Android Studio无法使用json绘制标记 [英] Android Studio unable to plot marker using json
本文介绍了Android Studio无法使用json绘制标记的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我试图用json绘制标记，其中没有显示标记。这里是我的地图活动代码。
I am trying to plot marker using json in which marker is not showing.here is my code of map activity.
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {
public GoogleMap mMap;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
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);
}
public void onMapSearch (View view) throws IOException {
//hide button when button is pressed
InputMethodManager inputManager = (InputMethodManager) getSystemService(this.INPUT_METHOD_SERVICE);
inputManager.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), InputMethodManager.HIDE_NOT_ALWAYS);
//preview the entered address as an Tost in bar
EditText locationSearch = (EditText) findViewById(R.id.editText);
String location = locationSearch.getText().toString();
//this will animate camera and zoom 12.0f
mMap.animateCamera(CameraUpdateFactory.zoomTo(12.0f));
//further address search codes
List<Address> addressList = null;
//if nothing will be entered in the edit-text will not show a toast rather than crashing of thekha app
if (locationSearch.getText().toString().equals("")){
Toast.makeText(this,"Bitch please enter A Value",Toast.LENGTH_LONG).show();
}
else {
//process of exception handling and finding location
if (location != null || !location.equals("")) {
Geocoder geocoder = new Geocoder(this);
try {
addressList = geocoder.getFromLocationName(location, 1);
} catch (IOException e) {
e.printStackTrace();
}
//if address is greater than one then these processes will happen
if(addressList.size()>0) {
Address address = addressList.get(0);
LatLng latLng = new LatLng(address.getLatitude(), address.getLongitude());
mMap.addMarker(new MarkerOptions()
.position(latLng)
.title(location + " is Here- ")
.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_BLUE)));
mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
Toast.makeText(this, location+" is here, Zoom In or Zoom Out to make your Thekha Visible ", Toast.LENGTH_LONG)
.show(); //popup type to show entered data
}
else {
//process where entered entry will not gonna find , this will gonna a toast to show popup
Toast.makeText(this,"Entered Address Not Found", Toast.LENGTH_LONG).show();
}
}
}
}
private void setUpMap (){
final MapsActivity that = this;
new Thread(new Runnable() {
@Override
public void run() {
try {
retriveAndAddMarker();
}catch (IOException e){
Toast.makeText(that,"Can not fetch data",Toast.LENGTH_LONG).show();
}
}
});
}
protected void retriveAndAddMarker () throws IOException {
final MapsActivity that = this;
HttpURLConnection conn = null;
final StringBuilder json = new StringBuilder();
try {
//connect to the web service
URL url = new URL("http://www.loofre.com/api-for-webservice/?debug=true&action=getLocations");
conn = (HttpURLConnection) url.openConnection();
InputStreamReader in = new InputStreamReader(conn.getInputStream());
//This will read the json data into string builder
int read;
char[] buff = new char[1024];
while ((read = in.read(buff)) != -1) {
json.append(buff, 0, read);
}
} catch (IOException e) {
Toast.makeText(this, "Error connecting to Service", Toast.LENGTH_LONG).show();
throw new IOException("Error Connecting to service ", e);
} finally {
if (conn != null)
conn.disconnect();
Toast.makeText(this,"Disconnected",Toast.LENGTH_LONG).show();
}
//create marker for the onMapReady over main thekha app
// Must run this on this on the UI thread since its the UI operation.
runOnUiThread(new Runnable() {
@Override
public void run() {
try {
Toast.makeText(that, "Connection SuccessFull", Toast.LENGTH_LONG).show();
createMarkerFromJson(json.toString());
}catch (JSONException e){
Toast.makeText(that,"",Toast.LENGTH_LONG).show();
}
}
});
}
void createMarkerFromJson (String json) throws JSONException {
// de-derialize the json string into an array of objects
JSONArray jsonArray = new JSONArray(json);
for (int i =0; i<jsonArray.length(); i++){
//create marker of each place in the json data
JSONObject jsonObject = jsonArray.getJSONObject(i);
mMap.addMarker(new MarkerOptions()
.title(jsonObject.getString("name"))
.snippet(Integer.toString((jsonObject.getInt("address"))))
.position(new LatLng(
jsonObject.getJSONArray("latlang").getDouble(0),
jsonObject.getJSONArray("latlang").getDouble(0)
)
)
);
}
}
//OnReady map starts here when we can enter or add Marker to the map
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
setUpMap();
// no 1 marker
LatLng dwarka = new LatLng(28.570317,77.32182);
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(dwarka, 13));
mMap.addMarker(new MarkerOptions()
.title("Wine Beer Liquor Shop, Sector 18, Noida")
.snippet("Sector 18, Near Centre Stage Mall, Noida")
.position( dwarka ));
//no 2 marker
LatLng OPG_world_School = new LatLng(28.581074,77.314349);
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(OPG_world_School,13));
mMap.addMarker(new MarkerOptions()
.title("Wine Beer Liquor Shop, Sector 15, Noida")
.snippet("Basoya Complex, Sector 15, Near Wipro, Noida")
.position(OPG_world_School));
//no 3 marker
LatLng sector27 = new LatLng(28.581074,77.314349);
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(sector27,13));
mMap.addMarker(new MarkerOptions()
.title("Wine Beer Liquor Shop, sector 27, Noida")
.snippet("Dharam Pali Palace, Sector 27, Near Vinayak Hospital, Noida")
.position(sector27));
//no 4 marker
LatLng gurgramamb = new LatLng(28.504865,77.094588); // tobe edited
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(gurgramamb,13));
mMap.addMarker(new MarkerOptions()
.title("Discovery Wines")
.snippet("Discovery Wines, Ambience Mall, Gurgaon")
.position(gurgramamb));
if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission
(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
// TODO: Consider calling
// ActivityCompat#requestPermissions
// here to request the missing permissions, and then overriding
// public void onRequestPermissionsResult(int requestCode, String[] permissions,
// int[] grantResults)
// to handle the case where the user grants the permission. See the documentation
// for ActivityCompat#requestPermissions for more details.
return;
}
//tool bar and other tool related on map uiSettings
mMap.setMyLocationEnabled(true);
mMap.getUiSettings().setZoomControlsEnabled(true);
mMap.getUiSettings().setMapToolbarEnabled(true);
mMap.getUiSettings().setMyLocationButtonEnabled(true);
}
}
推荐答案
你的问题在 retriveAndAddMarker 上。您正在使用应该使用AsyncTask运行的网络线程拨打电话。
Your issue is on retriveAndAddMarker. You're making a call using network thread that supposed to be run using AsyncTask.
网络操作可能涉及不可预知的延迟。为了防止这种情况导致糟糕的用户体验，请始终在UI的单独线程上执行网络操作。 AsyncTask类提供了一种最简单的方法来从UI线程中触发新任务 - Android开发人员[在单独线程上执行网络操作]
您可以尝试添加以下代码片段：
You can try adding this snippet:
private class RetrieveMarkerTask extends AsyncTask<StringBuilder, Void, StringBuilder> {
private Context context;
public RetrieveMarkerTask(Context context){
this.context = context;
}
@Override
protected StringBuilder doInBackground(StringBuilder... stringBuilders) {
HttpURLConnection conn = null;
final StringBuilder json = new StringBuilder();
try {
//connect to the web service
URL url = new URL("http://www.loofre.com/api-for-webservice/?debug=true&action=getLocations");
conn = (HttpURLConnection) url.openConnection();
InputStreamReader in = new InputStreamReader(conn.getInputStream());
//This will read the json data into string builder
int read;
char[] buff = new char[1024];
while ((read = in.read(buff)) != -1) {
json.append(buff, 0, read);
}
} catch (IOException e) {
return null;
} finally {
if (conn != null)
conn.disconnect();
}
return json;
}
@Override
protected void onPostExecute(StringBuilder stringBuilder) {
super.onPostExecute(stringBuilder);
if(null != stringBuilder){
try {
((MapsActivity)context).createMarkerFromJson(stringBuilder.toString());
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
在您的 retriveAndAddMarker（）中，删除此方法中的所有行，并用下面的行替换。
And in your retriveAndAddMarker(), remove all those lines inside this method and replace with line below.
protected void retriveAndAddMarker (){
//remove all the previous code
new RetrieveMarkerTask(this).execute();
}
注意：
我简单地创建基于你的代码的AsyncTask，所以我不确定它是否工作。您需要自行调试。
Note: I simply created the AsyncTask based on your code, so I am not sure if it is working or not. You need to debug it on your own.
这篇关于Android Studio无法使用json绘制标记的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
