本文概述
- Geocoder类的方法
现在，在本教程中，我们将在Google Map中实现位置搜索功能。
通过Geocoder类在Google Map API中搜索位置。 Geocoder类用于处理地理编码和反向地理编码。
地理编码是将街道地址转换为坐标（纬度，经度）的过程。反向地理编码是将坐标（纬度，经度）转换为地址的过程。
Geocoder类的方法
- List < Address> getFromLocation（双精度纬度，双精度经度，整数maxResults）：此方法返回一个Address数组，该数组指定周围的纬度和经度。
- List < Address> getFromLocationName（字符串位置，整数结果，double leftLatitude，double leftLongitude，double rightLatitude，double rightLongitude）：此方法返回一个Address数组，该数组描述给定的位置，例如位置，地址等。
- List < Address> getFromLocationName（字符串位置，整数结果）：此方法返回一个Address数组，该数组描述给定的位置，例如位置，地址等。
- 静态boolean isPresent（）：如果实现了方法getFromLocation（）和getFromLocationName（），则此方法返回true。
List<
Address> addressList = geocoder.getFromLocationName(location, 1);
Address address = addressList.get(0);
LatLng latLng = new LatLng(address.getLatitude(), address.getLongitude());
Android Google Map API搜索位置示例
让我们看一个Google Map搜索输入位置的示例。
activity_maps.xml
在activity_maps.xml文件中添加一个片段（SupportMapFragment），EditText和Button。
<
fragment xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:map="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/map"
android:name="com.google.android.gms.maps.SupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="example.com.mapexample.MapsActivity">
<
LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"><
EditText
android:layout_width="248dp"
android:layout_height="wrap_content"
android:id="@+id/editText"
android:layout_weight="0.5"
android:inputType="textPersonName"
android:hint="Search Location" /><
Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="0.5"
android:onClick="searchLocation"
android:text="Search" /><
/LinearLayout><
/fragment>build.gradel
在build.gradel文件中添加以下依赖项。
dependencies {
implementation fileTree(dir: 'libs', include: ['*.jar'])
implementation 'com.android.support:appcompat-v7:26.1.0'
implementation 'com.google.android.gms:play-services-maps:11.8.0'
compile 'com.google.android.gms:play-services-location:11.8.0'
testImplementation 'junit:junit:4.12'
androidTestImplementation 'com.android.support.test:runner:1.0.1'
androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.1'}MapsActivity.java
在MapsActivity.java文件中添加以下代码。
package example.com.mapexample;
import android.location.Address;
import android.location.Geocoder;
import android.os.Build;
import android.support.v4.app.FragmentActivity;
import android.os.Bundle;
import com.google.android.gms.common.api.GoogleApiClient;
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.BitmapDescriptorFactory;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.location.LocationServices;
import android.location.Location;
import android.Manifest;
import android.content.pm.PackageManager;
import android.support.v4.content.ContextCompat;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;
import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import java.io.IOException;
import java.util.List;
public class MapsActivity extends FragmentActivity implements OnMapReadyCallback, LocationListener, GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener{private GoogleMap mMap;
Location mLastLocation;
Marker mCurrLocationMarker;
GoogleApiClient mGoogleApiClient;
LocationRequest mLocationRequest;
@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);
}@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}
}
else {
buildGoogleApiClient();
mMap.setMyLocationEnabled(true);
}}
protected synchronized void buildGoogleApiClient() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this)
.addApi(LocationServices.API).build();
mGoogleApiClient.connect();
}@Override
public void onConnected(Bundle bundle) {mLocationRequest = new LocationRequest();
mLocationRequest.setInterval(1000);
mLocationRequest.setFastestInterval(1000);
mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
}}@Override
public void onConnectionSuspended(int i) {}@Override
public void onLocationChanged(Location location) {mLastLocation = location;
if (mCurrLocationMarker != null) {
mCurrLocationMarker.remove();
}
//Place current location marker
LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
MarkerOptions markerOptions = new MarkerOptions();
markerOptions.position(latLng);
markerOptions.title("Current Position");
markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
mCurrLocationMarker = mMap.addMarker(markerOptions);
//move map camera
mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
mMap.animateCamera(CameraUpdateFactory.zoomTo(11));
//stop location updates
if (mGoogleApiClient != null) {
LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
}}@Override
public void onConnectionFailed(ConnectionResult connectionResult) {}public void searchLocation(View view) {
EditText locationSearch = (EditText) findViewById(R.id.editText);
String location = locationSearch.getText().toString();
List<
Address> addressList = null;
if (location != null || !location.equals("")) {
Geocoder geocoder = new Geocoder(this);
try {
addressList = geocoder.getFromLocationName(location, 1);
} catch (IOException e) {
e.printStackTrace();
}
Address address = addressList.get(0);
LatLng latLng = new LatLng(address.getLatitude(), address.getLongitude());
mMap.addMarker(new MarkerOptions().position(latLng).title(location));
mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
Toast.makeText(getApplicationContext(), address.getLatitude()+" "+address.getLongitude(), Toast.LENGTH_LONG).show();
}
}}AndroidManifest.xml中的必需权限
在AndroidManifest.xml文件中添加以下用户权限。
<
uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<
uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<
uses-permission android:name="android.permission.INTERNET" />AndroidManifest.xml
<
?xml version="1.0" encoding="utf-8"?>
<
manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="example.com.mapexample">
<
!--
The ACCESS_COARSE/FINE_LOCATION permissions are not required to use
Google Maps Android API v2, but you must specify either coarse or fine
location permissions for the 'MyLocation' functionality.
-->
<
uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<
uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<
uses-permission android:name="android.permission.INTERNET" /><
application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<
!--
The API key for Google Maps-based APIs is defined as a string resource.
(See the file "res/values/google_maps_api.xml").
Note that the API key is linked to the encryption key used to sign the APK.
You need a different API key for each encryption key, including the release key that is used to
sign the APK for publishing.
You can define the keys for the debug and release targets in src/debug/ and src/release/.
-->
<
meta-data
android:name="com.google.android.geo.API_KEY"
android:value="http://www.srcmini.com/@string/google_maps_key" /><
activity
android:name=".MapsActivity"
android:label="@string/title_activity_maps">
<
intent-filter>
<
action android:name="android.intent.action.MAIN" /><
category android:name="android.intent.category.LAUNCHER" />
<
/intent-filter>
<
/activity>
<
/application><
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