问题
I have an autocomplete adapter for my app and I am getting back json results from the Google Places API. My trouble is with trying to get the results to display on the screen. I am using this guide: http://examples.javacodegeeks.com/android/android-google-places-autocomplete-api-example/
For the most part the code seems sound, but for whatever reason I can't get anything to print out onto my display. I don't really understand how the filter works, and maybe an explanation for how that works with the autocomplete adapter would help.
My onCreate is:
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
buildGoogleApiClient();
setContentView(R.layout.activity_maps);
// Obtain the SupportMapFragment and get notified when the map is ready to be used.
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
if (savedInstanceState != null) {
mIsResolving = savedInstanceState.getBoolean(KEY_IS_RESOLVING);
mShouldResolve = savedInstanceState.getBoolean(KEY_SHOULD_RESOLVE);
}
// Create the LocationRequest object
mLocationRequest = LocationRequest.create()
.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY)
.setInterval(10 * 1000) //10 seconds, in milliseconds
.setFastestInterval(1 * 1000); //1 second, in milliseconds
Log.d(TAG, "GoogleApiClient built");
if (savedInstanceState != null) {
mSignInProgress = savedInstanceState
.getInt(SAVED_PROGRESS, STATE_DEFAULT);
}
mShouldResolve = true;
mGoogleApiClient.connect();
Log.d(TAG, "Starting sign-in");
AutoCompleteTextView autoCompView = (AutoCompleteTextView)
findViewById(R.id.autoCompleteTextView);
autoCompView.setAdapter(new GooglePlacesAutocompleteAdapter(this, R.layout.activity_maps));
autoCompView.setOnItemClickListener(this);
}
My method for getting the Json results is:
public ArrayList<String> autocomplete(String input) {
Log.d(TAG, "performSearch()");
ArrayList resultList = null;
AsyncTask<ArrayList<String>, Void, ArrayList>
myTask = new AsyncTask<ArrayList<String>, Void, ArrayList>() {
AutoCompleteTextView text = (AutoCompleteTextView)
findViewById(R.id.autoCompleteTextView);
private String input = text.getText().toString();
@Override
protected ArrayList doInBackground(ArrayList<String>... params) {
Log.d(TAG, "Starting Search");
ArrayList resultList = null;
HttpURLConnection conn = null;
StringBuilder jsonResults = new StringBuilder();
try {
KEYWORD = input;
ENDPOINT = Uri
.parse("https://maps.googleapis.com/maps/api/place/nearbysearch/json")
.buildUpon()
.appendQueryParameter("location", LOCATION)
.appendQueryParameter("radius", "10000")
.appendQueryParameter("keyword", KEYWORD)
.appendQueryParameter("key", API_KEY)
.build();
URL url = new URL(ENDPOINT.toString());
Log.d(TAG, "URL: " + url);
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);
}
Log.d(TAG, jsonResults.toString());
} catch (MalformedURLException e) {
Log.e(TAG, "Error processing Places API URL", e);
return resultList;
} catch (IOException e) {
Log.e(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("results");
// 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("name"));
System.out.println(predsJsonArray.getJSONObject(i).getString("vicinity"));
System.out.println("=====================================================");
resultList.add(predsJsonArray.getJSONObject(i).getString("name"));
resultList.add(predsJsonArray.getJSONObject(i).getString("vicinity"));
}
} catch (JSONException e) {
Log.e(TAG, "Cannot process JSON results", e);
}
Log.d(TAG, resultList.toString());
return resultList;
}
};
myTask.execute();
Log.d(TAG, resultList.toString());
return resultList;
}
My filter class is:
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 (String) 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, Filter.FilterResults results) {
if (results != null && results.count > 0) {
notifyDataSetChanged();
} else {
notifyDataSetInvalidated();
}
}
};
return filter;
}
}
I know I'm getting a sound result back from google and my built array looks like this (it includes both name and vicinity):
[Midtown Global Market, 920 East Lake Street #G10, Minneapolis, The Anchor Fish & Chips, 302 13th Avenue Northeast, Minneapolis, Brasa Premium Rotisserie, 600 East Hennepin Avenue, Minneapolis, Wedge Community Co-Op, 2105 Lyndale Avenue South, Minneapolis, Tao Natural Foods, 2200 Hennepin Avenue, Minneapolis, Fresh & Natural Foods, 1075 Highway 96 West, Saint Paul, Whole Foods Market, 222 Hennepin Avenue, Minneapolis, Sen Yai Sen Lek Thai, 2422 Central Avenue Northeast, Minneapolis, Mississippi Market Natural Foods Co-op, 622 Selby Avenue, Saint Paul, Eastside Food Co-Op, 2551 Central Avenue Northeast, Minneapolis, Bills Imported Foods, 721 West Lake Street, Minneapolis, Seoul Foods, 1071 East Moore Lake Drive, Minneapolis, Seward Community Co-op - Franklin Store, 2823 East Franklin Avenue, Minneapolis, Foxy Falafel, 791 Raymond Avenue, Saint Paul, Asian Foods, 1300 L'Orient Street, Saint Paul, Pohl Distributing Co, 510 Kasota Avenue Southeast, Minneapolis, Rainbow Foods, 1566 University Avenue West, Saint Paul, Dandelion Kitchen Truck, 800 Nicollet Mall, Minneapolis, World Street Kitchen, 2743 Lyndale Avenue South #5, Minneapolis, CES Food Shelf, East 19th Street, Minneapolis]
Any help is appreciated, thanks!
[EDIT] Here is my XML for activity_maps:
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="com.hudsoncorp.zahudson.roadtrip.MapsActivity">
<fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:map="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/map"
tools:context="com.hudsoncorp.zahudson.roadtrip.MapsActivity"
android:name="com.google.android.gms.maps.SupportMapFragment"/>
<RelativeLayout
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="10dp">
<AutoCompleteTextView
android:id="@+id/autoCompleteTextView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dp"
android:hint="Search location"
android:background="#FFFFFF"
android:textColor="#00000F"
android:theme="@android:style/Widget.Material.AutoCompleteTextView"
android:ems="10"
android:shadowColor="@color/background_floating_material_dark">
<requestFocus />
</AutoCompleteTextView>
</RelativeLayout>
</RelativeLayout>
回答1:
I see you have an AsyncTask to access your data from the server, but you don't really need an AsyncTask because performFiltering() already runs in the background, so you can put your doInBackground() logic in performFiltering().
@Override
protected FilterResults performFiltering(CharSequence constraint) {
ArrayList<String> resultList = null;
FilterResults filterResults = new FilterResults();
if (constraint != null) {
// Retrieve the autocomplete results.
Log.d(TAG, "Starting Search");
HttpURLConnection conn = null;
StringBuilder jsonResults = new StringBuilder();
try {
KEYWORD = constraint.toString();
ENDPOINT = Uri
.parse("https://maps.googleapis.com/maps/api/place/nearbysearch/json")
.buildUpon()
.appendQueryParameter("location", LOCATION)
.appendQueryParameter("radius", "10000")
.appendQueryParameter("keyword", KEYWORD)
.appendQueryParameter("key", API_KEY)
.build();
URL url = new URL(ENDPOINT.toString());
Log.d(TAG, "URL: " + url);
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);
}
Log.d(TAG, jsonResults.toString());
} catch (MalformedURLException e) {
Log.e(TAG, "Error processing Places API URL", e);
return filterResults ;
} catch (IOException e) {
Log.e(TAG, "Error connecting to Places API", e);
return filterResults ;
} 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("results");
// 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("name"));
System.out.println(predsJsonArray.getJSONObject(i).getString("vicinity"));
System.out.println("=====================================================");
resultList.add(predsJsonArray.getJSONObject(i).getString("name"));
resultList.add(predsJsonArray.getJSONObject(i).getString("vicinity"));
}
} catch (JSONException e) {
Log.e(TAG, "Cannot process JSON results", e);
}
Log.d(TAG, resultList.toString());
// Assign the data to the FilterResults
filterResults.values = resultList;
filterResults.count = resultList.size();
}
return filterResults;
}
A Filter works like an AsyncTask. performFiltering is like doInBackground and publishResults() is like onPostExecute().
Incidentally, don't update the adapter list in a background thread. Create a new list and assign it to FilterResults.values, then assign the adapter list in publishResults().
publishResults() should look like this:
@Override
protected void publishResults(CharSequence constraint, Filter.FilterResults results) {
if (results != null && results.count > 0) {
resultList = (ArrayList) results.values;
notifyDataSetChanged();
} else {
notifyDataSetInvalidated();
}
}
来源：https://stackoverflow.com/questions/34247074/filter-json-results-for-autocomplete-adapter