android - OnMarkerDragStart 正在改变标记的原始位置

Question

我正在使用 Google map v2 创建一个应用程序。每次拍摄或选择照片时，我都会创建一个自定义标记并将其添加到 map 中，如下所示:

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (resultCode == RESULT_OK) {
        if (requestCode == SELECT_PICTURE_INTENT) {
            Bitmap photo = createBitmap(data);
            Marker m = map.addMarker(photoMarker(lastKnownLatLng, photo));
            markersInMap.add(m);
            Log.d(TAG, "Marker created with " + m.getPosition().toString());
        }
    }
}

然后，如果我想删除标记，我将它拖到垃圾桶图标上。如果标记触及垃圾桶图标，它就会从 map 中移除；效果很好。如果标记没有接触到垃圾桶，它应该回到原来的位置，但是失败了。当我开始拖动标记时，位置似乎发生了变化，最终略高于 map 。

@Override
public void onMarkerDragStart(Marker marker) {
    trashImageView.setVisibility(View.VISIBLE);
    draggedMarkerOriginalPosition = marker.getPosition();
    Log.d(TAG, "OnMarkerDragStart with " + draggedMarkerOriginalPosition.toString());
}

这两个方法dump了logcat中的nex信息，所以很明显，当我开始拖动时，标记位置发生了变化，但我不知道为什么，确实需要防止这种情况发生:

Marker created with lat/lng: (19.3457139,-99.1522399)
OnMarkerDragStart with lat/lng: (19.35094919370183,-99.15169514715672)

这是我的整个 Activity 代码:

public class MapsActivity extends FragmentActivity implements
        OnMapReadyCallback,
        GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener,
        com.google.android.gms.location.LocationListener,
        GoogleMap.OnMarkerDragListener {

    private static final String TAG = "MAP_ACTIVITY";
    private static final int SELECT_PICTURE_INTENT = 1;

    private GoogleMap map; 
    private Polyline gpsTrack; 
    private SupportMapFragment mapFragment; 
    private GoogleApiClient googleApiClient; 
    private Uri imageUri;
    private LatLng lastKnownLatLng;
    private List<Marker> markersInMap = new ArrayList<>();
    private ImageView trashImageView;
    private LatLng draggedMarkerOriginalPosition;

    private enum MapStatus {
        EXPANDED, NORMAL, MINIMIZED
    }

    private MapStatus mapStatus = MapStatus.NORMAL;

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

        mapFragment = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);

        moveMapLocationButton();

        ImageButton down = (ImageButton) findViewById(R.id.down_arrow);
        down.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                animateDownMapView();
            }
        });

        ImageButton up = (ImageButton) findViewById(R.id.up_arrow);
        up.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                animateUpMapView();
            }
        });

        ImageView camara = (ImageView) findViewById(R.id.camara);
        camara.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                startImageChoosingIntent();
            }
        });

        Button finalizar = (Button) findViewById(R.id.btn_finalizar_recorrido);
        finalizar.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                gpsTrack.setPoints(new ArrayList<LatLng>());
                for(Marker m : markersInMap) m.remove();
                markersInMap.clear();
            }
        });


        if (googleApiClient == null) {
            googleApiClient = new GoogleApiClient.Builder(this)
                    .addConnectionCallbacks(this)
                    .addOnConnectionFailedListener(this)
                    .addApi(LocationServices.API)
                    .build();
        }

        trashImageView = (ImageView) findViewById(R.id.trash);

    }

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

        map.addTileOverlay(new TileOverlayOptions().tileProvider(new CustomMapTileProvider(getResources().getAssets())));

        LatLng calymayor = new LatLng(19.345822, -99.152274);
        map.moveCamera(CameraUpdateFactory.newLatLng(calymayor));
        map.moveCamera(CameraUpdateFactory.newLatLngZoom(calymayor, 15));

        PolylineOptions polylineOptions = new PolylineOptions();
        polylineOptions.color(Color.CYAN);
        polylineOptions.width(4);
        gpsTrack = map.addPolyline(polylineOptions);

        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, 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;
        }
        map.setMyLocationEnabled(true);

        map.setOnMarkerDragListener(this);

    }


    private void moveMapLocationButton() {
        View locationButton = ((View) mapFragment.getView().findViewById(Integer.parseInt("1")).getParent()).findViewById(Integer.parseInt("2"));
        RelativeLayout.LayoutParams rlp = (RelativeLayout.LayoutParams) locationButton.getLayoutParams();
        rlp.addRule(RelativeLayout.ALIGN_PARENT_TOP, 0);
        rlp.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM, RelativeLayout.TRUE);
        rlp.setMargins(0, 0, 30, 30);
    }


    private void animateDownMapView() {
        ResizeAnimation a = new ResizeAnimation(mapFragment.getView());
        a.setDuration(250);

        if (mapStatus == MapStatus.NORMAL) {
            mapStatus = MapStatus.EXPANDED;
            a.setParams(mapFragment.getView().getLayoutParams().height, dpToPx(getResources(), pxToDp(getResources().getDisplayMetrics().heightPixels)));
            mapFragment.getView().startAnimation(a);
        } else if (mapStatus == MapStatus.MINIMIZED) {
            mapStatus = MapStatus.NORMAL;
            mapFragment.getView().setLayoutParams(
                    new LinearLayout.LayoutParams(
                            LinearLayout.LayoutParams.MATCH_PARENT,
                            0,
                            0.3333f
                    )
            );
        }
    }

    private void animateUpMapView() {
        if (mapStatus == MapStatus.NORMAL) {
            mapStatus = MapStatus.MINIMIZED;
            mapFragment.getView().setLayoutParams(
                    new LinearLayout.LayoutParams(
                            LinearLayout.LayoutParams.MATCH_PARENT,
                            0,
                            0.04f
                    )
            );
        } else if (mapStatus == MapStatus.EXPANDED) {
            mapStatus = MapStatus.NORMAL;
            mapFragment.getView().setLayoutParams(
                    new LinearLayout.LayoutParams(
                            LinearLayout.LayoutParams.MATCH_PARENT,
                            0,
                            0.3333f
                    )
            );
        }
    }

    private int pxToDp(int px) {
        DisplayMetrics displayMetrics = getResources().getDisplayMetrics();
        int dp = Math.round(px / (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
        return dp;
    }

    private int dpToPx(Resources res, int dp) {
        return (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dp, res.getDisplayMetrics());
    }

    @Override
    protected void onStart() {
        googleApiClient.connect();
        super.onStart();
    }

    @Override
    protected void onStop() {
        googleApiClient.disconnect();
        super.onStop();
    }

    @Override
    protected void onPause() {
        super.onPause();
        stopLocationUpdates();
    }

    @Override
    public void onResume() {
        super.onResume();
        if (googleApiClient.isConnected()) {
            startLocationUpdates();
        }
    }

    @Override
    public void onConnected(@Nullable Bundle bundle) {
        startLocationUpdates();
    }

    @Override
    public void onConnectionSuspended(int i) {

    }

    @Override
    public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {

    }

    @Override
    public void onLocationChanged(Location location) {
        lastKnownLatLng = new LatLng(location.getLatitude(), location.getLongitude());
        updateTrack();
    }

    protected void startLocationUpdates() {
        LocationRequest locationRequest = new LocationRequest();
        locationRequest.setInterval(5000);
        locationRequest.setFastestInterval(1000);
        locationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);

        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, 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;
        }
        LocationServices.FusedLocationApi.requestLocationUpdates(googleApiClient, locationRequest, this);
    }

    protected void stopLocationUpdates() {
        LocationServices.FusedLocationApi.removeLocationUpdates(
                googleApiClient, this);
    }

    private void startImageChoosingIntent() {
        Intent pickIntent = new Intent();
        pickIntent.setType("image/*");
        pickIntent.setAction(Intent.ACTION_GET_CONTENT);

        Intent takePhotoIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
        String pickTitle = "Seleccionar";

        ContentValues values = new ContentValues();
        values.put(MediaStore.Images.Media.TITLE, "New Picture");
        values.put(MediaStore.Images.Media.DESCRIPTION, "From your Camera");
        imageUri = getContentResolver().insert(
                MediaStore.Images.Media.EXTERNAL_CONTENT_URI, values);
        takePhotoIntent.putExtra(MediaStore.EXTRA_OUTPUT, imageUri);

        Intent chooserIntent = Intent.createChooser(pickIntent, pickTitle);
        chooserIntent.putExtra(Intent.EXTRA_INITIAL_INTENTS, new Intent[]{takePhotoIntent});

        startActivityForResult(chooserIntent, SELECT_PICTURE_INTENT);
    }

    @Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (resultCode == RESULT_OK) {
            if (requestCode == SELECT_PICTURE_INTENT) {
                Bitmap photo = createBitmap(data);
                Marker m = map.addMarker(photoMarker(lastKnownLatLng, photo));
                markersInMap.add(m);
                Log.d(TAG, "Marker created with " + m.getPosition().toString());
            }
        }
    }

    private Bitmap createBitmap(Intent data) {
        boolean isCamera;
        Bitmap photoTaken = null;

        if(data == null) {
            isCamera = true;
        } else {
            String action = data.getAction();
            if(action == null) {
                isCamera = false;
            } else {
                isCamera = action.equals(MediaStore.ACTION_IMAGE_CAPTURE);
            }
        }
        if(!isCamera) {
            imageUri = data.getData();
        }

        try {
            photoTaken = MediaStore.Images.Media.getBitmap(getContentResolver(), imageUri);
        } catch (IOException e) {
            e.printStackTrace();
        }

        return photoTaken;
    }

    private MarkerOptions photoMarker(LatLng latlng, Bitmap bitmap) {
        return new MarkerOptions()
                .position(latlng)
                .draggable(true)
                .icon(BitmapDescriptorFactory.fromBitmap(Utils.getMarkerBitmap(getBaseContext(), bitmap)));
    }

    private void updateTrack() {
        List<LatLng> points = gpsTrack.getPoints();
        points.add(lastKnownLatLng);
        gpsTrack.setPoints(points);
    }

    @Override
    public void onMarkerDragStart(Marker marker) {
        trashImageView.setVisibility(View.VISIBLE);
        draggedMarkerOriginalPosition = marker.getPosition();
        Log.d(TAG, "OnMarkerDragStart with " + draggedMarkerOriginalPosition.toString());
    }

    @Override
    public void onMarkerDrag(Marker marker) {
        Point markerScreenPosition = map.getProjection().toScreenLocation(marker.getPosition());
        int size = 0;
        if (overlap(markerScreenPosition, trashImageView)) {
            size = dpToPx(getResources(), 60);
        } else {
            size = dpToPx(getResources(), 40);
        }
        FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(size, size);
        params.gravity = Gravity.BOTTOM | Gravity.RIGHT;
        trashImageView.setLayoutParams(params);
    }

    @Override
    public void onMarkerDragEnd(Marker marker) {
        trashImageView.setVisibility(View.GONE);
        Point markerScreenPosition = map.getProjection().toScreenLocation(marker.getPosition());
        if (overlap(markerScreenPosition, trashImageView)) {
            marker.remove();
        } else {
            marker.setPosition(draggedMarkerOriginalPosition);
            Log.d(TAG, "OnMarkerDragEnd with " + draggedMarkerOriginalPosition.toString());
        }
    }

    private boolean overlap(Point point, ImageView imgview) {
        int[] imgCoords = new int[2];
        imgview.getLocationOnScreen(imgCoords);
        boolean overlapX = point.x < imgCoords[0] + imgview.getWidth() && point.x > imgCoords[0] - imgview.getWidth();
        boolean overlapY = point.y < imgCoords[1] + imgview.getHeight() && point.y > imgCoords[1] - imgview.getWidth();
        return overlapX && overlapY;
    }

}

这些图像显示了在我将标记拖到垃圾桶外的任何位置并释放后标记的开始位置和结束位置。

Answer 1

好的，所以我想到了这个解决方案。我不确定它是否是最好的，但它正在工作。

我改变了:

 private List<Marker> markersInMap = new ArrayList<>();

收件人:

 private Map<Marker, LatLng> markersInMap = new HashMap<>();

然后当我添加标记时:

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (resultCode == RESULT_OK) {
        if (requestCode == SELECT_PICTURE_INTENT) {
            Bitmap photo = createBitmap(data);
            Marker m = map.addMarker(photoMarker(lastKnownLatLng, photo));
            markersInMap.put(m, new LatLng(lastKnownLatLng.latitude, lastKnownLatLng.longitude));
            Log.d(TAG, "Marker created with " + m.getPosition().toString());
        }
    }
}

最后，将其设置回原来的位置:

 @Override
public void onMarkerDragEnd(Marker marker) {
    trashImageView.setVisibility(View.GONE);
    Point markerScreenPosition = map.getProjection().toScreenLocation(marker.getPosition());
    if (overlap(markerScreenPosition, trashImageView)) {
        marker.remove();
        Log.d(TAG, "OnMarkerDragEnd " + "removed");
    } else {
        marker.setPosition(markersInMap.get(marker));
        Log.d(TAG, "OnMarkerDragEnd " + marker.getPosition().toString());
    }
}