Question

我正在尝试在我的谷歌地图上绘制一个可调整大小的圆圈，用户可以使用触摸手势扩展或缩小（例如缩小圆圈，用户将在屏幕上捏圆圈，我希望它像地图中的放大/缩小选项一样工作，只有圆圈才会在地图上变得更大/更小）。这有可能实现吗？如果是这样，我将如何实现这一目标。

我搜索了Google和Stackoverflow，据我所知，我需要在我的地图片段顶部添加一个自定义视图，并将OnTouchListener实现到此视图（这只是开始）。有人可以建议做什么或如何进行？我可以在地图上画一个圆圈，但我不知道如何让它响应触摸事件。

提前致谢。

Answer 1

根据您的问题，您想要叠加一个“捏听”视图，该视图根据捏合绘制椭圆形状。我为此目的制作了一些测试不佳的代码，根据需要进行调整：

MainLayout：

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <!-- Replace the ImageView with your MapView or whatever you are 
         overlaying with the oval shape -->
    <ImageView
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:src="#F00" />

    <com.example.testapp.CircleTouchView
        android:id="@+id/circle_drawer_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</FrameLayout>

CircleTouchView：

public class CircleTouchView extends View {
private static final int MODE_PINCH = 0;
private static final int MODE_DONT_CARE = 1;

ShapeDrawable mCircleDrawable;
int mTouchMode = MODE_DONT_CARE;

public CircleTouchView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
    mCircleDrawable = new ShapeDrawable(new OvalShape());
    mCircleDrawable.getPaint().setColor(0x66FFFFFF);
}

public CircleTouchView(Context context, AttributeSet attrs) {
    this(context, attrs, 0);
}

public CircleTouchView(Context context) {
    this(context, null, 0);
}

@Override
public boolean onTouchEvent(MotionEvent event) {

    switch (event.getActionMasked()) {
    case MotionEvent.ACTION_DOWN:
        mCircleDrawable.setBounds(0, 0, 0, 0);
        invalidate();
        break;
    case MotionEvent.ACTION_POINTER_DOWN:
        prepareCircleDrawing(event);
        break;
    case MotionEvent.ACTION_MOVE:
        if (mTouchMode == MODE_PINCH) {
            prepareCircleDrawing(event);
        }
        break;
    case MotionEvent.ACTION_POINTER_UP:
        if (event.getActionIndex() <= 1) {
            mTouchMode = MODE_DONT_CARE;
        }
        break;
    default:
        super.onTouchEvent(event);
    }

    return true;
}

private void prepareCircleDrawing(MotionEvent event) {
    int top, right, bottom, left;
    int index = event.getActionIndex();

    if (index > 1) {
        return;
    }
    mTouchMode = MODE_PINCH;
    if (event.getX(0) < event.getX(1)) {
        left = (int) event.getX(0);
        right = (int) event.getX(1);
    } else {
        left = (int) event.getX(1);
        right = (int) event.getX(0);
    }

    if (event.getY(0) < event.getY(1)) {
        top = (int) event.getY(0);
        bottom = (int) event.getY(1);
    } else {
        top = (int) event.getY(1);
        bottom = (int) event.getY(0);
    }

    mCircleDrawable.setBounds(left, top, right, bottom);

    invalidate();
}

@Override
protected void onDraw(Canvas canvas) {
    mCircleDrawable.draw(canvas);
}
}

如果您想要一个完美的圆形而不是椭圆形，请更改prepareCircleDrawing（）方法，使其在事件0和1之间获取X和Y的最小值。

修改：您可以在调用mCircleDrawable.setBounds(left, top, right, bottom);之前添加下面的代码段以绘制完美的圆圈。还有其他绘制圆圈的方法，这取决于你想要它的表现方式。

int height = bottom - top;
int width = right - left;

if (height > width) {
    int delta = height - width;
    top += delta / 2;
    bottom -= delta / 2;
} else {
    int delta = width - height;
    left += delta / 2;
    right -= delta / 2;
}

希望我明确表达自己的意见。

Answer 2

自问题被问到已经有一段时间了，但我在过去使用过此功能，然后才转换为不同于圆形的内容。

它并不完美，但也许会对某人有所帮助。

public class CircleView extends View {

private static final String TAG = "CircleView";
private static final double MOVE_SENSITIVITY = 1.25;
private Paint circlePaint;
private boolean isPinchMode;
private int lastCircleX;
private int lastCircleY;
public Circle circle;
private boolean isDoneResizing = true;

public CircleView(Context context) {
    super(context);
    setCirclePaint(0x220000ff);
}

public CircleView(Context context, AttributeSet attrs) {
    super(context, attrs);
    setCirclePaint(0x220000ff);
}

public CircleView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    setCirclePaint(0x220000ff);
}

private void setCirclePaint(int color) {
    circle = new Circle();
    circlePaint = new Paint();
    circlePaint.setColor(color);
}

@Override
protected void onDraw(Canvas canvas) {
    canvas.drawCircle(circle.centerX, circle.centerY, circle.radius, circlePaint);      
}

@Override
public boolean onTouchEvent(final MotionEvent event) {

    int historySize;
    double lastDistance;
    double oneBeforeLastDistance;

    switch (event.getActionMasked()) {
        case MotionEvent.ACTION_DOWN:
            lastCircleX = circle.centerX;
            lastCircleY = circle.centerY;
            break;

        case MotionEvent.ACTION_POINTER_DOWN:
            isPinchMode = true;
            isDoneResizing = false;
            break;

        case MotionEvent.ACTION_MOVE:
            circle.centerX = lastCircleX;
            circle.centerY = lastCircleY;; 

            if (getTouchedCircle((int) event.getX(), (int) event.getY()) && !isPinchMode && isDoneResizing) {

                historySize = event.getHistorySize();
                if (historySize > 0) {

                    oneBeforeLastDistance = Math.sqrt((event.getX() - event.getHistoricalX(0, historySize - 1)) * 
                                                      (event.getX() - event.getHistoricalX(0, historySize - 1)) + 
                                                      (event.getY() - event.getHistoricalY(0, historySize - 1)) * 
                                                      (event.getY() - event.getHistoricalY(0, historySize - 1)));


                    if (oneBeforeLastDistance > MOVE_SENSITIVITY) {
                        circle.centerX = (int) event.getX();
                        circle.centerY = (int) event.getY();
                        lastCircleX = circle.centerX;
                        lastCircleY = circle.centerY;

                    }
                }
            }
            if (isPinchMode) {
                circle.centerX = lastCircleX;
                circle.centerY = lastCircleY;

                historySize = event.getHistorySize();
                if (historySize > 0) {

                    lastDistance = Math.sqrt((event.getX(0) - event.getX(1)) * (event.getX(0) - event.getX(1)) + 
                                             (event.getY(0) - event.getY(1)) * (event.getY(0) - event.getY(1)));

                    oneBeforeLastDistance = Math.sqrt((event.getHistoricalX(0, historySize - 1) - event.getHistoricalX(1, historySize - 1)) * 
                                                      (event.getHistoricalX(0, historySize - 1) - event.getHistoricalX(1, historySize - 1)) + 
                                                      (event.getHistoricalY(0, historySize - 1) - event.getHistoricalY(1, historySize - 1)) * 
                                                      (event.getHistoricalY(0, historySize - 1) - event.getHistoricalY(1, historySize - 1)));


                    if (lastDistance < oneBeforeLastDistance) {
                        circle.radius -= Math.abs(lastDistance - oneBeforeLastDistance);
                    } else {
                        circle.radius += Math.abs(lastDistance - oneBeforeLastDistance);
                    }
                }
            }
            lastCircleX = circle.centerX;
            lastCircleY = circle.centerY;
            invalidate();
            break;

        case MotionEvent.ACTION_POINTER_UP:
            circle.centerX = lastCircleX;
            circle.centerY = lastCircleY;
            isPinchMode = false;
            break;

        case MotionEvent.ACTION_UP:
            circle.centerX = lastCircleX;
            circle.centerY = lastCircleY;
            isPinchMode = false;
            isDoneResizing = true;
            break;

        case MotionEvent.ACTION_CANCEL:
            break;

        case MotionEvent.ACTION_HOVER_MOVE:
            break;



        default:
            super.onTouchEvent(event);
            break;

    }
    return true;
}

private Boolean getTouchedCircle(final int xTouch, final int yTouch) {
    if ((circle.centerX - xTouch) * (circle.centerX - xTouch) + 
        (circle.centerY - yTouch) * (circle.centerY - yTouch)   <= circle.radius * circle.radius) {
        return true;
    } else {
        return false;
    }

}

static class Circle {
    int radius;
    int centerX;
    int centerY;

    Circle() {
        this.radius = 150;
        this.centerX = 378;
        this.centerY = 478;
    }        
}



}

Answer 3

自问这个问题以来已经有一段时间了，但我想介绍另一种方法。我创建了自己的库来处理可拖动的可调整大小的地图区域（圆圈）。 https://github.com/ac-opensource/MarkerBuilder

只需初始化MarkerBuilderManager

即可实现

markerBuilderManager = new MarkerBuilderManagerV2.Builder(this)
          .map(mMap) // required
          .build();

android - 在谷歌地图上绘制可调整大小的圆圈

3 个答案: