Question

我有：

public class HFSim extends ApplicationTemplate
{
  private static  class AppFrame extends ApplicationTemplate.AppFrame 
 {
     void setBuoy()
        {
            //code
                Position buoypos=Position.fromDegrees(buoylat, buoylon);
        }
    void setVehicle()
        { 
           //code
           Position vehiclepos=Position.fromDegrees(lat, lon, elev);
        }

    double findDistance() 
        {
        //find distance between marker (vehicle) and a buoy
        Earth earth= new Earth();
        double radius = earth.getEquatorialRadius();

        double distancebetween=LatLon.ellipsoidalDistance(buoypos, vehiclepos, radius, 6356752.3); 
        return distancebetween;
        }

如何在findDistance（）方法的setBuoy和setVehicle方法中使用对象buoypos和vehiclepos？

Answer 1

使用类scope的变量。这基本上意味着

 ///outside of a method but within the class you'll want to set:
 private this.bouypos = new Position;
 private this vehiclepos = new Position;
 //method1 {
 Position this.buoypos=Position.fromDegrees(buoylat, buoylon);
 //method2 {
 Position this.vehiclepos=Position.fromDegrees(lat, lon, elev);
//method3 calls things set in method1 & 2
 findDistance(){
     //code
     double distancebetween=LatLon.ellipsoidalDistance(this.buoypos, this.vehiclepos, radius, 6356752.3); 
 }

Answer 2

使findDistance方法将两个位置作为参数

double findDistance(Position buoypos, Position vehiclepos){

}

Answer 3

这里有两个明确的选项：

制作buoypos和vehiclepos实例变量，或..
为setVehicle（）提供更多描述性名称，并为其提供Position返回类型。

选项1看起来像这样：

...classname...
{
    private Position vehiclePosition;
    private Position bouyPosition;

    public void setVehiclePosition()
    {
        this.vehiclePosition = ....
    }
}

选项2看起来像这样：

...classname...
{
    public Position createVehiclePosition()
    {
        vehiclePosition = ....
        return vehiclePosition.
    }
}

最后，您可以将它们用作：

...classname...
{
    public double findDistance()
    {
        ...this.vehiclePosition...
        or
        Position vehiclePos = this.createVehiclePosition();
    }
}

您选择的选项在很大程度上取决于课程的行为方式。

如何在方法之间共享实例化对象？

3 个答案: