kotlin，如何将HashMap放在Parcelable中 [英] kotlin, how to put HashMap in Parcelable

问题描述

在实现Parcelable的类中，它具有HashMap成员.

In a class who implements Parcelable it has a HashMap member.

看到包裹可具有 public final void readMap(Map outVal, ClassLoader loader)，但找不到使用它的示例.

Saw Parcelable has public final void readMap(Map outVal, ClassLoader loader), but could not find a sample to use it.

如果通过将地图展平并相应地逐一写入/读取来进行操作，那么如何从构造函数中的宗地中提取出来? (由于从可打包的cannot access buildTheMap() before constructor is called生成地图而出错)

If do it by flatten the map and write/read one by one accordingly, how to extract from the parcel in the constructor? (got error to build the map from the parcelable, cannot access buildTheMap() before constructor is called)

class CachedData(val type: Int,
             val name: String,
             val details: HashMap<String, String) :
    Parcelable {

constructor(parcel: Parcel) : this(
        parcel.readInt(),
        parcel.readString(),

        // how to get the hashMap out of the parcel???
        buildTheMap(parcel)   //<=== cannot access buildTheMap() before constructor is called
)

fun buildTheMap(parcel: Parcel) :HashMap<String, String> {

    val size = parcel.readInt()
    val map = HashMap<String, String>()

    for (i in 1..size) {
        val key = parcel.readString()
        val value = parcel.readString()
        map[key] = value
    }
    return map
}

override fun writeToParcel(parcel: Parcel, flags: Int) {
    parcel.writeInt(type)
    parcel.writeString(name)

    // how to write the HashMap<String, String> to the parcel
    //parcel.???

    parcel.writeInt(details.size)
    for ((key, value) in details) {
        parcel.writeString(key)
        parcel.writeString(value)
    }
}

override fun describeContents(): Int {
    return 0
}

companion object {
    @JvmField val CREATOR: Parcelable.Creator<CachedData> = object : Parcelable.Creator<CachedData>{
        override fun createFromParcel(parcel: Parcel): CachedData {
            return CachedData(parcel)
        }

        override fun newArray(size: Int): Array<CachedData?> {
            return arrayOfNulls(size)
        }
    }
}

}

推荐答案

对于我来说，面临同样的问题.为我工作的解决方案是:

As for me a faced with the same problem. The working for me solution was:

public class JoustBattler extends Parcelable {

...

 private Map<String, Integer> battleWins;


 protected JoustBattler(Parcel in) {
        super(in);

        int battleWinsSize = in.readInt();
        this.battleWins = new HashMap<String, Integer>(battleWinsSize);
        for (int i = 0; i < battleWinsSize; i++) {
            String key = in.readString();
            Integer value = (Integer) in.readValue(Integer.class.getClassLoader());
            this.battleWins.put(key, value);
        }

    }


    @Override
    public void writeToParcel(Parcel dest, int flags) {
        super.writeToParcel(dest, flags);

        dest.writeInt(this.battleWins.size());
        for (Map.Entry<String, Integer> entry : this.battleWins.entrySet()) {
            dest.writeString(entry.getKey());
            dest.writeValue(entry.getValue());
        }

    }

希望有帮助，祝您好运！

Hope it helps, good luck!

这篇关于kotlin，如何将HashMap放在Parcelable中的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！