我按照这个教程进行编程，使用Google Places API实现自动完成文本视图。我想要一个自动完成文本视图，当我们开始输入时，它会自动填充地点名称。上述提到的教程正是我需要的，但它对我不起作用。自动填充操作没有发生。有人能否提出解决方法？
以下是主要活动。
以下是主要活动。
public class MainActivity extends Activity {
AutoCompleteTextView atvPlaces;
PlacesTask placesTask;
ParserTask parserTask;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
atvPlaces = (AutoCompleteTextView) findViewById(R.id.atv_places);
atvPlaces.setThreshold(1);
atvPlaces.addTextChangedListener(new TextWatcher() {
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
placesTask = new PlacesTask();
placesTask.execute(s.toString());
}
@Override
public void beforeTextChanged(CharSequence s, int start, int count,
int after) {
// TODO Auto-generated method stub
}
@Override
public void afterTextChanged(Editable s) {
// TODO Auto-generated method stub
}
});
}
/** A method to download json data from url */
private String downloadUrl(String strUrl) throws IOException{
String data = "";
InputStream iStream = null;
HttpURLConnection urlConnection = null;
try{
URL url = new URL(strUrl);
// Creating an http connection to communicate with url
urlConnection = (HttpURLConnection) url.openConnection();
// Connecting to url
urlConnection.connect();
// Reading data from url
iStream = urlConnection.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(iStream));
StringBuilder sb = new StringBuilder();
String line = "";
while( ( line = br.readLine()) != null){
sb.append(line);
}
data = sb.toString();
br.close();
}catch(Exception e){
Log.d("Exception while downloading url", e.toString());
}finally{
iStream.close();
urlConnection.disconnect();
}
return data;
}
// Fetches all places from GooglePlaces AutoComplete Web Service
private class PlacesTask extends AsyncTask<String, Void, String>{
@Override
protected String doInBackground(String... place) {
// For storing data from web service
String data = "";
// Obtain browser key from https://code.google.com/apis/console
String key = "key=AIzaSyBB5KBkuA4-qm8QxaXX8FhHqhHsESMdAzI";
String input="";
try {
input = "input=" + URLEncoder.encode(place[0], "utf-8");
} catch (UnsupportedEncodingException e1) {
e1.printStackTrace();
}
// place type to be searched
String types = "types=geocode";
// Sensor enabled
String sensor = "sensor=false";
// Building the parameters to the web service
String parameters = input+"&"+types+"&"+sensor+"&"+key;
// Output format
String output = "json";
// Building the url to the web service
String url = "https://maps.googleapis.com/maps/api/place/autocomplete/"+output+"?"+parameters;
try{
// Fetching the data from we service
data = downloadUrl(url);
}catch(Exception e){
Log.d("Background Task",e.toString());
}
return data;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
// Creating ParserTask
parserTask = new ParserTask();
// Starting Parsing the JSON string returned by Web Service
parserTask.execute(result);
}
}
/** A class to parse the Google Places in JSON format */
private class ParserTask extends AsyncTask<String, Integer, List<HashMap<String,String>>>{
JSONObject jObject;
@Override
protected List<HashMap<String, String>> doInBackground(String... jsonData) {
List<HashMap<String, String>> places = null;
PlaceJSONParser placeJsonParser = new PlaceJSONParser();
try{
jObject = new JSONObject(jsonData[0]);
// Getting the parsed data as a List construct
places = placeJsonParser.parse(jObject);
}catch(Exception e){
Log.d("Exception",e.toString());
}
return places;
}
@Override
protected void onPostExecute(List<HashMap<String, String>> result) {
String[] from = new String[] { "description"};
int[] to = new int[] { android.R.id.text1 };
// Creating a SimpleAdapter for the AutoCompleteTextView
SimpleAdapter adapter = new SimpleAdapter(getBaseContext(), result, android.R.layout.simple_list_item_1, from, to);
// Setting the adapter
atvPlaces.setAdapter(adapter);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
这是PlaceJSONParser.java文件
public class PlaceJSONParser {
/** Receives a JSONObject and returns a list */
public List<HashMap<String,String>> parse(JSONObject jObject){
JSONArray jPlaces = null;
try {
/** Retrieves all the elements in the 'places' array */
jPlaces = jObject.getJSONArray("predictions");
} catch (JSONException e) {
e.printStackTrace();
}
/** Invoking getPlaces with the array of json object
* where each json object represent a place
*/
return getPlaces(jPlaces);
}
private List<HashMap<String, String>> getPlaces(JSONArray jPlaces){
int placesCount = jPlaces.length();
List<HashMap<String, String>> placesList = new ArrayList<HashMap<String,String>>();
HashMap<String, String> place = null;
/** Taking each place, parses and adds to list object */
for(int i=0; i<placesCount;i++){
try {
/** Call getPlace with place JSON object to parse the place */
place = getPlace((JSONObject)jPlaces.get(i));
placesList.add(place);
} catch (JSONException e) {
e.printStackTrace();
}
}
return placesList;
}
/** Parsing the Place JSON object */
private HashMap<String, String> getPlace(JSONObject jPlace){
HashMap<String, String> place = new HashMap<String, String>();
String id="";
String reference="";
String description="";
try {
description = jPlace.getString("description");
id = jPlace.getString("id");
reference = jPlace.getString("reference");
place.put("description", description);
place.put("_id",id);
place.put("reference",reference);
} catch (JSONException e) {
e.printStackTrace();
}
return place;
}
}
这是CustomAutoCompleteTextView.java文件
public class CustomAutoCompleteTextView extends AutoCompleteTextView {
public CustomAutoCompleteTextView(Context context, AttributeSet attrs) {
super(context, attrs);
}
/** Returns the place description corresponding to the selected item */
@Override
protected CharSequence convertSelectionToString(Object selectedItem) {
/** Each item in the autocompetetextview suggestion list is a hashmap object */
HashMap<String, String> hm = (HashMap<String, String>) selectedItem;
return hm.get("description");
}
}
这是清单文件
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.map5"
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="8"
android:targetSdkVersion="18" />
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@drawable/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name="com.example.map5.MainActivity"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>