| /* |
| * Copyright (C) 2010 The Android Open Source Project |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| */ |
| |
| package com.android.gallery3d.ui; |
| |
| import com.android.gallery3d.common.Utils; |
| |
| import android.content.Context; |
| import android.view.ViewConfiguration; |
| import android.widget.OverScroller; |
| |
| public class ScrollerHelper { |
| private OverScroller mScroller; |
| private int mOverflingDistance; |
| private boolean mOverflingEnabled; |
| |
| public ScrollerHelper(Context context) { |
| mScroller = new OverScroller(context); |
| ViewConfiguration configuration = ViewConfiguration.get(context); |
| mOverflingDistance = configuration.getScaledOverflingDistance(); |
| } |
| |
| public void setOverfling(boolean enabled) { |
| mOverflingEnabled = enabled; |
| } |
| |
| /** |
| * Call this when you want to know the new location. The position will be |
| * updated and can be obtained by getPosition(). Returns true if the |
| * animation is not yet finished. |
| */ |
| public boolean advanceAnimation(long currentTimeMillis) { |
| return mScroller.computeScrollOffset(); |
| } |
| |
| public boolean isFinished() { |
| return mScroller.isFinished(); |
| } |
| |
| public void forceFinished() { |
| mScroller.forceFinished(true); |
| } |
| |
| public int getPosition() { |
| return mScroller.getCurrX(); |
| } |
| |
| public void setPosition(int position) { |
| mScroller.startScroll( |
| position, 0, // startX, startY |
| 0, 0, 0); // dx, dy, duration |
| |
| // This forces the scroller to reach the final position. |
| mScroller.abortAnimation(); |
| } |
| |
| public void fling(int velocity, int min, int max) { |
| int currX = getPosition(); |
| mScroller.fling( |
| currX, 0, // startX, startY |
| velocity, 0, // velocityX, velocityY |
| min, max, // minX, maxX |
| 0, 0, // minY, maxY |
| mOverflingEnabled ? mOverflingDistance : 0, 0); |
| } |
| |
| public boolean startScroll(int distance, int min, int max) { |
| int currPosition = mScroller.getCurrX(); |
| int finalPosition = mScroller.getFinalX(); |
| int newPosition = Utils.clamp(finalPosition + distance, min, max); |
| if (newPosition != currPosition) { |
| mScroller.startScroll( |
| currPosition, 0, // startX, startY |
| newPosition - currPosition, 0, 0); // dx, dy, duration |
| return true; |
| } else { |
| return false; |
| } |
| } |
| } |