Android：使用ListView時在活動之間傳遞數據的最佳方式

Question

我有一個活動，名爲SearchActivity，其中ListView包含JSON下載的一部分數據（標題和距離）。我想顯示所有JSON數據並在另一個名爲ResultsActivity的活動中完成記錄。我知道如何從ListView本身獲取數據並將其傳遞給其他活動，但我不確定如何獲取所有數據以傳遞到第二個活動。

例如，我想爲onClickListener做一個查找到ArrayList中當前所選的項目，這樣我可以做這樣的事情：

in.putExtra（TAG_NAME，姓名）; in.putExtra（TAG_STREET，street）; in.putExtra（TAG_STREET，street）; 等。

問題是ListView中唯一顯示的是名稱和距離。我如何使用當前Listview選項獲取ArrayList條目，以便我可以顯示街道例如？

任何幫助表示讚賞。

SearchActivity.java 
package com.chance.squat; 

import com.chance.squat.R; 
import java.util.ArrayList; 
import java.util.HashMap; 
import org.json.JSONArray; 
import org.json.JSONException; 
import org.json.JSONObject; 

import android.app.Activity; 
import android.app.ListActivity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.util.Log; 
import android.view.View; 
import android.widget.AdapterView; 
import android.widget.AdapterView.OnItemClickListener; 
import android.widget.ImageView; 
import android.widget.ListAdapter; 
import android.widget.ListView; 
import android.widget.SimpleAdapter; 
import android.widget.TextView; 

public class SearchActivity extends ListActivity { 

    // url to make request 
    private static String url = "http://192.168.1.115:3000/bathrooms/nearby.json/?lat=45.580639&lon=-122.677682"; 

    // JSON Node names 
    private static final String TAG_BATHROOMS = "bathrooms"; 
    private static final String TAG_ID = "ID"; 
    private static final String TAG_ACCESS = "access"; 
    private static final String TAG_CITY = "city"; 
    private static final String TAG_COMMENT = "comment"; 
    private static final String TAG_DIRECTIONS = "directions"; 
    private static final String TAG_NAME = "name"; 
    private static final String TAG_STREET = "street"; 
    private static final String TAG_BATHROOMTYPE = "bathroomtype"; 
    private static final String TAG_DISTANCE = "distance"; 
    private static final String TAG_AVAIL = "avail"; 
    private static final String TAG_COUNTRY = "country"; 
    private static final String TAG_STATE = "state"; 
    private static final String TAG_POSTAL = "postal"; 

    // contacts JSONArray 
    JSONArray bathrooms = null; 

    @Override 
    public void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState);  
     setContentView(R.layout.activity_search); 

     // Hashmap for ListView 
     ArrayList<HashMap<String, String>> bathroomList = new ArrayList<HashMap<String, String>>(); 

     // Creating JSON Parser instance 
     JSONParser jParser = new JSONParser(); 

     // getting JSON string from URL 
     JSONObject json = jParser.getJSONFromUrl(url); 

     try { 
      // Getting Array of Contacts 
      bathrooms = json.getJSONArray(TAG_BATHROOMS); 

      // looping through All Contacts 
      for(int i = 0; i < bathrooms.length(); i++){ 
       JSONObject c = bathrooms.getJSONObject(i); 


       // Storing each json item in variable 
       String id = c.getString(TAG_ID); 
       String access = c.getString(TAG_ACCESS); 
       String city = c.getString(TAG_CITY); 
       String comment = c.getString(TAG_COMMENT); 
       String directions = c.getString(TAG_DIRECTIONS); 
       String name = c.getString(TAG_NAME); 
       String street = c.getString(TAG_STREET); 
       String bathroomtype = c.getString(TAG_BATHROOMTYPE);     
       String distance = c.getString(TAG_DISTANCE); 
       String distanceTrimmed = distance.substring(0,4) + " " + "miles away"; 
       String avail = c.getString(TAG_AVAIL); 
       String country = c.getString(TAG_COUNTRY); 
       String state = c.getString(TAG_STATE); 
       String postal = c.getString(TAG_POSTAL); 

       System.out.println(name); 

       // creating new HashMap 
       HashMap<String, String> map = new HashMap<String, String>(); 

       // adding each child node to HashMap key => value 
       map.put(TAG_ID, id); 
       map.put(TAG_ACCESS, access); 
       map.put(TAG_CITY, city); 
       map.put(TAG_COMMENT, comment); 
       map.put(TAG_DIRECTIONS, directions); 
       map.put(TAG_NAME, name); 
       map.put(TAG_STREET, street); 
       map.put(TAG_BATHROOMTYPE, bathroomtype); 
       map.put(TAG_DISTANCE, distanceTrimmed); 
       map.put(TAG_AVAIL, avail); 
       map.put(TAG_COUNTRY, country); 
       map.put(TAG_STATE, state); 
       map.put(TAG_POSTAL, postal); 

       // adding HashList to ArrayList 
       bathroomList.add(map); 
      } 
     } catch (JSONException e) { 
      e.printStackTrace(); 
     } 


     /** 
     * Updating parsed JSON data into ListView 
     * */ 

     ListAdapter adapter = new SimpleAdapter(this, bathroomList, 
       R.layout.list_item, 
       new String[] { TAG_NAME, TAG_DISTANCE}, new int[] { 
         R.id.name, R.id.distance }); 

     setListAdapter(adapter); 

     // selecting single ListView item 
     ListView lv = getListView(); 

     // Launching new screen on Selecting Single ListItem 
     lv.setOnItemClickListener(new OnItemClickListener() { 

      @Override 
      public void onItemClick(AdapterView<?> parent, View view, 
        int position, long id) { 
       // getting values from selected ListItem 
       //String name = ((TextView) view.findViewById(R.id.name)).getText().toString(); 
       //String distance = ((TextView) view.findViewById(R.id.distance)).getText().toString(); 


       // Starting new intent 
       //Intent in = new Intent(getApplicationContext(), SeachActivity.class); 
       //in.putExtra(TAG_NAME, name); 
       //in.putExtra(TAG_DISTANCE, distance); 
       //startActivity(in); 

      } 
     }); 


    } 

} 

Answer 1

Adapter getItem(position)

獲取與數據集的指定位置相關的數據項。

這是你在找什麼？

Answer 2

你可以在適配器上調用getItem。

或者，您可以創建自己的適配器，它可以從BaseAdapter擴展。在那裏您將完全控制要使用和返回的數據（使用getItem）。

此外，只要有可能，谷歌建議使用片段而不是活動。

Answer 3

您可以使用ListView適配器的onItemClickListener()方法從ListView中獲取特定的對象和值，該方法得到點擊。下一步是在ArrayList中搜索（假設您將完整的數據保存在ArrayList中），使用for loop。

例如，您可以從ListView中獲取標題字符串並在ArrayList中進行搜索。您需要訪問ListActivity中的ArrayList。如果無法訪問，請嘗試使用捆綁包，或者如果數據經常用於兩個以上的活動，則還可以使用靜態類來存儲數據。

Answer 4

嘗試才能得到選擇的列表項的ArrayList：

lv.setOnItemClickListener(new OnItemClickListener() { 

@Override 
    public void onItemClick(AdapterView<?> parent, View view, 
       int position, long id) { 
    // getting values from selected ListItem 
    ArrayList<HashMap<String, String>> arrhashmap= 
      (ArrayList<HashMap<String, String>>) lv.getItemAtPosition(position); 

    // Starting new intent 
    Intent in = new Intent(getApplicationContext(), SeachActivity.class); 
    in.putExtra("arralsthasmap", arrhashmap); 
    startActivity(in); 

} }）;

和其他活動取得的ArrayList爲：

ArrayList<HashMap<String, String>> arrhashmap 
         =(ArrayList<HashMap<String, String>>) 
      getIntent().getSerializableExtra("arralsthasmap");