1 /* 2 * Copyright (C) 2013 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.launcher3; 18 19 import android.support.v4.widget.AutoScrollHelper; 20 import android.widget.ScrollView; 21 22 /** 23 * An implementation of {@link AutoScrollHelper} that knows how to scroll 24 * through a {@link Folder}. 25 */ 26 public class FolderAutoScrollHelper extends AutoScrollHelper { 27 private static final float MAX_SCROLL_VELOCITY = 1500f; 28 29 private final ScrollView mTarget; 30 31 public FolderAutoScrollHelper(ScrollView target) { 32 super(target); 33 34 mTarget = target; 35 36 setActivationDelay(0); 37 setEdgeType(EDGE_TYPE_INSIDE_EXTEND); 38 setExclusive(true); 39 setMaximumVelocity(MAX_SCROLL_VELOCITY, MAX_SCROLL_VELOCITY); 40 setRampDownDuration(0); 41 setRampUpDuration(0); 42 } 43 44 @Override 45 public void scrollTargetBy(int deltaX, int deltaY) { 46 mTarget.scrollBy(deltaX, deltaY); 47 } 48 49 @Override 50 public boolean canTargetScrollHorizontally(int direction) { 51 // List do not scroll horizontally. 52 return false; 53 } 54 55 @Override 56 public boolean canTargetScrollVertically(int direction) { 57 return mTarget.canScrollVertically(direction); 58 } 59 }
