android - 如何绘制一个小标记图像并不断刷新其在我的自定义 map 图像上的位置？ - 安卓

Question

我目前正在开发一个跟踪系统来绘制用户在房间内或其他地方的移动轨迹。

现在我已经成功地将我的 map 导入到应用程序中， map 可以自由缩放和移动。下一步是放置一个标记以指示用户在 map 上的位置，并在 map 上四处移动标记。 (像漂浮在 map 上一样)

我在某处读到它，认为这可以用 MyLocationOverlay 来完成，但是网上的大多数示例都是将它应用到 google map 上。但是，就我而言，我的 map 不是google map，而是我自己的 map 。 ( map 可以是我房间的 map ，也可以是我自己画的 map !)

我已经完成了跟踪算法，即我知道在哪里放置我的标记图像。

因此剩下的唯一问题是如何在 map 图像之上显示标记图像。

具体来说，我有一个自定义 View MapView，如下:

package com.example.drsystem;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.util.Log;
import android.view.MotionEvent;
import android.view.ScaleGestureDetector;
import android.view.View;

public class MapView extends View {

    private static final int INVALID_POINTER_ID = -1;

    private Drawable mImage;
    private float mPosX;
    private float mPosY;

    private float mLastTouchX;
    private float mLastTouchY;
    private int mActivePointerId = INVALID_POINTER_ID;

    private ScaleGestureDetector mScaleDetector;
    private float mScaleFactor = 1.f;

    public MapView(Context context) {
        this(context, null, 0);

        mImage = getResources().getDrawable(R.drawable.lv12n);
        mImage.setBounds(0, 0, mImage.getIntrinsicWidth(), mImage.getIntrinsicHeight());
    }

    // called when XML tries to inflate this View
    public MapView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);

        mImage = getResources().getDrawable(R.drawable.lv12n);
        mImage.setBounds(0, 0, mImage.getIntrinsicWidth(), mImage.getIntrinsicHeight());
    }

    public MapView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
    }

    @Override
    public boolean onTouchEvent(MotionEvent ev) {
        // Let the ScaleGestureDetector inspect all events.
        mScaleDetector.onTouchEvent(ev);

        final int action = ev.getAction();
        switch (action & MotionEvent.ACTION_MASK) {
        case MotionEvent.ACTION_DOWN: {
            final float x = ev.getX();
            final float y = ev.getY();

            mLastTouchX = x;
            mLastTouchY = y;
            mActivePointerId = ev.getPointerId(0);
            break;
        }

        case MotionEvent.ACTION_MOVE: {
            final int pointerIndex = ev.findPointerIndex(mActivePointerId);
            final float x = ev.getX(pointerIndex);
            final float y = ev.getY(pointerIndex);

            // Only move if the ScaleGestureDetector isn't processing a gesture.
            if (!mScaleDetector.isInProgress()) {
                final float dx = x - mLastTouchX;
                final float dy = y - mLastTouchY;

                mPosX += dx;
                mPosY += dy;

                invalidate();
            }

            mLastTouchX = x;
            mLastTouchY = y;

            break;
        }

        case MotionEvent.ACTION_UP: {
            mActivePointerId = INVALID_POINTER_ID;
            break;
        }

        case MotionEvent.ACTION_CANCEL: {
            mActivePointerId = INVALID_POINTER_ID;
            break;
        }

        case MotionEvent.ACTION_POINTER_UP: {
            final int pointerIndex = (ev.getAction() & MotionEvent.ACTION_POINTER_INDEX_MASK) >> MotionEvent.ACTION_POINTER_INDEX_SHIFT;
            final int pointerId = ev.getPointerId(pointerIndex);
            if (pointerId == mActivePointerId) {
                // This was our active pointer going up. Choose a new
                // active pointer and adjust accordingly.
                final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
                mLastTouchX = ev.getX(newPointerIndex);
                mLastTouchY = ev.getY(newPointerIndex);
                mActivePointerId = ev.getPointerId(newPointerIndex);
            }
            break;
        }
        }

        return true;
    }

    @Override
    public void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        canvas.save();
        Log.d("MapView", "X: " + mPosX + " Y: " + mPosY);
        canvas.translate(mPosX, mPosY);
        canvas.scale(mScaleFactor, mScaleFactor);
        mImage.draw(canvas);
        canvas.restore();
    }

    private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener {
        @Override
        public boolean onScale(ScaleGestureDetector detector) {
            mScaleFactor *= detector.getScaleFactor();

            // Don't let the object get too small or too large.
            mScaleFactor = Math.max(0.1f, Math.min(mScaleFactor, 10.0f));

            invalidate();
            return true;
        }
    }

}

至此， map 已经成功输入到app中，并且可以移动和缩放。

然后，我将这个自定义 View 插入到布局 XML 文件中，如下所示:

<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"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context=".MapView" >

    <com.example.drsystem.MapView
        android:id="@+id/mapView1"
        android:layout_width="fill_parent"
        android:layout_height="400dp"
        android:layout_above="@+id/button2"
        android:layout_alignParentLeft="true"
        android:layout_alignParentRight="true"
        android:layout_alignParentTop="true" />

 ...

</RelativeLayout>

根据所有这些信息，我如何绘制一个点并不断更新它在我的 map 上的位置？

更新:

问题只是将另一个小图像放在自定义 View 的顶部并四处移动。

我在这里附上截图供大家引用:

按钮和 TextView 上方的区域是我的 MapView

Answer 1

首先，使用 LocationClient API(而不是 LocationManager)，因为它们与混合的 gps 供应商 wifi 和网络一起工作得非常好。他们还使用传感器来识别运动，从而节省电池电量。

我使用以下 LocationOverlay cod 将我的图标放置在 map 上。根据您的需要定制它。它有点粗糙但有效。

private class LocationMarker extends ItemizedOverlay<OverlayItem> {
    private Activity appContext;
    private List<OverlayItem> items = new ArrayList<OverlayItem>();
    private Drawable marker = null;
    private OverlayItem inDrag = null;
    private ImageView dragImage = null;
    private int xDragImageOffset = 0;
    private int yDragImageOffset = 0;
    private int xDragTouchOffset = 0;
    private int yDragTouchOffset = 0;
    private MapView location;
    private boolean pickupOrDrop;

    public LocationMarker(Activity newAppContext, MapView newLocation, Drawable newMarker,
            ImageView newPoint, boolean newWhichPoint) {
        super(newMarker);
        this.appContext = newAppContext;
        this.location = newLocation;
        this.marker = newMarker;
        this.dragImage = newPoint;
        this.pickupOrDrop = newWhichPoint;

        xDragImageOffset = dragImage.getDrawable().getIntrinsicWidth() / 2;
        yDragImageOffset = dragImage.getDrawable().getIntrinsicHeight();
        populate();
    }

    public void placeMarker(GeoPoint myPoint) {
        OverlayItem toDrop = new OverlayItem(myPoint, "", "");
        items.add(toDrop);
        populate();
    }

    @Override
    protected OverlayItem createItem(int i) {
        return (items.get(i));
    }

    @Override
    public void draw(Canvas canvas, MapView mapView, boolean shadow) {
        super.draw(canvas, mapView, shadow);
        boundCenterBottom(marker);
    }

    @Override
    public int size() {
        return (items.size());
    }

    @Override
    public boolean onTouchEvent(MotionEvent event, MapView mapView) {
        if (pickupOrDrop != whichPoint)
            return false;
        final int action = event.getAction();
        final int x = (int) event.getX();
        final int y = (int) event.getY();
        boolean result = false;

        // Draw temp image
        if (action == MotionEvent.ACTION_DOWN) {
            Log.d("iTaxeeta:Overlay", "Action Down" + marker.toString());
            GeoPoint myPoint = null;
            if (items.isEmpty()) {
                if (whichPoint == PICKUP) {
                    myPoint = source = location.getProjection().fromPixels(
                            x - xDragTouchOffset, y - yDragTouchOffset);
                } else if (whichPoint == DROP) {
                    myPoint = destination = location.getProjection().fromPixels(
                            x - xDragTouchOffset, y - yDragTouchOffset);
                }
                OverlayItem toDrop = new OverlayItem(myPoint, "", "");
                items.add(toDrop);
                populate();
            }
            for (OverlayItem item : items) {
                Point p = new Point(0, 0);
                Log.d("iTaxeeta:Overlay", item.getTitle());
                location.getProjection().toPixels(item.getPoint(), p);
                if (hitTest(item, marker, x - p.x, y - p.y)) {
                    result = true;
                    inDrag = item;
                    items.remove(inDrag);
                    populate();

                    xDragTouchOffset = 0;
                    yDragTouchOffset = 0;
                    setDragImagePosition(p.x, p.y);

                    dragImage.setVisibility(View.VISIBLE);
                    xDragTouchOffset = x - p.x;
                    yDragTouchOffset = y - p.y;

                    break;
                } 
                else {
                    items.clear();
                    populate();
                    if (whichPoint == PICKUP)
                        myPoint = source = location.getProjection().fromPixels(
                                x - xDragTouchOffset, y - yDragTouchOffset);
                    else if (whichPoint == DROP)
                        myPoint = destination = location.getProjection().fromPixels(
                                x - xDragTouchOffset, y - yDragTouchOffset);
                    new GetGeoAddress((IActionBar) appContext, myPoint).execute();
                    OverlayItem toDrop = new OverlayItem(myPoint, "", "");
                    items.add(toDrop);
                    populate();
                    if (source != null && destination != null) {
                        searchCabs.setEnabled(true);
                        // tip.startAnimation(rollUpAnimation);
                        searchCabs.setTextColor(Color.parseColor("#eeeee4"));
                        if (whichPoint == PICKUP)
                            searchCabs.setBackgroundColor(Color.parseColor("#fe000a"));
                        else if (whichPoint == DROP)
                            searchCabs.setBackgroundColor(Color.parseColor("#17ee27"));
                    }
                    break;
                }
            }
        }
        // Draw temp image while moving finger across the screen
        else if (action == MotionEvent.ACTION_MOVE && inDrag != null) {
            Log.d("iTaxeeta:Overlay", "Action Move" + marker.toString());
            setDragImagePosition(x, y);
            result = true;
        }
        // Position the selected point now
        else if (action == MotionEvent.ACTION_UP && inDrag != null) {
            GeoPoint myPoint = null;
            Log.d("iTaxeeta:Overlay", "Action Up" + marker.toString());
            dragImage.setVisibility(View.VISIBLE);
            if (whichPoint == PICKUP)
                myPoint = source = location.getProjection().fromPixels(x - xDragTouchOffset,
                        y - yDragTouchOffset);
            else if (whichPoint == DROP)
                myPoint = destination = location.getProjection().fromPixels(
                        x - xDragTouchOffset, y - yDragTouchOffset);
            OverlayItem toDrop = new OverlayItem(myPoint, inDrag.getTitle(),
                    inDrag.getSnippet());
            items.add(toDrop);
            populate();
            inDrag = null;
            new GetGeoAddress((IActionBar) appContext, myPoint).execute();
            if (source != null && destination != null) {
                searchCabs.setEnabled(true);
                // tip.startAnimation(rollUpAnimation);
                searchCabs.setTextColor(Color.parseColor("#eeeee4"));
                if (whichPoint == PICKUP)
                    searchCabs.setBackgroundColor(Color.parseColor("#fe000a"));
                else if (whichPoint == DROP)
                    searchCabs.setBackgroundColor(Color.parseColor("#17ee27"));
            }
            result = true;

        }

        return (result || super.onTouchEvent(event, mapView));
    }