使用 gson 将自定义数组列表保存到 Sharedpreferences

Question

我正在尝试将我的应用程序的状态保存到共享偏好中。我要保存的信息是自定义对象的数组列表，其中每个对象（PatientInfo）包含一些字符串和另外 2 个自定义数组列表（SkinPhotoInfo、TreatmentsInfo）。我能够保存和加载自定义对象的数组列表，但我无法保存其中包含数组列表的数组列表。

有人知道最简单的方法是什么吗？如果它有任何帮助，对象本身就已经可以解析了。

P。 S. 何时是保存到共享偏好的最佳时间 - onPause 或 onDelete？

感谢您的帮助！！

患者信息：

public class PatientInfo implements Parcelable {

String name;
String skinType;
String notes;
String image;
ArrayList<SkinPhotoInfo> skinPhotos;
ArrayList<TreatmentsInfo> treatments;
Boolean showDeleteButton;

@Override
public int describeContents() {
    return 0;
}

@Override
public void writeToParcel(Parcel dest, int flags) {
    dest.writeString(name);
    dest.writeString(skinType);
    dest.writeString(notes);
    dest.writeValue(image);
    dest.writeValue(skinPhotos);
    dest.writeValue(treatments);
}

public static final Creator<PatientInfo> CREATOR = new Creator<PatientInfo>()
{
    @Override
    public PatientInfo createFromParcel(Parcel source) {
        PatientInfo ret = new PatientInfo();
        ret.name = source.readString();
        ret.skinType = source.readString();
        ret.notes = source.readString();
        ret.image = (String)source.readString();
        ret.skinPhotos = source.readArrayList(null);
        ret.treatments = source.readArrayList(null);

        return ret;
    }

    @Override
    public PatientInfo[] newArray(int size) {
        return new PatientInfo[size];
    }
};

public PatientInfo() {
    this.name = "";
    this.skinType = "";
    this.image = "";
    this.skinPhotos = new ArrayList<SkinPhotoInfo>();
    this.showDeleteButton = false;
    this.treatments = new ArrayList<TreatmentsInfo>();
}}

皮肤照片信息：

public class SkinPhotoInfo implements Parcelable {

String photoDate;
Boolean showDeleteButton;
Uri imageUri;

@Override
public int describeContents() {
    return 0;
}

@Override
public void writeToParcel(Parcel dest, int flags) {
    dest.writeString(photoDate);
    dest.writeByte((byte)(showDeleteButton ? 1 : 0)); // If showDeleteButton == true, byte == 1
    dest.writeValue(imageUri);
}

public static final Creator<SkinPhotoInfo> CREATOR = new Creator<SkinPhotoInfo>()
{
    @Override
    public SkinPhotoInfo createFromParcel(Parcel source) {
        SkinPhotoInfo ret = new SkinPhotoInfo();
      ret.skinImageThumnail = (Bitmap)source.readValue(Bitmap.class.getClassLoader());
        ret.photoDate = source.readString();
        ret.showDeleteButton = source.readByte() != 1;
        ret.imageUri = (Uri) source.readValue(Uri.class.getClassLoader());
        return ret;
    }

    @Override
    public SkinPhotoInfo[] newArray(int size) {
        return new SkinPhotoInfo[size];
    }
};

    public SkinPhotoInfo(Uri imageUri, String photoDate) {
    this.imageUri = imageUri;
    this.photoDate = photoDate;
    showDeleteButton = false;
}}

治疗信息：

public class TreatmentsInfo implements Parcelable {
String treatmentDate;
String treatmentName;
String pattern = "MM-dd-yy";
Boolean showDeleteButton;

@Override
public int describeContents() {
    return 0;
}

@Override
public void writeToParcel(Parcel dest, int flags) {
    dest.writeString(treatmentDate);
    dest.writeString(treatmentName);
    dest.writeString(pattern);
    dest.writeByte((byte)(showDeleteButton ? 1 : 0)); // If showDeleteButton == true, byte == 1
}

public static final Creator<TreatmentsInfo> CREATOR = new Creator<TreatmentsInfo>()
{
    @Override
    public TreatmentsInfo createFromParcel(Parcel source) {
        TreatmentsInfo ret = new TreatmentsInfo();
        ret.treatmentDate = source.readString();
        ret.treatmentName = source.readString();
        ret.pattern = source.readString();
        ret.showDeleteButton = source.readByte() != 1;
        return ret;
    }

    @Override
    public TreatmentsInfo[] newArray(int size) {
        return new TreatmentsInfo[size];
    }
};

public TreatmentsInfo(){
    this.treatmentDate = "";
    this.treatmentName = "";
    this.showDeleteButton = false;
    this.pattern = "";
}

public TreatmentsInfo(String treatmentDate, String treatmentName) {
    this.treatmentDate = treatmentDate;
    this.treatmentName = treatmentName;
    this.showDeleteButton = false;
}}

Answer 1

使用 Gson 库并将数组列表保存为字符串。 下面的片段保存为文件，但您也可以在 sharedpreference 中使用它：

public static void saveGroupChatFile(File file, List<GCRoom> list) throws IOException {
    String data = new Gson().toJson(list);
    FileOutputStream fout = new FileOutputStream(file, false);
    OutputStreamWriter osw = new OutputStreamWriter(fout);
    osw.write(data);
    osw.close();
}

public static List<GCRoom> readGroupChatFile(File file) throws IOException {
    Type listType = new TypeToken<List<GCRoom>>() {
    }.getType();
    JsonReader reader = new JsonReader(new FileReader(file));

    return new Gson().fromJson(reader, listType);
}

至于图书馆：

implementation 'com.google.code.gson:gson:2.8.5'

Answer 2

你可以这样做：

String json = new Gson().toJson(YourObject);

保存在共享首选项中。 要检索 json 并将其转换为 YourObejct，只需执行以下操作：

String json = myPrefsObject.getString(TAG, "");    
return new Gson().fromJson(json, YourObject.class);

至于PS问题，答案是onPause。 如果您还需要其他东西，请告诉我

Answer 3

GSON 提供了将对象转换为字符串的方法，反之亦然。

使用toJson()将对象转换为字符串

PatientInfo patientInfo = new PatientInfo();
Gson gson = new Gson();   
String objectAsString = gson.toJson(patientInfo);   

使用fromJson()将字符串转换为对象

Gson gson = new Gson();
PatientInfo  patientinfo = gson.fromJson(data, PatientInfo.class);
//data is object that that you saved in shared preference after converting to string

Answer 4

将响应转换为 gson 并将其用作列表，因此只需将列表 setvalue 转换并使用 putArray() 到该集合

public class staticpref{
  private static SharedPreferences prefs;
   private static SharedPreferences.Editor editor;

 public static void putArray(String key, Set<String> arrayList){
    editor.putStringSet(key, arrayList);
    editor.commit();
}

public static Set getArray(String key,Set<String> defvalue){
    return prefs.getStringSet(key,defvalue);
}

}

或者你可以制作静态类来获取和数组，你必须将 gson 转换为 arraylist 并且像这样

String strResponse = anyjsonResponse;
Modelclass model= new Gson().fromJson(strResponse, Modelclass .class);
List<String> datalist= model.anyvalue();
Putandgetarray.addArrayList(datalist);

实现此目的的静态方法

public class Putandgetarray{

public static void addArrayList(List<data> dataList){
    String strputdata = new Gson().toJson(dataList, new TypeToken<List<MutedChat>>() {}.getType());
    SharedPreferenceUtils.putString("key", strputdata);
}

public static List<data> getArrayList(){
    Type type = new TypeToken<List<data>>(){}.getType();
    String strreturndata=SharedPreferenceUtils.getString("key","");
    return  new Gson().fromJson(strreturndata, type);
}

}

Answer 5

在 sharedPreferece 中你只能放 putStringSet(String key, @Nullable Set values);在共享偏好中