1 /* 2 * Copyright (C) 2018 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 package com.android.dumpviewer.utils; 17 18 import android.content.SharedPreferences; 19 import android.text.TextUtils; 20 21 import java.util.ArrayList; 22 import java.util.Arrays; 23 import java.util.Collection; 24 25 public class History { 26 private final SharedPreferences mPrefs; 27 private final String mSharedPrefKey; 28 private final int mMaxSize; 29 30 private static final String SEPARATOR = "\u0001sep\u0001"; 31 32 private ArrayList<String> mItems = new ArrayList<>(); 33 History(SharedPreferences prefs, String sharedPrefKey, int maxSize)34 public History(SharedPreferences prefs, String sharedPrefKey, int maxSize) { 35 mPrefs = prefs; 36 mSharedPrefKey = sharedPrefKey; 37 mMaxSize = maxSize; 38 } 39 ensureMaxSize()40 private void ensureMaxSize() { 41 while (mItems.size() > mMaxSize) { 42 mItems.remove(0); 43 } 44 } 45 load()46 public void load() { 47 mItems.clear(); 48 49 mItems.addAll(Arrays.asList( 50 TextUtils.split(mPrefs.getString(mSharedPrefKey, ""), SEPARATOR))); 51 ensureMaxSize(); 52 } 53 save()54 private void save() { 55 String[] items = mItems.toArray(new String[mItems.size()]); 56 mPrefs.edit().putString(mSharedPrefKey, TextUtils.join(SEPARATOR, items)).apply(); 57 } 58 add(String item)59 public void add(String item) { 60 item = item.trim(); 61 if (item.length() == 0) { 62 return; 63 } 64 String fitem = item; 65 mItems.removeIf(v -> v.equals(fitem)); 66 mItems.add(item); 67 ensureMaxSize(); 68 69 save(); 70 } 71 addAllTo(Collection<String> col)72 public void addAllTo(Collection<String> col) { 73 for (int i = mItems.size() - 1; i >= 0; i--) { 74 col.add(mItems.get(i)); 75 } 76 } 77 } 78