Question

我的代码从服务器获取数据并在listview中显示第一个加载，listview显示10个项目，我去点击更多按钮，它添加10个新项目列表，显示20个项目怎么做??

我的代码我的问题是当点击更多按钮时显示10个新项目和旧项目错过了如何解决它

public class Main extends ListActivity {

String[] id,name,content,commentcount,purl,views;
String tid,tname,tcontent,tcomment,tpurl,tviews;

private int count;
private int cpage=1;
private double apage;
private String res="";
private ImageView more;
private Bitmap[] img;   

public static String url="http:...";
private ProgressDialog pr;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);        

    more=(ImageView) findViewById(R.id.main_next_page);
    new getpost().execute();        

    more.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View arg0) {
            if(cpage==apage){                   
            }else{                  
                cpage++;
                new getpost().execute();                    
            }               
        }
    });       
}    

@Override
protected void onListItemClick(ListView l, View v, int position, long idt) {        
    Intent i=new Intent(Main.this,post.class);
    i.putExtra("id",Integer.parseInt(id[position]));
    startActivity(i);       
}    

private void makearray(int c){

    id=new String[c];
    name=new String[c];
    content=new String[c];
    commentcount=new String[c];
    purl=new String[c];
    views=new String[c];
    img=new Bitmap[c];
    Arrays.fill(name, "");

    Bitmap temp=BitmapFactory.decodeResource(getResources(), R.drawable.a);
    Arrays.fill(img, temp);     
}

/////////////////////////////////get data from server//////////////////////////////
public class getpost extends AsyncTask{     

    @Override
    protected void onPreExecute() {
        // TODO Auto-generated method stub
        super.onPreExecute();

        pr=ProgressDialog.show(Main.this, "wait...");
        more.setVisibility(View.INVISIBLE);         
    }

    @Override
    protected Object doInBackground(Object... arg0) {
        // TODO Auto-generated method stub          

        try{
            String data=URLEncoder.encode("page","utf8")+"="+URLEncoder.encode(cpage+"","utf8");

            URL link=new URL(url+"get_list_post.php");
            URLConnection connect=link.openConnection();                

            //send data
            connect.setDoOutput(true);
            OutputStreamWriter wr=new OutputStreamWriter(connect.getOutputStream());
            wr.write(data);
            wr.flush();

            BufferedReader reader=new BufferedReader(new InputStreamReader(connect.getInputStream()));

            StringBuilder sb=new StringBuilder();               
            String line=null;

            while((line=reader.readLine()) != null){                    
                sb.append(line);                    
            }                           

            res=sb.toString();              

            for(int y=0;y<4;y++){
                if(res.charAt(y)=='☻'){
                    count=Integer.parseInt(res.substring(0, y));
                    res=res.substring(y+1);
                    break;
                }
            }

            for(int y=0;y<4;y++){
                if(res.charAt(y)=='☻'){
                    apage=Integer.parseInt(res.substring(0, y));
                    res=res.substring(y+1);
                    break;
                }
            }
            makearray(count);           

            int f=0,c=0;

            for(int i=0;i<res.length();i++){
                if(res.charAt(i)=='☻'){
                    String temp=res.substring(f,i);

                    if(c==0){                           
                        tid=temp;                           
                    }
                    if(c==1){                           
                        tname=temp;                         
                    }
                    if(c==2){                           
                        tcontent=temp;                          
                    }
                    if(c==3){                           
                        tcomment=temp;                          
                    }
                    if(c==4){                           
                        tviews=temp;                            
                    }
                    if(c==5){                           
                        tpurl=temp;                         

                        for(int t=0;t<count;t++){
                            if(name[t].equals("")){
                                id[t]=tid;
                                name[t]=tname;
                                content[t]=tcontent;
                                commentcount[t]=tcomment;
                                purl[t]=tpurl;
                                views[t]=tviews;
                                new getimage(tpurl,t).execute();
                                break;
                            }
                        }
                        c=-1;
                    }

                    f=i+1;
                    c+=1;
                }
            }               
        }catch(Exception e){                
            res=e.toString();               
        }

        return "";
    }       

    @Override
    protected void onPostExecute(Object result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);            

        if(res.substring(0, 2).toString().equals("ja")  || res.substring(0, 2).toString().equals("<b") ){

            Toast.makeText(getApplicationContext(), "conection failed", Toast.LENGTH_LONG).show();
            pr.dismiss();

        }else{              
            apage= Math.ceil(apage/10);

            pr.dismiss();
            more.setVisibility(View.VISIBLE);

            setListAdapter(new IA());               
        }           
    }       
}

public class getimage extends AsyncTask<String,Void,Bitmap>{

    private String url;
    private int p;
    public getimage(String u,int P){

        url=u;
        p=P;
    }       

    @Override
    protected Bitmap doInBackground(String... arg0) {
        // TODO Auto-generated method stub

        Bitmap temp=null;   

        try{                
            InputStream in=new java.net.URL(url).openStream();
            temp=BitmapFactory.decodeStream(in);

        }catch(Exception e){            
        }

        return temp;
    }       

    protected void onPostExecute(Bitmap result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);
        if(result != null){
            img[p]=result;
        }
        if(p==0 || p==1 || p==2 || p==3){

            setListAdapter(new IA());
        }           
    }       
}   

///////////////////////////////fill list////////////////////////////////////////
class IA extends ArrayAdapter<String>{

    public IA() {
        super(Main.this, R.layout.row_main,name);           
    }   

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {                     
        LayoutInflater in=getLayoutInflater();
        View row=in.inflate(R.layout.row_main, parent,false);

        TextView titr=(TextView) row.findViewById(R.id.row_main_titr);
        TextView matn=(TextView) row.findViewById(R.id.row_main_content);
        TextView extra=(TextView) row.findViewById(R.id.row_main_extra);
        ImageView image=(ImageView) row.findViewById(R.id.row_main_image);

        ViewGroup.LayoutParams paramsi = image.getLayoutParams();
        paramsi.height= (W/2)-10;
        image.setLayoutParams(paramsi);         

        image.setImageBitmap(img[position]);            
        titr.setTextSize((float)W/30);          
        titr.setText(name[position]);
        matn.setText(Html.fromHtml(content[position]).toString().replace("•", "\n"));
        extra.setText("comments: "+commentcount[position] +"    "+"views:"+views[position]);
        titr.setTypeface(yekan);

        matn.setTypeface(yekan);
        extra.setTypeface(Main.koodak);         

        return (row);
    }       
}

Answer 1

问题是你的setListAdapter，因为它的参数总是IA（（）类的新等。

你必须在onCreate（）的开头创建一次ListView，你的适配器和一个ArrayList，然后像这样设置适配器 listView.setAdapter（适配器）; 在此之后，您可以调用所需的每个Asynctask或线程以获取新数据，并将其添加到现有的arraylist中。然后调用adapter.notifyDataSetChanged（）。

在单击按钮中将新项添加到listview

1 个答案: