Question

我想在活动开始时缩放到用户的当前位置。我有两个java类。一个是MapActivity.java，另一个是MapFragment.java。我试图在MapFragment.java上做这个工作。

  private Actvity activity;
  private volatile GoogleMap googleMap;
  GoogleApiClient mGoogleApiClient;
  LocationRequest mLocationRequest;

  @Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    activity = getActivity();
}

MapFragment.java/onMapReady;

@Override
public void onMapReady(GoogleMap map) {
    googleMap = map;

    mGoogleApiClient=new GoogleApiClient.Builder(activity)
            .addApi(LocationServices.API)
            .addConnectionCallbacks(activity)
            .addOnConnectionFailedListener(activity)
            .build();

    mGoogleApiClient.connect();

}

在这个onMapReady中，.addConnectionCallbacks（activity）和.addOnConnectionFailedListener（activity）给出了图像中的警告;

enter image description here

在我们实施GoogleApiClient.ConnectionCallbacks和GoogleApiCleint.OnConnectionFailedListener之前我已经分析过的示例中。没有实施，我就无法获得这些功能;

 @Override
public void onConnected(Bundle bundle) {

    mLocationRequest=LocationRequest.create();
    mLocationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);

    mLocationRequest.setInterval(1000);

    LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient,mLocationRequest,this);

}

@Override
public void onConnectionSuspended(int i) {

}
 @Override
public void onConnectionFailed(ConnectionResult connectionResult) {

}

而且我必须得到LocationListeners的方法;

@Override
public void onLocationChanged(Location location) {
    if(location == null){
        Toast.makeText(this,"Cant get current location",Toast.LENGTH_LONG).show();

    }
    else{
        LatLng ll= new LatLng(location.getLatitude(),location.getLongitude());
        CameraUpdate update= CameraUpdateFactory.newLatLngZoom(ll,15);
        mGoogleMap.animateCamera(update);
    }
}

如果我在片段中手动实现它们，是否会导致任何问题？在片段活动中获取当前位置的正确方法是什么？

Answer 1

如果我在片段中手动实现它们，它是否会导致它们问题

没有。您需要做的就是实施ConnectionCallbacks和OnConnectionFailedListener。

在片段活动中获取当前位置的正确方法是什么？

public class MyFragment extends Fragment implements
        ConnectionCallbacks, OnConnectionFailedListener {

    // Create an instance of GoogleAPIClient.
    if (mGoogleApiClient == null) {
    mGoogleApiClient = new GoogleApiClient.Builder(this)
        .addConnectionCallbacks(this)
        .addOnConnectionFailedListener(this)
        .addApi(LocationServices.API)
        .build();
    }

    protected void onStart() {
        mGoogleApiClient.connect();
        super.onStart();
    }

    protected void onStop() {
        mGoogleApiClient.disconnect();
        super.onStop();
    }
   @Override
   public void onConnected(Bundle connectionHint) {
        mLastLocation = LocationServices.FusedLocationApi.getLastLocation(
                mGoogleApiClient); // this is your location
        if (mLastLocation != null) {              
         mLatitudeText.setText(String.valueOf(mLastLocation.getLatitude()));
       mLongitudeText.setText(String.valueOf(mLastLocation.getLongitude()));
        }
    }
}

Reference

Answer 2

我在Activity和Location侦听器中实现了Fragment，并在片段中调用MapReady来获取当前位置。请参阅以下代码。

MainActivity.Java

public class MainActivity extends AppCompatActivity {
     public static final String TAG = MainActivity.class.getSimpleName();
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        setFragment(new MapFragment());
    }
    // class for being re-used by several instances
    protected void setFragment(Fragment fragment) {
        FragmentManager fragmentManager = getSupportFragmentManager();
        FragmentTransaction fragmentTransaction =
                fragmentManager.beginTransaction();
        fragmentTransaction.replace(android.R.id.content, fragment);
        fragmentTransaction.commit();
    }
}

activity_main.xml中

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:android="http://schemas.android.com/apk/res/android">
        <FrameLayout
        android:id="@+id/frame_containerone"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />
    <ImageView
        android:id="@+id/imagenext"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentRight="true"
        android:layout_margin="16dp"
        />
</RelativeLayout>

MapFragment.Java

public class MapFragment extends Fragment implements GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener,
        LocationListener, OnMapReadyCallback {
    private static final String TAG = "MapFragment";
    MainActivity mActivity;
    private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;
    private GoogleMap mMap; // Might be null if Google Play services APK is not available.
    SupportMapFragment mapFragment;
    private GoogleApiClient mGoogleApiClient;
    private LocationRequest mLocationRequest;
    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.map_fragment, null, true);
        mActivity = ((MainActivity) getActivity());
        initViews(view);
        return view;
    }
    private void initViews(View view) {
        mGoogleApiClient = new GoogleApiClient.Builder(mActivity)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
        // Create the LocationRequest object
        mLocationRequest = LocationRequest.create()
                .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
                .setInterval(10 * 1000)        // 10 seconds, in milliseconds
                .setFastestInterval(1 * 1000); // 1 second, in milliseconds
        mapFragment = (SupportMapFragment) this.getChildFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
    }
    @Override
    public void onMapReady(GoogleMap map) {
        mMap = map;
        mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
    }
    @Override
    public void onConnected(@Nullable Bundle bundle) {
        if (ActivityCompat.checkSelfPermission(mActivity, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(mActivity, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            return;
        }
        Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
        if (location == null) {
            LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
        } else {
            handleNewLocation(location);
        }
    }
    private void handleNewLocation(Location location) {
        Log.d(TAG, location.toString());
        double currentLatitude = location.getLatitude();
        double currentLongitude = location.getLongitude();
        LatLng latLng = new LatLng(currentLatitude, currentLongitude);
        MarkerOptions options = new MarkerOptions()
                .position(latLng)
                .title("I am here!");
        mMap.addMarker(options);
        mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
    }
    @Override
    public void onConnectionSuspended(int i) {
    }
    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {
        if (connectionResult.hasResolution()) {
            try {
                // Start an Activity that tries to resolve the error
                connectionResult.startResolutionForResult(mActivity, CONNECTION_FAILURE_RESOLUTION_REQUEST);
                /*
                 * Thrown if Google Play services canceled the original
                 * PendingIntent
                 */
            } catch (IntentSender.SendIntentException e) {
                // Log the error
                e.printStackTrace();
            }
        } else {
            /*
             * If no resolution is available, display a dialog to the
             * user with the error.
             */
            Log.i(TAG, "Location services connection failed with code " + connectionResult.getErrorCode());
        }
    }
    @Override
    public void onLocationChanged(Location location) {
        handleNewLocation(location);
    }
    @Override
    public void onResume() {
        super.onResume();
        setUpMapIfNeeded();
        mGoogleApiClient.connect();
    }
    private void setUpMapIfNeeded() {
        // Do a null check to confirm that we have not already instantiated the map.
        if (mMap == null) {
            // Try to obtain the map from the SupportMapFragment.
            mapFragment = (SupportMapFragment) this.getChildFragmentManager().findFragmentById(R.id.map);
            mapFragment.getMapAsync(this);//    mapFragment.getMapAsync((OnMapReadyCallback) mActivity);
        }
    }
    @Override
    public void onPause() {
        super.onPause();
        if (mGoogleApiClient.isConnected()) {
            LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
            mGoogleApiClient.disconnect();
        }
    }
}

map_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">
   <!-- <fragment xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/map"
        android:name="com.google.android.gms.maps.SupportMapFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />-->
        <fragment
            android:id="@+id/map"
            android:name="com.google.android.gms.maps.SupportMapFragment"
            android:layout_width="match_parent"
            android:layout_height="388dp"
            android:layout_weight="0.40" />
</LinearLayout>

清单：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.theme.fragment">
    <permission
        android:name="com.theme.fragment.permission.MAPS_RECEIVE"
        android:protectionLevel="signature" />
    <uses-permission android:name="com.theme.fragment.permission.MAPS_RECEIVE" />
    <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
    <uses-permission android:name="android.permission.INTERNET" />
    <uses-permission android:name="com.google.android.providers.gsf.permission.READ_GSERVICES" />
    <uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    <!-- Required to show current location -->
    <uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
    <uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <!-- Goolge API Key -->
        <meta-data
            android:name="com.google.android.maps.v2.API_KEY"
            android:value="Your_Api key" />
    </application>
</manifest>

在活动开始时尝试获取当前位置

2 个答案: