我有一个自定义 BaseAdapter 类,它为评论、用户名和数字创建视图。此 BaseAdapter 从 An AsyncTask 接收此信息。当用户到达 listView 的底部时,AsyncTask 运行。问题是 BaseAdapter 不会添加新数据。当我尝试添加新数据时,它会删除列表中的当前数据,然后添加新数据。我希望它保留所有数据,并将数据添加到 listView 的底部。所有这些类都在同一个活动中。这是我当前的代码。
class CreateCommentLists extends BaseAdapter{
Context ctx_invitation;
String[] listComments;
String[] listNumbers;
String[] listUsernames;
public CreateCommentLists(String[] comments, String[] usernames, String[] numbers, DashboardActivity context)
{
super();
ctx_invitation = context;
listComments = comments;
listNumbers = usernames;
listUsernames = numbers;
}
@Override
public int getCount() {
if(null == listComments)
{
return 0;
}
// TODO Auto-generated method stub
return listComments.length;
}
@Override
public Object getItem(int position) {
// TODO Auto-generated method stub
return listComments[position];
}
@Override
public long getItemId(int position) {
// TODO Auto-generated method stub
return 0;
}
@Override
public View getView(final int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
View v = null;
try
{
String inflater = Context.LAYOUT_INFLATER_SERVICE;
LayoutInflater li = (LayoutInflater)ctx_invitation.getSystemService(inflater);
v = li.inflate(R.layout.list_item, null);
TextView commentView = (TextView)v.findViewById(R.id.listComment);
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(listComments[position]);
NumbersView.setText(listNumbers[position]);
usernamesView.setText(listUsernames[position]);
usernameButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent i = new Intent(getApplicationContext(), ProfileActivity.class);
i.putExtra("usernameOfProfile",listUsernames[position]);
startActivity(i);
finish();
}
});
numberButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
Intent i = new Intent(getApplicationContext(), ProfileActivity.class);
i.putExtra("NumberProfile",listNumbers[position]);
startActivity(i);
finish();
}
});
}
catch(Exception e)
{
e.printStackTrace();
}
return v;
}
public void add(String[] comments, String[] usernames,
String[] numbers) {
listComments = comments;
listNumbers = usernames;
listUsernames = numbers;
}
public int getCount1() {
if(null == listComments)
{
return 0;
}
// TODO Auto-generated method stub
return listComments.length;
}
public Object getItem1(int position) {
// TODO Auto-generated method stub
return listComments[position];
}
public long getItemId1(int position) {
// TODO Auto-generated method stub
return 0;
}
public View getView1(final int position, View convertView, ViewGroup parent) {
// TODO Auto-generated method stub
View v = null;
try
{
String inflater = Context.LAYOUT_INFLATER_SERVICE;
LayoutInflater li = (LayoutInflater)ctx_invitation.getSystemService(inflater);
v = li.inflate(R.layout.list_item, null);
TextView commentView = (TextView)v.findViewById(R.id.listComment);
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(listComments[position]);
NumbersView.setText(listNumbers[position]);
usernamesView.setText(listUsernames[position]);
usernameButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Intent i = new Intent(getApplicationContext(), ProfileActivity.class);
i.putExtra("usernameOfProfile",listUsernames[position]);
startActivity(i);
finish();
}
});
numberButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View arg0) {
Intent i = new Intent(getApplicationContext(), ProfileActivity.class);
i.putExtra("NumberProfile",listNumbers[position]);
startActivity(i);
finish();
}
});
}
catch(Exception e)
{
e.printStackTrace();
}
return v;
}
final CreateCommentLists mycmlist = new CreateCommentLists(comments, usernames, numbers, DashboardActivity.this);
lstComments = (ListView)findViewById(android.R.id.list);
lstComments.setAdapter(mycmlist);
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){
JSONArray commentArray = json2.getJSONArray(KEY_COMMENT);
String comments[] = new String[commentArray.length()];
for ( int i=0; i<commentArray.length(); i++ ) {
comments[i] = commentArray.getString(i);
}
JSONArray numberArray = json2.getJSONArray(KEY_NUMBER);
String numbers[] = new String[numberArray.length()];
for ( int i=0; i<numberArray.length(); i++ ) {
numbers[i] = numberArray.getString(i);
}
JSONArray usernameArray = json2.getJSONArray(KEY_USERNAME);
String usernames[] = new String[usernameArray.length()];
for ( int i=0; i<usernameArray.length(); i++ ) {
usernames[i] = usernameArray.getString(i);
}
mycmlist.add(comments,usernames,numbers);
mycmlist.notifyDataSetChanged();
}//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();
}
}
mainListView = (ListView) findViewById(android.R.id.list);
class EndlessScrollListener implements OnScrollListener {
private int i = 0;
private int visibleThreshold = 5;
private int previousTotal = 0;
private boolean loading = true;
public EndlessScrollListener() {
}
public EndlessScrollListener(int visibleThreshold) {
this.visibleThreshold = visibleThreshold;
}
@Override
public void onScroll(AbsListView view, int firstVisibleItem,
int visibleItemCount, int totalItemCount) {
if ((firstVisibleItem + visibleItemCount) == totalItemCount) {
new loadComments().execute();
mainListView.smoothScrollToPosition(0);
}
}
@Override
public void onScrollStateChanged(AbsListView view, int scrollState) {
}
}
mainListView.setOnScrollListener(new EndlessScrollListener());