问题描述
我有一个应用程序，每当我按下按钮时都会给我一些字符串，然后使用 sharedpreferences 保存这个值.但是，我想限制这个保存功能，所以它只会保存最后三个收到的字符串.
I have application that gives me some string whenever I press the button and then save this value using sharedpreferences. However, I would like to limit this saving function, so it will save only the last three received strings.
结构如下:字符串 A字符串 B字符串 C
The structure is of the following: String A String B String C
下次我点击按钮时，它会将值记录到字符串 A 中，同时将旧字符串 A 移动到字符串 B，将字符串 B 的旧值移动到字符串 C，并相应地删除字符串 C 的旧值.
Next time when i click my button it will record the value into String A, while move the old String A to String B and old value of String B to String C, as well as, delete the old value of String C accordingly.
目前我不确定它是如何完成的.
At the moment I'm not sure how its done.
期待您的帮助.
推荐答案
试试这样的:
//Obtain values
SharedPreferences prefs =
getSharedPreferences("PreferencesKey", Context.MODE_PRIVATE);
String stringA = prefs.getString("stringA", "defaultValue");
String stringB = prefs.getString("stringB", "defaultValue");
String stringC = prefs.getString("stringC", "defaultValue");
//Save values
SharedPreferences.Editor editor = prefs.edit();
editor.putString("stringA", lastValueSelected);
editor.putString("stringB", stringA);
editor.putString("stringC", stringB);
editor.commit();
问候
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