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下一个代码应该将数据解析为listView我正在使用的XmlPullParser方法，但是当我运行此活动时，应用程序崩溃:(我在另一个类中使用了相同的代码并且工作完美，但在这里我不知道原因？？logCat阻止了我在 ：rewardsList.setAdapter(adapter);

//Class:
     @Override
            protected void onCreate(Bundle savedInstanceState) {
                // TODO Auto-generated method stub
                super.onCreate(savedInstanceState);
                setContentView(R.layout.rewards);
                rewards2=new ArrayList<HashMap<String,String>>();
                rewardsList=(ListView) findViewById(R.id.reward);
                tv=(TextView) findViewById(R.id.text);
                try {
                    url=new URL("http://api.androidhive.info/pizza/?format=xml");

                    xpf=XmlPullParserFactory.newInstance();
                    xpf.setNamespaceAware(false);
                    xpp=xpf.newPullParser();
                    xpp.setInput(getInputStream(url),"UTF_8");
                    insideItem = false;
                   HashMap<String, String> map=new HashMap<String, String>();

                    int type=xpp.getEventType();
                    while(type!=XmlPullParser.END_DOCUMENT){
                        if(type==XmlPullParser.START_TAG){
                            if(xpp.getName().equalsIgnoreCase("item")){
                                 map=new HashMap<String, String>();
                                insideItem=true;

                            }else if(xpp.getName().equalsIgnoreCase("id")){
                                if(insideItem)
                                //  map.add(xpp.nextText());
                               map.put("item", xpp.nextText());
                            }//
                        }else if(type==XmlPullParser.END_TAG && xpp.getName().equalsIgnoreCase("item")){

                            insideItem=false;
                           rewards2.add(map); 
                        }

                        type=xpp.nextTag();
                    }


                } catch (MalformedURLException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (XmlPullParserException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }


                ListAdapter adapter = new SimpleAdapter(this,rewards2, R.layout.rewards_list,
                        new String[] {"item"}, new int[] 
                           {R.id.t3});
               rewardsList.setAdapter(adapter);
                //tv.setText(rewards2.get(0));
            }


            private InputStream getInputStream(URL url2) {
                // TODO Auto-generated method stub
                try{
                    return url.openConnection().getInputStream();
                }catch(IOException e){
                return null;


    }

日志猫：

10-23 06:43:54.365: E/AndroidRuntime(937):  at com.university.app.Rwards.onCreate(Rwards.java:131)
10-23 06:49:28.995: E/AndroidRuntime(1006): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.university.app/com.university.app.Rwards}: java.lang.NullPointerException
10-23 06:49:28.995: E/AndroidRuntime(1006):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at android.app.ActivityThread.access$600(ActivityThread.java:123)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at android.os.Handler.dispatchMessage(Handler.java:99)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at android.os.Looper.loop(Looper.java:137)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at android.app.ActivityThread.main(ActivityThread.java:4424)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at java.lang.reflect.Method.invokeNative(Native Method)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at java.lang.reflect.Method.invoke(Method.java:511)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at dalvik.system.NativeStart.main(Native Method)
10-23 06:49:28.995: E/AndroidRuntime(1006): Caused by: java.lang.NullPointerException
10-23 06:49:28.995: E/AndroidRuntime(1006):     at com.university.app.Rwards.onCreate(Rwards.java:132)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at android.app.Activity.performCreate(Activity.java:4465)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1049)
10-23 06:49:28.995: E/AndroidRuntime(1006):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1920)

xml布局：奖励：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
     android:background="@drawable/bg">


    <LinearLayout android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@drawable/title_bar">

        <TextView android:layout_width="fill_parent"
            android:layout_height="fill_parent"
            android:text="Rwards"/>


    </LinearLayout>



    <LinearLayout
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:background="@drawable/white_strip_4header" >



        <TextView
            android:id="@+id/textView1"
            android:layout_width="60dp"
            android:layout_height="wrap_content"
            android:layout_weight="1.10"
            android:text="notes" />
        <TextView
            android:id="@+id/textView2"
            android:layout_width="70dp"
            android:layout_height="wrap_content"
            android:layout_weight="1.10"
            android:text="Amount owed" />
        <TextView
            android:id="@+id/textView3"
            android:layout_width="20dp"
            android:layout_height="wrap_content"
            android:layout_weight="1.10"
            android:text="month" 
            android:gravity="center"/>
        <TextView
            android:id="@+id/textView4"
            android:layout_width="20dp"
            android:layout_height="wrap_content"
            android:layout_weight="1.10"
            android:text="year" 
            android:gravity="center"/>
    </LinearLayout>


 <TextView
            android:id="@+id/text"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            />

    <ListView
        android:id="@+id/reward"
        android:layout_width="match_parent"
        android:layout_height="wrap_content" >
    </ListView>

</LinearLayout>

奖励清单

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >
    <TextView
            android:id="@+id/t3"
            android:layout_width="50dp"
            android:layout_height="wrap_content"
            android:gravity="left"
            android:layout_weight="1"
            android:layout_margin="1dp"/>


        <TextView
            android:id="@+id/t2"
            android:layout_width="70dp"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:layout_margin="2dp"
            android:gravity="left">
        </TextView>

     <TextView
            android:id="@+id/t1"
            android:layout_width="130dp"
            android:layout_height="wrap_content"
           android:gravity="left"
           android:layout_weight="1"
            android:layout_margin="1dp"
             />    

</LinearLayout>

我试图在没有使用textView它的列表的情况下运行它也崩溃了！！所以请有人知道为什么？我已经将活动添加到了manifest！

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