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      1 /*
      2  * Copyright (C) 2009 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.phone;
     18 
     19 import android.content.Context;
     20 import android.content.ContentResolver;
     21 import android.content.res.Resources;
     22 import android.os.Vibrator;
     23 import android.util.Log;
     24 import android.provider.Settings;
     25 import android.provider.Settings.System;
     26 
     27 /**
     28  * Handles the haptic feedback: a light buzz happening when the user
     29  * presses a soft key (UI button or capacitive key).  The haptic
     30  * feedback is controlled by:
     31  * - a system resource for the pattern
     32  *   The pattern used is tuned per device and stored in an internal
     33  *   resource (config_virtualKeyVibePattern.)
     34  * - a system setting HAPTIC_FEEDBACK_ENABLED.
     35  *   HAPTIC_FEEDBACK_ENABLED can be changed by the user using the
     36  *   system Settings activity. It must be rechecked each time the
     37  *   activity comes in the foreground (onResume).
     38  *
     39  * This class is not thread safe. It assumes it'll be called from the
     40  * UI thead.
     41  *
     42  * Typical usage:
     43  * --------------
     44  *   static private final boolean HAPTIC_ENABLED = true;
     45  *   private HapticFeedback mHaptic = new HapticFeedback();
     46  *
     47  *   protected void onCreate(Bundle icicle) {
     48  *     mHaptic.init((Context)this, HAPTIC_ENABLED);
     49  *   }
     50  *
     51  *   protected void onResume() {
     52  *     // Refresh the system setting.
     53  *     mHaptic.checkSystemSetting();
     54  *   }
     55  *
     56  *   public void foo() {
     57  *     mHaptic.vibrate();
     58  *   }
     59  *
     60  */
     61 
     62 public class HapticFeedback {
     63     private static final int VIBRATION_PATTERN_ID =
     64             com.android.internal.R.array.config_virtualKeyVibePattern;
     65     /** If no pattern was found, vibrate for a small amount of time. */
     66     private static final long DURATION = 10;  // millisec.
     67     /** Play the haptic pattern only once. */
     68     private static final int NO_REPEAT = -1;
     69 
     70     private static final String TAG = "HapticFeedback";
     71     private Context mContext;
     72     private long[] mHapticPattern;
     73     private Vibrator mVibrator;
     74 
     75     private boolean mEnabled;
     76     private Settings.System mSystemSettings;
     77     private ContentResolver mContentResolver;
     78     private boolean mSettingEnabled;
     79 
     80     /**
     81      * Initialize this instance using the app and system
     82      * configs. Since these don't change, init is typically called
     83      * once in 'onCreate'.
     84      * checkSettings is not called during init.
     85      * @param context To look up the resources and system settings.
     86      * @param enabled If false, vibrate will be a no-op regardless of
     87      * the system settings.
     88      */
     89     public void init(Context context, boolean enabled) {
     90         mEnabled = enabled;
     91         if (enabled) {
     92             mVibrator = new Vibrator();
     93             if (!loadHapticSystemPattern(context.getResources())) {
     94                 mHapticPattern = new long[] {0, DURATION, 2 * DURATION, 3 * DURATION};
     95             }
     96             mSystemSettings = new Settings.System();
     97             mContentResolver = context.getContentResolver();
     98         }
     99     }
    100 
    101 
    102     /**
    103      * Reload the system settings to check if the user enabled the
    104      * haptic feedback.
    105      */
    106     public void checkSystemSetting() {
    107         if (!mEnabled) {
    108             return;
    109         }
    110         try {
    111             int val = mSystemSettings.getInt(mContentResolver, System.HAPTIC_FEEDBACK_ENABLED, 0);
    112             mSettingEnabled = val != 0;
    113         } catch (Resources.NotFoundException nfe) {
    114             Log.e(TAG, "Could not retrieve system setting.", nfe);
    115             mSettingEnabled = false;
    116         }
    117 
    118     }
    119 
    120 
    121     /**
    122      * Generate the haptic feedback vibration. Only one thread can
    123      * request it. If the phone is already in a middle of an haptic
    124      * feedback sequence, the request is ignored.
    125      */
    126     public void vibrate() {
    127         if (!mEnabled || !mSettingEnabled) {
    128             return;
    129         }
    130         mVibrator.vibrate(mHapticPattern, NO_REPEAT);
    131     }
    132 
    133     /**
    134      * @return true If the system haptic pattern was found.
    135      */
    136     private boolean loadHapticSystemPattern(Resources r) {
    137         int[] pattern;
    138 
    139         mHapticPattern = null;
    140         try {
    141             pattern = r.getIntArray(VIBRATION_PATTERN_ID);
    142         } catch (Resources.NotFoundException nfe) {
    143             Log.e(TAG, "Vibrate pattern missing.", nfe);
    144             return false;
    145         }
    146 
    147         if (null == pattern || pattern.length == 0) {
    148             Log.e(TAG, "Haptic pattern is null or empty.");
    149             return false;
    150         }
    151 
    152         // int[] to long[] conversion.
    153         mHapticPattern = new long[pattern.length];
    154         for (int i = 0; i < pattern.length; i++) {
    155             mHapticPattern[i] = pattern[i];
    156         }
    157         return true;
    158     }
    159 }
    160