Question

从文档来看，似乎CameraPosition应该使用度数作为其承载成员。但它的构建器类将传入的度数转换为弧度。

/**
 * Sets the direction that the camera is pointing in, in degrees clockwise from north.
 *
 * @param bearing Bearing
 * @return Builder
 */
public Builder bearing(double bearing) {
    if (isRadiant) {
        this.bearing = bearing;
    } else {
        // converting degrees to radiant
        this.bearing = (float) (-bearing * MathConstants.DEG2RAD);
    }
    return this;
}

这是CameraPosition的构造函数。如果构造函数期望度数，那么构建器应该保持轴承的度数或转换为度数（如果它是弧度）。

/**
 * Constructs a CameraPosition.
 *
 * @param target  The target location to align with the center of the screen.
 * @param zoom    Zoom level at target. See zoom(float) for details of restrictions.
 * @param tilt    The camera angle, in degrees, from the nadir (directly down). See tilt(float) for details of restrictions.
 * @param bearing Direction that the camera is pointing in, in degrees clockwise from north. This value will be normalized to be within 0 degrees inclusive and 360 degrees exclusive.
 * @throws NullPointerException     if target is null
 * @throws IllegalArgumentException if tilt is outside the range of 0 to 90 degrees inclusive.
 */
CameraPosition(LatLng target, double zoom, double tilt, double bearing) {
    this.target = target;
    this.bearing = bearing;
    this.tilt = tilt;
    this.zoom = zoom;

Answer 1

默认单位为degrees。

正如您所提到的，构建器将度数转换为弧度。除非Builder使用isRadiant并将其设置为true，否则将保持不变，然后将弧度保留为double。看起来在Mapbox Android SDK 3.x和4.0.0之间引入了isRadiant。

if (isRadiant) {
    this.bearing = bearing;
} else {
    // converting degrees to radiant
    this.bearing = (float) (-bearing * MathConstants.DEG2RAD);
}

构建器执行算术提升。在内部，轴承显然是弧度，但开发人员输入为degrees。

来自文档

@param bearing相机指向的方向，以北为顺时针方向的度数。该值将标准化为0   包含度和360度独家。

Mapbox Android SDK 4.0中的示例明确设置了isRadiant(false) -

                CameraPosition position = new CameraPosition.Builder()
                        .target(new LatLng(32.9, -116.9))
                        .zoom(17) // Sets the zoom
                        .isRadiant(false)
                        .bearing(180) // Rotate the camera 180 degrees
                        .tilt(30) // Set the camera tilt
                        .build(); // Creates a CameraPosition from the builder

                mapboxMap.animateCamera(CameraUpdateFactory
                        .newCameraPosition(position), 7000);

处理CameraPostion，CameraPostion.Builder时，正确的单位是什么？

1 个答案: