Android SharedPreferences保存集合（List类型）

安卓项目中会经常遇到使用SharedPreferences的情况，如果要保存的类型是List，可以这样实现：
1.定义MessageModel .java

public class MessageModel implements Serializable{
    private String name;
    private String title;
    private String body;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getTitle() {
        return title;
    }

    public void setTitle(String title) {
        this.title = title;
    }

    public String getBody() {
        return body;
    }

    public void setBody(String body) {
        this.body = body;
    }
}

2.集合中添加数据并保存：

List<MessageModel> namelist = new ArrayList<>();
MessageModel messageModel = new MessageModel();
messageModel.setName(name.getText().toString());
messageModel.setTitle(title.getText().toString());
messageModel.setBody(body.getText().toString());
namelist.add(messageModel);
SharedPreferences sp = mBaseActivity.getSharedPreferences("SP_NewUserModel_List", Activity.MODE_PRIVATE);//创建sp对象
Gson gson = new Gson();
String jsonStr=gson.toJson(namelist); //将List转换成Json
SharedPreferences.Editor editor = sp.edit() ;
editor.putString("KEY_NewUserModel_LIST_DATA", jsonStr) ; //存入json串
editor.commit() ;  //提交

3.读取数据

SharedPreferences sp = mBaseActivity.getSharedPreferences("SP_NewUserModel_List",Activity.MODE_PRIVATE);//创建sp对象,如果有key为"SP_PEOPLE"的sp就取出
        String peopleListJson = sp.getString("KEY_NewUserModel_LIST_DATA","");  //取出key为"KEY_PEOPLE_DATA"的值，如果值为空，则将第二个参数作为默认值赋值
        if(peopleListJson!="")  //防空判断
        {
            Gson gson = new Gson();
            namelist = gson.fromJson(peopleListJson, new TypeToken<List<MessageModel>>() {}.getType()); //将json字符串转换成List集合
        }