How to show more than one location in Blackberry MapField?

问题

I can able to show one location using co ordinates or longtitude and latitude but i dont know how to show more than one location in the blackberry MapField.If is it possible pls share with me how to do this..

回答1:

Same way as How to show our own icon in BlackBerry Map?.

Pass an array of Coordinates into custom MapField, define a bitmap for location point and paint it for each Coordinate in custom MapField paint() method.

Remember to zoom in/out CustomMapField for best fit of all location points.

Sample of implementation

Lets display Liverpool Sheffield and London with custom bitmap icons (yellow circle with black border). Code for custom MapField:

class MultyMapField extends MapField {
    Coordinates[] mPoints = new Coordinates[0];
    Bitmap mPoint;
    Bitmap mPointsBitmap;
    XYRect mDest;
    XYRect[] mPointDest;

    public void addCoordinates(Coordinates coordinates) {
        Arrays.add(mPoints, coordinates);
        zoomToFitPoints();
        repaintPoints();
    }

    protected void zoomToFitPoints() {
        // zoom to max
        setZoom(getMaxZoom());

        // get pixels of all points
        int minLeft = getWidth();
        int minUp = getHeight();
        int maxRight = 0;
        int maxDown = 0;
        Coordinates minLeftCoordinates = null;
        Coordinates minUpCoordinates = null;
        Coordinates maxRightCoordinates = null;
        Coordinates maxDownCoordinates = null;
        for (int i = 0; i < mPoints.length; i++) {
            XYPoint point = new XYPoint();
            convertWorldToField(mPoints[i], point);
            if (point.x <= minLeft) {
                minLeft = point.x;
                minLeftCoordinates = mPoints[i];
            }
            if (point.x >= maxRight) {
                maxRight = point.x;
                maxRightCoordinates = mPoints[i];
            }
            if (point.y <= minUp) {
                minUp = point.y;
                minUpCoordinates = mPoints[i];
            }
            if (point.y >= maxDown) {
                maxDown = point.y;
                maxDownCoordinates = mPoints[i];
            }
        }

        double moveToLat = maxDownCoordinates.getLatitude()
                + (minUpCoordinates.getLatitude() - maxDownCoordinates
                        .getLatitude()) / 2;
        double moveToLong = minLeftCoordinates.getLongitude()
                + (maxRightCoordinates.getLongitude() - minLeftCoordinates
                        .getLongitude()) / 2;
        Coordinates moveTo = new Coordinates(moveToLat, moveToLong, 0);
        moveTo(moveTo);
        // zoom to min left up, max right down pixels + 1
        int zoom = getZoom();
        boolean outOfBounds = false;
        while (!outOfBounds && zoom > getMinZoom()) {
            zoom--;
            setZoom(zoom);
            XYPoint point = new XYPoint();
            try {
                convertWorldToField(minLeftCoordinates, point);
                if (point.x < 0)
                    outOfBounds = true;
                convertWorldToField(minUpCoordinates, point);
                if (point.y < 0)
                    outOfBounds = true;
                convertWorldToField(maxRightCoordinates, point);
                if (point.x > getWidth())
                    outOfBounds = true;
                convertWorldToField(maxDownCoordinates, point);
                if (point.y > getHeight())
                    outOfBounds = true;
            } catch (IllegalArgumentException ex) {
                outOfBounds = true;
            }
        }
        zoom++;
        setZoom(zoom);
    }

    protected void repaintPoints() {
        mPointsBitmap = new Bitmap(getWidth(), getHeight());
        mPointsBitmap.createAlpha(Bitmap.ALPHA_BITDEPTH_8BPP);
        mDest = new XYRect(0, 0, mPointsBitmap.getWidth(), mPointsBitmap
                .getHeight());
        Graphics g = new Graphics(mPointsBitmap);
        if (null != mPoint) {
            mPointDest = new XYRect[mPoints.length];
            for (int i = 0; i < mPoints.length; i++) {
                if (null == mPointDest[i]) {
                    XYPoint fieldOut = new XYPoint();
                    convertWorldToField(mPoints[i], fieldOut);
                    int imgW = mPoint.getWidth();
                    int imgH = mPoint.getHeight();
                    mPointDest[i] = new XYRect(fieldOut.x - imgW / 2,
                            fieldOut.y - imgH, imgW, imgH);
                }
                g.drawBitmap(mPointDest[i], mPoint, 0, 0);
            }
        }
    }

    protected void paint(Graphics graphics) {
        super.paint(graphics);
        if (null != mPointsBitmap) {
            graphics.setGlobalAlpha(100);
            graphics.drawBitmap(mDest, mPointsBitmap, 0, 0);
        }
    }
}

Sample of use:

class Scr extends MainScreen {
    // test coordinates:
    // London
    // 51.507778, -0.128056
    Coordinates mLondonC = new Coordinates(51.507778, -0.128056, 0);
    // Liverpool
    // 53.4, -2.983333
    Coordinates mLiverpoolC = new Coordinates(53.4, -2.983333, 0);
    // Sheffield
    // 53.385833, -1.469444
    Coordinates mSheffieldC = new Coordinates(53.385833, -1.469444, 0);

    MultyMapField mMultyMapField;

    public Scr() {
        add(mMultyMapField = new MultyMapField());
        mMultyMapField.mPoint = createPointBitmap();
    }

    protected void onUiEngineAttached(boolean attached) {
        super.onUiEngineAttached(attached);
        if (attached) {
            mMultyMapField.addCoordinates(mLondonC);
            mMultyMapField.addCoordinates(mLiverpoolC);
            mMultyMapField.addCoordinates(mSheffieldC);
        }
    }

    private Bitmap createPointBitmap() {
        int r = 10;
        Bitmap result = new Bitmap(2 * r, 2 * r);
        result.createAlpha(Bitmap.ALPHA_BITDEPTH_8BPP);
        Graphics g = new Graphics(result);
        g.setColor(Color.BLACK);
        g.fillEllipse(r, r, 2 * r, r, r, 2 * r, 0, 360);
        g.setColor(Color.YELLOW);
        g.fillEllipse(r, r, r + (r - 2), r, r, r + (r - 2), 0, 360);
        return result;
    }
}

回答2:

A valid and probably simpler option would be to use this open source library by Monits https://github.com/Monits/blackberry-commons

It contains several common functionality found in BB applications and is compatible for BB 4.6.1+

Among other things, it provides a map field with the ability to add and display markers on top of it, with and without focus, and optionally "open" them. This makes for an API much more alike that found on other smart phones such as iPhone or Android.

The documentation is pretty good, and the wiki even has a tutorial on how to achieve it https://github.com/Monits/blackberry-commons/wiki/CustomMap

来源：https://stackoverflow.com/questions/1554016/how-to-show-more-than-one-location-in-blackberry-mapfield