我正在制作搜索功能，当用户在edittext中输入名称时，会向网络服务发送一个截击请求，结果会显示在列表视图中。我希望在每次文本更改时发送截击请求，这就是我使用edittextwatcher的原因。但每次文本更改时，我都会在Toast中收到com.android.volley.VolleyError:java.lang.NullPointerException错误。我不知道造成它的原因，而且logcat中也没有任何东西。 This是搜索的json响应。那么有人可以帮我纠正这个凌空错误吗？
POJO的：
public class GridItem {
private String nameUrls, imageUrls, sportsCat, userId, userName;
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 getSportsCat(){
return sportsCat;
}
public void setSportsCat(String sportsCat){
this.sportsCat = sportsCat;
}
public String getUserId(){
return userId;
}
public void setUserId(String userId){
this.userId = userId;
}
public String getUserName(){ return userName; }
public void setUserName(String userName) { this.userName = userName; }
}
适配器：
public class ListAdapter extends ArrayAdapter<GridItem> {
private Context mContext;
int resource;
private ArrayList<GridItem> mGridData = new ArrayList<GridItem>();
public ListAdapter(Context mContext, int resource, ArrayList<GridItem> mGridData) {
super(mContext, resource, mGridData);
this.resource = resource;
this.mContext = mContext;
this.mGridData = mGridData;
}
public void setGridData(ArrayList<GridItem> mGridData) {
this.mGridData = mGridData;
notifyDataSetChanged();
}
@Override
public GridItem getItem(int position) {
return super.getItem(position);
}
@Override
public View getView(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(R.layout.listrow, parent, false);
holder.image = (ImageView) v.findViewById(R.id.item_image);
holder.name = (TextView) v.findViewById(R.id.item_name);
holder.image = (ImageView) v.findViewById(R.id.item_image);
v.setTag(holder);
} else {
holder = (ViewHolder) v.getTag();
}
GridItem item = mGridData.get(position);
Picasso.with(mContext)
.load(item.getImage())
.placeholder(R.drawable.placeholder)
.fit()
.into(holder.image);
holder.name.setText(item.getName());
return v;
}
class ViewHolder {
ImageView image;
TextView name;
}
}
片段：
public class SearchName extends Fragment{
private ListView mListView;
private GridItem newItem;
private ListAdapter mListAdapter;
private ArrayList<GridItem> mGridData;
private EditText editText;
public static final String KEY_USERID = "user_id", KEY_NAME = "search_text", SPORTS_ID = "sports_id";
private static final String SEARCH_MEMBER = "http://example.com/api/member/search/";
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
return inflater.inflate(R.layout.searchname, container, false);
}
@Override
public void onViewCreated(View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
editText = (EditText)view.findViewById(R.id.search_et);
editText.addTextChangedListener(textWatcher);
mListView = (ListView)view.findViewById(R.id.list_view);
mGridData = new ArrayList<>();
mListAdapter = new ListAdapter(getContext(), R.layout.listrow, mGridData);
mListView.setAdapter(mListAdapter);
}
private final TextWatcher textWatcher = new TextWatcher() {
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
public void afterTextChanged(Editable s) {
if (s.length() == 0) {
} else{
searchmember();
}
}
};
private void searchmember(){
StringRequest stringRequest = new StringRequest(Request.Method.POST, SEARCH_MEMBER,
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(getActivity(), "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 user_id = json_data.getString("user_id");
String username = json_data.getString("username");
newItem = new GridItem();
newItem.setName(name);
newItem.setUserId(user_id);
newItem.setUserName(username);
if(json_data.has("profile_picture")){
newItem.setImage(json_data.getString("profile_picture"));
}else{
Uri path = Uri.parse("android.resource://com.sam.fitlincsearch/" + 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(getActivity(), errorMsg, Toast.LENGTH_LONG).show();
}
} catch (JSONException e) {
// JSON error
e.printStackTrace();
Toast.makeText(getActivity(), "Json error: " + e.getMessage(), Toast.LENGTH_LONG).show();
}
}
}, new Response.ErrorListener() {
@Override
public void onErrorResponse(VolleyError error) {
Toast.makeText(getActivity(), 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.
params.put(KEY_NAME, editText.getText().toString());
return params;
}
};
RequestQueue requestQueue = Volley.newRequestQueue(getActivity());
requestQueue.add(stringRequest);
}
}
答案 0 :(得分：0)
protected Map<String, String> getParams(){
Map<String, String> params = new HashMap<String, String>();
params.put("key1", value1);
params.put("key2",value2);
params.put("key3",value3);
return checkParams(params);
};
private Map<String, String> checkParams(Map<String, String> map){
Iterator<Entry<String, String>> it = map.entrySet().iterator();
while (it.hasNext()) {
Map.Entry<String, String> pairs = (Map.Entry<String, String>)it.next();
if(pairs.getValue()==null){
map.put(pairs.getKey(), "");
}
}
return map;
}
在Volley Error的情况下，将此作为errorResponse使用。我希望这能解决你的目的。
更新：
http://stackoverflow.com/questions/4709093/jquery-mobile-val-not-working
我认为这比在将每个值放入地图之前检查每个值更容易。