Problema ListView: NullPointerException

Ho bisogno di una list view con due colonne, i quali dati vengono letti da un database SQLite preventivamente caricato sul device. Per quanto riguarda tutta la gestione db, compresa la lettura da query non ho problemi.

Il mio problema è che la funzione setAdapter() lancia l'eccezione:

codice:

---

ERROR/AndroidRuntime(4638): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.eReporting/com.eReporting.Report}: java.lang.NullPointerException


---

Di seguito il codice utilizzato:

codice:

---

ListView list = (ListView) findViewById(R.id.viaSearchLView);
       
        ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();
        HashMap<String, String> map = new HashMap<String, String>();
        map.put("from", "6:30 AM");
        map.put("to", "7:40 AM");
        mylist.add(map);

        SimpleAdapter mSchedule = new SimpleAdapter(this,
                        mylist,
                        R.layout.via_listview,
                new String[] {"from", "to"},
                    new int[] {R.id.viaTVId, R.id.viaTVVia});
        list.setAdapter(mSchedule);

---

Ho provato (dopo aver cambiato extends Activity con extends ListActivity)

codice:

---

ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();
        HashMap<String, String> map = new HashMap<String, String>();
        map.put("from", "6:30 AM");
        map.put("to", "7:40 AM");
        mylist.add(map);

        SimpleAdapter mSchedule = new SimpleAdapter(this,
                        mylist,
                        R.layout.via_listview,
                new String[] {"from", "to"},
                    new int[] {R.id.viaTVId, R.id.viaTVVia});
        setListAdapter(mSchedule);

---

che mi lancia la seguente eccezione:

codice:

---

ERROR/AndroidRuntime(4942): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.eReporting/com.eReporting.Report}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'


---

A voi la parola !
Vi ringrazio in anticipo per i suggerimenti che mi darete!

Quote:

---

Originariamente inviato da Link88

Ho bisogno di una list view con due colonne, i quali dati vengono letti da un database SQLite preventivamente caricato sul device. Per quanto riguarda tutta la gestione db, compresa la lettura da query non ho problemi.



Il mio problema è che la funzione setAdapter() lancia l'eccezione:



ERROR/AndroidRuntime(4638): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.eReporting/com.eReporting.Report}: java.lang.NullPointerException





Di seguito il codice utilizzato:



ListView list = (ListView) findViewById(R.id.viaSearchLView);



ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();

HashMap<String, String> map = new HashMap<String, String>();

map.put("from", "6:30 AM");

map.put("to", "7:40 AM");

mylist.add(map);



SimpleAdapter mSchedule = new SimpleAdapter(this,

mylist,

R.layout.via_listview,

new String[] {"from", "to"},

new int[] {R.id.viaTVId, R.id.viaTVVia});

list.setAdapter(mSchedule);



Ho provato (dopo aver cambiato extends Activity con extends ListActivity)



ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();

HashMap<String, String> map = new HashMap<String, String>();

map.put("from", "6:30 AM");

map.put("to", "7:40 AM");

mylist.add(map);



SimpleAdapter mSchedule = new SimpleAdapter(this,

mylist,

R.layout.via_listview,

new String[] {"from", "to"},

new int[] {R.id.viaTVId, R.id.viaTVVia});

setListAdapter(mSchedule);



che mi lancia la seguente eccezione:



ERROR/AndroidRuntime(4942): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.eReporting/com.eReporting.Report}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'









A voi la parola !

Vi ringrazio in anticipo per i suggerimenti che mi darete!

---

ci passeresti l intero errore perfavore?


Inviato dal mio HTC Vision usando Androidiani App

Per il primo caso

codice:

---

03-02 12:40:09.455: WARN/dalvikvm(4638): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
03-02 12:40:09.455: ERROR/AndroidRuntime(4638): Uncaught handler: thread main exiting due to uncaught exception
03-02 12:40:09.486: ERROR/AndroidRuntime(4638): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.eReporting/com.eReporting.Report}: java.lang.NullPointerException
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at android.app.ActivityThread.access$2200(ActivityThread.java:119)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at android.os.Handler.dispatchMessage(Handler.java:99)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at android.os.Looper.loop(Looper.java:123)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at android.app.ActivityThread.main(ActivityThread.java:4363)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at java.lang.reflect.Method.invokeNative(Native Method)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at java.lang.reflect.Method.invoke(Method.java:521)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at dalvik.system.NativeStart.main(Native Method)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638): Caused by: java.lang.NullPointerException
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at com.eReporting.Report.onCreate(Report.java:126)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
03-02 12:40:09.486: ERROR/AndroidRuntime(4638):    ... 11 more

---

Per il secondo caso

codice:

---

03-02 12:51:44.955: WARN/dalvikvm(4942): threadid=3: thread exiting with uncaught exception (group=0x4001b188)
03-02 12:51:44.964: ERROR/AndroidRuntime(4942): Uncaught handler: thread main exiting due to uncaught exception
03-02 12:51:45.005: ERROR/AndroidRuntime(4942): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.eReporting/com.eReporting.Report}: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2496)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2512)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at android.app.ActivityThread.access$2200(ActivityThread.java:119)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1863)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at android.os.Handler.dispatchMessage(Handler.java:99)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at android.os.Looper.loop(Looper.java:123)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at android.app.ActivityThread.main(ActivityThread.java:4363)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at java.lang.reflect.Method.invokeNative(Native Method)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at java.lang.reflect.Method.invoke(Method.java:521)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:860)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:618)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at dalvik.system.NativeStart.main(Native Method)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942): Caused by: java.lang.RuntimeException: Your content must have a ListView whose id attribute is 'android.R.id.list'
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at android.app.ListActivity.onContentChanged(ListActivity.java:236)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at com.android.internal.policy.impl.PhoneWindow.setContentView(PhoneWindow.java:201)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at android.app.Activity.setContentView(Activity.java:1622)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at com.eReporting.Report.onCreate(Report.java:90)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2459)
03-02 12:51:45.005: ERROR/AndroidRuntime(4942):    ... 11 more

---

Sono assolutamente disponibile per qualunque altra cosa voi abbiate bisogno

Allora per il primo caso ci serve il sorgente di com.eReporting.Report.onCreate.

Per il secondo caso siccome la tua activity è una ListActivity, la lista nell'xml la devi definire con l'attributo id="@+id/android:list" come nell'esempio qui
<br /> <ListView android:id="@+id/android:list" android:layout_width="fill_parent"<br /> android:clickable="false" android:cacheColorHint="#e5e5e5"<br /> android:divider="#00000000" android:dividerHeight="0.1dip"<br /> android:layout_weight="1" android:layout_height="fill_parent" /><br />

Siccome il metodo onCreate è molto molto lungo ho rimesso la funzione in un progetto a parte. Preferirei concentrarmi sul primo metodo (che usa extends Activity)...

Ho riscritto per bene tutto:

codice:

---

package com.provalistview;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import android.app.Activity;
import android.os.Bundle;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class ProvaListV extends Activity {
           

    public void onCreate(Bundle savedInstanceState) {
               
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
       
        ListView lv1;
       
        lv1= (ListView) findViewById(R.id.listview);
            List<HashMap<String, String>> fillMaps = new ArrayList<HashMap<String, String>>();
           
                    for(int i = 0; i < 10; i++){
           
                        HashMap<String, String> map = new HashMap<String, String>();
           
                        map.put("col_1", "col_1_item_" + i);
           
                        map.put("col_2", "col_2_item_" + i);
           
                        fillMaps.add(map);
           
                    }
                   
            String lv_arr[]={"Android","Andr"};
       
            ListAdapter adp= new SimpleAdapter(this,
                            fillMaps,
                            R.layout.listview_lay,
                            lv_arr, new int[]{R.id.viaTVId, R.id.viaTVVia});
           
            lv1.setAdapter(adp);
    }
}

---

main.xml:

codice:

---

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout android:id="@+id/main"
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:orientation="vertical"
        android:layout_height="fill_parent"
        android:layout_width="fill_parent">
                <ListView android:id="@+id/listview"
                        android:layout_height="fill_parent"
                        android:layout_width="fill_parent">
                </ListView>
</LinearLayout>

---

listview_lay.xml:

codice:

---

<?xml version="1.0" encoding="utf-8"?>
<TableLayout
        xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_height="wrap_content"
        android:gravity="left|center"
        android:layout_width="wrap_content" >
        <TableRow>
                <TextView
                        android:id="@+id/viaTVId"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:gravity="left|top"
                        android:textStyle="bold"
                        android:text="hi"/>
        </TableRow>
        <TableRow>
                <TextView
                        android:id="@+id/viaTVVia"
                        android:text="Prova"
                        android:layout_width="wrap_content"
                        android:layout_height="wrap_content"
                        android:gravity="left|center"/>
        </TableRow>
</TableLayout>

---

Up! Ho risolto, di seguito il codice (in parte preso da qui)

codice:

---

package com.provalistview;

import java.util.ArrayList;
import java.util.HashMap;
import android.app.ListActivity;
import android.os.Bundle;
import android.widget.ListAdapter;
import android.widget.ListView;
import android.widget.SimpleAdapter;

public class ProvaListV extends ListActivity {
           

    public void onCreate(Bundle savedInstanceState) {
           
               
           
            super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
            ListAdapter mSchedule;
           
            ArrayList<HashMap<String, String>> mylist = new ArrayList<HashMap<String, String>>();
            HashMap<String, String> map = new HashMap<String, String>();
            map.put("train", "101");
            map.put("from", "6:30 AM");
            mylist.add(map);
            map = new HashMap<String, String>();
            map.put("train", "103(x)");
            map.put("from", "6:35 AM");
            mylist.add(map);
            mSchedule = new SimpleAdapter(this, mylist, R.layout.row,
                        new String[] {"train", "from"}, new int[] {R.id.TRAIN_CELL, R.id.FROM_CELL});
            setListAdapter(mSchedule);
    }
}

---