java - android studio中的类转换异常错误

Question

爪哇代码：

package com.example.nearest_masjid;

public class GetNearByPlaces extends AsyncTask<Object,String,String>
{
    private String GooglePlaceData, url;
    GoogleMap mMap;
    @Override
    protected String doInBackground(Object... objects) {
        mMap = (GoogleMap)objects[0];
        url = (String)objects[1];
        DownloadUrl downloadUrl = new DownloadUrl();
        try
        {
            GooglePlaceData = downloadUrl.ReadTheUrl(url);
        }
        catch (IOException e) {
            e.printStackTrace();
        }
        return GooglePlaceData;
    }

标签： javagoogle-mapsandroid-studio

Answer 1

显然，这里的问题是您将 String 作为第一个参数传递，方法实现需要 GoogleMap 类型的 Object。所以检查调用方法并确保参数的顺序正确。

除此之外，您需要使您的代码类型安全。我会定义一个 POJO 并将其作为参数传递。

class MyData {
  String url;
  GoogleMap map;

  //define getters and setters 
  .....
}

public class GetNearByPlaces extends AsyncTask<MyData,String,String>
{
    private String GooglePlaceData, url;
    GoogleMap mMap;
    @Override
    protected String doInBackground(MyData... data) {
        mMap = data[0].getMap();
        url = data[0].getUrl();
        DownloadUrl downloadUrl = new DownloadUrl();
        ......
    }