如何将自动完成文本视图所选项目转换为置入对象

Question

我的应用程序中有一个自动完成的文本视图，允许用户输入地址，文本视图使用地点 API 向他们显示以用户正在使用的字母开头的不同位置。我实现了 Places API，用户能够看到地点，但是当他们选择一个地方时，我想检索该地点并根据我的需要使用它（例如检索 LatLng 和类似的东西），但地点对象是字符串对象，我不知道如何将其检索为 Place 或将字符串对象转换为 Place 对象。到目前为止，我尝试了以下内容，但无济于事。这是我的适配器类。

class GooglePlacesAutocompleteAdapter extends ArrayAdapter implements Filterable {
        private ArrayList resultList;
        public GooglePlacesAutocompleteAdapter(Context context, int list, int textViewResourceId) {
            super(context, list, textViewResourceId);
        }
        @Override
        public int getCount() {
            return resultList.size();
        }
        @Override
        public String getItem(int index) {
            return resultList.get(index).toString();
        }
        @Override
        public Filter getFilter() {
            Filter filter = new Filter() {
                @Override
                protected FilterResults performFiltering(CharSequence constraint) {
                    FilterResults filterResults = new FilterResults();
                    if (constraint != null) {
                        // Retrieve the autocomplete results.
                        resultList = autocomplete(constraint.toString());
                        // Assign the data to the FilterResults
                        filterResults.values = resultList;
                        filterResults.count = resultList.size();
                    }
                    return filterResults;
                }
                @Override
                protected void publishResults(CharSequence constraint, FilterResults results) {
                    if (results != null && results.count > 0) {
                        notifyDataSetChanged();
                    } else {
                        notifyDataSetInvalidated();
                    }
                }
            };
            return filter;
        }
    }
msg.setAdapter(new GooglePlacesAutocompleteAdapter(this, R.layout.search_results_list_item, R.id.tvSearchResultItem));
        msg.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                final String selectedPlace = (String) parent.getItemAtPosition(position);
                Place pl = new Place() {
                    @Override
                    public String getId() {
                        return null;
                    }
                    @Override
                    public List<Integer> getPlaceTypes() {
                        return null;
                    }
                    @Override
                    public CharSequence getAddress() {
                        return null;
                    }
                    @Override
                    public Locale getLocale() {
                        return null;
                    }
                    @Override
                    public CharSequence getName() {
                        return selectedPlace;
                    }
                    @Override
                    public LatLng getLatLng() {
                        return null;
                    }
                    @Override
                    public LatLngBounds getViewport() {
                        return null;
                    }
                    @Override
                    public Uri getWebsiteUri() {
                        return null;
                    }
                    @Override
                    public CharSequence getPhoneNumber() {
                        return null;
                    }
                    @Override
                    public float getRating() {
                        return 0;
                    }
                    @Override
                    public int getPriceLevel() {
                        return 0;
                    }
                    @Override
                    public Place freeze() {
                        return null;
                    }
                    @Override
                    public boolean isDataValid() {
                        return true;
                    }
                };
                LatLng selectedltlng = getSelectedLatLng(pl);
                Log.e("selected", selectedltlng.toString());
                //Place selectedPlace = Places.GeoDataApi.getPlaceById(mGoogleApiClient, );
                //Toast.makeText(this, str, Toast.LENGTH_SHORT).show();
            }
            private LatLng getSelectedLatLng(Place placeStringe) {
                LatLng placeltlg = placeStringe.getLatLng();
                Log.e("selcete", placeltlg.toString());
                return placeltlg;
            }
        });

但这会引发空指针异常。我还尝试将字符串对象转换为 Object 像这样

Object selectedPlace = (Object) parent.getItemAtPosition(position); 
Place plac = (Place)selectedPlace;

但这抛出了投射异常。我怎样才能以有效的方式做到这一点？

Answer 1

一周前我做了一个城市选择器。它使用自定义扩展的自动完成文本视图小部件。也许这对你有帮助。此小部件允许用户输入字符（灰色），然后显示匹配城市的列表。用户从列表中选择一个城市（它变成黑色），然后选择保存在cityData对象中的城市，可以通过.getCity（）调用进行检索。

这是代码：

public class CityAutoCompleteEditText extends AutoCompleteTextView implements View.OnFocusChangeListener, TextWatcherAdapter.TextWatcherListener {
    // City object (code, name, type, level and so on)
    private OKTMOUnit cityData;
    // One of the constructors. You need to implement all with init() inside
    public CityAutoCompleteEditText(Context context) {
        super(context);
        init(context, null);
    }
    // Initial data setter
    public void setCity(OKTMOUnit city) {
        setText(city.toString());
        setTextColor(resource_black);
        cityData = city;
    }
    // Data getter
    public OKTMOUnit getCity() {
        return cityData;
    }
    private void init(Context context, AttributeSet attrs) {
        ......
        super.setOnItemClickListener(new AdapterView.OnItemClickListener() {
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                // On click - set color black and init cityData
                cityData = (OKTMOUnit) getAdapter().getItem(position);
                setTextColor(resource_black);
            }
        });
        .....
     }
    @Override
    public void onTextChanged(EditText view, String text) {
        // Text changed by hand - grey it and clear cityData
        cityData = null;
        setTextColor(resource_grey);
    }
    @Override
    public void onFocusChange(View v, boolean hasFocus) {
        if (cityData == null) {
            setText("");
        }
    }
}

和适配器：

public class CityAutoCompleteAdapter extends BaseAdapter implements Filterable {
    private static final int MAX_RESULTS = 20;
    private Context mContext;
    private ArrayList<OKTMOUnit> mData;
    public CityAutoCompleteAdapter(Context context) {
        mData = new ArrayList<>();
        mContext = context;
    }
    @Override
    public long getItemId(int position) {
        return position;
    }
    @Override
    public int getCount() {
        return mData.size();
    }
    @Override
    public OKTMOUnit getItem(int index) {
        return mData.get(index);
    }
    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        if (convertView == null) {
            LayoutInflater inflater = (LayoutInflater) mContext.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            convertView = inflater.inflate(R.layout.autocomplete_dropdown_item, parent, false);
        }
        if (convertView != null) {
            ((TextView) convertView.findViewById(R.id.autoCompleteCity)).setText(getItem(position).getFullCity());
            ((TextView) convertView.findViewById(R.id.autoCompleteRegion)).setText(getItem(position).getFullRegion());
        }
        return convertView;
    }
}

补充：我从适配器中删除了public Filter getFilter() {}代码以简化它。

Answer 2

试试这个 它是用模型类完成的，你可以得到地名，地址，纬度，长 我发现非常有用 http://coderzpassion.com/android-working-google-places-api/