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      */
init(Context context, boolean enabled)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      */
checkSystemSetting()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      */
vibrate()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