将java.util.Map传递到另一个活动

Question

我正在使用jsoup解析网站。
我在mainactivity中有一个映射 cookies 。
并且我需要将值cookies传递给secondactivity。
所以我创建了一个类实现pracelable。

DataPasser dataPass = new DataPasser(id, pw, cookies);
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
intent.putExtra("data", dataPass);
MainActivity.this.startActivity(intent);

dataPasser dataPass = getIntent().getParcelableExtra("data");
String id = dataPass.getId();
String pw = dataPass.getPw();
Map<String, String> cookies = dataPass.getCookies();

java prettyprint-override">public class DataPasser implements Parcelable {

    private String id;
    private String pw;
    Map<String, String> cookies;

    public String getId() {
        return id;
    }

    public String getPw() {
        return pw;
    }

    public Map<String, String> getCookies() {
        return cookies;
    }

    public DataPasser(Parcel in) {
        this.id = in.readString();
        this.pw = in.readString();
        in.readMap(cookies, Map.class.getClassLoader()); /** NullPointerException here. **/
    }

    public DataPasser(String id, String pw, Map<String, String> cookies) {
        this.id = id;
        this.pw = pw;
        this.cookies = cookies;
    }


    @Override
    public void writeToParcel(Parcel out, int flags) {
        out.writeString(id);
        out.writeString(pw);
        out.writeMap(cookies);        
    }

    public int describeContents() {
        return 0;
    }

    public static final Parcelable.Creator<DataPasser> CREATOR = new Parcelable.Creator<DataPasser>() {
        public DataPasser createFromParcel(Parcel in) {
            return new DataPasser(in);
        }
        public DataPasser[] newArray (int size) {
            return new DataPasser[size];
        }
    };    
}

但是，我在DataPasser类中得到了一个NullPointerException。
如何将map 传递给另一个活动？

Answer 1

另一种可能的解决方案是在DataPasser中实现Serializable接口

public class DataPasser implements Serializable {

像您一样从mainactivity.java中传递数据

DataPasser dataPass = new DataPasser(id, pw, cookies);
Intent intent = new Intent(MainActivity.this, SecondActivity.class);
intent.putExtra("data", dataPass);
MainActivity.this.startActivity(intent);

并在secondactivity.java中获得相同的内容，如下所示

DataPasser dataPass = (DataPasser) getIntent().getExtras().get("data");

希望能成功。

对于parcelable也请参考此内容