我目前有一个从用户输入创建URL的方法，发送HTTP请求以获取JSONArray，然后将JSONArray转换为ArrayList。由于某些原因，用于添加每个JSONObject之一的循环仅复制相同的10次，尽管循环计数器并不告诉它这样做。显然我错过了一些东西，但下面是代码：
MainActivity
public ArrayList<Eatery> fillArray(String url) {
String line;
Eatery eatery = new Eatery("null","null","null","null","null",
"null","null","null","null","null");
ArrayList<Eatery> eateryList = new ArrayList<>();
if (getConnection() == true) {
try {
URL urlFinal = createURL(url);
HttpURLConnection postcodeConnection = (HttpURLConnection) urlFinal.openConnection();
InputStreamReader isr = new InputStreamReader(postcodeConnection.getInputStream());
BufferedReader bf = new BufferedReader(isr);
while ((line = bf.readLine()) != null) {
JSONArray ja = new JSONArray(line);
for (int i = 0; i < ja.length(); i++) {
JSONObject jo = ja.getJSONObject(i);
String id = jo.getString("id");
String businessName = jo.getString("BusinessName");
String addressLine1 = jo.getString("AddressLine1");
String addressLine2 = jo.getString("AddressLine2");
String addressLine3 = jo.getString("AddressLine3");
String postcode = jo.getString("PostCode");
String ratingValue = jo.getString("RatingValue");
String ratingDate = jo.getString("RatingDate");
String lati = jo.getString("Latitude");
String longi = jo.getString("Longitude");
eatery.setId(id);
eatery.setBusinessName(businessName);
eatery.setAddressLine1(addressLine1);
eatery.setAddressLine2(addressLine2);
eatery.setAddressLine3(addressLine3);
eatery.setPostcode(postcode);
eatery.setRatingValue(ratingValue);
eatery.setRatingDate(ratingDate);
eatery.setLati(lati);
eatery.setLati(longi);
eateryList.add(eatery);
}
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}catch (IndexOutOfBoundsException e){
Toast nameToast = Toast.makeText(getApplicationContext(), "Invalid search", Toast.LENGTH_LONG);
nameToast.show();
}
} else {
Toast nameToast = Toast.makeText(getApplicationContext(), "Error: No Active Connection", Toast.LENGTH_LONG);
nameToast.show();
}
return (eateryList);
}
内部方法：
public boolean getConnection(){
conMgr = (ConnectivityManager) getSystemService(Context.CONNECTIVITY_SERVICE);
networkInfo = conMgr.getActiveNetworkInfo();
boolean connected;
if(networkInfo != null && networkInfo.isConnected())
{
connected = true;
}
else
{
connected = false;
}
return connected;
}
public URL createURL(String searchType) {
String URLstart = "http://sandbox.kriswelsh.com/hygieneapi/hygiene.php?op=";
searchType = searchType.replace(" ", "%20");
String finalURL = URLstart.concat(searchType);
URL nameURL = null;
try {
nameURL = new URL(finalURL);
} catch (MalformedURLException e) {
e.printStackTrace();
}
return nameURL;
}
以上是在ActivityMain中，目前正在从一个片段中调用，该片段从EditText框中获取用户输入，将其添加到fillArray方法，然后将结果返回到Fragment上实例化的另一个ArrayList。
下面的片段代码：
public class NameFragment extends Fragment {
EditText enterName;
Button searchNameButton;
TableLayout nameTableLayout;
TextView testTextView, tv;
TableRow tr;
ArrayList<Eatery> nameEateryList;
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.name_search_fragment, container, false);
enterName = (EditText) rootView.findViewById(R.id.enterNameText);
searchNameButton = (Button)rootView.findViewById(R.id.searchNameButton);
testTextView = (TextView)rootView.findViewById(R.id.testTextView);
nameTableLayout = (TableLayout)rootView.findViewById(R.id.NameTableLayout);
searchNameButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String nameSearch = enterName.getText().toString().trim();
String nameURLKey = "s_name&name=";
nameURLKey = nameURLKey.concat(nameSearch);
//Grab ArrayList
nameEateryList = ((MainActivity)getActivity()).fillArray(nameURLKey);
for(int i = 0; i < nameEateryList.size(); i++) {
tv = new TextView(getActivity().getApplicationContext());
tr = new TableRow(getActivity().getApplicationContext());
//Create Table Counter
int turn = nameTableLayout.getChildCount();
turn += 1;
String turnString = turn + "";
//Add TextView
tv.setText(nameEateryList.get(i).eateryToString());
tv.setPadding(15, 15, 15, 15);
tr.setPadding(5,5,5,5);
tv.setBackgroundColor(Color.parseColor("#557788"));
tv.setTextAlignment(View.TEXT_ALIGNMENT_TEXT_START);
tr.addView(tv);
nameTableLayout.addView(tr);
}
}
});
return rootView;
}
出于某种原因，当这循环通过ArrayList并将结果复制到我的片段中时，所有结果都是相同的。代码运行并且ArrayList被填充但似乎无法遍历ArrayList。已经坚持了一段时间，但我无法弄清楚是什么导致ArrayList重复复制同一个对象而不是循环遍历所有结果。我希望这是有道理的。如果需要任何进一步的信息，那么我当然可以提供更多的代码。这是一个非常具体的问题，我无法确定另一个有这个问题的线程，如果这个答案存在于其他地方，我会道歉。
答案 0 :(得分：0)
为for循环的每次迭代创建一个新的Eatery对象，如下所示：
for (int i = 0; i < ja.length(); i++) {
Eatery eatery = new Eatery("null","null","null","null","null",
"null","null","null","null","null");
JSONObject jo = ja.getJSONObject(i);
String id = jo.getString("id");
String businessName = jo.getString("BusinessName");
String addressLine1 = jo.getString("AddressLine1");
String addressLine2 = jo.getString("AddressLine2");
String addressLine3 = jo.getString("AddressLine3");
String postcode = jo.getString("PostCode");
String ratingValue = jo.getString("RatingValue");
String ratingDate = jo.getString("RatingDate");
String lati = jo.getString("Latitude");
String longi = jo.getString("Longitude");
eatery.setId(id);
eatery.setBusinessName(businessName);
eatery.setAddressLine1(addressLine1);
eatery.setAddressLine2(addressLine2);
eatery.setAddressLine3(addressLine3);
eatery.setPostcode(postcode);
eatery.setRatingValue(ratingValue);
eatery.setRatingDate(ratingDate);
eatery.setLati(lati);
eatery.setLati(longi);
eateryList.add(eatery);
}
您面临的问题是因为您为每个循环迭代仅向列表中添加一个对象，该对象的值将是您为Eatery对象设置的最后一个值。
希望这有帮助！