Question

我遇到了TypeConverters的问题，我想用它来将整数列表存储到我的房间数据库中。但我不断遇到问题“无法找到方法'值'”，“错误：元素值必须是常量表达式”，“错误：注释类型不适用于此类声明”这是代码。

@Entity
public class Movie {

@PrimaryKey
@SerializedName("id")
private int id;

@ColumnInfo(name = "poster_path")
@SerializedName("poster_path")
private String posterPath;

@ColumnInfo(name = "overview")
@SerializedName("overview")
private String overview;

@ColumnInfo(name = "original_title")
@SerializedName("original_title")
private String title;

@ColumnInfo(name = "release_date")
@SerializedName("release_date")
private String releasedDate;

@ColumnInfo(name = "vote_average")
@SerializedName("vote_average")
private double voteAverage;


@ColumnInfo(name = "genre_ids")
@SerializedName("genre_ids")
private List<Integer> genreIds = null;

public Movie() {
} 

    public List<Integer> getGenreIds() {
    return genreIds;
}

public void setGenreIds(List<Integer> genreIds) {
    this.genreIds = genreIds;
}

转换器

public class Converters {

@TypeConverter
public List<Integer> gettingListFromString(String genreIds) {
    List<Integer> list = new ArrayList<>();
    String[] array = genreIds.split(",");
    for(String s: array){
     list.add(Integer.parseInt(s));
    }
    return list;
}

@TypeConverter
public  String writingStringFromList(List<Integer> list) {
    String genreIds = "";
    for(int i : list){
        genreIds += ","+i;
    }
    return genreIds;
}
}

和db

@Database(entities = {Movie.class, Genre.class}, version = 4)
@TypeConverter({Converters.class})
public abstract class AppDatabase extends RoomDatabase {

private static AppDatabase instance;

public static AppDatabase getInstance(Context context){
    if(instance == null) instance = Room.databaseBuilder(context, AppDatabase.class, "movies_db")
            .build();
    return instance;
}

public abstract MovieDao movieDao();

public abstract GenreDao genreDao();

}

Answer 1

好的，最后我找到了解决方案。而不是

@TypeConverter({Converters.class})

我需要写

@TypeConverters({Converters.class})

错字。

在房间里的Converters.class上找不到方法'value'

1 个答案: