当我尝试添加监听器时，EditText会崩溃应用程序

Question

当我尝试将TextChangedListener添加到我的EditText时，应用程序崩溃，即使我没有在AfterTextChangedMethod中写任何内容。 我正在尝试让用户插入字符串，但是一旦我添加了我的监听器，它就会崩溃。

public class MainActivityFragment extends Fragment {

    ArrayList<HashMap<String,String>> city_list;

    public MainActivityFragment() {
    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        EditText search = (EditText) getActivity().findViewById(R.id.search_view);
        search.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {    }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {     }

            @Override
            public void afterTextChanged(Editable s) {
                String inserted = s.toString();
                for(int i=0; i< city_list.size();i++){
                    if(city_list.get(i).toString().equalsIgnoreCase(inserted)){
                        TextView id = (TextView) getActivity().findViewById(R.id.city_id);
                        id.setText(city_list.get(i).get("_id").toString());
                        TextView lat = (TextView) getActivity().findViewById(R.id.city_lat);
                        lat.setText(city_list.get(i).get("lat").toString());
                        TextView lon = (TextView) getActivity().findViewById(R.id.city_long);
                        lon.setText(city_list.get(i).get("lon").toString());
                    }
                }
            }
        });

        return inflater.inflate(R.layout.fragment_main, container, false);
    }

Answer 1

尝试这个，

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {

        View view = inflater.inflate(R.layout.fragment_main, container, false);

        EditText search = (EditText)view.findViewById(R.id.search_view);
        search.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }

            @Override
            public void afterTextChanged(Editable s) {
                String inserted = s.toString();
                for(int i=0; i< city_list.size();i++){
                    if(city_list.get(i).toString().equalsIgnoreCase(inserted)){
                        TextView id = (TextView) view .findViewById(R.id.city_id);
                        id.setText(city_list.get(i).get("_id").toString());
                        TextView lat = (TextView) view .findViewById(R.id.city_lat);
                        lat.setText(city_list.get(i).get("lat").toString());
                        TextView lon = (TextView) view .findViewById(R.id.city_long);
                        lon.setText(city_list.get(i).get("lon").toString());
                    }
                }
            }
        });


        return view;
    }

Answer 2

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {

    View view = inflater.inflate(R.layout.fragment_main, container, false);

    EditText search = (EditText)view.findViewById(R.id.search_view);
    search.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

        }

        @Override
        public void afterTextChanged(Editable s) {
            String inserted = s.toString();
            for(int i=0; i< city_list.size();i++){
                if(city_list.get(i).toString().equalsIgnoreCase(inserted)){
                    TextView id = (TextView) view .findViewById(R.id.city_id);
                    id.setText(city_list.get(i).get("_id").toString());
                    TextView lat = (TextView) view .findViewById(R.id.city_lat);
                    lat.setText(city_list.get(i).get("lat").toString());
                    TextView lon = (TextView) getActivity()view .findViewById(R.id.city_long);
                    lon.setText(city_list.get(i).get("lon").toString());
                }
            }
        }
    });


    return view;
}

Answer 3

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
View view=    inflater.inflate(R.layout.fragment_main, container, false);
        EditText search = (EditText) view.findViewById(R.id.search_view);
  TextView id = (TextView) view.findViewById(R.id.city_id);
  TextView lat = (TextView) view.findViewById(R.id.city_lat);
  TextView lon = (TextView) view.findViewById(R.id.city_long);
        search.addTextChangedListener(new TextWatcher() {
            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {

            }

            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {

            }

            @Override
            public void afterTextChanged(Editable s) {
                String inserted = s.toString();
                for(int i=0; i< city_list.size();i++){
                    if(city_list.get(i).toString().equalsIgnoreCase(inserted)){

                      id.setText(city_list.get(i).get("_id").toString());

                       lat.setText(city_list.get(i).get("lat").toString());

                     lon.setText(city_list.get(i).get("lon").toString());
                    }
                }
            }
        });


        return view;
    }

Answer 4

您不是首先在onCreateViewMethod中夸大您的视图。 首先膨胀您的视图，然后查找子视图。

Answer 5

您的应用程序崩溃了，因为您正在尝试将侦听器添加到空引用对象。 仔细检查您分配给您的editext的ID。 此外，尝试以下代码。

只需在onCreateView方法中返回此内容即可。

return inflater.inflate(R.layout.fragment_main, container, false);

覆盖onViewCreated方法，使用传入的View变量初始化EditText。

@Override
public void onViewCreated(View view, Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    EditText etSearch = (EditText) view.findViewById(R.id.search_view);

}

然后将textChangeListener添加到它。

   etSearch.addTextChangedListener(new TextWatcher() {
        @Override
        public void beforeTextChanged(CharSequence s, int start, int count, int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {

        }

        @Override
        public void afterTextChanged(Editable s) {
           //your code here
        }
    });

希望能帮助到你。

Answer 6

尝试这个...

我想你想在你的视图中使用LayoutInflater。

LayoutInflater inflater1 = (LayoutInflater) getActivity().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
View view = inflater.inflate(R.layout.fragment_main, container, false);
EditText search = (EditText)view.findViewById(R.id.search_view);

然后，您可以覆盖TextChangedMethod方法