1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
|
/*
* Copyright (C) 2019 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.launcher3.anim;
import androidx.dynamicanimation.animation.DynamicAnimation.OnAnimationEndListener;
import androidx.dynamicanimation.animation.FlingAnimation;
import androidx.dynamicanimation.animation.FloatPropertyCompat;
import androidx.dynamicanimation.animation.SpringAnimation;
import androidx.dynamicanimation.animation.SpringForce;
/**
* Given a property to animate and a target value and starting velocity, first apply friction to
* the fling until we pass the target, then apply a spring force to pull towards the target.
*/
public class FlingSpringAnim {
private static final float FLING_FRICTION = 1.5f;
private static final float SPRING_STIFFNESS = 200;
private static final float SPRING_DAMPING = 0.8f;
private final FlingAnimation mFlingAnim;
private SpringAnimation mSpringAnim;
private float mTargetPosition;
public <K> FlingSpringAnim(K object, FloatPropertyCompat<K> property, float startPosition,
float targetPosition, float startVelocity, float minVisChange, float minValue,
float maxValue, float springVelocityFactor, OnAnimationEndListener onEndListener) {
mFlingAnim = new FlingAnimation(object, property)
.setFriction(FLING_FRICTION)
// Have the spring pull towards the target if we've slowed down too much before
// reaching it.
.setMinimumVisibleChange(minVisChange)
.setStartVelocity(startVelocity)
.setMinValue(minValue)
.setMaxValue(maxValue);
mTargetPosition = targetPosition;
mFlingAnim.addEndListener(((animation, canceled, value, velocity) -> {
mSpringAnim = new SpringAnimation(object, property)
.setStartValue(value)
.setStartVelocity(velocity * springVelocityFactor)
.setSpring(new SpringForce(mTargetPosition)
.setStiffness(SPRING_STIFFNESS)
.setDampingRatio(SPRING_DAMPING));
mSpringAnim.addEndListener(onEndListener);
mSpringAnim.animateToFinalPosition(mTargetPosition);
}));
}
public float getTargetPosition() {
return mTargetPosition;
}
public void updatePosition(float startPosition, float targetPosition) {
mFlingAnim.setMinValue(Math.min(startPosition, targetPosition))
.setMaxValue(Math.max(startPosition, targetPosition));
mTargetPosition = targetPosition;
if (mSpringAnim != null) {
mSpringAnim.animateToFinalPosition(mTargetPosition);
}
}
public void start() {
mFlingAnim.start();
}
public void end() {
mFlingAnim.cancel();
if (mSpringAnim.canSkipToEnd()) {
mSpringAnim.skipToEnd();
}
}
}
|
