Java 每次我获取pdf文件时,我的ArrayAdapter堆栈
每当单击按钮获取文件时,我需要有关如何刷新ArrayAdapter的帮助。它继续堆积新列表,而不清除最后一个列表。请帮忙,也不要介意我的英语 这是我的阵列适配器Java 每次我获取pdf文件时,我的ArrayAdapter堆栈,java,android,android-arrayadapter,Java,Android,Android Arrayadapter,每当单击按钮获取文件时,我需要有关如何刷新ArrayAdapter的帮助。它继续堆积新列表,而不清除最后一个列表。请帮忙,也不要介意我的英语 这是我的阵列适配器 public View getView(int position, View convertView, ViewGroup parent) { View row = convertView; PdfHolder holder = null; if(row == null) { Layou
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
PdfHolder holder = null;
if(row == null)
{
LayoutInflater inflater=LayoutInflater.from(activity);
row = inflater.inflate(layoutResourceId,parent,false);
holder = new PdfHolder();
holder.textViewName = (TextView) row.findViewById(R.id.textViewName);
holder.textViewUrl = (TextView) row.findViewById(R.id.textViewUrl);
row.setTag(holder);
}
else
{
holder= (PdfHolder) row.getTag();
}
pdf = data.get(position);
holder.textViewName.setText(pdf.getName());
holder.textViewUrl.setText(pdf.getUrl());
return row;
}
class PdfHolder
{
TextView textViewName,textViewUrl;
}
private void getPdfs() {
progressDialog.setMessage("Fetching pdfs from server...");
progressDialog.show();
StringRequest stringRequest = new StringRequest(Request.Method.POST, PDF_FETCH_URL,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
progressDialog.dismiss();
try {
JSONObject obj = new JSONObject(response);
Toast.makeText (Files.this,obj.getString("message"), Toast.LENGTH_SHORT).show();
JSONArray jsonArray = obj.getJSONArray("pdfs");
for(int i=0;i<jsonArray.length();i++){
JSONObject jsonObject = jsonArray.getJSONObject(i);
Pdf pdf = new Pdf();
String pdfName = jsonObject.getString("name");
String pdfUrl = jsonObject.getString("url");
pdf.setName(pdfName);
pdf.setUrl(pdfUrl);
pdfList.add(pdf);
}
pdfAdapter = new PdfAdapter(Files.this, R.layout.list_layout, pdfList);
listView.setAdapter(pdfAdapter);
pdfAdapter.notifyDataSetChanged();
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
}
);
RequestQueue request = Volley.newRequestQueue(this);
request.add(stringRequest);
}
这是我从实时服务器获取文件的代码
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
PdfHolder holder = null;
if(row == null)
{
LayoutInflater inflater=LayoutInflater.from(activity);
row = inflater.inflate(layoutResourceId,parent,false);
holder = new PdfHolder();
holder.textViewName = (TextView) row.findViewById(R.id.textViewName);
holder.textViewUrl = (TextView) row.findViewById(R.id.textViewUrl);
row.setTag(holder);
}
else
{
holder= (PdfHolder) row.getTag();
}
pdf = data.get(position);
holder.textViewName.setText(pdf.getName());
holder.textViewUrl.setText(pdf.getUrl());
return row;
}
class PdfHolder
{
TextView textViewName,textViewUrl;
}
private void getPdfs() {
progressDialog.setMessage("Fetching pdfs from server...");
progressDialog.show();
StringRequest stringRequest = new StringRequest(Request.Method.POST, PDF_FETCH_URL,
new Response.Listener<String>() {
@Override
public void onResponse(String response) {
progressDialog.dismiss();
try {
JSONObject obj = new JSONObject(response);
Toast.makeText (Files.this,obj.getString("message"), Toast.LENGTH_SHORT).show();
JSONArray jsonArray = obj.getJSONArray("pdfs");
for(int i=0;i<jsonArray.length();i++){
JSONObject jsonObject = jsonArray.getJSONObject(i);
Pdf pdf = new Pdf();
String pdfName = jsonObject.getString("name");
String pdfUrl = jsonObject.getString("url");
pdf.setName(pdfName);
pdf.setUrl(pdfUrl);
pdfList.add(pdf);
}
pdfAdapter = new PdfAdapter(Files.this, R.layout.list_layout, pdfList);
listView.setAdapter(pdfAdapter);
pdfAdapter.notifyDataSetChanged();
} catch (JSONException e) {
e.printStackTrace();
}
}
},
new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
}
}
);
RequestQueue request = Volley.newRequestQueue(this);
request.add(stringRequest);
}
private void getPdfs(){
setMessage(“正在从服务器获取PDF…”);
progressDialog.show();
StringRequest StringRequest=新的StringRequest(Request.Method.POST,PDF\u FETCH\u URL,
新的Response.Listener(){
@凌驾
公共void onResponse(字符串响应){
progressDialog.disclose();
试一试{
JSONObject obj=新的JSONObject(响应);
Toast.makeText(Files.this,obj.getString(“message”),Toast.LENGTH_SHORT.show();
JSONArray JSONArray=obj.getJSONArray(“PDF”);
对于(int i=0;i,每次加载新数据时,您都将新的pdf
s添加到同一列表中
要解决这个问题,在
for(int i=0;i<jsonArray.length();i++){
您正在通过internet下载数据吗?如果您这样做,那么您的问题可能是由于您的应用程序冻结而在主线程中下载数据。或者您如何填充适配器?问题不在代码的这一部分。此代码没有显示问题。您如何将适配器连接到列表视图?您如何填充适配器?@Yupi是的,我得到了来自我的live的文件server@davidxxx我正在使用arraylist Sir在获取新数据时是否清除pdfList(或创建新的pdfList)?如果是类变量,则使用pdfList.add(pdf)将新对象添加到旧列表中;