我的项目需要一些帮助。我已经创建了一个自定义适配器，因为我希望我的列表视图显示5个textview，而不是我迄今为止设法做的那个。这是我的CustomAdapterPn活动：
public class CustomAdapterPn extends BaseAdapter {
private static ArrayList<Poniedzialek> searchPnArrayList;
private LayoutInflater mInflater;
public CustomAdapterPn(final Context context, final ArrayList<Poniedzialek> results) {
searchPnArrayList = results;
mInflater = LayoutInflater.from(context);
}
public int getCount() {
return searchPnArrayList.size();
}
public Object getItem(int position) {
return searchPnArrayList.get(position);
}
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder;
if (convertView == null) {
convertView = mInflater.inflate(R.layout.entry, null);
holder = new ViewHolder();
holder.txtSession = (TextView) convertView.findViewById(R.id.textSession);
holder.txtName = (TextView) convertView.findViewById(R.id.textName);
holder.txtStart = (TextView) convertView.findViewById(R.id.textStartTime);
holder.txtEnd = (TextView) convertView.findViewById(R.id.textEndTime);
holder.txtRoom = (TextView) convertView.findViewById(R.id.textRoom);
convertView.setTag(holder);
} else {
holder = (ViewHolder) convertView.getTag();
}
holder.txtSession.setText(searchPnArrayList.get(position).getTypeOfSession());
holder.txtName.setText(searchPnArrayList.get(position).getName());
holder.txtStart.setText(searchPnArrayList.get(position).getStartTime());
holder.txtEnd.setText(searchPnArrayList.get(position).getEndTime());
holder.txtRoom.setText(searchPnArrayList.get(position).getRoom());
return convertView;
}
static class ViewHolder {
TextView txtSession;
TextView txtName;
TextView txtStart;
TextView txtEnd;
TextView txtRoom;
}
}
这是我希望使用此CustomAdapter的Activity。请注意，我使用ArrayAdapter来显示列表项 - 我还没有修改代码，因为我无法正确地管理这个自定义适配器（我试图，但没有任何效果）。我是一个新手，所以我很难得到这个，虽然我正在阅读大量的教程。
public class PoniedzialekActivity extends Activity implements OnClickListener, OnItemClickListener{ // z ListActivity na Activity
private Button butPnAdd;
private Button butPnDelete;
private ListView list_Pn;
private static final int DIALOG_ALERT = 10;
// We need some kind of Adapter to made the connection between ListView UI component and SQLite data set.
private ListAdapter pn_list_adapter;
// We need this while we read the query using Cursor and pass data
private ArrayList<Poniedzialek> pn_list;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout_poniedzialek);
butPnAdd = (Button) findViewById(R.id.butPnAdd);
butPnAdd.setOnClickListener(this);
butPnDelete = (Button) findViewById(R.id.butPnDel);
butPnDelete.setOnClickListener(this);
// Initialize UI components
list_Pn = (ListView) findViewById(R.id.listPn);
list_Pn.setOnItemClickListener(this);
pn_list = new ArrayList<Poniedzialek>();
// For the third argument, we need a List that contains Strings.
//We decided to display undergraduates names on the ListView.
//Therefore we need to create List that contains undergraduates names
pn_list_adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, populateList());
list_Pn.setAdapter(pn_list_adapter);
}
@Override
public void onClick(View v) {
if(v.getId()==R.id.butPnAdd){
Intent i = new Intent(PoniedzialekActivity.this,dodawaniePoniedzialek.class);
startActivity(i);
}
if(v.getId()==R.id.butPnDel){
showDialog(DIALOG_ALERT);
}
}
/**
* DIALOG
*/
protected Dialog onCreateDialog(int id) {
switch (id) {
case DIALOG_ALERT:
// Create out AlterDialog
Builder builder = new AlertDialog.Builder(this);
builder.setTitle("Czy na pewno chcesz usunac wszystkie wpisy ?");
builder.setCancelable(true);
builder.setPositiveButton("Tak", new OkOnClickListener());
builder.setNegativeButton("Nie", new CancelOnClickListener());
AlertDialog dialog = builder.create();
dialog.show();
}
return super.onCreateDialog(id);
}
private final class CancelOnClickListener implements
DialogInterface.OnClickListener {
public void onClick(DialogInterface dialog, int which) {
// Nic nie robi
}
}
private final class OkOnClickListener implements
DialogInterface.OnClickListener {
public void onClick(DialogInterface dialog, int which) {
DeletePn();
onResume();
}
}
public void DeletePn(){
DatabaseHelper openHelperClass = new DatabaseHelper(this);
SQLiteDatabase sqliteDatabase = openHelperClass.getWritableDatabase();
sqliteDatabase.delete(DatabaseHelper.PN_TABLE, null, null);
}
@Override
public void onItemClick(AdapterView<?> arg0, View arg1, int arg2, long arg3) {
// TODO Auto-generated method stub
}
// To create a List that contains undergraduate names, we have to read the SQLite database
//We are going to do it in the separate method
public List<String> populateList(){
// We have to return a List which contains only String values. Lets create a List first
List<String> pn_string_list = new ArrayList<String>();
// First we need to make contact with the database we have created using the DbHelper class
DatabaseHelper openHelperClass = new DatabaseHelper(this);
// Then we need to get a readable database
SQLiteDatabase sqliteDatabase = openHelperClass.getReadableDatabase();
// We need a a guy to read the database query. Cursor interface will do it for us
//(String table, String[] columns, String selection, String[] selectionArgs, String groupBy, String having, String orderBy)
Cursor cursor = sqliteDatabase.query(DatabaseHelper.PN_TABLE, null, null, null, null, null, null);
// Above given query, read all the columns and fields of the table
startManagingCursor(cursor);
// Cursor object read all the fields. So we make sure to check it will not miss any by looping through a while loop
while (cursor.moveToNext()) {
// In one loop, cursor read one undergraduate all details
// Assume, we also need to see all the details of each and every undergraduate
// What we have to do is in each loop, read all the values, pass them to the POJO class
//and create a ArrayList of undergraduates
String session = cursor.getString(cursor.getColumnIndex(DatabaseHelper.PN_KEY_TYPE_OF_SESSION));
String start = cursor.getString(cursor.getColumnIndex(DatabaseHelper.PN_KEY_START_TIME));
String end = cursor.getString(cursor.getColumnIndex(DatabaseHelper.PN_KEY_END_TIME));
String name = cursor.getString(cursor.getColumnIndex(DatabaseHelper.PN_KEY_NAME));
String room = cursor.getString(cursor.getColumnIndex(DatabaseHelper.PN_KEY_ROOM));
// Finish reading one raw, now we have to pass them to the POJO
Poniedzialek pn = new Poniedzialek();
pn.setTypeOfSession(session);
pn.setName(name);
pn.setStartTime(start);
pn.setEndTime(end);
pn.setRoom(room);
// Przekazujemy pn do arraylist
pn_list.add(pn);
// But we need a List of String to display in the ListView also.
// That is why we create "pn_string_list"
pn_string_list.add(name);
}
// Jezeli Baza Danych nie zostanie zamknieta dostaniemy error
sqliteDatabase.close();
return pn_string_list;
}
// If you don't write the following code, you wont be able to see what you have just insert to the database
@SuppressWarnings("unchecked")
@Override
protected void onResume() {
super.onResume();
pn_list_adapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, populateList());
list_Pn.setAdapter(pn_list_adapter);
((ArrayAdapter<String>) pn_list_adapter).notifyDataSetChanged(); // dodano
list_Pn.refreshDrawableState(); // dodanoe
list_Pn.invalidate(); // dodanoe
}
} // end PoniedzialekActivity
答案 0 :(得分：1)
为自定义适配器类CustomAdapterPn创建一个对象，并将此自定义适配器对象设置为列表视图。不是阵列适配器。
答案 1 :(得分：0)
查看这些行并根据它进行更改
CustomAdapterPn pn_list_adapter; //change 1
pn_list = new ArrayList<Poniedzialek>();
populateList() // Change 2
pn_list_adapter = new CustomAdapterPn(this,pn_list); // Change 3
list_Pn.setAdapter(pn_list_adapter);
试试这个，让我知道发生了什么......