1 /* 2 * Copyright (C) 2017 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 17 package com.android.settings.widget; 18 19 import android.content.Context; 20 import android.text.TextUtils; 21 22 /** 23 * Helper class that listens to settings changes and notifies client when there is update in 24 * corresponding summary info. 25 */ 26 public abstract class SummaryUpdater { 27 28 protected final Context mContext; 29 30 private final OnSummaryChangeListener mListener; 31 private String mSummary; 32 33 /** 34 * Interface definition for a callback to be invoked when the summary has been changed. 35 */ 36 public interface OnSummaryChangeListener { 37 /** 38 * Called when summary has changed. 39 * 40 * @param summary The new summary . 41 */ onSummaryChanged(String summary)42 void onSummaryChanged(String summary); 43 } 44 45 /** 46 * Constructor 47 * 48 * @param context The Context the updater is running in, through which it can register broadcast 49 * receiver etc. 50 * @param listener The listener that would like to receive summary change notification. 51 * 52 */ SummaryUpdater(Context context, OnSummaryChangeListener listener)53 public SummaryUpdater(Context context, OnSummaryChangeListener listener) { 54 mContext = context; 55 mListener = listener; 56 } 57 58 /** 59 * Notifies the listener when there is update in summary 60 */ notifyChangeIfNeeded()61 protected void notifyChangeIfNeeded() { 62 String summary = getSummary(); 63 if (!TextUtils.equals(mSummary, summary)) { 64 mSummary = summary; 65 if (mListener != null) { 66 mListener.onSummaryChanged(summary); 67 } 68 } 69 } 70 71 /** 72 * Starts/stops receiving updates on the summary. 73 * 74 * @param register true if we want to receive updates, false otherwise 75 */ register(boolean register)76 public abstract void register(boolean register); 77 78 /** 79 * Gets the summary. Subclass should checks latest conditions and update the summary 80 * accordingly. 81 * 82 * @return the latest summary text 83 */ getSummary()84 protected abstract String getSummary(); 85 86 } 87