1 /*
2  * Copyright (C) 2018 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.util;
18 
19 import android.os.SystemClock;
20 
21 /**
22  * Determines whether a fling should be blocked. Currently we block flings when crossing thresholds
23  * to new states, and unblock after a short duration.
24  */
25 public class FlingBlockCheck {
26     // Allow flinging to a new state after waiting this many milliseconds.
27     private static final long UNBLOCK_FLING_PAUSE_DURATION = 200;
28 
29     private boolean mBlockFling;
30     private long mBlockFlingTime;
31 
blockFling()32     public void blockFling() {
33         mBlockFling = true;
34         mBlockFlingTime = SystemClock.uptimeMillis();
35     }
36 
unblockFling()37     public void unblockFling() {
38         mBlockFling = false;
39         mBlockFlingTime = 0;
40     }
41 
onEvent()42     public void onEvent() {
43         // We prevent flinging after passing a state, but allow it if the user pauses briefly.
44         if (SystemClock.uptimeMillis() - mBlockFlingTime >= UNBLOCK_FLING_PAUSE_DURATION) {
45             mBlockFling = false;
46         }
47     }
48 
isBlocked()49     public boolean isBlocked() {
50         return mBlockFling;
51     }
52 }
53