null) {
// When an item's content is being set we convert it a little
// bit:
// - All styles and JavaScript information are removed
// - Content is URL encoded so that the WebView component can
// display it correctly
// - We remove two sections which are added by the ATOM feed,
// the post info section
// and the code download section (only github link is present in
// the text)
currentItem.setContent(TextConverter
.clearStylesAndJS(TextConverter.URLEncode(TextConverter
.removePostInfoSection(TextConverter
.removeDownloadSection(currentContentSb
.toString())))));
// Update progressBar
progressBar.setProgress(progressBar.getProgress() + 1);
} else if ("author".equals(qName)) {
parsingAuthorName = false;
if (currentItem != null) {
currentItem.setAuthor(currentAuthorSb.toString());
// Update progressBar
progressBar.setProgress(progressBar.getProgress() + 1);
}
} else if ("published".equals(qName)) {
parsingPublishedDate = false;
if (currentItem != null)
try {
// We convert the date from the WordPress format to
// DD-MM-YYYY format
currentItem.setPublishDate(TextConverter
.convertDate(currentPubishDateSb.toString()));
} catch (ParseException e) {
currentItem.setPublishDate("no date");
Log.e("ITCRssReader", "No publish date available");
}
}
}
}
@Override
public void characters(char[] ch, int start, int length)
throws SAXException {
// title, contents and date tags contents values are set here.
// This method can be called multiple times for one tag, it depends
// on how much text tag's contents has. Remember that SAX is a
// stream parser so it parses feed stream sequentially.
if (parsingTitle) {
if (currentItem != null)
currentTitleSb.append(new String(ch, start, length));
} else if (parsingAuthorName) {
if (currentItem != null)
currentAuthorSb.append(new String(ch, start, length));
else if (parsingContents) {
if (currentItem != null)
currentContentSb.append(new String(ch, start, length));
} else if (parsingPublishedDate) {
if (currentItem != null)
currentPubishDateSb.append(new String(ch, start, length));
}
}
}
}
Here's the Splash Activity that uses AsyncTask.
package com.itcuties.app;
import java.util.List;
import android.app.Activity;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.ProgressBar;
import android.widget.Toast;
import com.itcuties.app.reader.data.RssAtomItem;
import com.itcuties.app.reader.data.RssResults;
import com.itcuties.app.util.atom.RssAtomReader;
/**
* Application splash screen. It also loads data.
*
*/
public class SplashActivity extends Activity {
private ProgressBar progressBar;
private Toast t;
String done ="Done!";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.splash);
progressBar = (ProgressBar)findViewById(R.id.progressBar);
progressBar.setProgress(0); // No progress so far
// Download data in the new thread
GetRSSDataTask grdt = new GetRSSDataTask();
grdt.execute("[Feed Address goes here]");
}
/**
* Read RSS channel data.
*
*
*/
private class GetRSSDataTask extends AsyncTask<String, Void, List<RssAtomItem> > {
@Override
protected List<RssAtomItem> doInBackground(String... urls) {
try {
// Create RSS reader
RssAtomReader rssReader = new RssAtomReader(urls[0]);
rssReader.setProgressBar(progressBar); // Set the progress bar to show real progress
// Parse RSS, get items
return rssReader.getItems();
} catch (Exception e) {
Log.e("BlanketCoffeeRSS", e.getMessage());
}
return null;
}
@Override
protected void onPostExecute(List<RssAtomItem> results) {
// When the download is done the main activity needs to be started
Intent i = new Intent(SplashActivity.this, ListPostsActivity.class);
// You might find this not right to use a static attribute to pass data between the
// the activities in the application. We tried to pass the List of the RssAtomItem
// object with no luck although RssAtomItem implemented Serializable interface.
// ListPostActivity read null values. So this is the engineer's solution. It works :)
RssResults.setResults(results); //We need to set the results of the download process
// Show 100% progress
progressBar.setProgress(100);
t.setText(done);
t.show();
// Start new activity and finish this splash activity
SplashActivity.this.startActivity(i);
SplashActivity.this.finish();
}
}
}
Can Anybody tell me where am I doing it wrong? The number of author tags are 50, as supposed to the 15 odd posts. Is that creating a problem or something else?
解决方案
Your code shows that your toast t is null. You create nowhere an instance of it nor call the one-line toast call. E.g. this one:
Toast.makeText(getActivty(), R.string.YOUR_STRING, Toast.LENGTH_SHORT).show();
You're calling t.setText(done); that would cause the null pointer exception, because there is no instance of it.
