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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.common;
     18 
     19 import android.content.ContentResolver;
     20 import android.content.Context;
     21 import android.content.res.Resources;
     22 import android.os.Vibrator;
     23 import android.provider.Settings;
     24 import android.provider.Settings.System;
     25 import android.util.Log;
     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     /** If no pattern was found, vibrate for a small amount of time. */
     64     private static final long DURATION = 10;  // millisec.
     65     /** Play the haptic pattern only once. */
     66     private static final int NO_REPEAT = -1;
     67 
     68     private static final String TAG = "HapticFeedback";
     69     private Context mContext;
     70     private long[] mHapticPattern;
     71     private Vibrator mVibrator;
     72 
     73     private boolean mEnabled;
     74     private Settings.System mSystemSettings;
     75     private ContentResolver mContentResolver;
     76     private boolean mSettingEnabled;
     77 
     78     /**
     79      * Initialize this instance using the app and system
     80      * configs. Since these don't change, init is typically called
     81      * once in 'onCreate'.
     82      * checkSettings is not called during init.
     83      * @param context To look up the resources and system settings.
     84      * @param enabled If false, vibrate will be a no-op regardless of
     85      * the system settings.
     86      */
     87     public void init(Context context, boolean enabled) {
     88         mEnabled = enabled;
     89         if (enabled) {
     90             mVibrator = (Vibrator) context.getSystemService(Context.VIBRATOR_SERVICE);
     91             mHapticPattern = new long[] {0, DURATION, 2 * DURATION, 3 * DURATION};
     92             mSystemSettings = new Settings.System();
     93             mContentResolver = context.getContentResolver();
     94         }
     95     }
     96 
     97 
     98     /**
     99      * Reload the system settings to check if the user enabled the
    100      * haptic feedback.
    101      */
    102     public void checkSystemSetting() {
    103         if (!mEnabled) {
    104             return;
    105         }
    106         try {
    107             int val = mSystemSettings.getInt(mContentResolver, System.HAPTIC_FEEDBACK_ENABLED, 0);
    108             mSettingEnabled = val != 0;
    109         } catch (Resources.NotFoundException nfe) {
    110             Log.e(TAG, "Could not retrieve system setting.", nfe);
    111             mSettingEnabled = false;
    112         }
    113 
    114     }
    115 
    116 
    117     /**
    118      * Generate the haptic feedback vibration. Only one thread can
    119      * request it. If the phone is already in a middle of an haptic
    120      * feedback sequence, the request is ignored.
    121      */
    122     public void vibrate() {
    123         if (!mEnabled || !mSettingEnabled) {
    124             return;
    125         }
    126         // System-wide configuration may return different styles of haptic feedback pattern.
    127         // - an array with one value implies "one-shot vibration"
    128         // - an array with multiple values implies "pattern vibration"
    129         // We need to switch methods to call depending on the difference.
    130         // See also PhoneWindowManager#performHapticFeedbackLw() for another example.
    131         if (mHapticPattern != null && mHapticPattern.length == 1) {
    132             mVibrator.vibrate(mHapticPattern[0]);
    133         } else {
    134             mVibrator.vibrate(mHapticPattern, NO_REPEAT);
    135         }
    136     }
    137 }
    138