Question

根据通用结果“T”寻找更简洁/更好的强制“num”类型的方法。例如：

int iCartesianAngleInDegrees=45, _iDistanceBetween=85;
Vector<int> ivectXY=new Vector<int>(10,30);
ivectXY.moveByDegreesAndDistance(iCartesianAngleInDegrees, _iDistanceBetween);

在moveByDegreesAndDistance方法中，我的kludge检查runtimeType以调用toInt或toDouble。这对我来说似乎不合适。有什么建议/提示赞赏吗？

class Vector<T extends num> extends Coordinate<T> {
...
/**
 * Advance x/y in Direction(Cartesian Degrees) for a given Distance
 * TODO:PerfTest
 **/
Vector<T> moveByDegreesAndDistance(T iDegrees, T iDistance) {
    //cartesianToCompass(135) = 225
    double _dblAngleInRadians = degreesToRadians(iDegrees),
            _dblX = iDistance * math.cos(_dblAngleInRadians),
            _dblY = iDistance * math.sin(_dblAngleInRadians);

    //This will not automatically coerce type
    //      x += _dblX as T;
    //      y += _dblY as T;

    if (_dblX is T) {
        x += _dblX;
        y += _dblY;
    } else {
        if (x.runtimeType == int) {
            x += _dblX.toInt();
            y += _dblY.toInt();
        } else {
            x += _dblX.toDouble();
            y += _dblY.toDouble();
        }
    }
    return this;
}

}

Answer 1

_dblAngleInRadians，_dblX，_dblY为double您只需测试iDegrees是int并使用toInt()在这种情况下。

class Vector<T extends num> extends Coordinate<T> {
...
/**
 * Advance x/y in Direction(Cartesian Degrees) for a given Distance
 * TODO:PerfTest
 **/
Vector<T> moveByDegreesAndDistance(T iDegrees, T iDistance) {
    //cartesianToCompass(135) = 225
    double _dblAngleInRadians = degreesToRadians(iDegrees),
            _dblX = iDistance * math.cos(_dblAngleInRadians),
            _dblY = iDistance * math.sin(_dblAngleInRadians);

    //This will not automatically coerce type
    //      x += _dblX as T;
    //      y += _dblY as T;
    final isInt = iDegrees is int;
    x += isInt ? _dblX.toInt() : _dblX;
    y += isInt ? _dblY.toInt() : _dblY;
    return this;
}

如何在double和int之间强制使用num类型

1 个答案: