问题
I created a class that select latitudes and longitude from sqlite then mark on map then draw polyLine.
Problem :
Every time I select my records 100 to 100, when I saw first 100 then I clear map then I get second 100 but when I start animate it show me last polyline how I can clear last polyline ?
My code :
public class PathActivity_F extends AppCompatActivity implements OnMapReadyCallback {
private GoogleMap mMap;
Query_DB QDB;
private List<Marker> markers = new ArrayList<>();
private final Handler mHandler = new Handler();
ImageView imgBack, imgClear, imgStop, imgPath, imgToggle, imgForward;
boolean flag = true;
int loadLimit = 0;
int ival = 0;
boolean ff = true;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_path);
SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.mapPath);
mapFragment.getMapAsync(this);
imgBack = (ImageView) findViewById(R.id.imgBack);
imgClear = (ImageView) findViewById(R.id.imgClear);
imgStop = (ImageView) findViewById(R.id.imgStop);
imgPath = (ImageView) findViewById(R.id.imgPath);
imgToggle = (ImageView) findViewById(R.id.imgToggle);
imgForward = (ImageView) findViewById(R.id.imgForward);
Button btnFill = (Button) findViewById(R.id.btnFill);
Button btnStop = (Button) findViewById(R.id.btnStop);
Button btnClear = (Button) findViewById(R.id.btnClear);
Button btnToggle = (Button) findViewById(R.id.btnToggle);*/
QDB = new Query_DB(PathActivity_F.this);
imgBack.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
addLocations();
}
});
imgForward.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
}
});
imgPath.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
animator.startAnimation(true);
}
});
imgStop.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
animator.stopAnimation();
}
});
imgClear.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
clearMarkers();
}
});
imgToggle.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
toggleStyle();
}
});
}
public void toggleStyle() {
if (GoogleMap.MAP_TYPE_NORMAL == mMap.getMapType()) {
mMap.setMapType(GoogleMap.MAP_TYPE_SATELLITE);
} else {
mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
}
}
/**
* Clears all markers from the map.
*/
public void clearMarkers() {
mMap.clear();
markers.clear();
}
private void addLocations() {
List<Marketing_Points_B> listPath = new ArrayList<>();
listPath.clear();
markers.clear();
String query;
if (flag) {
query = "select Time,Lat,Lng from ReportAct_tbl group by LatLng order by Time ASC LIMIT 100; ";
flag = false;
} else {
loadLimit = ival + 100;
ival = loadLimit;
query = "select Time,Lat,Lng from ReportAct_tbl group by LatLng order by Time ASC LIMIT 100 OFFSET " + loadLimit + ";";
}
Cursor cursor = QDB.db().rawQuery(query, null);
cursor.moveToFirst();
try {
if (cursor != null) {
if (cursor.moveToFirst()) {
do {
Marketing_Points_B MP = new Marketing_Points_B();
Double lat = cursor.getDouble(cursor.getColumnIndex("Lat"));
Double lng = cursor.getDouble(cursor.getColumnIndex("Lng"));
String Time = cursor.getString(cursor.getColumnIndex("Time"));
MP.setLat(lat);
MP.setLng(lng);
MP.setTime(Time);
listPath.add(MP);
} while (cursor.moveToNext());
}
}
} catch (Exception ex) {
} finally {
cursor.close();
QDB.db().close();
}
for (int i = 0; i < listPath.size(); i++) {
Double lat = listPath.get(i).getLat();
Double lng = listPath.get(i).getLng();
addMarkerToMap(new LatLng(lat, lng));
}
}
@Override
public void onMapReady(GoogleMap googleMap) {
mMap = googleMap;
// Add a marker in Sydney and move the camera
LatLng sydney = new LatLng(34.637727, 50.877688);
mMap.addMarker(new MarkerOptions().position(sydney).title("OK").icon(BitmapDescriptorFactory.fromResource(R.drawable.map_marker_red)));
mMap.moveCamera(CameraUpdateFactory.newLatLng(sydney));
}
private Animator animator = new Animator();
int currentPt;
GoogleMap.CancelableCallback MyCancelableCallback =
new GoogleMap.CancelableCallback() {
@Override
public void onCancel() {
System.out.println("onCancelled called");
}
@Override
public void onFinish() {
if (++currentPt < markers.size()) {
float targetBearing = bearingBetweenLatLngs(mMap.getCameraPosition().target, markers.get(currentPt).getPosition());
LatLng targetLatLng = markers.get(currentPt).getPosition();
Log.i("currentPt", "currentPt = " + currentPt);
Log.i("size", "size = " + markers.size());
//Create a new CameraPosition
CameraPosition cameraPosition =
new CameraPosition.Builder()
.target(targetLatLng)
.tilt(currentPt < markers.size() - 1 ? 90 : 0)
.bearing(targetBearing)
.zoom(mMap.getCameraPosition().zoom)
.build();
mMap.animateCamera(
CameraUpdateFactory.newCameraPosition(cameraPosition),
3000,
MyCancelableCallback);
System.out.println("Animate to: " + markers.get(currentPt).getPosition() + "\n" +
"Bearing: " + targetBearing);
markers.get(currentPt).showInfoWindow();
} else {
}
}
};
private float bearingBetweenLatLngs(LatLng begin, LatLng end) {
Location beginL = convertLatLngToLocation(begin);
Location endL = convertLatLngToLocation(end);
return beginL.bearingTo(endL);
}
private Location convertLatLngToLocation(LatLng latLng) {
Location loc = new Location("someLoc");
loc.setLatitude(latLng.latitude);
loc.setLongitude(latLng.longitude);
return loc;
}
public class Animator implements Runnable {
private static final int ANIMATE_SPEEED = 100;
private static final int ANIMATE_SPEEED_TURN = 1000;
private static final int BEARING_OFFSET = 20;
private final Interpolator interpolator = new LinearInterpolator();
int currentIndex = 0;
float tilt = 90;
float zoom = 15.5f;
boolean upward = true;
long start = SystemClock.uptimeMillis();
LatLng endLatLng = null;
LatLng beginLatLng = null;
boolean showPolyline = false;
private Marker trackingMarker;
public void reset() {
resetMarkers();
start = SystemClock.uptimeMillis();
currentIndex = 0;
endLatLng = getEndLatLng();
beginLatLng = getBeginLatLng();
}
public void stop() {
trackingMarker.remove();
mHandler.removeCallbacks(animator);
}
public void initialize(boolean showPolyLine) {
reset();
this.showPolyline = showPolyLine;
highLightMarker(0);
if (showPolyLine) {
polyLine = initializePolyLine();
}
// We first need to put the camera in the correct position for the first run (we need 2 markers for this).....
LatLng markerPos = markers.get(0).getPosition();
LatLng secondPos = markers.get(1).getPosition();
setupCameraPositionForMovement(markerPos, secondPos);
}
private void setupCameraPositionForMovement(LatLng markerPos,
LatLng secondPos) {
float bearing = bearingBetweenLatLngs(markerPos, secondPos);
trackingMarker = mMap.addMarker(new MarkerOptions().position(markerPos)
.title("title")
.snippet("snippet").icon(BitmapDescriptorFactory.fromResource(R.drawable.map_marker_red)));
CameraPosition cameraPosition =
new CameraPosition.Builder()
.target(markerPos)
.bearing(bearing + BEARING_OFFSET)
.tilt(90)
.zoom(mMap.getCameraPosition().zoom >= 16 ? mMap.getCameraPosition().zoom : 16)
.build();
mMap.animateCamera(
CameraUpdateFactory.newCameraPosition(cameraPosition),
ANIMATE_SPEEED_TURN,
new GoogleMap.CancelableCallback() {
@Override
public void onFinish() {
System.out.println("finished camera");
animator.reset();
Handler handler = new Handler();
handler.post(animator);
}
@Override
public void onCancel() {
System.out.println("cancelling camera");
}
}
);
}
private Polyline polyLine;
private PolylineOptions rectOptions = new PolylineOptions();
private Polyline initializePolyLine() {
//polyLinePoints = new ArrayList<LatLng>();
rectOptions.add(markers.get(0).getPosition());
return mMap.addPolyline(rectOptions);
}
/**
* Add the marker to the polyline.
*/
private void updatePolyLine(LatLng latLng) {
List<LatLng> points = polyLine.getPoints();
points.add(latLng);
polyLine.setPoints(points);
}
public void stopAnimation() {
animator.stop();
}
public void startAnimation(boolean showPolyLine) {
if (markers.size() > 2) {
animator.initialize(showPolyLine);
}
}
@Override
public void run() {
long elapsed = SystemClock.uptimeMillis() - start;
double t = interpolator.getInterpolation((float) elapsed / ANIMATE_SPEEED);
double lat = t * endLatLng.latitude + (1 - t) * beginLatLng.latitude;
double lng = t * endLatLng.longitude + (1 - t) * beginLatLng.longitude;
LatLng newPosition = new LatLng(lat, lng);
trackingMarker.setPosition(newPosition);
if (showPolyline) {
updatePolyLine(newPosition);
}
// It's not possible to move the marker + center it through a cameraposition update while another camerapostioning was already happening.
//navigateToPoint(newPosition,tilt,bearing,currentZoom,false);
//navigateToPoint(newPosition,false);
if (t < 1) {
mHandler.postDelayed(this, 16);
} else {
System.out.println("Move to next marker.... current = " + currentIndex + " and size = " + markers.size());
// imagine 5 elements - 0|1|2|3|4 currentindex must be smaller than 4
if (currentIndex < markers.size() - 2) {
currentIndex++;
endLatLng = getEndLatLng();
beginLatLng = getBeginLatLng();
start = SystemClock.uptimeMillis();
LatLng begin = getBeginLatLng();
LatLng end = getEndLatLng();
float bearingL = bearingBetweenLatLngs(begin, end);
highLightMarker(currentIndex);
CameraPosition cameraPosition =
new CameraPosition.Builder()
.target(end) // changed this...
.bearing(bearingL + BEARING_OFFSET)
.tilt(tilt)
.zoom(mMap.getCameraPosition().zoom)
.build();
mMap.animateCamera(
CameraUpdateFactory.newCameraPosition(cameraPosition),
ANIMATE_SPEEED_TURN,
null
);
start = SystemClock.uptimeMillis();
mHandler.postDelayed(animator, 16);
} else {
currentIndex++;
highLightMarker(currentIndex);
stopAnimation();
}
}
}
private LatLng getEndLatLng() {
return markers.get(currentIndex + 1).getPosition();
}
private LatLng getBeginLatLng() {
return markers.get(currentIndex).getPosition();
}
private void adjustCameraPosition() {
if (upward) {
if (tilt < 90) {
tilt++;
zoom -= 0.01f;
} else {
upward = false;
}
} else {
if (tilt > 0) {
tilt--;
zoom += 0.01f;
} else {
upward = true;
}
}
}
}
/**
* Adds a marker to the map.
*/
public void addMarkerToMap(LatLng latLng) {
Marker marker = mMap.addMarker(new MarkerOptions().position(latLng)
.title("title")
.snippet("snippet").icon(BitmapDescriptorFactory.fromResource(R.drawable.map_marker_red)));
markers.add(marker);
}
private void resetMarkers() {
for (Marker marker : this.markers) {
marker.setIcon(BitmapDescriptorFactory.fromResource(R.drawable.map_marker_green));
}
}
/**
* Highlight the marker by index.
*/
private void highLightMarker(int index) {
highLightMarker(markers.get(index));
}
/**
* Highlight the marker by marker.
*/
private void highLightMarker(Marker marker) {
marker.setIcon(BitmapDescriptorFactory.fromResource(R.drawable.map_marker_yellow));
marker.showInfoWindow();
}
}
回答1:
Resolve my problem, I commented this line:
//rectOptions.add(markers.get(0).getPosition());
回答2:
have track added polyline on map and remove it by polyline.remove();. For reference you can use How to remove all the polylines from a map
来源：https://stackoverflow.com/questions/39145192/remove-the-last-polyline-line-from-google-map-android