Android Listview顯示重複條目

Question

我試圖顯示從列表視圖中的json數組的值。但它顯示了所有列表視圖按鈕中的重複條目。這裏是我的代碼

MenuFragment：

JSONObject json = jParser.makeHttpRequest(CommonUtilities.SERVERURL_GET_MENUS, "GET", params); 
      SUCCESS = json.getString(TAG_SUCCESS); 
      if (SUCCESS.equalsIgnoreCase("false")) { 
       JSONArray jsonarrays = json.getJSONArray("sub_menus"); 
       HashMap<String, String> sb = new HashMap<String, String>(); 
       for (int k = 0; k < jsonarrays.length(); k++) { 
        JSONObject main_menus = jsonarrays.getJSONObject(k); 
        SUB_MENU_ID = main_menus.getString("sub_menu_id"); 
        SUB_MENU_NAME = main_menus.getString("sub_menu_name"); 
        sb.put(SUB_MENU_ID, SUB_MENU_NAME); 
        submenus.add(sb); 
       } } 

    protected void onPostExecute(String result) { 
     try { 
     submenuadapter=new SubmenuCategoryAdapter(submenus,getActivity()); 
     sb_list.setAdapter(submenuadapter); 
     } 

SubmenuCategoryAdapter：

適配器包含按鈕顯示列表值。

public class SubmenuCategoryAdapter extends BaseAdapter { 
    ArrayList<HashMap<String, String>> mainmenu; 
    HashMap<String, String> mainmenumap = new HashMap<String, String>(); 
    Context con; 
    public SubmenuCategoryAdapter(ArrayList<HashMap<String, String>> mainmenu, Context con) { 
     super(); 
     this.mainmenu = mainmenu; 
     this.con = con; 
    } 
    @Override 
    public int getCount() { 
     return mainmenu.size(); 
    } 
    @Override 
    public Object getItem(int position) { 
     return position; 
    } 
    @Override 
    public long getItemId(int position) { 
     return position; 
    } 
    @SuppressLint("ViewHolder") 
    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     final Holder holder = new Holder(); 
     LayoutInflater layoutInflater = (LayoutInflater) con.getSystemService(Context.LAYOUT_INFLATER_SERVICE); 
     mainmenumap = mainmenu.get(position); 
     View submenuview = layoutInflater.inflate(R.layout.submenu_button, null); 
     holder.submenu_btn=(Button)submenuview.findViewById(R.id.submenu_layout_button); 
     String btn_name=mainmenu.get(position).toString(); 
     holder.submenu_btn.setText(btn_name); 
     return submenuview; 
    } 
    public class Holder { 
     Button submenu_btn; 
    } 
} 

Answer 1

更改getView方法如下

@Override 
public View getView(int position, View convertView, ViewGroup parent) { 
    Holder viewHolder;  
    if(convertView == null){ 
     convertView = LayoutInflater.from(parent.getContext()) 
            .inflate(R.layout.submenu_button, parent, false); 
     viewHolder = new Holder(); 
     viewHolder.submenu_btn = (Button) convertView 
             .findViewById(R.id.submenu_layout_button); 
     convertView.setTag(viewHolder); 
    } else { 
     viewHolder = (Holder) convertView.getTag(); 
    } 

    String btn_name=mainmenu.get(position).toString(); 
    viewHolder.submenu_btn.setText(btn_name); 
    return convertView; 
} 

UPDATE

要回答你的第二個問題的意見，你爲什麼要使用包含HashMap的ArrayList的我不知道。爲什麼不使用普通的java對象？我顯示下面我將如何使用POJO（普通Java對象）做

創建一個POJO描述你的菜單項

public class MenuItem { 
    public int MenuId; 
    public String MenuName; 
} 

MenuFragment

//initialize submenus 
List<MenuItem> submenus = new ArrayList<>(); 

JSONArray jsonarrays = json.getJSONArray("sub_menus"); 
for (int k = 0; k < jsonarrays.length(); k++) { 
    JSONObject main_menus = jsonarrays.getJSONObject(k); 
    MenuItem item = new MenuItem(); 
    item.MenuId = main_menus.getInt("sub_menu_id"); 
    item.MenuName = main_menus.getString("sub_menu_name"); 
    submenus.add(item); 
} 

//initializing adapter 
submenuadapter = new SubmenuCategoryAdapter(submenus, getActivity()); 
sb_list.setAdapter(submenuadapter); 

適配器類

public class SubmenuCategoryAdapter extends BaseAdapter { 
    List<MenuItem> mainmenu; 
    Context con; 
    public SubmenuCategoryAdapter(List<MenuItem> mainmenu, Context con) { 
     super(); 
     this.mainmenu = mainmenu; 
     this.con = con; 
    } 

    .... 

    @Override 
    public View getView(int position, View convertView, ViewGroup parent) { 
     Holder viewHolder;  
     if(convertView == null){ 
      convertView = LayoutInflater.from(parent.getContext()) 
            .inflate(R.layout.submenu_button, parent, false); 
      viewHolder = new Holder(); 
      viewHolder.submenu_btn = (Button) convertView 
             .findViewById(R.id.submenu_layout_button); 
      convertView.setTag(viewHolder); 
     } else { 
      viewHolder = (Holder) convertView.getTag(); 
     } 

     String btn_name = mainmenu.get(position).MenuName; 
     viewHolder.submenu_btn.setText(btn_name); 
     return convertView; 
    } 

}