我正在使用API数据库开发卡路里应用程序。当用户单击搜索按钮时，它获取字符串，然后搜索数据库。由于某种原因，用户编辑文本“字符串”未被检索，因此无法搜索api数据库。当我进行调试时，我注意到字符串“”表示空。
再次感谢，api和android工作室的新手。
public class AddEntry extends Fragment implements View.OnClickListener {
EditText FoodET,CalorieET;
ImageButton Savebtn, Cancelbtn;
Button searchbutton;
String foodET,calorieET;
//database
private DatabaseHandler dba;
public AddEntry() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
View myView = inflater.inflate(R.layout.fragment_add_entry, container,
false);
Savebtn = (ImageButton) myView.findViewById(R.id.SaveBtn);
Savebtn.setBackgroundColor(Color.TRANSPARENT);
Savebtn.setOnClickListener(this);
searchbutton = (Button) myView.findViewById(R.id.SearchButton);
searchbutton.setOnClickListener(this);
Cancelbtn = (ImageButton) myView.findViewById(R.id.CancelBtn);
Cancelbtn.setBackgroundColor(Color.TRANSPARENT);
Cancelbtn.setOnClickListener(this);
return myView;
}
@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
FoodET= (EditText)view.findViewById(R.id.foodEditText);
FoodET.setInputType(InputType.TYPE_CLASS_TEXT);
CalorieET=(EditText)view.findViewById(R.id.caloriesEditText);
CalorieET.setInputType(InputType.TYPE_CLASS_NUMBER);
foodET = ((EditText)
view.findViewById(R.id.foodEditText)).getText().toString();
foodET.isEmpty();
FoodET.setText("");
CalorieET.setText("");
calorieET = ((EditText)
view.findViewById(R.id.caloriesEditText)).getText().toString();
}
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.SearchButton:
FoodSearch search = new FoodSearch(foodET, CalorieET );
search.execute();
break;
case R.id.SaveBtn:
if (FoodET.getText().toString().equals(null) ||
CalorieET.getText().toString().equals(null)||
CalorieET.getText().toString().equals("") ||
CalorieET.getText().toString().equals("")){
Toast.makeText(getActivity(), "Please enter information",
Toast.LENGTH_LONG).show();
AlertDialog NotFound = new
AlertDialog.Builder(getContext()).create();
NotFound.setTitle("Error");
NotFound.setMessage("Food not found :(");
NotFound.setButton(AlertDialog.BUTTON_NEUTRAL, "OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int
which) {
dialog.dismiss();
}
});
}
else
((appMain) getActivity()).loadSelection(0);
break;
case R.id.CancelBtn:
// EditText descriptionET=
(EditText)getView().findViewById(R.id.foodEditText);
//descriptionET.setText("");
//EditText calorieET=
(EditText)getView().findViewById(R.id.caloriesEditText);
//calorieET.setText("");
((appMain) getActivity()).loadSelection(0);
break;
}
}
@Override
public void onDestroy() {
super.onDestroy();
}
@Override
public void onDetach() {
super.onDetach();
}
private class FoodSearch extends AsyncTask<Void, Void, String> {
String food;
EditText calories;
FoodSearch(String food, EditText calories){
this.food = food;
this.calories = calories;
}
@Override
protected String doInBackground(Void... params) {
try {
food = food.replaceAll(" ", "%20");
URL url = new URL("http://api.nal.usda.gov/ndb/search/?
format=JSON&q=" + food +
"&max=1&offset=0&sort=r&api_
key=xMJV33vSmKsquFqcBwZ23oJ7DlL2abmfsrDUUx1l");
HttpURLConnection urlConnection = (HttpURLConnection)
url.openConnection();
try {
BufferedReader bufferedReader = new BufferedReader(new
InputStreamReader(urlConnection.getInputStream()));
StringBuilder stringBuilder = new StringBuilder();
String line;
while ((line = bufferedReader.readLine()) != null) {
stringBuilder.append(line).append("\n");
}
bufferedReader.close();
String result = stringBuilder.toString();
if(result.contains("zero results")) {
String s = "empty";
return s;
}
JSONObject object = (JSONObject) new
JSONTokener(result).nextValue();
JSONObject list = object.getJSONObject("list");
JSONArray items = list.getJSONArray("item");
String item = items.get(0).toString();
int i = item.indexOf("ndbno\":\"") + 8;
int f = item.indexOf("\"", i);
String ndbno = item.substring(i,f);
Log.d("DEBUG", ndbno);
URL url2 = new URL("http://api.nal.usda.gov/ndb/reports/?
ndbno=" + ndbno +
"&type=b&format=JSON&api_
key=xMJV33vSmKsquFqcBwZ23oJ7DlL2abmfsrDUUx1l");
HttpURLConnection urlConnection2 = (HttpURLConnection)
url2.openConnection();
BufferedReader bufferedReader2 = new BufferedReader(new
InputStreamReader(urlConnection2.getInputStream()));
StringBuilder stringBuilder2 = new StringBuilder();
String line2;
while ((line2 = bufferedReader2.readLine()) != null) {
stringBuilder2.append(line2).append("\n");
}
bufferedReader2.close();
String res = stringBuilder2.toString();
int index = res.indexOf("\"unit\": \"kcal\",") + 46;
int index2 = res.indexOf("\"", index);
String calories = res.substring(index,index2);
urlConnection2.disconnect();
return calories;
}
finally{
urlConnection.disconnect();
}
}
catch(Exception e) {
Log.e("ERROR", e.getMessage(), e);
String s = "empty";
return s;
}
}
protected void onPostExecute(String response) {
if(!response.isEmpty() && !response.equals("empty")) {
calories.setText(response);
} else {
AlertDialog foodNotFound = new
AlertDialog.Builder(getContext()).create();
foodNotFound.setTitle("Error");
foodNotFound.setMessage("Food not found :(");
foodNotFound.setButton(AlertDialog.BUTTON_NEUTRAL, "OK",
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int
which) {
dialog.dismiss();
}
});
}
}
}
}
答案 0 :(得分：1)
当您执行AsyncTask
时，请改用这些值FoodSearch search = new FoodSearch(foodET, CalorieET );
创建视图时，以下值始终为空（在代码中不是必需的）。
getText这就解释了为什么这不起作用
"file:///android_asset"您应该始终尝试调用context.getResources().getAssets().open("fileName")以响应用户事件，以获取输入字段的最新值
我还建议你学习如何正确解析JSON数据（不要使用indexOf），或者到目前为止看看Retrofit库
答案 1 :(得分：1)
试试这个
case R.id.SearchButton:
String foodEtString=FoodET.getText().toString();
FoodSearch search = new FoodSearch(foodEtString, CalorieET );
search.execute();
break;
并在onCreate中添加此内容
FoodET= (EditText)view.findViewById(R.id.foodEditText);
FoodET.setInputType(InputType.TYPE_CLASS_TEXT);
CalorieET=(EditText)view.findViewById(R.id.caloriesEditText);
CalorieET.setInputType(InputType.TYPE_CLASS_NUMBER);