在arraylist中保存所選列表項

Question

我有一個listview顯示webservice的名稱和json web響應中的名稱也是user_id。我使用pojo作爲名字和user_id的getter和setter。我想過濾所選列表視圖的名稱和它們的user_id，並將user_id保存在一個數組列表中。

活動：

public class InvitedMembers extends AppCompatActivity{ 


    Button invite; 
    private ListView mListView; 
    private GridItem newItem; 
    private ListAdapter mListAdapter; 
    private ArrayList<GridItem> mGridData; 
    private static final String FETCH_FOLLOWING = "http://www.example.com/api/member/get-followings/", KEY_USERID = "user_id"; 


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


     invite = (Button)findViewById(R.id.btn_invite); 

     mListView = (ListView)findViewById(R.id.list_view); 
     mGridData = new ArrayList<>(); 
     mListAdapter = new ListAdapter(InvitedMembers.this, R.layout.listrow, mGridData); 
     mListView.setAdapter(mListAdapter); 
     mListView.setEmptyView(findViewById(R.id.empty)); 
     mListView.setChoiceMode(ListView.CHOICE_MODE_MULTIPLE); 


     loadfollowinglist(); 

     invite.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 

       /* SparseBooleanArray checked = mListView.getCheckedItemPositions(); 

       for (int i = 0; i < mListView.getAdapter().getCount(); i++) { 
        if (checked.get(i)) { 
         ArrayList<String> newList = new ArrayList<String>(); 
        } 
       } */ 


        // Here I want to fetch the user_id's of the selected names. 


      } 
     }); 
    } 



    private void loadfollowinglist(){ 
     StringRequest stringRequest = new StringRequest(Request.Method.POST, FETCH_FOLLOWING, 
       new Response.Listener<String>() { 
        @Override 
        public void onResponse(String response) { 

         try { 
          JSONObject jObj = new JSONObject(response); 

          System.out.println(jObj); 

          String status = jObj.getString("status"); 

          // Now check status value 
          if (status.equals("0")) { 
           Toast.makeText(getApplicationContext(), "There was some error! Please try again.", Toast.LENGTH_LONG).show(); 
          } else if (status.equals("1")) { 

           JSONArray result = jObj.getJSONArray("result"); 
           for (int i = 0; i < result.length(); i++) { 
            JSONObject json_data = result.getJSONObject(i); 
            String name = json_data.getString("name"); 
            String regtdemail = json_data.getString("username"); 
            String user_id = json_data.getString("user_id"); 

            newItem = new GridItem(); 

            newItem.setName(name); 
            newItem.setRegtdEmail(regtdemail); 
            newItem.setUserId(user_id); 
            if(json_data.has("profile_picture")){ 

             newItem.setImage(json_data.getString("profile_picture")); 

            }else{ 

             Uri path = Uri.parse("android.resource://com.example.sam.fitlincevent/" + R.drawable.default_profile); 
             String image_def = path.toString(); 
             newItem.setImage(image_def); 

            } 


            mGridData.add(newItem); 
           } 


           mListAdapter.notifyDataSetChanged(); 


          } else { 
           // Error in login. Get the error message 
           String errorMsg = jObj.getString("error_msg"); 
           Toast.makeText(getApplicationContext(), errorMsg, Toast.LENGTH_LONG).show(); 
          } 
         } catch (JSONException e) { 
          // JSON error 
          e.printStackTrace(); 
          Toast.makeText(getApplicationContext(), "Json error: " + e.getMessage(), Toast.LENGTH_LONG).show(); 
         } 
        } 
       }, new Response.ErrorListener() { 
      @Override 
      public void onErrorResponse(VolleyError error) { 
       Toast.makeText(getApplicationContext(), error.toString(), Toast.LENGTH_LONG).show(); 
      } 
     }) { 
      @Override 
      protected Map<String, String> getParams() { 
       Map<String, String> params = new HashMap<String, String>(); 
       params.put(KEY_USERID, "1"); //get user_id from SQLite database. 
       return params; 
      } 

     }; 

     RequestQueue requestQueue = Volley.newRequestQueue(getApplicationContext()); 
     requestQueue.add(stringRequest); 
    } 
} 

Listadapter：

public class ListAdapter extends ArrayAdapter<GridItem> { 



    private Context mContext; 
    int resource; 
    private ArrayList<GridItem> mListData = new ArrayList<GridItem>(); 

    public ListAdapter(Context mContext, int resource, ArrayList<GridItem> mListData) { 
     super(mContext, resource, mListData); 
     this.resource = resource; 
     this.mContext = mContext; 
     this.mListData = mListData; 
    } 

    public void setListData(ArrayList<GridItem> mListData) { 
     this.mListData = mListData; 
     notifyDataSetChanged(); 
    } 




    @Override 
    public GridItem getItem(int position) { 
     return super.getItem(position); 
    } 



    @Override 
    public View getView(final int position, View convertView, ViewGroup parent) { 
     View v = convertView; 

     ViewHolder holder; 
     if (v == null) { 
      holder = new ViewHolder(); 
      LayoutInflater inflater = ((Activity) mContext).getLayoutInflater(); 

      v = inflater.inflate(resource, parent, false); 
      holder.image = (ImageView) v.findViewById(R.id.item_image); 
      holder.name = (TextView) v.findViewById(R.id.item_name); 
      holder.regtdemail = (TextView) v.findViewById(R.id.item_regtdemail); 
      holder.checkBox = (CheckBox)v.findViewById(R.id.checkBox); 


      v.setTag(holder); 

     } else { 
      holder = (ViewHolder) v.getTag(); 
     } 

     GridItem item = mListData.get(position); 
     Picasso.with(mContext) 
       .load(item.getImage()) 
       .placeholder(R.drawable.placeholder) 
       .fit() 
       .into(holder.image); 
     holder.name.setText(item.getName()); 
     holder.regtdemail.setText(item.getRegtdEmail()); 




     return v; 
    } 

    class ViewHolder { 
     ImageView image; 
     TextView name, regtdemail; 
     CheckBox checkBox; 
    } 

} 

POJO的：

public class GridItem { 
    private String nameUrls, imageUrls, userIdUrls, regtdEmailUrls, sportsIdUrls; 
    private boolean selected; 

    public GridItem() { 
     super(); 
    } 

    public String getImage() { 
     return imageUrls; 
    } 

    public void setImage(String imageUrls) { 
     this.imageUrls = imageUrls; 
    } 

    public String getName() { 
     return nameUrls; 
    } 

    public void setName(String nameUrls) { 
     this.nameUrls = nameUrls; 
    } 


    public String getRegtdEmail(){ 
     return regtdEmailUrls; 
    } 

    public void setRegtdEmail(String regtdEmailUrls){ 
     this.regtdEmailUrls = regtdEmailUrls; 
    } 


    public String getUserId(){ 
     return userIdUrls; 
    } 

    public void setUserId(String userIdUrls){ 
     this.userIdUrls = userIdUrls; 
    } 

    public String getSportsId() { return sportsIdUrls; } 

    public void setSportsId(String sportsIdUrls) { this.sportsIdUrls = sportsIdUrls; } 


} 

Answer 1

使用SparseBooleanArray.get返回boolean

你需要檢查它的每個位置在列表中

int length = listView.getCount(); 
SparseBooleanArray checked = listView.getCheckedItemPositions(); 
for (int i = 0; i < length; i++) 
if (checked.get(i)) { 
String item = list.get(i); 

/* do your code with the checked item */ 
}