我的应用程序在第一次活动中有两个活动**我检查是否打开了gps。打开它后，我检查Play服务已安装/更新，然后如果我单击按钮，它将转到我的Map.Activity：**：
public class MainActivity extends AppCompatActivity implements GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, ResultCallback {
private static final String TAG = "MainActivity";
private static final int ERROR_DIALOG_REQUEST = 9001;
protected GoogleApiClient mGoogleApiClient;
protected LocationRequest locationRequest;
int REQUEST_CHECK_SETTINGS = 100;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initializeGPS();
}
private void initializeGPS() {
mGoogleApiClient = new GoogleApiClient.Builder(this)
.addApi(LocationServices.API)
.addConnectionCallbacks(this)
.addOnConnectionFailedListener(this).build();
mGoogleApiClient.connect();
locationRequest = LocationRequest.create();
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
locationRequest.setInterval(30 * 1000);
locationRequest.setFastestInterval(5 * 1000);
}
@Override
public void onConnected(@Nullable Bundle bundle) {
LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder()
.addLocationRequest(locationRequest);
builder.setAlwaysShow(true);
PendingResult result =
LocationServices.SettingsApi.checkLocationSettings(
mGoogleApiClient,
builder.build()
);
result.setResultCallback(this);
}
@Override
public void onConnectionSuspended(int i) {
}
@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
}
@Override
public void onResult(@NonNull Result result) {
final Status status = result.getStatus();
switch (status.getStatusCode()) {
case LocationSettingsStatusCodes.SUCCESS:
// NO need to show the dialog;
if (isServicesOK()){
init();
}
break;
case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
// GPS turned off, Show the user a dialog
try {
// Show the dialog by calling startResolutionForResult(), and check the result
// in onActivityResult(). status.startResolutionForResult(MainActivity.this, REQUEST_CHECK_SETTINGS);
} catch (IntentSender.SendIntentException e) {
//failed to show dialog
}
break;
case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
// Location settings are unavailable so not possible to show any dialog now
break;
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == REQUEST_CHECK_SETTINGS) {
if (resultCode == RESULT_OK) {
Toast.makeText(getApplicationContext(), "GPS enabled", Toast.LENGTH_LONG).show();
if (isServicesOK()){
init();
}
} else {
Toast.makeText(getApplicationContext(), "GPS is not enabled", Toast.LENGTH_LONG).show();
}
}
}
@Override
protected void onDestroy() {
super.onDestroy();
if (mGoogleApiClient.isConnected()) {
mGoogleApiClient.disconnect();
}
}
private void init(){
Button buttonMap = (Button) findViewById(R.id.map_btn);
buttonMap.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this, MapActivity.class);
startActivity(intent);
}
});
}
public boolean isServicesOK(){
Log.d(TAG, "isServicesOk: checking google services version");
int available = GoogleApiAvailability.getInstance().isGooglePlayServicesAvailable(MainActivity.this);
if (available == ConnectionResult.SUCCESS){
Log.d(TAG, "isServiceOK: Google Play Services is working ");
return true;
}
else if (GoogleApiAvailability.getInstance().isUserResolvableError(available)){
Log.d(TAG, "isServiceOK: fixable error occurred ");
Dialog dialog = GoogleApiAvailability.getInstance().getErrorDialog(MainActivity.this, available, ERROR_DIALOG_REQUEST);
dialog.show();
}
else {
Toast.makeText(this, "You are not allowed to use this app", Toast.LENGTH_SHORT).show();
}
return false;
}
}
**然后在第二个活动中，我初始化地图并找到我的位置，如果一切正常，它将用蓝点显示我的位置：
public class MapActivity extends AppCompatActivity implements OnMapReadyCallback {
@Override
public void onMapReady(GoogleMap googleMap) {
Toast.makeText(this, "Map is ready", Toast.LENGTH_SHORT).show();
mMap = googleMap;
if (mLocationPermissionGranted) {
getDevicesLocation();
if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
!= PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this,
Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
return;
}
mMap.setMyLocationEnabled(true);
mMap.getUiSettings().setMyLocationButtonEnabled(false);
}
}
private static final String TAG = "MapActivity";
private static final String FINE_LOCATION = Manifest.permission.ACCESS_FINE_LOCATION;
private static final String COARSE_LOCATION = Manifest.permission.ACCESS_COARSE_LOCATION;
private static final int LOCATION_PERMISSION_REQUEST_CODE = 1234;
private static final float DEFAULT_ZOOM = 15f;
private boolean mLocationPermissionGranted = false;
private GoogleMap mMap;
private FusedLocationProviderClient mFusedLocationProviderClient;
protected GoogleApiClient mGoogleApiClient;
protected LocationRequest locationRequest;
int REQUEST_CHECK_SETTINGS = 100;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_map);
getLocationPermission();
}
private void getDevicesLocation(){
mFusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
try{
if (mLocationPermissionGranted){
final Task location = mFusedLocationProviderClient.getLastLocation().addOnCompleteListener(new OnCompleteListener() {
@Override
public void onComplete(@NonNull Task task) {
if (task.isSuccessful() && task.getResult() != null) {
Location currentLocation = (Location) task.getResult();
moveCamera(new LatLng( currentLocation.getLatitude(), currentLocation.getLongitude()), DEFAULT_ZOOM);
}
else{
Toast.makeText(MapActivity.this, "Unable to get current location", Toast.LENGTH_SHORT).show();
}
}
});
}
}catch (SecurityException e){
Log.d(TAG, "getDevicesLocation: " + e.getMessage());
}
}
private void moveCamera(LatLng latLng, float zoom){
mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng, zoom));
}
private void initMap(){
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mapFragment.getMapAsync(MapActivity.this);
}
private void getLocationPermission(){
String[] permissions = {FINE_LOCATION,COARSE_LOCATION};
if (ContextCompat.checkSelfPermission(this.getApplicationContext(), FINE_LOCATION) ==
PackageManager.PERMISSION_GRANTED){
if (ContextCompat.checkSelfPermission(this.getApplicationContext(), COARSE_LOCATION) ==
PackageManager.PERMISSION_GRANTED){
mLocationPermissionGranted = true;
initMap();
}
else {
ActivityCompat.requestPermissions(this, permissions, LOCATION_PERMISSION_REQUEST_CODE);
}
}
else {
ActivityCompat.requestPermissions(this, permissions, LOCATION_PERMISSION_REQUEST_CODE);
}
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
mLocationPermissionGranted = false;
switch (requestCode){
case LOCATION_PERMISSION_REQUEST_CODE:{
if (grantResults.length > 0){
for (int i = 0; i < grantResults.length; i++){
if (grantResults[i] != PackageManager.PERMISSION_GRANTED){
mLocationPermissionGranted = false;
return;
}
}
mLocationPermissionGranted = true;
initMap();
}
}
}
}
}
我的问题是在打开应用程序之前是否打开了gps，并且如果我单击按钮会显示地图和我的位置。但是，如果我通过在位置警报对话框中单击“是”在应用程序中打开GPS，然后单击该按钮，则会向我显示地图，但不会将相机移至我的位置。但是，如果我重新打开该活动，或者如果我在第一次活动中等待5-10秒，它将显示我的位置。但是我不希望任何用户在第一次活动中等待或重新打开应用程序以显示其位置。 **我的问题是：如何以一种简单的方式实现这一目标？ **