Joe Onorato | e77c08d | 2009-08-01 00:01:20 -0700 | [diff] [blame] | 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.launcher2; |
| 18 | |
| 19 | import android.os.Handler; |
Joe Onorato | e77c08d | 2009-08-01 00:01:20 -0700 | [diff] [blame] | 20 | import android.os.SystemClock; |
Joe Onorato | e77c08d | 2009-08-01 00:01:20 -0700 | [diff] [blame] | 21 | |
| 22 | /** |
| 23 | * Provides an animation between 0.0f and 1.0f over a given duration. |
| 24 | */ |
| 25 | class SymmetricalLinearTween { |
| 26 | |
| 27 | private static final int FPS = 30; |
| 28 | private static final int FRAME_TIME = 1000 / FPS; |
| 29 | |
| 30 | Handler mHandler; |
| 31 | int mDuration; |
| 32 | TweenCallback mCallback; |
| 33 | |
| 34 | boolean mRunning; |
| 35 | long mBase; |
| 36 | boolean mDirection; |
| 37 | float mValue; |
| 38 | |
| 39 | /** |
| 40 | * @param duration milliseconds duration |
| 41 | * @param callback callbacks |
| 42 | */ |
| 43 | public SymmetricalLinearTween(boolean initial, int duration, TweenCallback callback) { |
| 44 | mValue = initial ? 1.0f : 0.0f; |
| 45 | mDirection = initial; |
| 46 | mDuration = duration; |
| 47 | mCallback = callback; |
| 48 | mHandler = new Handler(); |
| 49 | } |
| 50 | |
| 51 | /** |
| 52 | * Starts the tweening. |
| 53 | * |
| 54 | * @param direction If direction is true, the value goes towards 1.0f. If direction |
| 55 | * is false, the value goes towards 0.0f. |
| 56 | */ |
| 57 | public void start(boolean direction) { |
| 58 | start(direction, SystemClock.uptimeMillis()); |
| 59 | } |
| 60 | |
| 61 | /** |
| 62 | * Starts the tweening. |
| 63 | * |
| 64 | * @param direction If direction is true, the value goes towards 1.0f. If direction |
| 65 | * is false, the value goes towards 0.0f. |
| 66 | * @param baseTime The time to use as zero for this animation, in the |
| 67 | * {@link SystemClock.uptimeMillis} time base. This allows you to |
| 68 | * synchronize multiple animations. |
| 69 | */ |
| 70 | public void start(boolean direction, long baseTime) { |
| 71 | if (direction != mDirection) { |
| 72 | if (!mRunning) { |
| 73 | mBase = baseTime; |
| 74 | mRunning = true; |
| 75 | mCallback.onTweenStarted(); |
| 76 | long next = SystemClock.uptimeMillis() + FRAME_TIME; |
| 77 | mHandler.postAtTime(mTick, next); |
| 78 | } else { |
| 79 | // reverse direction |
| 80 | long now = SystemClock.uptimeMillis(); |
| 81 | long diff = now - mBase; |
| 82 | mBase = now + diff - mDuration; |
| 83 | } |
| 84 | mDirection = direction; |
| 85 | } |
| 86 | } |
| 87 | |
| 88 | Runnable mTick = new Runnable() { |
| 89 | public void run() { |
| 90 | long base = mBase; |
| 91 | long now = SystemClock.uptimeMillis(); |
| 92 | long diff = now-base; |
| 93 | int duration = mDuration; |
| 94 | float val = diff/(float)duration; |
| 95 | if (!mDirection) { |
| 96 | val = 1.0f - val; |
| 97 | } |
| 98 | if (val > 1.0f) { |
| 99 | val = 1.0f; |
| 100 | } else if (val < 0.0f) { |
| 101 | val = 0.0f; |
| 102 | } |
| 103 | float old = mValue; |
| 104 | mValue = val; |
| 105 | mCallback.onTweenValueChanged(val, old); |
| 106 | int frame = (int)(diff / FRAME_TIME); |
| 107 | long next = base + ((frame+1)*FRAME_TIME); |
| 108 | if (diff < duration) { |
| 109 | mHandler.postAtTime(this, next); |
| 110 | } |
| 111 | if (diff >= duration) { |
| 112 | mCallback.onTweenFinished(); |
| 113 | mRunning = false; |
| 114 | } |
| 115 | } |
| 116 | }; |
| 117 | } |
| 118 | |