ANDROID STUDIO - 如何将标记添加到当前位置？
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【中文标题】ANDROID STUDIO - 如何将标记添加到当前位置？【英文标题】：ANDROID STUDIO - How to add marker to current location? 【发布时间】：2021-09-03 08:15:53 【问题描述】：我是 android Studio 的新手，我正在尝试一件事。当我用地图加载我的片段时，我想显示我的位置（这不起作用 - 市场没有出现，相机也没有放大），当我点击按钮时，它会搜索附近的麦当劳。我在 youtube 上找到了它，但我不想让滚动条来选择一个位置，我只想要一个位置，我认为这就是问题所在。
MapActivity.java
import android.Manifest;
import android.content.pm.PackageManager;
import android.location.Location;
import android.os.AsyncTask;
import android.os.Bundle;
import android.widget.Button;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import java.util.HashMap;
import java.util.List;
public class MapActivity extends AppCompatActivity
Button btFind;
SupportMapFragment supportMapFragment;
GoogleMap googleMap;
FusedLocationProviderClient fusedLocationProviderClient;
double currentLat = 0, currentLong = 0;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_map);
btFind = findViewById(R.id.bt_find);
supportMapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.google_map);
String[] placeNameList = "McDonald's";
String[] placeTypeList = "McDonald's";
fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
if (ActivityCompat.checkSelfPermission(MapActivity.this
, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED)
getCurrentLocation();
btFind.setOnClickListener(v ->
String url = "https://maps.google.com/maps/api/place/nearbysearch/json" +
"?location=" + currentLat + "," + currentLong +
"&radius=15000" +
"&types=" + placeTypeList +
"&sensor=true" +
"&key=" + "AIzaSyB-c4k2RXcThSgX9YxeK56QDbzsqK5xPu8";
new PlaceTask().execute(url);
);
private void getCurrentLocation()
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)
return;
Task<Location> task = fusedLocationProviderClient.getLastLocation();
task.addOnSuccessListener(new OnSuccessListener<Location>()
@Override
public void onSuccess(Location location)
if (location != null)
currentLat = location.getLatitude();
currentLong = location.getLongitude();
supportMapFragment.getMapAsync(new OnMapReadyCallback()
@Override
public void onMapReady(GoogleMap googleMap)
GoogleMap map = googleMap;
map.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(currentLong, currentLong), 15.5f), 4000, null
);
);
);
private class PlaceTask extends AsyncTask<String, Integer, String>
@Override
protected String doInBackground(String... strings)
String data = null;
try
data = downloadUrl(strings[0]);
catch (IOException e)
e.printStackTrace();
return data;
@Override
protected void onPostExecute(String s)
new ParserTask().execute(s);
private String downloadUrl(String string) throws IOException
URL url = new URL(string);
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream stream = connection.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(stream));
StringBuilder builder = new StringBuilder();
String line = "";
while ((line = reader.readLine()) != null)
builder.append(line);
String data = builder.toString();
reader.close();
return data;
private class ParserTask extends AsyncTask<String, Integer, List<HashMap<String, String>>>
@Override
protected List<HashMap<String, String>> doInBackground(String... strings)
JsonParser jsonParser = new JsonParser();
List<HashMap<String, String>> mapList = null;
JSONObject object = null;
try
object = new JSONObject(strings[0]);
mapList = jsonParser.parseResult(object);
catch (JSONException e)
e.printStackTrace();
return mapList;
@Override
protected void onPostExecute(List<HashMap<String, String>> hashMaps)
googleMap.clear();
for (int i = 0; i < hashMaps.size(); i++)
HashMap<String, String> hashMapList = hashMaps.get(i);
double lat = Double.parseDouble(hashMapList.get("lat"));
double lng = Double.parseDouble(hashMapList.get("lng"));
String name = hashMapList.get("name");
LatLng latLng = new LatLng(lat, lng);
MarkerOptions options = new MarkerOptions();
options.position(latLng);
options.title(name);
googleMap.addMarker(options);
JsonParser.java
package com.example.mcdonaldscoupons;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.ResourceBundle;
public class JsonParser
private HashMap<String,String> parseJsonObject(JSONObject JSONObject)
HashMap<String, String> dataList = new HashMap<>();
try
JSONArray object = null;
String name = object.getString(Integer.parseInt("name"));
String latitude = object.getJSONObject(Integer.parseInt("geometry"))
.getJSONObject("location").getString("lat");
String longitude = object.getJSONObject(Integer.parseInt("geometry"))
.getJSONObject("location").getString("lng");
dataList.put("name", name);
dataList.put("lat", latitude);
dataList.put("lng", longitude);
catch (JSONException e)
e.printStackTrace();
return dataList;
private List<HashMap<String, String>> parseJsonArray(JSONArray jsonArray) throws JSONException
List<HashMap<String, String>> dataList = new ArrayList<>();
for (int i = 0; i < jsonArray.length(); i++)
HashMap<String, String> data = parseJsonObject((JSONObject) jsonArray.get(i));
dataList.add(data);
return dataList;
public List<HashMap<String, String>> parseResult(JSONObject object) throws JSONException
JSONArray jsonArray = null;
jsonArray = object.getJSONArray("results");
return parseJsonArray(jsonArray);
fragment_map.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_
android:layout_
xmlns:tools="http://schemas.android.com/tools"
android:orientation="vertical"
tools:context=".MapActivity">
<LinearLayout
android:layout_
android:layout_
android:orientation="horizontal"
android:padding="8dp">
<Button
android:id="@+id/bt_find"
android:layout_
android:layout_
android:layout_centerInParent="true"
android:text="Hledej!" />
</LinearLayout>
<androidx.fragment.app.FragmentContainerView
android:layout_
android:layout_
android:id="@+id/google_map"
android:name="com.google.android.gms.maps.SupportMapFragment"/>
</LinearLayout>
【问题讨论】：
你已经输入了你的谷歌密钥，删除这篇文章并创建一个新的。永远不要在 SO 上发布密钥或密码。 你检查了 currentLat,currentLng 在 getCurrentLocation() 中有值吗？ @androidLearner 我该怎么做？ （我是 android 新手，这段代码来自 youtube） 【参考方案1】：如果currentLat,currentLng有值，添加标记
supportMapFragment.getMapAsync(new OnMapReadyCallback()
@Override
public void onMapReady(GoogleMap googleMap)
//use your global map instance.
googleMap= googleMap;
//check value in "Run" tab .
log.i("currrentLat",currrentLat);
log.i("currrentLang",currentLng);
LatLng latLng = new LatLng(currrentLat, currentLng);
MarkerOptions options = new MarkerOptions();
options.position(latLng);
options.title(name);
googleMap.addMarker(options);
googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
new LatLng(currentLong, currentLong), 15.5f), 4000, null
);
);
【讨论】：
错误：找不到符号 options.title(name); 你可以给任何你想要的标题。@VojtěchAdam options.title("test");没有错误，但它仍然不起作用：/ 试试这个 onMapReady(GoogleMap map) googleMap= map; @VojtěchAdam 使用 googleMap= map 它没有工作必须做 googleMap= googleMap 但再次......仍然没有工作【参考方案2】：我看到你这里有一个错字：
new LatLng(currentLong, currentLong),
^^^^^^^^^^^
应该是 currentLat
【讨论】：
当前位置和按钮都不起作用 @VojtěchAdam 你确定你知道位置吗？您是否为清单文件添加了适当的权限？ @VojtěchAdam 您应该使用 ActivityCompat.requestPermissions 请求权限，请参见此处：developers.google.com/android/guides/permissions 一旦授予权限，将在您可以请求位置的地方调用回调 onRequestPermissionsResult。 是的，我在清单中执行它，在我的 MainActivity 中我有一个对话框（互联网、access_fine_location 和 access_coarse_location） 但是在提供的代码中，一旦检查权限失败，您就不要调用 ActivityCompat.requestPermissions。您的代码应包含 ActivityCompat.requestPermissions【参考方案3】：更新伙计们！ 我尝试了不同的代码来显示我当前的位置，但它仍然不起作用：/
MapActivity.java
import android.Manifest;
import android.content.pm.PackageManager;
import android.location.Location;
import android.os.Bundle;
import android.widget.Toast;
import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.app.ActivityCompat;
import androidx.fragment.app.FragmentActivity;
import com.google.android.gms.location.FusedLocationProviderClient;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.OnMapReadyCallback;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.tasks.OnSuccessListener;
import com.google.android.gms.tasks.Task;
import org.jetbrains.annotations.NotNull;
public class MapActivity extends FragmentActivity implements OnMapReadyCallback
Location currentLocation;
FusedLocationProviderClient fusedLocationProviderClient;
private static final int REQUEST_CODE = 101;
@Override
protected void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_map);
fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
fetchLastLocation();
private void fetchLastLocation()
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)
ActivityCompat.requestPermissions(this,new String[]
Manifest.permission.ACCESS_FINE_LOCATION, REQUEST_CODE);
return;
Task<Location> task = fusedLocationProviderClient.getLastLocation();
task.addOnSuccessListener(location ->
if (location != null)
currentLocation = location;
Toast.makeText(getApplicationContext(),currentLocation.getLatitude()
+""+currentLocation.getLongitude(),Toast.LENGTH_SHORT).show();
SupportMapFragment supportMapFragment = (SupportMapFragment)
getSupportFragmentManager().findFragmentById(R.id.google_map);
supportMapFragment.getMapAsync(MapActivity.this);
);
@Override
public void onMapReady(@NonNull @NotNull GoogleMap googleMap)
LatLng latLng = new LatLng(currentLocation.getLatitude(),currentLocation.getLongitude());
MarkerOptions markerOptions = new MarkerOptions().position(latLng)
.title("Here I am!");
googleMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(latLng, 5));
googleMap.addMarker(markerOptions);
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull @NotNull String[] permissions, @NonNull @NotNull int[] grantResults)
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
switch (requestCode)
case REQUEST_CODE:
if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
fetchLastLocation();
break;
fragment_map.xml
<?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_
android:layout_
tools:context=".MapActivity">
<fragment
android:id="@+id/google_map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_
android:layout_ />
</RelativeLayout>
【讨论】：
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