Question

**我有一张地图，我添加了一些标记和半径的本地化 - 我想要一些代码让我知道我是否在半径范围内**

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);
    }}

总是当我在圆圈半径范围内搜索做某事时我可以理解这段代码的效果，我不知道在哪里可以将它插入我的FirstFragment

 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

只需使用getActivity()代替this

Answer 2

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 3

在活动中，您必须使用this来接受上下文，游标 ..等等

但在片段中，我们使用getActivity()代替。

Answer 4

对片段使用getActivity（）和ContextCompact：

替换它：

 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)

使用：

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)

检查我是否在圆的半径范围内或外圆

4 个答案: