请如果有人可以帮我解决这个问题。我找了几天这个解决方案，找不到任何东西。感谢各位开发者！
问题是行中的 NullPointerExceptionlistView.setAdapter(adapter);避免此问题的唯一方法是添加行setContentView(R.layaut.pestana0);，但这会使他们不再看到带有 viewpager 的页面。这是我的应用程序的代码：
主要活动
public class AwesomePagerActivity extends Activity {
String[] countries = new String[] { "India", "Pakistan", "Sri Lanka",
"China", "Bangladesh", "Nepal", "Afghanistan", "North Korea",
"South Korea", "Japan" };
// Array of integers points to images stored in /res/drawable-ldpi/
int[] flags = new int[] { R.drawable.ic_launcher, R.drawable.ic_launcher,
R.drawable.ic_launcher, R.drawable.ic_launcher,
R.drawable.ic_launcher, R.drawable.ic_launcher,
R.drawable.ic_launcher, R.drawable.ic_launcher,
R.drawable.ic_launcher, R.drawable.ic_launcher };
// Array of strings to store currencies
String[] currency = new String[] { "Indian Rupee", "Pakistani Rupee",
"Sri Lankan Rupee", "Renminbi", "Bangladeshi Taka",
"Nepalese Rupee", "Afghani", "North Korean Won",
"South Korean Won", "Japanese Yen" };
private ViewPager columnas;
private static int NUM_COLUMNAS = 3;
private ColumnasAdapter miAdapter;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
miAdapter = new ColumnasAdapter();
columnas = (ViewPager) findViewById(R.id.columnas);
columnas.setAdapter(miAdapter);
// Parte nueva: Añadimos el Adapter al indicador
TitlePageIndicator titleIndicator = (TitlePageIndicator) findViewById(R.id.titulos);
titleIndicator.setViewPager(columnas);
}
private class ColumnasAdapter extends PagerAdapter {
@Override
public int getCount() {
return NUM_COLUMNAS;
}
@Override
public Object instantiateItem(View collection, int position) {
final LayoutInflater inflater = (LayoutInflater) AwesomePagerActivity.this
.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View v;
switch (position) {
case 0: {
// setContentView(R.layout.pestana0);
v = inflater.inflate(R.layout.pestana0, null, false);
/*
* Codigo De Cada Pestaña
*/
// Each row in the list stores country name, currency and flag
List<HashMap<String, String>> aList = new ArrayList<HashMap<String, String>>();
for (int i = 0; i < 10; i++) {
HashMap<String, String> hm = new HashMap<String, String>();
hm.put("txt", "Country : " + countries[i]);
hm.put("cur", "Currency : " + currency[i]);
hm.put("flag", Integer.toString(flags[i]));
aList.add(hm);
}
// Keys used in Hashmap
String[] from = { "flag", "txt", "cur" };
// Ids of views in listview_layout
int[] to = { R.id.flag, R.id.txt, R.id.cur };
// Instantiating an adapter to store each items
// R.layout.listview_layout defines the layout of each item
SimpleAdapter adapter = new SimpleAdapter(getBaseContext(),
aList, R.layout.listview_layout, from, to);
// Getting a reference to listview of main.xml layout file
ListView listView = (ListView) findViewById(R.id.listview);
// Setting the adapter to the listView
listView.setAdapter(adapter);
}
case 1: // Full ExpandableList code here
{
v = inflater.inflate(R.layout.pestana1, null, false);
/*
* Codigo De Cada Pestaña
*/
((ViewPager) collection).addView(v, 0);
return v;
}
case 2: // Full ExpandableList code here
{
v = inflater.inflate(R.layout.pestana2, null, false);
/*
* Codigo De Cada Pestaña
*/
((ViewPager) collection).addView(v, 0);
return v;
}
default:
v = inflater.inflate(R.layout.pestana0, null, false);
/*
* Codigo De Cada Pestaña
*/
((ViewPager) collection).addView(v, 0);
return v;
}
}
@Override
public void destroyItem(View collection, int position, Object view) {
((ViewPager) collection).removeView((LinearLayout) view);
}
@Override
public CharSequence getPageTitle(int position) {
if (position == 0)
return "Autos";
else {
if (position == 1) {
return "Planes";
} else {
if (position == 2) {
return "Contactenos";
}
}
}
return "Autos";
}
@Override
public boolean isViewFromObject(View view, Object object) {
return view == ((LinearLayout) object);
}
@Override
public void finishUpdate(View arg0) {
}
@Override
public void restoreState(Parcelable arg0, ClassLoader arg1) {
}
@Override
public Parcelable saveState() {
return null;
}
@Override
public void startUpdate(View arg0) {
}
}
}
xml 佩斯塔纳0
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/textview"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
<ListView
android:id="@+id/listview"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
</LinearLayout>
listview_layout.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="horizontal">
<ImageView android:id="@+id/flag"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:contentDescription="@string/app_name"
android:paddingTop="10dp"
android:paddingRight="10dp"
android:paddingBottom="10dp"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<TextView
android:id="@+id/txt"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="15dp"/>
<TextView
android:id="@+id/cur"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="10dp"/>
</LinearLayout>
</LinearLayout>