怎样用ArrayList<Parcelable> 实现Parcelable

最新推荐文章于 2021-05-27 11:56:45 发布

翻译最新推荐文章于 2021-05-27 11:56:45 发布 · 3.2k 阅读

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本文详细介绍了如何在Android中实现自定义类的Parcelable接口，特别是在处理ArrayList类型的成员变量时的正确做法。通过对比错误和正确的代码示例，帮助读者理解如何正确地在Parcel中写入和读取数据。

I am having trouble making my class Parcelable. The trouble is, I am trying to write to the parcel a member in the class which is an ArrayList object. The ArrayList is serializable, and the objects (ZigBeeDev) in the list are Parcelable.

在使用Parcelable的过程中，我需要实例化一个ArrayList对象，下面是代码：

package com.gnychis.coexisyst;

import java.util.ArrayList;
import java.util.Iterator;

import android.os.Parcel;
import android.os.Parcelable;

public class ZigBeeNetwork implements Parcelable {

    public String _mac;             // the source address (of the coordinator?)
    public String _pan;             // the network address
    public int _band;               // the channel
    ArrayList<Integer> _lqis;       // link quality indicators (to all devices?)
    ArrayList<ZigBeeDev> _devices;  // the devices in the network

    public void writeToParcel(Parcel out, int flags) {
        out.writeString(_mac);
        out.writeString(_pan);
        out.writeInt(_band);
        out.writeSerializable(_lqis);
        out.writeParcelable(_devices, 0);  // help here
    }

    private ZigBeeNetwork(Parcel in) {
        _mac = in.readString();
        _pan = in.readString();
        _band = in.readInt();
        _lqis = (ArrayList<Integer>) in.readSerializable();
        _devices = in.readParcelable(ZigBeeDev.class.getClassLoader());  // help here
    }

    public int describeContents() {
        return this.hashCode();
    }

    public static final Parcelable.Creator<ZigBeeNetwork> CREATOR = 
            new Parcelable.Creator<ZigBeeNetwork>() {
        public ZigBeeNetwork createFromParcel(Parcel in) {
            return new ZigBeeNetwork(in);
        }

        public ZigBeeNetwork[] newArray(int size) {
            return new ZigBeeNetwork[size];
        }
    };

    //...
}

但是上面的代码是错误的，下面给出解决方法：

public void writeToParcel(Parcel out, int flags) {
    out.writeString(_mac);
    out.writeString(_pan);
    out.writeInt(_band);
    out.writeSerializable(_lqis);
    out.writeTypedList(_devices);
}

private ZigBeeNetwork(Parcel in) {
    _mac = in.readString();
    _pan = in.readString();
    _band = in.readInt();
    _lqis = (ArrayList<Integer>) in.readSerializable();
    in.readTypedList(_devices, ZigBeeDev.Creator);
}

That's all!

For your list of Integer, you can also do :

out.writeList(_lqis);
in.readList(_lqis Integer.class.getClassLoader());

这个是我在Stackoverflow上面找到的。