我的应用程序有一个自动完成适配器，我正在从Google Places API中获取json结果。我的麻烦在于试图让结果显示在屏幕上。我正在使用本指南：http://examples.javacodegeeks.com/android/android-google-places-autocomplete-api-example/
在大多数情况下，代码看似合理，但无论出于何种原因，我都无法将任何内容打印到显示器上。我真的不明白过滤器是如何工作的，也许对自动完成适配器如何工作的解释会有所帮助。
我的onCreate是：
@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);
}
获取Json结果的方法是：
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;
}
我的过滤器类是：
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;
}
}
我知道我从谷歌获得了良好的结果，我的内置阵列看起来像这样（包括名称和附近）：
[Midtown Global Market，920 East Lake Street＃G10，Minneapolis，The Anchor Fish＆amp;芯片，302 13th Avenue Northeast，Minneapolis，Brasa Premium Rotisserie，600 East Hennepin Avenue，Minneapolis，Wedge 社区合作社，2105 Lyndale Avenue South，Minneapolis，Tao Natural Foods，2200 Hennepin Avenue，Minneapolis，Fresh＆amp;天然食品，1075 Highway 96 West，Saint Paul，Whole Foods Market，222 Hennepin Avenue， 明尼阿波利斯，Sen Yai Sen Lek Thai，2422 Central Avenue Northeast， 明尼阿波利斯，密西西比市场天然食品合作社，622塞尔比大道， 圣保罗，Eastside Food Co-Op，2551 Central Avenue Northeast， 明尼阿波利斯，明尼阿波利斯西湖街721号，进口食品， Seoul Foods，1071 East Moore Lake Drive，Minneapolis，Seward Community 合作社 - 富兰克林商店，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， 明尼阿波利斯，Rainbow Foods，1566 University Avenue West，Saint Paul， 蒲公英厨房卡车，800 Nicollet购物中心，明尼阿波利斯，世界街 厨房，2743 Lyndale Avenue South＃5，Minneapolis，CES Food Shelf， 明尼阿波利斯东19街]
感谢任何帮助，谢谢！
[编辑] 这是我的activity_maps的XML：
<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>
答案 0 :(得分：1)
我发现您有一个AsyncTask来从服务器访问您的数据，但您并不需要AsyncTask，因为performFiltering()已经在后台运行，所以你可以将doInBackground()逻辑放在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;
}
Filter就像AsyncTask一样。 performFiltering与doInBackground类似，publishResults()与onPostExecute()类似。
顺便说一句，不要在后台线程中更新适配器列表。创建一个新列表并将其分配给FilterResults.values，然后在publishResults()中分配适配器列表。
publishResults()应如下所示：
@Override
protected void publishResults(CharSequence constraint, Filter.FilterResults results) {
if (results != null && results.count > 0) {
resultList = (ArrayList) results.values;
notifyDataSetChanged();
} else {
notifyDataSetInvalidated();
}
}