如何绘制一个小标记图像并不断刷新其在我的CUSTOM地图图像上的位置？ - Android

Question

我目前正在开发一种跟踪系统,用于绘制用户在房间内或移动窗口内的移动轨迹.

现在我已经设法将我的地图导入到应用程序中,地图可以自由缩放和移动.下一步是放置一个标记以指示地图上的用户位置,并在地图上移动标记.(就像漂浮在地图上一样)

我在某个地方阅读并认为这可以完成MyLocationOverlay,但大多数在线的例子都是将它应用到google map.但是,在我的情况下,我的地图不是google map,这是我的OWN地图.(地图可以是我房间的地图,也可以是我自己绘制的地图!)

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,唯一的问题仍然是如何在地图图像上显示标记图像.

在细节上,我有一个自定义的视图MapView,如下所示:

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;
        }
    }

}

到目前为止,地图已成功输入到应用程序中,并且它既可移动又可缩放.

然后,我将此自定义视图插入到布局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>

基于所有这些信息,我如何绘制一个点并不断更新其在我的地图上的位置？

更新:

问题只是将另一个小图像放在自定义视图的顶部并移动它.

我还附上了这里的截图供您参考:

按钮和文本视图上方的区域是我的 MapView

Answer 1

这是我的代码的一部分，它执行了您所要求的操作（但仅适用于拖动手势），缩放有点复杂。我需要知道你的缩放基于哪个点，例如两个手指的中间或屏幕上的（0.0）

第一个首字母点但看不见

ImageButton dot = new ImageButton(this);// since I add onClick for the dot     
//setImageBitmap
dot.setVisibility(View.INVISIBLE);
RelativeLayout.LayoutParams dotparams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
dotparams.setMargins(0,0,0,0); 
dot.setLayoutParams(dotparams);
final RelativeLayout myLayout = (RelativeLayout)findViewById(R.id.maplayout);//set an Id for your RelativeLayout 
myLayout.addView(dot,dotparams);

用于向地图添加具有相关位置的点

dotImageWidth/Height 可以通过 Bitmap.getWidth()/getHeight() 获取

private void displayPositon(int dotx, int doty) {
    dot.setVisibility(View.VISIBLE);
    RelativeLayout.LayoutParams dotparams = new RelativeLayout.LayoutParams(RelativeLayout.LayoutParams.WRAP_CONTENT, RelativeLayout.LayoutParams.WRAP_CONTENT);
    dotparams.setMargins((int)(((android.widget.RelativeLayout.LayoutParams) mImage.getLayoutParams()).leftMargin + dotx - dotImageWidth/2 ),(int)(((android.widget.RelativeLayout.LayoutParams) mImage.getLayoutParams()).topMargin + doty - dotImageHeight),0,0);
    dot.setLayoutParams(params);

在 onTouchEvent 中切换之前

RelativeLayout.LayoutParams params[];
params = new RelativeLayout.LayoutParams[2];//one is the top-left of your mapView, one is the dot
params[0]= (android.widget.RelativeLayout.LayoutParams) dot.getLayoutParams();
params[1]= (android.widget.RelativeLayout.LayoutParams) mImage.getLayoutParams();

案例 Action_Down

dotleftMargin = ((android.widget.RelativeLayout.LayoutParams) dot.getLayoutParams()).leftMargin;
dottopMargin = ((android.widget.RelativeLayout.LayoutParams) dot.getLayoutParams()).topMargin;
mapleftMargin = ((android.widget.RelativeLayout.LayoutParams) mImage.getLayoutParams()).leftMargin;
maptopMargin = ((android.widget.RelativeLayout.LayoutParams) mImage.getLayoutParams()).topMargin;

案例ACTION_MOVE

params[0].setMargins((int)(x - mLastTouchX  + dotleftMargin), (int)(y- mLastTouchY + dottopMargin), 0, 0);
params[1].setMargins((int)(x - mLastTouchX  + mapleftMargin), (int)(y- mLastTouchY + maptopMargin), 0, 0);