下例展示了如何启用“我的位置”图层，并演示了用于在地图上显示设备当前位置（以蓝点表示）的“我的位置”按钮。
如需了解详情，请参阅相关文档。
开始使用
您必须先配置开发环境，然后才能试用该示例代码。如需了解详情，请参阅 Maps SDK for Android 代码示例。
查看代码
class MyLocationDemoActivity : AppCompatActivity(),
OnMyLocationButtonClickListener,
OnMyLocationClickListener, OnMapReadyCallback,
OnRequestPermissionsResultCallback {
/**
* Flag indicating whether a requested permission has been denied after returning in
* [.onRequestPermissionsResult].
*/
private var permissionDenied = false
private lateinit var map: GoogleMap
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.my_location_demo)
val mapFragment =
supportFragmentManager.findFragmentById(R.id.map) as SupportMapFragment?
mapFragment?.getMapAsync(this)
}
override fun onMapReady(googleMap: GoogleMap) {
map = googleMap
googleMap.setOnMyLocationButtonClickListener(this)
googleMap.setOnMyLocationClickListener(this)
enableMyLocation()
}
/**
* Enables the My Location layer if the fine location permission has been granted.
*/
@SuppressLint("MissingPermission")
private fun enableMyLocation() {
// 1. Check if permissions are granted, if so, enable the my location layer
if (ContextCompat.checkSelfPermission(
this,
Manifest.permission.ACCESS_FINE_LOCATION
) == PackageManager.PERMISSION_GRANTED || ContextCompat.checkSelfPermission(
this,
Manifest.permission.ACCESS_COARSE_LOCATION
) == PackageManager.PERMISSION_GRANTED
) {
map.isMyLocationEnabled = true
return
}
// 2. If if a permission rationale dialog should be shown
if (ActivityCompat.shouldShowRequestPermissionRationale(
this,
Manifest.permission.ACCESS_FINE_LOCATION
) || ActivityCompat.shouldShowRequestPermissionRationale(
this,
Manifest.permission.ACCESS_COARSE_LOCATION
)
) {
PermissionUtils.RationaleDialog.newInstance(
LOCATION_PERMISSION_REQUEST_CODE, true
).show(supportFragmentManager, "dialog")
return
}
// 3. Otherwise, request permission
ActivityCompat.requestPermissions(
this,
arrayOf(
Manifest.permission.ACCESS_FINE_LOCATION,
Manifest.permission.ACCESS_COARSE_LOCATION
),
LOCATION_PERMISSION_REQUEST_CODE
)
}
override fun onMyLocationButtonClick(): Boolean {
Toast.makeText(this, "MyLocation button clicked", Toast.LENGTH_SHORT)
.show()
// Return false so that we don't consume the event and the default behavior still occurs
// (the camera animates to the user's current position).
return false
}
override fun onMyLocationClick(location: Location) {
Toast.makeText(this, "Current location:\n$location", Toast.LENGTH_LONG)
.show()
}
override fun onRequestPermissionsResult(
requestCode: Int,
permissions: Array<String>,
grantResults: IntArray
) {
if (requestCode != LOCATION_PERMISSION_REQUEST_CODE) {
super.onRequestPermissionsResult(
requestCode,
permissions,
grantResults
)
return
}
if (isPermissionGranted(
permissions,
grantResults,
Manifest.permission.ACCESS_FINE_LOCATION
) || isPermissionGranted(
permissions,
grantResults,
Manifest.permission.ACCESS_COARSE_LOCATION
)
) {
// Enable the my location layer if the permission has been granted.
enableMyLocation()
} else {
// Permission was denied. Display an error message
// ...
}
}
override fun onResumeFragments() {
super.onResumeFragments()
if (permissionDenied) {
// Permission was not granted, display error dialog.
showMissingPermissionError()
permissionDenied = false
}
}
/**
* Displays a dialog with error message explaining that the location permission is missing.
*/
private fun showMissingPermissionError() {
newInstance(true).show(supportFragmentManager, "dialog")
}
companion object {
/**
* Request code for location permission request.
*
* @see .onRequestPermissionsResult
*/
private const val LOCATION_PERMISSION_REQUEST_CODE = 1
}
}
public class MyLocationDemoActivity extends AppCompatActivity
implements
OnMyLocationButtonClickListener,
OnMyLocationClickListener,
OnMapReadyCallback,
ActivityCompat.OnRequestPermissionsResultCallback {
/**
* Request code for location permission request.
*
* @see #onRequestPermissionsResult(int, String[], int[])
*/
private static final int LOCATION_PERMISSION_REQUEST_CODE = 1;
/**
* Flag indicating whether a requested permission has been denied after returning in {@link
* #onRequestPermissionsResult(int, String[], int[])}.
*/
private boolean permissionDenied = false;
private GoogleMap map;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.my_location_demo);
SupportMapFragment mapFragment =
(SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(this);
}
@Override
public void onMapReady(@NonNull GoogleMap googleMap) {
map = googleMap;
map.setOnMyLocationButtonClickListener(this);
map.setOnMyLocationClickListener(this);
enableMyLocation();
}
/**
* Enables the My Location layer if the fine location permission has been granted.
*/
@SuppressLint("MissingPermission")
private void enableMyLocation() {
// 1. Check if permissions are granted, if so, enable the my location layer
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
== PackageManager.PERMISSION_GRANTED
|| ContextCompat.checkSelfPermission(this, permission.ACCESS_COARSE_LOCATION)
== PackageManager.PERMISSION_GRANTED) {
map.setMyLocationEnabled(true);
return;
}
// 2. Otherwise, request location permissions from the user.
PermissionUtils.requestLocationPermissions(this, LOCATION_PERMISSION_REQUEST_CODE, true);
}
@Override
public boolean onMyLocationButtonClick() {
Toast.makeText(this, "MyLocation button clicked", Toast.LENGTH_SHORT).show();
// Return false so that we don't consume the event and the default behavior still occurs
// (the camera animates to the user's current position).
return false;
}
@Override
public void onMyLocationClick(@NonNull Location location) {
Toast.makeText(this, "Current location:\n" + location, Toast.LENGTH_LONG).show();
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
@NonNull int[] grantResults) {
if (requestCode != LOCATION_PERMISSION_REQUEST_CODE) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
return;
}
if (PermissionUtils.isPermissionGranted(permissions, grantResults,
Manifest.permission.ACCESS_FINE_LOCATION) || PermissionUtils
.isPermissionGranted(permissions, grantResults,
Manifest.permission.ACCESS_COARSE_LOCATION)) {
// Enable the my location layer if the permission has been granted.
enableMyLocation();
} else {
// Permission was denied. Display an error message
// ...
}
}
@Override
protected void onResumeFragments() {
super.onResumeFragments();
if (permissionDenied) {
// Permission was not granted, display error dialog.
showMissingPermissionError();
permissionDenied = false;
}
}
/**
* Displays a dialog with error message explaining that the location permission is missing.
*/
private void showMissingPermissionError() {
PermissionUtils.PermissionDeniedDialog
.newInstance(true).show(getSupportFragmentManager(), "dialog");
}
}
克隆并运行示例
您必须拥有 Git，才能在本地运行此示例。以下命令会克隆示例应用代码库。
git clone git@github.com:googlemaps-samples/android-samples.git
将示例项目导入到 Android Studio：
- 在 Android Studio 中，依次选择 File > New > Import Project。
前往代码库的保存位置并选择 Kotlin 或 Java 的项目目录：
- Kotlin：
PATH-REPO/android-samples/ApiDemos/kotlin - Java：
PATH-REPO/android-samples/ApiDemos/java
- Kotlin：
- 选择 Open。Android Studio 会使用 Gradle 构建工具来构建您的项目。
- 在项目的
local.properties文件所在的同一目录中，创建一个空白secrets.properties文件。如需了解详情，请参阅将您的 API 密钥添加到项目中。 在
secrets.properties中添加以下字符串，并将 YOUR_API_KEY 替换为您的 API 密钥的值：MAPS_API_KEY=
YOUR_API_KEY - 运行应用。