创建OnDragListener的谷歌地图V2片段 [英] Creating OnDragListener for Google Map v2 Fragment

问题描述

我试图建立一个监听器ondrag当了谷歌地图的片段，但不能得到拖拽事件触发。由于地图不直接支持拖放事件，我想实现一拖侦听查看。我了解onMarkerDrag事件，但确实我没有好，因为我不是要四处移动的标记。

I’m trying to setup an onDrag Listener for a google map fragment, but can’t get the drag event to fire. Since the map doesn't support drag events directly, I'm trying to implement a drag listener for the View. I know about the onMarkerDrag event, but that does me no good since I'm not trying to move markers around.

原因陷阱地图拖动事件是双重的：

The reason for trapping map drag events is twofold:

首先，以检测用户是否已平移的地图。如果他们没有，我想保持在屏幕上的位置，和动画自己的位置，如果它不是在地图上。如果他们平移地图，我认为他们知道他们想看到和在屏幕上强制位置。 （这似乎喜欢的事，应该包含在API中）

First to detect if the user has panned the map. If they haven't, I like to keep their location on the screen, and animate to their location if it's not on the map. If they have panned the map, I assume they know what they want to see and force the location on the screen. (this seems like something that should be included in the API)

第二个原因诱捕是让用户绘制线条和多边形在地图上。我能做到这一点与事件的onTap（加分），但我希望能够让他们写意它。

The second reason for trapping is to allow users to draw lines and polygons on the map. I can do this with onTap events(adding points), but I'd like to be able to let them freehand it as well.

我的code是这样的：

My code looks like this:

mainActivity：

mainActivity:

    mMap = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();
    setUpMapIfNeeded();
    mMapView = findViewById(R.id.map);
    myMapDragListener = new MapDragListener();
    mMapView.setOnDragListener(myMapDragListener);

监听器：

public class MapDragListener implements OnDragListener {
    /**
     * 
     */
    public MapDragListener() {
        super();
        say.logCat("MapDragListener: I'm ALIVE!!!!");
    }

    private AkamaiAnnounce say = new AkamaiAnnounce();
    private boolean inDrag;
    private boolean hasPanned=false;

    @Override
    public boolean onDrag(View v, DragEvent event) {
        say.logCat("MapDragListener.onDrag: " + event.toString());
        //String dotTAG = (String) getTag();
        if (event.getLocalState() != this) {
          return false;
        }
        boolean myResult = true;
        int action = event.getAction();
        float x = event.getX();
        float y = event.getY();
        switch (action) {
        case DragEvent.ACTION_DRAG_STARTED:
          inDrag = true;
          break;
        case DragEvent.ACTION_DRAG_LOCATION:
          break;
        case DragEvent.ACTION_DRAG_ENTERED:
          break;
        case DragEvent.ACTION_DRAG_EXITED:
          break;
        case DragEvent.ACTION_DROP:
          myResult = false;
          break;
        case DragEvent.ACTION_DRAG_ENDED:
          inDrag = false; // change color of original dot back
          hasPanned=true;
          break;
        default:
          myResult = false;
          break;
        }
        return false;
        //return myResult;

    }

    public boolean hasPanned() {
        return hasPanned;
    }

    public void setHasPanned(boolean hasPanned) {
        this.hasPanned = hasPanned;
    }

}

地图工作正常。监听器实例，但ondrag当我的事件永远不会触发。任何想法？

The map works fine. The listener instantiates, but my onDrag event never fires. Any ideas?

推荐答案

1）创建包装类：

public class MapWrapperLayout extends FrameLayout {

    public interface OnDragListener {
        public void onDrag(MotionEvent motionEvent);
    }

    private OnDragListener mOnDragListener;

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

    @Override
    public boolean dispatchTouchEvent(MotionEvent ev) {
        if (mOnDragListener != null) {
            mOnDragListener.onDrag(ev);
        }
        return super.dispatchTouchEvent(ev);
    }

    public void setOnDragListener(OnDragListener mOnDragListener) {
        this.mOnDragListener = mOnDragListener;
    }
}

2）创建MapFragment类的子类：

2) Create subclass of MapFragment class:

public class CustomMapFragment extends SupportMapFragment {

    private View mOriginalView;
    private MapWrapperLayout mMapWrapperLayout;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        mOriginalView = super.onCreateView(inflater, container, savedInstanceState);

        mMapWrapperLayout = new MapWrapperLayout(getActivity());
        mMapWrapperLayout.addView(mOriginalView);

        return mMapWrapperLayout;
}

    @Override
    public View getView() {
        return mOriginalView;
    }

    public void setOnDragListener(MapWrapperLayout.OnDragListener onDragListener) {
        mMapWrapperLayout.setOnDragListener(onDragListener);
    }

3.1）最后，在你的活动：

3.1) Finally, in your activity:

    // Google map init block
    CustomMapFragment customMapFragment = ((CustomMapFragment) getSupportFragmentManager().findFragmentById(R.id.map));
    customMapFragment.setOnDragListener(new MapWrapperLayout.OnDragListener() {
        @Override
        public void onDrag(MotionEvent motionEvent) {
            Log.d("ON_DRAG", String.format("ME: %s", motionEvent));
            // Handle motion event:
        }
    });
    GoogleMap map = customMapFragment.getMap();

3.2）...在你的布局：

3.2) ... and in your layout:

<fragment android:id="@+id/map"
          android:layout_width="match_parent"
          android:layout_height="match_parent"
          android:name="your.package.CustomMapFragment"/>

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