我需要在我的自定义类“ArtistInfo”中使用以下结构实现parcelable:
public class ArtistInfo implements Parcelable {
private String artist;
// album name to list of ids of songs
private HashMap> albumInfo;
// song id to songInfo
private SparseArray songsMap;
protected ArtistInfo(Parcel in) {
artist = in.readString();
}
public static final Creator CREATOR = new Creator() {
@Override
public ArtistInfo createFromParcel(Parcel in) {
return new ArtistInfo(in);
}
@Override
public ArtistInfo[] newArray(int size) {
return new ArtistInfo[size];
}
};
public String getArtist() {
return artist;
}
public void setArtist(String artist) {
this.artist = artist;
}
public void addSongsInfoToAlbum(List songsInfo, String album) {
if (albumInfo == null) {
albumInfo = new HashMap();
}
if (songsMap == null) {
songsMap = new SparseArray();
}
List songsIds = new ArrayList();
for (SongInfo songInfo : songsInfo) {
songsIds.add(songInfo.getId());
songsMap.put(songInfo.getId(), songInfo);
}
List songsIdsForAlbum = getSongIdsForAlbum(album);
songsIdsForAlbum.addAll(songsIds);
albumInfo.put(album, songsIdsForAlbum);
}
private List getSongIdsForAlbum(String album) {
if (albumInfo == null) {
return new ArrayList();
}
List songsIds = albumInfo.get(album);
return songsIds == null ? new ArrayList() : songsIds;
}
public HashMap> getAlbumInfo() {
return albumInfo;
}
public SparseArray getSongsMap() {
if (songsMap == null) {
songsMap = new SparseArray();
}
return songsMap;
}
@Override
public String toString() {
return "ArtistInfo{" +
"artist='" + artist + '\'' +
", albumInfo=" + albumInfo.toString() +
", songsMap=" + songsMap.toString() +
'}';
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
dest.writeString(artist);
}
}
以下是上述类中使用的“SongInfo”类的结构:
public class SongInfo implements Parcelable {
private Integer id;
private String name;
private String url;
public SongInfo(Integer id, String name, String url) {
this.id = id;
this.name = name;
this.url = url;
}
protected SongInfo(Parcel in) {
if (in.readByte() == 0) {
id = null;
} else {
id = in.readInt();
}
name = in.readString();
url = in.readString();
}
public static final Creator CREATOR = new Creator() {
@Override
public SongInfo createFromParcel(Parcel in) {
return new SongInfo(in);
}
@Override
public SongInfo[] newArray(int size) {
return new SongInfo[size];
}
};
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel dest, int flags) {
if (id == null) {
dest.writeByte((byte) 0);
} else {
dest.writeByte((byte) 1);
dest.writeInt(id);
}
dest.writeString(name);
dest.writeString(url);
}
}
现在您可以看到在SongInfo类中实现Parcelable接口没有问题,但是我无法理解如何分别在构造函数和writeToParcel方法中读取和写入 albumInfo 和 songsMap 变量 . 有人可以帮我理解我应该怎么做 . 谢谢!
1 回答
这个想法遍历
albumInfo
和songsMap
中的每个项目,然后将其添加到Parcelable
中 .写入包裹 .
从包裹中读取