这是我的第一个 stackoverflow 问题。我在这方面做了很多谷歌搜索。在 Hashsets、Treesets、LinkedHashSets、Collections、Stacks（不推荐使用 Stack 类？）...我意识到我可以只使用 SQLite，但我暂时试图避免这种情况。
我正在开发 Android Studio 中的应用程序。该应用程序与人打交道，列出他们并以不同的方式联系他们。App 用户可以维护和控制三种类型的列表：最近联系、阻止和收藏。这些列表保存为共享首选项中的字符串集，因此它们在应用程序关闭和重新打开时仍然存在。当使用在线数据库填充列表时，各个字符串充当主键。我最关心的是“最近联系”列表，因为这个列表的顺序很重要。
问题是，据我了解，当我声明一个字符串集时，如下所示：
Set<String> faveArray = new LinkedHashSet<String>;
据我了解，我只能在右侧使用 HashSet、LinkedHashSet 或 TreeSet。
因为我使用了 LinkedHashset，所以我期望当我重新打开应用程序并将数据从 sharedpreferences 中拉回时，字符串将从最近添加的（LIFO / stack）开始被拉出，因此当我填充列表视图时，他们将与列表顶部的“最近联系”的人一起显示，依此类推……或者至少我期望有某种可预测的顺序/行为，我可以使用。
所以.......我已经为我的共享首选项 I/O 类附加了我的代码。
在我的主应用程序中，我执行以下操作：
static SharedPrefUTIL sharedPrefUTIL;
sharedPrefUTIL = new SharedPrefUTIL(this);
sharedPrefUTIL.addRecent("derp");
sharedPrefUTIL.addRecent("nerp");
sharedPrefUTIL.addRecent("gerp");
sharedPrefUTIL.addRecent("herp");
此时，代码
Log.i(TAG, set + " committed to " + key);
在 SharedPrefUTIL Logs 类的 commit() 方法中：
" [derp, nerp, gerp, herp] 致力于recentArray "
Bur 在关闭并重新打开应用程序后，如果我们执行：
sharedPrefUTIL.toastContents("R");
结果似乎是随机顺序。<<<<这是我的问题。
非常感谢任何帮助。
package com.secretsoft.booberbunz;
import android.content.Context;
import android.content.SharedPreferences;
import android.util.Log;
import android.widget.Toast;
import java.util.Arrays;
import java.util.HashSet;
import java.util.LinkedHashSet;
import java.util.Queue;
import java.util.Set;
import java.util.TreeSet;
/**
* Created by Programming on 2/22/2016.
*/
public class SharedPrefUTIL {
protected static final String TAG = "CXX SharedPrefUTIL";
Context context;
SharedPreferences sharedPreferences;
Set<String> faveArray;
Set<String> blockArray;
Set<String> recentArray;
public static final Set<String> DEFAULT = new HashSet<String>(Arrays.asList("empty"));
public SharedPrefUTIL(Context context){
this.context = context;
// load shared prefs into static arrays (new objects to prevent problems)
sharedPreferences = context.getSharedPreferences("prefs", Context.MODE_PRIVATE);
recentArray = new LinkedHashSet<String>(sharedPreferences.getStringSet("recentArray",DEFAULT));
blockArray = new LinkedHashSet<String>(sharedPreferences.getStringSet("blockArray",DEFAULT));
faveArray = new LinkedHashSet<String>(sharedPreferences.getStringSet("faveArray",DEFAULT));
Log.i(TAG, "SharedPrefUTIL instance created");
if (recentArray.contains("empty")) {
recentArray.clear();
Log.i(TAG, "recentArray contains the string -empty- and was cleared");
}
if (blockArray.contains("empty")) {
blockArray.clear();
Log.i(TAG, "blockArray contains the string -empty- and was cleared");
}
if (faveArray.contains("empty")) {
faveArray.clear();
Log.i(TAG, "faveArray contains the string -empty- and was cleared");
}
}
public void toastLength(String type){
if (type == "R"){
String temp = type + " array is this long: " + recentArray.size();
Toast.makeText(context, temp,
Toast.LENGTH_LONG).show();
Log.i(TAG, temp);
}
else if (type == "B"){
String temp = type + " array is this long: " + blockArray.size();
Toast.makeText(context, temp,
Toast.LENGTH_LONG).show();
Log.i(TAG, temp);
}
else if (type == "F"){
String temp = type + " array is this long: " + faveArray.size();
Toast.makeText(context, temp,
Toast.LENGTH_LONG).show();
Log.i(TAG, temp);
}
else {
Log.i(TAG, "invalid type param given to toastLength()");
}
}
public void toastContents(String type){
if (type == "R"){
for (String temp : recentArray) {
Toast.makeText(context, temp,
Toast.LENGTH_LONG).show();
Log.i(TAG, "recentArray contains: " + temp);
}
}
else if (type == "B"){
for (String temp : blockArray) {
Toast.makeText(context, temp,
Toast.LENGTH_LONG).show();
Log.i(TAG, "blockArray contains: " + temp);
}
}
else if (type == "F"){
for (String temp : faveArray) {
Toast.makeText(context, temp,
Toast.LENGTH_LONG).show();
Log.i(TAG, "faveArray contains: " + temp);
}
}
else {
Log.i(TAG, "invalid type param given to toastContents()");
}
}
public void clearList(String type){
if (type == "R"){
recentArray.clear();
commit("recentArray", recentArray);
Toast.makeText(context,"recent list has been cleared.", Toast.LENGTH_LONG);
}
else if (type == "B"){
blockArray.clear();
commit("blockArray", blockArray);
Toast.makeText(context,"blacklist has been cleared.", Toast.LENGTH_LONG);
}
else if (type == "F"){
faveArray.clear();
commit("faveArray", faveArray);
Toast.makeText(context,"favorites have been cleared.", Toast.LENGTH_LONG);
}
else {
Log.i(TAG, "invalid type param given to clearList()");
}
}
public void addRecent(String newRecent){
recentArray.add(newRecent);
commit("recentArray", recentArray);
Log.i(TAG, newRecent + " added to recentArray");
}
public void addBlocked(String newBlocked, String nick){
blockArray.add(newBlocked);
commit("blockArray", blockArray);
Toast.makeText(context, nick + " has been blacklisted!", Toast.LENGTH_SHORT);
}
public void remBlocked(String remBlocked, String nick){
blockArray.remove(remBlocked);
commit("blockArray", blockArray);
Toast.makeText(context, nick + " has been unblocked.", Toast.LENGTH_SHORT);
}
public void addFave(String newFave, String nick){
faveArray.add(newFave);
commit("faveArray", faveArray);
Toast.makeText(context, nick + " added to favorites!", Toast.LENGTH_SHORT);
}
public void remFave(String remFave, String nick){
faveArray.remove(remFave);
commit("faveArray", faveArray);
Toast.makeText(context, nick + " removed from favorites.", Toast.LENGTH_SHORT);
}
public void commit(String key, Set<String> set){
SharedPreferences.Editor editor = sharedPreferences.edit();
editor.putStringSet(key,set);
editor.commit();
Log.i(TAG, set + " committed to " + key);
}
}