public class Locations extends Fragment {
private Location currentLocation = null;
private LocationManager locationManager;
private GeoPoint currentPoint;
TextView location1;
ArrayList<LatLng> markerPoints;
GoogleMap map;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getLastLocation();
}
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.activity_locations, container, false);
...some other stuff being done here...
// Return view
return view;
}
public void getLastLocation(){
String provider = getBestProvider();
currentLocation = locationManager.getLastKnownLocation(provider);
this.markerPoints = new ArrayList<LatLng>();
LatLng fromPosition = new LatLng(currentLocation.getLatitude(), currentLocation.getLongitude());
LatLng toPosition = new LatLng(29.633289, -82.305838);
// These are the other 3 end locations
LatLng toPosition1 = new LatLng(35.205374, -82.614587);
LatLng toPosition2 = new LatLng(35.405342, -82.316587);
LatLng toPosition3 = new LatLng(35.702354, -82.515837);
Locations.this.markerPoints.add(fromPosition);
Locations.this.markerPoints.add(toPosition);
// Getting URL to the Google Directions API
String url = Locations.this.getDirectionsUrl(fromPosition, toPosition);
DownloadTask downloadTask = new DownloadTask();
// Start downloading json data from Google Directions API
downloadTask.execute(url);
if(currentLocation != null) {
setCurrentLocation(currentLocation);
} else {
// do something
}
}
public String getBestProvider() {
locationManager = (LocationManager) getActivity().getSystemService(Context.LOCATION_SERVICE);
Criteria criteria = new Criteria();
criteria.setPowerRequirement(Criteria.NO_REQUIREMENT);
criteria.setAccuracy(Criteria.NO_REQUIREMENT);
String bestProvider = locationManager.getBestProvider(criteria, true);
return bestProvider;
}
public void setCurrentLocation(Location location){
// Get current location
int currLatitude = (int) (location.getLatitude()*1E6);
int currLongitude = (int) (location.getLongitude()*1E6);
currentPoint = new GeoPoint(currLatitude,currLongitude);
// Set current location
currentLocation = new Location("");
currentLocation.setLatitude(currentPoint.getLatitudeE6() / 1e6);
currentLocation.setLongitude(currentPoint.getLongitudeE6() / 1e6);
}
private String getDirectionsUrl(LatLng origin, LatLng dest) {
// Origin of route
String str_origin = "origin=" + origin.latitude + "," + origin.longitude;
// Destination of route
String str_dest = "destination=" + dest.latitude + "," + dest.longitude;
// Sensor enabled
String sensor = "sensor=false";
// Building the parameters to the web service
String parameters = str_origin + "&" + str_dest + "&" + sensor;
// Output format
String output = "json";
// Building the url to the web service
String url = "https://maps.googleapis.com/maps/api/directions/" + output + "?" + parameters;
return url;
}
/** 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));
StringBuffer sb = new StringBuffer();
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 data from url passed
private class DownloadTask extends AsyncTask<String, Void, ArrayList<String>> {
@Override
protected ArrayList<String> doInBackground(String... urlList) {
try {
ArrayList<String> returnList = new ArrayList<String>();
for (String url : urlList) {
// Fetching the data from web service
String data = Locations.this.downloadUrl(url);
returnList.add(data);
}
return returnList;
} catch (Exception e) {
Log.d("Background Task", e.toString());
return null; // Failed, return null
}
}
// Executes in UI thread, after the execution of
// doInBackground()
@Override
protected void onPostExecute(ArrayList<String> results) {
super.onPostExecute(results);
ParserTask parserTask = new ParserTask();
for (String url : results) {
parserTask.execute(url);
}
// Invokes the thread for parsing the JSON data
// parserTask.execute(results);
}
}
/** A class to parse the Google Places in JSON format */
private class ParserTask extends AsyncTask<String, Integer, ArrayList<List<HashMap<String, String>>>> {
// Parsing the data in non-ui thread
@Override
protected ArrayList<List<HashMap<String, String>>> doInBackground(String... jsonData) {
try {
ArrayList<List<HashMap<String, String>>> routes = new ArrayList<List<HashMap<String, String>>>();
// for (String url : jsonData) {
for (int i = 0; i < jsonData.length; i++) {
JSONObject jObject = new JSONObject(jsonData[i]);
DirectionsJSONParser parser = new DirectionsJSONParser();
// Starts parsing data
routes = (ArrayList<List<HashMap<String, String>>>) parser.parse(jObject);
}
return routes;
} catch (Exception e) {
Log.d("Background task", e.toString());
return null; // Failed, return null
}
}
// Executes in UI thread, after the parsing process
@Override
protected void onPostExecute(ArrayList<List<HashMap<String, String>>> result) {
if (result.size() < 1) {
Toast.makeText(getActivity(), "No Points", Toast.LENGTH_LONG).show();
return;
}
TextView tv1 = (TextView) getActivity().findViewById(R.id.location1);
TextView tv2 = (TextView) getActivity().findViewById(R.id.location2);
TextView tv3 = (TextView) getActivity().findViewById(R.id.location3);
TextView tv4 = (TextView) getActivity().findViewById(R.id.location4);
TextView[] views = { tv1, tv2, tv3, tv4 };
// Traversing through all the routes
for (int i = 0; i < result.size(); i++) {
// Fetching i-th route
List<HashMap<String, String>> path = result.get(i);
String distance = "No distance";
// Fetching all the points in i-th route
for (int j = 0; j < path.size(); j++) {
HashMap<String, String> point = path.get(j);
if (j == 0) {
distance = point.get("distance");
continue;
}
}
Log.d("Distance: ", distance);
// Set text
views[i].setText(distance);
}
}
}
<?xml version="1.0" encoding="utf-8"?>
<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" >
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="vertical" >
<TextView
android:id="@+id/location1"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<TextView
android:id="@+id/location2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:text="TextView" />
<TextView
android:id="@+id/location3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:text="TextView" />
<TextView
android:id="@+id/location4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginTop="5dp"
android:text="TextView" />
</LinearLayout>
</RelativeLayout>
以下是现有代码的更新:
// Executes in UI thread, after the parsing process
@Override
protected void onPostExecute(List<List<HashMap<String, String>>> result)
{
if (result.size() < 1)
{
Toast.makeText(getActivity(), "No Points", Toast.LENGTH_SHORT).show();
return;
}
TextView tv1 = (TextView) getActivity().findViewById(R.id.location1);
TextView tv2 = (TextView) getActivity().findViewById(R.id.location2);
TextView tv3 = (TextView) getActivity().findViewById(R.id.location3);
TextView tv4 = (TextView) getActivity().findViewById(R.id.location4);
TextView[] views = {tv1, tv2, tv3, tv4};
// Traversing through all the routes
for (int i = 0; i < result.size(); i++)
{
// Fetching i-th route
List<HashMap<String, String>> path = result.get(i);
String distance = "No distance";
// Fetching all the points in i-th route
for (int j = 0; j < path.size(); j++)
{
HashMap<String, String> point = path.get(j);
if (j == 0)
{
distance = point.get("distance");
continue;
}
}
// Set text
views[i].setText(distance);
}
}
这段代码做了一个不太好的假设:它假设result
的大小与views
相同,在您的例子中应该是4。在运行此代码时,如果有超过4个结果,则可能会出现indexoutofbounds
错误(这是不应该发生的)。最终,您需要验证result
的大小是否为4,或者textview
的数量是否为。如果你有任何问题或这不是正确的,请让我知道:)
编辑:要同时获得所有距离,可以修改DownloadTask
以接收多个URL。
更改类定义:
private class DownloadTask extends AsyncTask<String, Void, ArrayList<String>>
这表明您的后台操作将返回字符串
的列表。
修改了doinbackground()
,现在可以处理多个URL:
// Downloading data in non-ui thread
@Override
protected ArrayList<String> doInBackground(String... urlList)
{
try
{
ArrayList<String> returnList = new ArrayList<String>();
for(String url : urlList)
{
// Fetching the data from web service
String data = Locations.this.downloadUrl(url);
returnList.add(data);
}
return returnList;
}
catch (Exception e)
{
Log.d("Background Task", e.toString());
return null; // Failed, return null
}
}
// Executes in UI thread, after the execution of
// doInBackground()
@Override
protected void onPostExecute(ArrayList<String> results)
{
super.onPostExecute(results);
ParserTask parserTask = new ParserTask();
// Invokes the thread for parsing the JSON data
parserTask.execute(results);
}
编辑两个:在getlastlocation()
中,您只使用一个URL调用downloadtask
,但是您应该放置四个URL,类似于downloadtask.execute(url1,url2,url3,url4)
。另外,由于ParserTask
仍然只处理一个JSON字符串,因此应该从onPostExecute()
中取出四个TextView
和数组循环。要告诉ParserTask
要填充哪个TextView
,请向ParserTask
添加一个构造函数,该构造函数接受TextView
作为参数。然后在ParserTask
中创建一个实例变量,该变量在构造函数中赋值,并在onPostExecute()
中使用,以显示距离。
然后,将我之前给出的TextView
数组内容放在DownloadTask
的onPostExecute()
中。在遍历字符串结果时,也要遍历TextView
数组,并在ParserTask
构造函数中传入TextView
。
基本上,您要在ParserTask
中添加一个构造函数来告诉它要在哪个TextView
上绘制。当DownloadTask
完成时,将为URL传递正确的TextView
。例如,第三个URL的r.id.location3
。
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