Question

我正在使用Google Maps API。

我想要的是当我移动到某个特定位置并且我已经在地图上绘制了一个圆圈时，它将转到另一个活动。

所以它就像：

我的位置是a =（X，Y）
圆圈位置为b =（X，Y）半径= 10
当我在半径范围内时，它将转到另一个活动或做某事。

有什么想法吗？

我已经在使用distanceTo()，但仍然没有成功。

编辑：这是更新的代码仍然不适合我：

public void onLocationChanged(Location location)
{
float [] distance = new float[];
Location.distanceBetween(location.getLatitude(),location.getLongitude(),-6.xxxxxxx,106.xxxxxxx,distance);

if (distance[0] < 50)
   {
   Intent i = new Intent(student_activity.this,indoor.class);
   student_activity.this,startActivity(i);
   }
}

此方法setUpMapIfNeeded（）在onCreate方法中调用：

public void circle()
{
Circle circle = mMap.addCircle (new CircleOptions()
.center(new LatLng(-6.xxxxxxx,106.xxxxxxx))
.radius(50)
.strokeColor(Color.RED)
.strokeWidth(1)
.fillColor(Color.RED)
}

Answer 1

您可以使用地理围栏，但如果您只是想确定当前位置是否在地图上绘制的圆圈内，则可以使用此技术。

只需比较当前位置到圆心的距离，并检查距离是否小于半径。

我回答了类似问题here，您可以在其中查看更多信息和屏幕截图示例。

请注意，下面的代码使用了被删除的onMyLocationChangeListener，但您可以使用任何类型的位置回调来执行此操作，包括FusedLocationProviderApi。

googleMap.setOnMyLocationChangeListener(new GoogleMap.OnMyLocationChangeListener() {
            @Override
            public void onMyLocationChange(Location location) {
                float[] distance = new float[2];

                Location.distanceBetween( location.getLatitude(), location.getLongitude(),
                        mCircle.getCenter().latitude, mCircle.getCenter().longitude, distance);

                if( distance[0] < mCircle.getRadius() ){
                    //current location is within circle
                    //start new activity
                    Intent i = new Intent(ThisActivity.this, OtherActivity.class);
                    ThisActivity.this.startActivity(i);
                }

            }
        });

编辑：这是一个完全正常运行且经过测试的类，它使用FusedLocationApi来获取当前位置：

import android.content.Intent;
import android.graphics.Color;
import android.location.Location;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.widget.Toast;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
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.SupportMapFragment;
import com.google.android.gms.maps.model.Circle;
import com.google.android.gms.maps.model.CircleOptions;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.LatLngBounds;
import com.google.android.gms.maps.model.MarkerOptions;

public class MapsActivity extends ActionBarActivity implements
        GoogleApiClient.ConnectionCallbacks, GoogleApiClient.OnConnectionFailedListener, LocationListener {

    private GoogleMap mMap;
    LocationRequest mLocationRequest;
    GoogleApiClient mGoogleApiClient;
    Circle mCircle;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        setUpMapIfNeeded();

        buildGoogleApiClient();
        mGoogleApiClient.connect();
    }

    @Override
    protected void onResume() {
        super.onResume();
        setUpMapIfNeeded();
    }

    @Override
    protected void onPause(){
        super.onPause();
        if (mGoogleApiClient != null) {
            LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
        }
    }


    protected synchronized void buildGoogleApiClient() {
        Toast.makeText(this,"buildGoogleApiClient",Toast.LENGTH_SHORT).show();
        mGoogleApiClient = new GoogleApiClient.Builder(this)
                .addConnectionCallbacks(this)
                .addOnConnectionFailedListener(this)
                .addApi(LocationServices.API)
                .build();
    }

    @Override
    public void onConnected(Bundle bundle) {
        Toast.makeText(this,"onConnected", Toast.LENGTH_SHORT).show();

        mLocationRequest = new LocationRequest();
        mLocationRequest.setInterval(10);
        mLocationRequest.setFastestInterval(10);
        mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
        mLocationRequest.setSmallestDisplacement(0.1F);

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


    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.
            mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                    .getMap();
            // Check if we were successful in obtaining the map.
            if (mMap != null) {
                setUpMap();
            }
        }
    }

    private void setUpMap() {
        mMap.getUiSettings().setMapToolbarEnabled(true);
        mMap.getUiSettings().setZoomControlsEnabled(true);
        mMap.setMyLocationEnabled(true);

        circle();

    }

    public void circle()
    {
        double radiusInMeters = 50.0;
        int strokeColor = 0xffff0000; //red outline
        int shadeColor = 0x44ff0000; //opaque red fill

        mCircle = mMap.addCircle (new CircleOptions()
                .center(new LatLng(37.9614, -122.105))
                .radius(radiusInMeters)
                .fillColor(shadeColor)
                .strokeColor(strokeColor)
                .strokeWidth(1));
    }

    @Override
    public void onConnectionSuspended(int i) {
        Toast.makeText(this,"onConnectionSuspended",Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onConnectionFailed(ConnectionResult connectionResult) {
        Toast.makeText(this,"onConnectionFailed",Toast.LENGTH_SHORT).show();
    }

    @Override
    public void onLocationChanged(Location location) {

        Log.d("locationtesting",  "lat: " + location.getLatitude() + " lon: " + location.getLongitude());

        Toast.makeText(this,"Location Changed",Toast.LENGTH_SHORT).show();

        float[] distance = new float[2];

        Location.distanceBetween( location.getLatitude(), location.getLongitude(),
                mCircle.getCenter().latitude, mCircle.getCenter().longitude, distance);

        if( distance[0] < mCircle.getRadius() ){
            //current location is within circle
            //start new activity
            Intent i = new Intent(this, OtherActivity.class);
            startActivity(i);
        }
    }
}

布局xml：

<fragment xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:id="@+id/map" tools:context=".MapsActivity"
    android:name="com.google.android.gms.maps.SupportMapFragment" />

build.gradle中的依赖项：

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    compile 'com.android.support:appcompat-v7:22.1.1'
    compile 'com.google.android.gms:play-services:7.0.0'
}

首先，我在没有调用startActivity()的情况下进行了测试，以确保我当前的位置在圈内。正如您在屏幕截图中看到的那样：

Map Test

然后，我在startActivity()回调中添加了对onLocationChanged()的调用，并在启动应用后立即启动了OtherActivity。

Answer 2

这听起来像是在描述Google的地理围栏API Geofencing tutorial

当我在圆的半径范围内做某事时

2 个答案: