如何使用ArrayList正确实现Mailable<Parcelable>？

serialization android java parcelable

2022-08-31 13:07:55

我在上课时遇到了麻烦。麻烦的是，我试图将类中的成员写入包裹，这是一个对象。列表中的 is 和对象（）是。ParcelableArrayList<Parcelable>ArrayListSerializableZigBeeDevParcelable

以下是相关代码：

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];
        }
    };

    //...
}

我已经标记了两个点“//帮助这里”，以了解如何正确写入包裹以及如何重建它。如果是（经过适当测试），我该如何正确执行此操作？ZigBeeDevParcelable

答案 1

你几乎明白了！

你只需要做：

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);
}

就这样！

对于整数列表，您还可以执行以下操作：

out.writeList(_lqis);
_lqis = new ArrayList<>();
in.readList(_lqis Integer.class.getClassLoader());

它应该有效。

答案 2

在我的情况下给了我一个.所以我用了这个：in.readTypedList(_devices, ZigBeeDev.CREATOR);NullPointerException_devices

_devices = in.createTypedArrayList(ZigBeeDev.CREATOR);