我对android开发很新。我正在尝试使用制表符（通过片段添加）构建应用程序。在其中一个片段（Sector1）中，我试图显示一个ListView。此列表已使用UserCustomAdapter填充，我已从ArrayAdapter扩展。 问题是ListView不显示，如果我尝试填充列表，应用程序崩溃！ thx for All !!
这是 UserCustomAdapter.java
public class UserCustomAdapter extends ArrayAdapter<User> {
private static final int INVISIBLE = 4;
private static final int VISIBLE = 0;
Context context;
int layoutResourceId;
ArrayList<User> data = new ArrayList<User>();
public UserCustomAdapter(Context context, int layoutResourceId, ArrayList<User> data) {
super(context, layoutResourceId, data);
this.layoutResourceId = layoutResourceId;
this.context = context;
this.data = data;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
UserHolder holder = null;
System.out.println("@@@-getView-@@@");
if (row == null) {
LayoutInflater inflater = ((Activity) context).getLayoutInflater();
row = inflater.inflate(layoutResourceId, parent, false);
holder = new UserHolder();
holder.textName = (TextView) row.findViewById(R.id.tv_prodotto);
holder.textQta = (TextView) row.findViewById(R.id.tv_qta);
//holder.textLocation = (TextView) row.findViewById(R.id.textView3);
holder.btnEdit = (ImageButton) row.findViewById(R.id.button1);
holder.btnDelete = (ImageButton) row.findViewById(R.id.button2);
row.setTag(holder);
} else {
holder = (UserHolder) row.getTag();
}
User user = data.get(position);
holder.Useritem = data.get(position);
holder.textName.setText(user.getName());
holder.textQta.setText(user.getAddress());
//holder.textLocation.setText(user.getLocation());
holder.btnDelete.setTag(holder.Useritem);// mi segno la posizione in modo da recuperarla poi in seguito!!
holder.btnEdit.setTag(holder.Useritem);// mi segno la posizione in modo da recuperarla poi in seguito!!
//rendo invisibili i pulsanti per la prima riga
if(position == 0){
holder.btnDelete.setVisibility(INVISIBLE);
holder.btnEdit.setVisibility(INVISIBLE);
}else{
holder.btnDelete.setVisibility(VISIBLE);
holder.btnEdit.setVisibility(VISIBLE);
}
holder.btnDelete.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Log.i("Delete Button Clicked", "**********");
Toast.makeText(context, "Delete button Clicked",
Toast.LENGTH_LONG).show();
User itemToRemove = (User)v.getTag();
Sector1.userAdapter.remove(itemToRemove);
Sector1.userAdapter.notifyDataSetChanged();
}
});
return row;
}
static class UserHolder {
TextView textName;
TextView textQta;
//TextView textLocation;
ImageButton btnEdit;
ImageButton btnDelete;
User Useritem;
}
这是 Sector1.java
public class Sector1 extends Fragment
{
private Button btnNew_order,btnAggiungi;
private Spinner spin_prodotto, spin_tipo;
private EditText EtQta;
ListView userList;
Static UserCustomAdapter userAdapter;
ArrayList<User> userArray = new ArrayList<User>();
@Override
public View onCreateView(LayoutInflater inflater,
ViewGroup container,
Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.sector1, container, false);
userAdapter = new UserCustomAdapter(getActivity().getBaseContext(), R.layout.row, userArray);
userList = (ListView) rootView.findViewById(R.id.listView);
userList.setItemsCanFocus(false);
userList.setAdapter(userAdapter);
//userAdapter.setListAdapter();
//userList.setListAdapter(userAdapter);
//userAdapter.getView(0, rootView, container);
spin_prodotto = (Spinner) rootView.findViewById(R.id.spin_prodotto);
spin_tipo = (Spinner) rootView.findViewById(R.id.spin_tipo);
btnNew_order = (Button) rootView.findViewById(R.id.btn_new_order);
btnAggiungi = (Button) rootView.findViewById(R.id.btn_aggiungi);
EtQta = (EditText) rootView.findViewById(R.id.Et_qta);
btnAggiungi.setEnabled(false);
btnNew_order.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
btnAggiungi.setEnabled(true);
Date now = new Date();
SimpleDateFormat DesiredFormat = new SimpleDateFormat("dd/MM/yyyy kk:MM");
String newFormat = DesiredFormat.format(now.getTime());
String Order = "Ordine del:\n" +newFormat;
// userAdapter.add(new User(Order, "Fornitore: Passerini"));
// userAdapter.notifyDataSetChanged();
}
});
//return super.onCreateView(inflater, container, savedInstanceState);
return rootView;
}
public void removeItemClickHandler(final View v) {
User itemToRemove = (User)v.getTag();
userAdapter.remove(itemToRemove);
userAdapter.notifyDataSetChanged();
}
}
这是我的 sector1.xml
<FrameLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:id="@+id/LinearLayout1"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
android:id="@+id/btn_new_order"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/new_order" />
</LinearLayout>
<LinearLayout
android:id="@+id/LinearLayout2"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="50dp"
android:orientation="horizontal" >
<Spinner
android:id="@+id/spin_prodotto"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:entries="@array/passerini_product"
android:prompt="@string/product_prompt"/>
</LinearLayout>
<LinearLayout
android:id="@+id/LinearLayout3"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="120dp"
android:orientation="horizontal" >
<TextView
android:id="@+id/lb_tv_qta"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textSize="10sp"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:text="qta:" />
<EditText
android:id="@+id/Et_qta"
android:layout_width="50dp"
android:layout_height="wrap_content"
android:layout_marginLeft="3dp"
android:ems="2"
android:inputType="numberSigned|numberDecimal"
android:text="1" >
<requestFocus />
</EditText>
<Spinner
android:id="@+id/spin_tipo"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_marginLeft="3dp"
android:layout_weight="50"
android:entries="@array/type_product" />
<Button
android:id="@+id/btn_aggiungi"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:drawableLeft="@android:drawable/ic_input_add"
android:text="Aggiungi" />
</LinearLayout>
<LinearLayout
android:id="@+id/LinearLayout5"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_marginTop="170dp"
android:background="#ccffcc"
android:orientation="horizontal" >
<ListView
android:id="@+id/listView"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
<!-- tools:listitem="@layout/row"> -->
</ListView>
</LinearLayout>
</FrameLayout>
这是 row.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="5dp"
tools:context=".MainActivity" >
<TextView
android:id="@+id/tv_prodotto"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_alignParentTop="true"
android:layout_marginLeft="50dp"
android:text="Prodotto"
android:textStyle="bold" android:textColor="#000000" />
<ImageButton
android:id="@+id/button2"
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_alignParentRight="true"
android:layout_alignParentTop="true"
android:focusable="false"
android:focusableInTouchMode="false"
android:src="@android:drawable/ic_menu_delete"
android:textColor="#0099CC" />
</RelativeLayout>
这是我的 MainActivity.java
public class MainActivity extends FragmentActivity implements ActionBar.TabListener {
AppSectionsPagerAdapter mAppSectionsPagerAdapter;
ViewPager mViewPager;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Settare il tipo di navigazione
mAppSectionsPagerAdapter = new AppSectionsPagerAdapter(getSupportFragmentManager());
final ActionBar actionBar = getActionBar();
actionBar.setHomeButtonEnabled(false);
actionBar.setNavigationMode(ActionBar.NAVIGATION_MODE_TABS);
mViewPager = (ViewPager) findViewById(R.id.pager);
mViewPager.setAdapter(mAppSectionsPagerAdapter);
mViewPager.setOnPageChangeListener(new ViewPager.SimpleOnPageChangeListener() {
@Override
public void onPageSelected(int position) {
actionBar.setSelectedNavigationItem(position);
}
});
// creo icona e scritta per il primo Tab
Tab tab = actionBar.newTab()
.setText("Ordine")
.setTabListener(this)
.setIcon(R.drawable.computer);
actionBar.addTab(tab);
// creo icona e scritta per il primo Tab
tab = actionBar.newTab()
.setText("Invio")
.setTabListener(this)
.setIcon(R.drawable.email);
actionBar.addTab(tab);
}
//public void removeItemClickHandler(final View v) {
// User itemToRemove = (User)v.getTag();
// userAdapter.remove(itemToRemove);
// userAdapter.notifyDataSetChanged();
// }
@Override
public void onTabUnselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
@Override
public void onTabSelected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
mViewPager.setCurrentItem(tab.getPosition());
}
@Override
public void onTabReselected(ActionBar.Tab tab, FragmentTransaction fragmentTransaction) {
}
public class AppSectionsPagerAdapter extends FragmentPagerAdapter {
public AppSectionsPagerAdapter(FragmentManager fm) {
super(fm);
}
// Il return new chiama le altre classi (i Fragment)
@Override
public Fragment getItem(int i) {
switch (i) {
case 0:
return new Sector1();
case 1:
return new Sector2();
default:
Fragment fragment = new Sector1();
Bundle args = new Bundle();
fragment.setArguments(args);
return fragment;
}
}
// Settare il titolo dei Sector
@Override
public int getCount() {
return 2;
}
public CharSequence getPageTitle(int position) {
String tabLabel = null;
switch (position) {
case 0:
tabLabel = getString(R.string.title_section1);
break;
case 1:
tabLabel = getString(R.string.title_section2);
break;
}
return tabLabel;
}
}
}
答案 0 :(得分：3)
替换
LayoutInflater inflater = ((Activity) context).getLayoutInflater();
带
LayoutInflater.from(context);
。
始终查看您的日志 - 在大多数情况下，确定崩溃原因很有用。你认为ClassCastException是可以自我解释的。在创建将getActivity（）。getBaseContext（）传递给适配器的适配器的同时，尝试将适配器属性上下文转换为Activity（适配器的第43行）。