使用 google Places API (Android) 时无法使用过滤

Question

我正在尝试在我的 Android 上使用 Google Places API，但在过滤过程中失败了。 我使用了本指南中显示的代码： https://developers.google.com/places/training/autocomplete-android

-我的 API 密钥很好（我已经在浏览器中测试过，它运行良好）。 - 另外，我提供的 URL 很好（也在浏览器中测试过）。 - 我在发帖前故意删除了我的真实 API 密钥。

我得到的错误是关于 "performFiltering" 方法。它向我发送 NullPointerException。

我一直试图找出问题所在，但没有成功。

如果您能帮助我了解问题所在，我将不胜感激。

这是我的代码：

public class MainActivity extends Activity {
private static final String LOG_TAG = "ExampleApp";

private static final String PLACES_API_BASE = "https://maps.googleapis.com/maps/api/place";
private static final String TYPE_AUTOCOMPLETE = "/autocomplete";
private static final String OUT_JSON = "/json";

private static final String API_KEY = "MY_API_KEY";


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    AutoCompleteTextView autoCompView = (AutoCompleteTextView) findViewById(R.id.autocompleteView);
    autoCompView.setAdapter(new PlacesAutoCompleteAdapter(this, R.layout.list_item));

}


private ArrayList<String> autocomplete(String input) {
    ArrayList<String> resultList = null;


    HttpURLConnection conn = null;
    StringBuilder jsonResults = new StringBuilder();
    try {
        StringBuilder sb = new StringBuilder(PLACES_API_BASE + TYPE_AUTOCOMPLETE + OUT_JSON);
        sb.append("?key=" + API_KEY);
        sb.append("&components;=country:Israel");
        sb.append("&input=" + URLEncoder.encode(input, "utf8"));
        sb.append("&types;=geocode");

        URL url = new URL(sb.toString());
        conn = (HttpURLConnection) url.openConnection();
        InputStreamReader in = new InputStreamReader(conn.getInputStream());

        // Load the results into a StringBuilder
        int read;
        char[] buff = new char[1024];
        while ((read = in.read(buff)) != -1) {
            jsonResults.append(buff, 0, read);
        }
    } catch (MalformedURLException e) {
        Log.e(LOG_TAG, "Error processing Places API URL", e);
        return resultList;
    } catch (IOException e) {
        Log.e(LOG_TAG, "Error connecting to Places API", e);
        return resultList;
    } finally {
        if (conn != null) {
            conn.disconnect();
        }
    }

    try {
        // Create a JSON object hierarchy from the results
        JSONObject jsonObj = new JSONObject(jsonResults.toString());
        JSONArray predsJsonArray = jsonObj.getJSONArray("predictions");

        // Extract the Place descriptions from the results
        resultList = new ArrayList<String>(predsJsonArray.length());
        for (int i = 0; i < predsJsonArray.length(); i++) {
            resultList.add(predsJsonArray.getJSONObject(i).getString("description"));
        }
    } catch (JSONException e) {
        Log.e(LOG_TAG, "Cannot process JSON results", e);
    }

    return resultList;
}


private class PlacesAutoCompleteAdapter extends ArrayAdapter<String> implements Filterable {
    private ArrayList<String> resultList;

    public PlacesAutoCompleteAdapter(Context context, int textViewResourceId) {
        super(context, textViewResourceId);
    }

    @Override
    public int getCount() {
        return resultList.size();
    }

    @Override
    public String getItem(int index) {
        return resultList.get(index);
    }

    @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;
    }
}

}

*我也将阈值设置为 1。仍然是同样的错误。

Answer 1

请发布 LogCat， 还要检查并验证您的 Manifest 文件是否包含所有必需的权限和定义的 google play 服务版本。