检查我在里面或圈外的半径

Question

**我有一个地图，我添加一些本地化具有带有标记的半径 - 我想一些代码，让我知道，如果我在半径与否**

这是我的代码：

public class FirstFragment extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.map_layout1);
    // 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);
    }

    public void buttonClicked(View v) {

    switch (v.getId()) {
     case R.id.gps:
                if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                    // TODO: Consider calling
                    //    ActivityCompat#requestPermissions
                    // here to request the missing permissions, and then overriding
                    //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
                    //                                          int[] grantResults)
                    // to handle the case where the user grants the permission. See the documentation
                    // for ActivityCompat#requestPermissions for more details.
                    return;
                }
    //Enable the GPS
                mMap.setMyLocationEnabled(true);
        }}
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;

        // first place where i want Marker
        // first place where i want Radius
        LatLng COLLEGE = new LatLng(36.848339, 10.268338);
        Marker college = mMap.addMarker(new MarkerOptions().position(COLLEGE));
        mMap.moveCamera(CameraUpdateFactory.newLatLng(COLLEGE));
        mMap.animateCamera(CameraUpdateFactory.newLatLng(COLLEGE));
    //add the circle
        CircleOptions circleOptions = new CircleOptions();
     circleOptions.center(COLLEGE);
        circleOptions.radius(1000);//add the radius
        mMap.addCircle(circleOptions);

        // first place where i want Marker
        // first place where i want Radius

        LatLng MAR = new LatLng(36.806495, 10.181532);
        Marker mar = mMap.addMarker(new MarkerOptions().position(MAR));
        mMap.moveCamera(CameraUpdateFactory.newLatLng(MAR));
        mMap.animateCamera(CameraUpdateFactory.newLatLng(MAI));
      //add the circle
        CircleOptions circle = new CircleOptions();
        circle.center(MAR);
      //add the radius
        circle.radius(1000);
        mMap.addCircle(circle);
    }}

总是当我搜索一下做一些事情时，我在里面的圆半径，我可以理解这段代码的效果，我不知道在哪里可以在我的FirstFragment插入

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

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

Answer 1

在活动中，你必须使用this访问上下文，cursor..etc

但在片段，我们使用getActivity()代替。

Answer 2

只需使用getActivity()代替this的

Answer 3

使用getActivity（）

      if (ActivityCompat.checkSelfPermission(getActivity(), android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(getActivity(), android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                // TODO: Consider calling // ActivityCompat#requestPermissions // here to request the missing permissions, and then overriding // public void onRequestPermissionsResult(int requestCode, String[] permissions, // int[] grantResults) // to handle the case where the user grants the permission. See the documentation // for ActivityCompat#requestPermissions for more details. return; } mgoogleMap.setMyLocationEnabled(true);
            }      

Answer 4

使用getActivity（）和ContextCompact的片段：

替换此：

 if (ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)

附：

if (ContextCompat.checkSelfPermission(getActivity(), android.Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ContextCompat.checkSelfPermission(this, android.Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED)