android中的自定义,禁用和空白地图
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我想在地图上只显示标记的半径部分,而地图的其余部分必须为空白。就像标记半径是5公里并且我希望只有地图的半径部分必须对用户可见,并且地图的其余部分必须为空白。
我已经阅读了有关Google Map Overlays的信息,还搜索了各种类似MapBox和Skobbler的SDK,但它们都没有提供我想要的功能。
在图像中,您可以看到标记周围只有部分可见,其余部分为空白。我想在android Maps中实现这个功能。
如果有人有任何解决方案或想法,请告诉我。
谢谢。
答案
您可以在隐藏它的地图上添加View
,并在其上绘制一个圆圈以仅显示所需的位置。
我的答案基于
- Draw transparent circle filled outside
- Android - Google Maps inside CircleView
- How can I draw a static target circle on Google Maps?
MapsActivity:
public class MapsActivity extends FragmentActivity implements GoogleMap.OnCameraChangeListener {
private GoogleMap mMap;
private HideOverlayView hideView;
private List<Marker> visibleMarkers = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_maps);
hideView = (HideOverlayView) findViewById(R.id.hideview);
setUpMapIfNeeded();
}
@Override
protected void onResume() {
super.onResume();
setUpMapIfNeeded();
}
@SuppressLint("NewApi")
private void setUpMapIfNeeded() {
if (mMap == null) {
final SupportMapFragment f = (SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map);
mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
.getMap();
if (mMap != null) {
setUpMap();
}
}
}
private void setUpMap() {
mMap.setMapType(GoogleMap.MAP_TYPE_HYBRID);
mMap.getUiSettings().setAllGesturesEnabled(true);
mMap.getUiSettings().setZoomControlsEnabled(true);
mMap.getUiSettings().setMyLocationButtonEnabled(true);
mMap.setMyLocationEnabled(true);
mMap.setOnCameraChangeListener(this);
mMap.moveCamera(CameraUpdateFactory.newCameraPosition(
CameraPosition.fromLatLngZoom(new LatLng(40.22861, -3.95567), 15)));
visibleMarkers.add(mMap.addMarker(new MarkerOptions().position(
new LatLng(40.22861, -3.95567))));
visibleMarkers.add(mMap.addMarker(new MarkerOptions().position(
new LatLng(40.22977, -3.95338))));
}
@Override
public void onCameraChange(final CameraPosition cameraPosition) {
List<Point> visiblePoints = new ArrayList<>();
Projection projection = mMap.getProjection();
for (Marker visibleMarker : visibleMarkers) {
visiblePoints.add(projection.toScreenLocation(visibleMarker.getPosition()));
}
float radius = 150f; // meters
Point centerPoint = projection.toScreenLocation(cameraPosition.target);
Point radiusPoint = projection.toScreenLocation(
SphericalUtil.computeOffset(cameraPosition.target, radius, 90));
float radiusPx = (float) Math.sqrt(Math.pow(centerPoint.x - radiusPoint.x, 2));
hideView.reDraw(visiblePoints, radiusPx);
}
}
HideOverlayView:
public class HideOverlayView extends LinearLayout {
private Bitmap windowFrame;
private float radius = 0f;
private List<Point> points;
public HideOverlayView(Context context) {
super(context);
}
public HideOverlayView(Context context, AttributeSet attrs) {
super(context, attrs);
}
@Override
protected void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
createWindowFrame();
canvas.drawBitmap(windowFrame, 0, 0, null);
}
@Override
public boolean isEnabled() {
return false;
}
@Override
public boolean isClickable() {
return false;
}
public void reDraw(List<Point> points, float radius) {
this.points = points;
this.radius = radius;
invalidate();
}
protected void createWindowFrame() {
windowFrame = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888);
Canvas osCanvas = new Canvas(windowFrame);
RectF outerRectangle = new RectF(0, 0, getWidth(), getHeight());
Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
paint.setColor(Color.BLACK);
osCanvas.drawRect(outerRectangle, paint);
if (radius > 0 && points != null) {
for (Point point : points) {
paint.setColor(Color.TRANSPARENT);
paint.setXfermode(new PorterDuffXfermode(PorterDuff.Mode.SRC_OUT));
paint.setStyle(Paint.Style.FILL);
osCanvas.drawCircle(point.x, point.y, radius, paint);
}
}
}
@Override
public boolean isInEditMode() {
return true;
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
super.onLayout(changed, l, t, r, b);
windowFrame = null;
}
}
activity_maps.xml:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<fragment
android:id="@+id/map"
android:name="mypackage.MySupportMapFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MapsActivity"/>
<mypackage.HideOverlayView
android:id="@+id/hideview"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_centerInParent="true"
app:radius="150dp"/>
</RelativeLayout>
结果:
限制:
- 此解决方案仅更新
HideOverlayView
上的onCameraChange
,因此当用户缩放或平移地图时,可以显示地图上的其他位置 - 用于计算半径的计算不考虑地图的旋转和倾斜
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