我有一个扩展ArrayAdapter的类。这个类是有效的，但问题是当我将一个项添加到List时，它会使该项加倍，因此有两个相同的列表项。这是我当前的ArrayAdapter类，
class Item {
String username;
String number;
String content;
public Item (String username, String number, String content){
this.username = username;
this.number = number;
this.content = content;
}
public CharSequence getNumber() {
// TODO Auto-generated method stub
return username;
}
public CharSequence getUsername() {
// TODO Auto-generated method stub
return number;
}
public CharSequence getContent() {
// TODO Auto-generated method stub
return content;
}
}
class ListAdapter extends ArrayAdapter<Item> {
public ListAdapter(Context context, int textViewResourceId) {
super(context, textViewResourceId);
// TODO Auto-generated constructor stub
}
private List<Item> items;
public ListAdapter(Context context, int resource, List<Item> items) {
super(context, resource, items);
this.items = items;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View v = convertView;
if (v == null) {
LayoutInflater vi;
vi = LayoutInflater.from(getContext());
v = vi.inflate(R.layout.list_item, null);
}
final Item p = items.get(position);
if (p != null) {
TextView NumbersView = (TextView)v.findViewById(R.id.listNumber);
TextView usernamesView = (TextView)v.findViewById(R.id.listPostedBy);
Button usernameButton = (Button)v.findViewById(R.id.listUsernameButton);
Button numberButton = (Button)v.findViewById(R.id.listNumberButton);
commentView.setText(p.getContent());
NumbersView.setText(p.getNumber());
usernamesView.setText(p.getUsername());
usernameButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent i = new Intent(getApplicationContext(), ProfileActivity.class);
i.putExtra("usernameOfProfile", p.username);
startActivity(i);
finish();
}
});
numberButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
Intent i = new Intent(getApplicationContext(), ProfileActivity.class);
i.putExtra("NumberProfile", p.number);
startActivity(i);
finish();
}
});
}
return v;
}
}
final List <Item> tempList = new ArrayList <Item>();
ListView yourListView = (ListView) findViewById(android.R.id.list);
final ListAdapter customAdapter = new ListAdapter(DashboardActivity.this, R.layout.list_item, tempList);
yourListView.setAdapter(customAdapter);
这是我在后台收集信息的AsyncTask。在onPostExecute中，我将项目添加到我的列表中。
final ProgressDialog progDailog = new ProgressDialog(DashboardActivity.this);
class loadComments extends AsyncTask<JSONObject, String, JSONObject> {
@Override
protected void onPreExecute() {
super.onPreExecute();
progDailog.setIndeterminate(false);
progDailog.setCancelable(true);
progDailog.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);
progDailog.show();
progDailog.setContentView(R.layout.progress_circle);
}
@Override
protected void onProgressUpdate(String... values) {
super.onProgressUpdate(values);
}
protected JSONObject doInBackground(JSONObject... params) {
JSONObject json2 = CollectComments.collectComments(usernameforcomments, offsetNumber);
return json2;
}
@Override
protected void onPostExecute(JSONObject json2) {
try {
if (json2.getString(KEY_SUCCESS) != null) {
registerErrorMsg.setText("");
String res2 = json2.getString(KEY_SUCCESS);
if(Integer.parseInt(res2) == 1){
String username = json2.getString(KEY_USERNAME);
String number = json2.getString(KEY_NUMBER);
String content = json2.getString(KEY_COMMENT);
tempList.add (new Item (username, number, content));
customAdapter.addAll(tempList);
}//end if key is == 1
else{
// Error in registration
registerErrorMsg.setText(json2.getString(KEY_ERROR_MSG));
}//end else
}//end if
} //end try
catch (JSONException e) {
e.printStackTrace();
}//end catch
progDailog.dismiss();
}
}
new loadComments().execute();
在添加所有之前，请尝试清除适配器的内容