android - 如何在googleMap android中检测onDoubleTap缩放

Question

我正在尝试在 anroid 中检测 googleMap 上的 onDoubleTap 缩放(仅缩放既不滚动也不旋转/倾斜)。实际上我想实现 uber 使用的缩放概念，就像你在 map 上双击标记一样与缩放 map 之前的位置一样稳定，我的意思是无论缩放级别如何，坐标都应该相同。例如，如果我双击 map 上的任何地方，它应该始终放大到 mapView 的中心。

Answer 1

您可以在 that 中修改 public boolean dispatchTouchEvent(MotionEvent event)回答您之前关于检测第一次和第二次点击之间延迟的双击的问题，例如这样:

public class TouchableWrapper extends FrameLayout {

    private GoogleMap mGoogleMap = null;
    private long mLastTouchTime = -1;      // time of first tap

    public TouchableWrapper(Context context) {
        super(context);
    }

    public void setGoogleMap(GoogleMap googleMap) {
        mGoogleMap = googleMap;
    }

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {

        switch (event.getAction() & MotionEvent.ACTION_MASK) {

            case MotionEvent.ACTION_DOWN:
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(true);

                long thisTime = System.currentTimeMillis();  // time of second tap tap
                if (thisTime - mLastTouchTime < ViewConfiguration.getDoubleTapTimeout()) {
                    // double tap detected! do you magic here:
                    if (mGoogleMap != null) {
                        LatLng zoomCenter = mGoogleMap.getProjection().fromScreenLocation(new Point((int)event.getX(), (int)event.getY()));
                                                    mGoogleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(zoomCenter, currentZoom + 1));
                    }
                    mLastTouchTime = -1;
                } else {
                    mLastTouchTime = thisTime;
                    mGoogleMap.getUiSettings().setZoomGesturesEnabled(true);
                }

            break;

            case MotionEvent.ACTION_POINTER_DOWN:
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(false);
            break;

            case MotionEvent.ACTION_POINTER_UP:
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(true);
            break;

            case MotionEvent.ACTION_UP:
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(true);
            break;
        }

        return super.dispatchTouchEvent(event);
    }
}

更新:

如果您使用 MapView 而不是 MapFregment - 更好的方法是创建自定义 View ，它扩展 MapView 实现 OnMapReadyCallback(这是获取 GoogleMap 对象所必需的)，并覆盖 dispatchTouchEvent()(用于双击检测)。类似的东西:

public class EnhanchedMapView extends MapView implements OnMapReadyCallback {
    private long mLastTouchTime = -1;

    private OnMapReadyCallback mMapReadyCallback;
    private GoogleMap mGoogleMap;
    private Marker mMarker;
    private Paint mPaintArrow;

    public EnhanchedMapView(@NonNull Context context) {
        super(context);
        init();
    }

    public EnhanchedMapView(@NonNull Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public EnhanchedMapView(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    public EnhanchedMapView(@NonNull Context context, @Nullable GoogleMapOptions options) {
        super(context, options);
        init();
    }

    private void init() {
    }

    @Override
    public void getMapAsync(OnMapReadyCallback callback) {
        mMapReadyCallback = callback;
        super.getMapAsync(this);
    }

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

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {

        switch (event.getAction() & MotionEvent.ACTION_MASK) {

            case MotionEvent.ACTION_DOWN:
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(true);

                long thisTime = System.currentTimeMillis();
                if (thisTime - mLastTouchTime < ViewConfiguration.getDoubleTapTimeout()) {

                    if (mGoogleMap != null) {
                        LatLng zoomCenter = mGoogleMap.getProjection().fromScreenLocation(new Point((int) event.getX(), (int) event.getY()));
                        float currentZoom = mGoogleMap.getCameraPosition().zoom;
                        mGoogleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(zoomCenter, currentZoom + 1));
                    }
                    mLastTouchTime = -1;
                } else {
                    mLastTouchTime = thisTime;
                    mGoogleMap.getUiSettings().setZoomGesturesEnabled(true);
                }

                break;

            case MotionEvent.ACTION_POINTER_DOWN:
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(false);
                break;

            case MotionEvent.ACTION_POINTER_UP:
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(true);
                break;

            case MotionEvent.ACTION_UP:
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(true);
                break;
        }

        return super.dispatchTouchEvent(event);
    }
}

更新#2:

Activity 的 Activity 布局 (MainActivity) 这种情况可以是这样的:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="{YOUR_PACKAGE}.MainActivity">

    <{YOUR_PACKAGE}.EnhanchedMapView
        android:id="@+id/mapview"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent"
        />

</RelativeLayout>

MainActivity 源代码中唯一的变化是:

...
private EnhanchedMapView mMapView;
...

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

    ...
    mMapView = (EnhanchedMapView) findViewById(R.id.mapview);
    ...
}

更新 #3:

public class EnhanchedMapView extends MapView implements OnMapReadyCallback {
    private long mLastTouchTime = -1;

    private OnMapReadyCallback mMapReadyCallback;
    private GoogleMap mGoogleMap;

    private LatLng mZoomCenter;

    public EnhanchedMapView(@NonNull Context context) {
        super(context);
        init();
    }

    public EnhanchedMapView(@NonNull Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public EnhanchedMapView(@NonNull Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init();
    }

    public EnhanchedMapView(@NonNull Context context, @Nullable GoogleMapOptions options) {
        super(context, options);
        init();
    }

    private void init() {
    }

    @Override
    public void getMapAsync(OnMapReadyCallback callback) {
        mMapReadyCallback = callback;
        super.getMapAsync(this);
    }

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

    @Override
    public boolean dispatchTouchEvent(MotionEvent event) {

        switch (event.getAction() & MotionEvent.ACTION_MASK) {

            case MotionEvent.ACTION_DOWN:
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(true);
                mGoogleMap.getUiSettings().setZoomGesturesEnabled(false);

                mZoomCenter = mGoogleMap.getCameraPosition().target;

                long thisTime = System.currentTimeMillis();
                if (thisTime - mLastTouchTime < ViewConfiguration.getDoubleTapTimeout()) {

                    if (mGoogleMap != null) {
                        LatLng zoomCenter = mGoogleMap.getProjection().fromScreenLocation(new Point((int) event.getX(), (int) event.getY()));
                        float currentZoom = mGoogleMap.getCameraPosition().zoom;
                        mGoogleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(mZoomCenter, currentZoom + 1));
                    }
                    mLastTouchTime = -1;
                } else {
                    mLastTouchTime = thisTime;
                    mGoogleMap.getUiSettings().setZoomGesturesEnabled(true);
                }

                break;

            case MotionEvent.ACTION_POINTER_DOWN:
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(false);
                break;

            case MotionEvent.ACTION_POINTER_UP:
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(true);
                break;

            case MotionEvent.ACTION_UP:
                mGoogleMap.getUiSettings().setScrollGesturesEnabled(true);
                break;
        }

        return super.dispatchTouchEvent(event);
    }
}