AsycTask を使用してアプリのコードを「最適化」しようとしていますが、java.lang.NullPointerException エラーが発生します。
私がどこで間違っているのかを理解するのを手伝ってもらえますか？
package it.vscreazioni.farmachimica;
import java.io.IOException;
import java.io.InputStream;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.widget.ListView;
import com.actionbarsherlock.app.SherlockActivity;
import com.actionbarsherlock.view.Menu;
public class MostraTutti extends SherlockActivity {
final ListView lv = (ListView) findViewById(R.id.listView);
final List<ListViewItem> items = new ArrayList<MostraTutti.ListViewItem>();
final ArrayList<String> nome = new ArrayList<String>();
final ArrayList<String> immagine = new ArrayList<String>();
...
...
final int array_image2[] ={R.drawable.iodocloroidrossichinolina,R.drawable.acidoacetilsalicilico,
R.drawable.acidoascorbico,R.drawable.acidobarbiturico,R.drawable.acidobenzoico,...};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mostra_tutti);
getSupportActionBar().setDisplayShowHomeEnabled(false);
RssFeedTask rssTask = new RssFeedTask();
rssTask.execute();
}
private class RssFeedTask extends AsyncTask<String, Void, String> {
private ProgressDialog Dialog;
String response = "";
@Override
protected void onPreExecute() {
Dialog = new ProgressDialog(MostraTutti.this);
Dialog.setMessage("Leggo...");
Dialog.show();
}
@Override
protected String doInBackground(String... urls) {
InputStream xmlFile = getResources().openRawResource(R.raw.sostanze);
try {
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
final Document document = documentBuilder.parse(xmlFile);
document.getDocumentElement().normalize();
NodeList nodeList = document.getElementsByTagName("sostanza");
for (int i = 0; i < nodeList.getLength(); i++) {
final int indice = i;
nome.add(document.getElementsByTagName("nome").item(indice).getTextContent());
iupac.add(document.getElementsByTagName("iupac").item(indice).getTextContent());
aspetto.add(document.getElementsByTagName("aspetto").item(indice).getTextContent());
formula.add(document.getElementsByTagName("formula").item(indice).getTextContent());
immagine.add(document.getElementsByTagName("immagine").item(indice).getTextContent());
appartenenza.add(document.getElementsByTagName("appartenenza").item(indice).getTextContent());
spiegazione.add(document.getElementsByTagName("spiegazione").item(indice).getTextContent());
tempFus.add(document.getElementsByTagName("temperaturaFusione").item(indice).getTextContent());
tempEboll.add(document.getElementsByTagName("temperaturaEbollizione").item(indice).getTextContent());
solubilita.add(document.getElementsByTagName("solubilita").item(indice).getTextContent());
note.add(document.getElementsByTagName("eccezioni").item(indice).getTextContent());
String str = document.getElementsByTagName("formula").item(indice).getTextContent();
str = str.replaceAll("0", "\u2080");
str = str.replaceAll("1", "\u2081");
str = str.replaceAll("2", "\u2082");
str = str.replaceAll("3", "\u2083");
str = str.replaceAll("4", "\u2084");
str = str.replaceAll("5", "\u2085");
str = str.replaceAll("6", "\u2086");
str = str.replaceAll("7", "\u2087");
str = str.replaceAll("8", "\u2088");
str = str.replaceAll("9", "\u2089");
final String stringa = str;
formulaConvertita.add(stringa);
items.add(new ListViewItem()
{{
ThumbnailResource = array_image2[indice];
Title = document.getElementsByTagName("nome").item(indice).getTextContent();
SubTitle = stringa;
}});
};
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return response;
}
@Override
protected void onPostExecute(String result) {
CustomListViewAdapter adapter = new CustomListViewAdapter(MostraTutti.this,items);
lv.setAdapter(adapter);
/*
_adapter = new CustomListViewAdapter(News.this,Rssparser.items);
lv=(ListView)findViewById(R.id.list);
lv.setAdapter(_adapter);
Dialog.dismiss();
lv.setOnItemClickListener(new OnItemClickListener()
{
public void onItemClick(AdapterView<?> arg0, View v, int position, long id)
{
Context context = getBaseContext();
Intent myIntent = new Intent(context, LeggiArticolo.class);
myIntent.putExtra("testo",Rssparser.testo.get(position));
myIntent.putExtra("titolo",Rssparser.titolo.get(position));
myIntent.putExtra("immagine",Rssparser.immagini.get(position));
myIntent.putExtra("link",Rssparser.indirizzo.get(position));
startActivityForResult(myIntent, 0);
}
}
);
*/
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getSupportMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
class ListViewItem {
public int ThumbnailResource;
public String Title;
public String SubTitle;
}
}
そして、私はこのエラーを受け取ります:
04-25 11:43:57.872: W/dalvikvm(1663): threadid=1: thread exiting with uncaught exception
(group=0x40a13300)
04-25 11:43:57.902: E/AndroidRuntime(1663): FATAL EXCEPTION: main
04-25 11:43:57.902: E/AndroidRuntime(1663): java.lang.RuntimeException: Unable to
instantiate activity
ComponentInfo{it.vscreazioni.farmachimica/it.vscreazioni.farmachimica.MostraTutti}:
java.lang.NullPointerException
04-25 11:43:57.902: E/AndroidRuntime(1663): at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1983)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2084)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
android.app.ActivityThread.access$600(ActivityThread.java:130)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
android.app.ActivityThread$H.handleMessage(ActivityThread.java:1195)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
android.os.Handler.dispatchMessage(Handler.java:99)
04-25 11:43:57.902: E/AndroidRuntime(1663): at android.os.Looper.loop(Looper.java:137)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
android.app.ActivityThread.main(ActivityThread.java:4745)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
java.lang.reflect.Method.invokeNative(Native Method)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
java.lang.reflect.Method.invoke(Method.java:511)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
04-25 11:43:57.902: E/AndroidRuntime(1663): at dalvik.system.NativeStart.main(Native
Method)
04-25 11:43:57.902: E/AndroidRuntime(1663): Caused by: java.lang.NullPointerException
04-25 11:43:57.902: E/AndroidRuntime(1663): at
android.app.Activity.findViewById(Activity.java:1825)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
it.vscreazioni.farmachimica.MostraTutti.<init>(MostraTutti.java:25)
04-25 11:43:57.902: E/AndroidRuntime(1663): at java.lang.Class.newInstanceImpl(Native
Method)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
java.lang.Class.newInstance(Class.java:1319)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
android.app.Instrumentation.newActivity(Instrumentation.java:1053)
04-25 11:43:57.902: E/AndroidRuntime(1663): at
android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1974)
04-25 11:43:57.902: E/AndroidRuntime(1663): ... 11 more
手伝ってくれませんか？
回答後に編集:
public class MostraTutti extends SherlockActivity {
ListView lv;
final List<ListViewItem> items = new ArrayList<MostraTutti.ListViewItem>();
final ArrayList<String> nome = new ArrayList<String>();
...
final int array_image2[] ={R.drawable.iodocloroidrossichinolina,R.drawable.acidoacetilsalicilico,
R.drawable.acidoascorbico,R.drawable.acidobarbiturico,R.drawable.acidobenzoico,
... };
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.mostra_tutti);
lv = (ListView) findViewById(R.id.listView);
getSupportActionBar().setDisplayShowHomeEnabled(false);
RssFeedTask rssTask = new RssFeedTask();
rssTask.execute();
}
private class RssFeedTask extends AsyncTask<String, Void, String> {
private ProgressDialog Dialog;
String response = "";
@Override
protected void onPreExecute() {
Dialog = new ProgressDialog(MostraTutti.this);
Dialog.setMessage("Leggo le sostanze...");
Dialog.show();
}
@Override
protected String doInBackground(String... urls) {
InputStream xmlFile = getResources().openRawResource(R.raw.sostanze);
try {
DocumentBuilderFactory documentBuilderFactory = DocumentBuilderFactory.newInstance();
DocumentBuilder documentBuilder = documentBuilderFactory.newDocumentBuilder();
final Document document = documentBuilder.parse(xmlFile);
document.getDocumentElement().normalize();
//tagHandler.handleChannelTag(document);
NodeList nodeList = document.getElementsByTagName("sostanza");
for (int i = 0; i < nodeList.getLength(); i++) {
final int indice = i;
nome.add(document.getElementsByTagName("nome").item(indice).getTextContent());
iupac.add(document.getElementsByTagName("iupac").item(indice).getTextContent());
aspetto.add(document.getElementsByTagName("aspetto").item(indice).getTextContent());
formula.add(document.getElementsByTagName("formula").item(indice).getTextContent());
immagine.add(document.getElementsByTagName("immagine").item(indice).getTextContent());
appartenenza.add(document.getElementsByTagName("appartenenza").item(indice).getTextContent());
spiegazione.add(document.getElementsByTagName("spiegazione").item(indice).getTextContent());
tempFus.add(document.getElementsByTagName("temperaturaFusione").item(indice).getTextContent());
tempEboll.add(document.getElementsByTagName("temperaturaEbollizione").item(indice).getTextContent());
solubilita.add(document.getElementsByTagName("solubilita").item(indice).getTextContent());
note.add(document.getElementsByTagName("eccezioni").item(indice).getTextContent());
String str = document.getElementsByTagName("formula").item(indice).getTextContent();
str = str.replaceAll("0", "\u2080");
str = str.replaceAll("1", "\u2081");
str = str.replaceAll("2", "\u2082");
str = str.replaceAll("3", "\u2083");
str = str.replaceAll("4", "\u2084");
str = str.replaceAll("5", "\u2085");
str = str.replaceAll("6", "\u2086");
str = str.replaceAll("7", "\u2087");
str = str.replaceAll("8", "\u2088");
str = str.replaceAll("9", "\u2089");
final String stringa = str;
formulaConvertita.add(stringa);
items.add(new ListViewItem()
{{
ThumbnailResource = array_image2[indice];
Title = document.getElementsByTagName("nome").item(indice).getTextContent();
SubTitle = stringa;
}});
};
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
} catch (ParserConfigurationException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return response;
}
@Override
protected void onPostExecute(String result) {
Dialog.dismiss();
CustomListViewAdapter adapter = new CustomListViewAdapter(MostraTutti.this,items);
lv.setAdapter(adapter);
lv.setOnItemClickListener(
new OnItemClickListener()
{
public void onItemClick(AdapterView<?> arg0, View v, int position, long id)
{
Context context = getBaseContext();
Intent myIntent = new Intent(context, Dettagli.class);
myIntent.putExtra("nome_sostanza",nome.get(position));
// myIntent.putExtra("formula",formula.get(position));
myIntent.putExtra("iupac",iupac.get(position));
myIntent.putExtra("aspetto",aspetto.get(position));
myIntent.putExtra("appartenenza",appartenenza.get(position));
myIntent.putExtra("solubilita",solubilita.get(position));
myIntent.putExtra("tempFus",tempFus.get(position));
myIntent.putExtra("tempEboll",tempEboll.get(position));
myIntent.putExtra("spiegazione",spiegazione.get(position));
myIntent.putExtra("immagine", array_image2[position]);
myIntent.putExtra("formulaConvertita", formulaConvertita.get(position));
myIntent.putExtra("note", note.get(position));
startActivityForResult(myIntent, 0);
}
}
);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getSupportMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
class ListViewItem {
public int ThumbnailResource;
public String Title;
public String SubTitle;
}
}
そして、エラーはなくなりました！しかし、奇妙な動作があります。シミュレーターでは、「通常の」方法よりも時間がかかります。
非非同期で16秒、非同期で1分...