Question

我正在关注this教程，以便能够在搜索视图中实施Google Places API。我在这一行收到以下错误：

不兼容的类型需要java.lang.string找到java.lang.object

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

代码段：

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_preferences);
    AutoCompleteTextView autoCompView = (AutoCompleteTextView) findViewById(R.id.autoCompleteTextView);
    autoCompView.setAdapter(new GooglePlacesAutocompleteAdapter(this, R.layout.list_item));
    autoCompView.setOnItemClickListener(this);
}

public void onItemClick(AdapterView adapterView, View view, int position, long id) {
    String str = (String) adapterView.getItemAtPosition(position);
    Toast.makeText(this, str, Toast.LENGTH_SHORT).show();
}

public static ArrayList autocomplete(String input) {
    ArrayList 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:gr");
        sb.append("&input=" + URLEncoder.encode(input, "utf8"));

        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(predsJsonArray.length());
        for (int i = 0; i < predsJsonArray.length(); i++) {
            System.out.println(predsJsonArray.getJSONObject(i).getString("description"));
            System.out.println("============================================================");
            resultList.add(predsJsonArray.getJSONObject(i).getString("description"));
        }
    } catch (JSONException e) {
        Log.e(LOG_TAG, "Cannot process JSON results", e);
    }

    return resultList;
}

class GooglePlacesAutocompleteAdapter extends ArrayAdapter implements Filterable {
    private ArrayList resultList;

    public GooglePlacesAutocompleteAdapter(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;
    }
}

关于如何纠正这个问题的任何想法？

Answer 1

ArrayList resultList没有分配任何类型信息，因此它被视为一个Object。当您从getItem()中的此列表中获取某些内容时，您希望它是一个字符串，这就是导致错误的原因。

您有两种方法可以解决此问题。将ArrayList更改为ArrayList<String>，或者在getItem（）中将结果转换为String。

Answer 2

请检查 StackTrace 。您可以解决此错误，因为仅发生datatype不匹配。请嵌入 StackTrace 以确定Exception实际出现的行。

编译时错误

必需 java.lang.string 发现 java.lang.object请仔细阅读。

Answer 3

更改此行

private ArrayList resultList;

到此：

private ArrayList<String> resultList;

Answer 4

更改你的getItem（）方法如下：

def Trailing_White_Space (input_str):

    count = 0
    for i in range (len(input_str)-1, 0, -1):
        if (input_str[i] != ' '):
            count = i
            break
    slice_index= (len(input_str)-count)-1
    new_s = input_str[0:-1*slice_index]
    return (new_s)

#Main Program
input_str = "    Hello    "
result = Trailing_White_Space (input_str)
print (result)

不兼容的类型需要java.lang.string找到java.lang.object

4 个答案:

编译时错误