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migrate animation to nullsafety (#62485)
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* migrate animation to nullsafety

* nullable tween

* fix generic type issue

* address review comment
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@a14n
a14n committed Jul 29, 2020
1 parent d6a25ae commit a7e868d
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Showing 8 changed files with 135 additions and 146 deletions.
2 changes: 0 additions & 2 deletions packages/flutter/lib/animation.dart
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Expand Up @@ -2,8 +2,6 @@
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// @dart = 2.8

/// The Flutter animation system.
///
/// To use, import `package:flutter/animation.dart`.
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2 changes: 0 additions & 2 deletions packages/flutter/lib/src/animation/animation.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -2,8 +2,6 @@
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// @dart = 2.8


import 'package:flutter/foundation.dart';

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75 changes: 37 additions & 38 deletions packages/flutter/lib/src/animation/animation_controller.dart
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Original file line number Diff line number Diff line change
Expand Up @@ -2,7 +2,6 @@
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

// @dart = 2.8

import 'dart:async';
import 'dart:ui' as ui show lerpDouble;
Expand Down Expand Up @@ -233,14 +232,14 @@ class AnimationController extends Animation<double>
/// changed by calling [resync]. It is required and must not be null. See
/// [TickerProvider] for advice on obtaining a ticker provider.
AnimationController({
double value,
double? value,
this.duration,
this.reverseDuration,
this.debugLabel,
this.lowerBound = 0.0,
this.upperBound = 1.0,
this.animationBehavior = AnimationBehavior.normal,
@required TickerProvider vsync,
required TickerProvider vsync,
}) : assert(lowerBound != null),
assert(upperBound != null),
assert(upperBound >= lowerBound),
Expand Down Expand Up @@ -272,7 +271,7 @@ class AnimationController extends Animation<double>
this.duration,
this.reverseDuration,
this.debugLabel,
@required TickerProvider vsync,
required TickerProvider vsync,
this.animationBehavior = AnimationBehavior.preserve,
}) : assert(value != null),
assert(vsync != null),
Expand All @@ -291,7 +290,7 @@ class AnimationController extends Animation<double>

/// A label that is used in the [toString] output. Intended to aid with
/// identifying animation controller instances in debug output.
final String debugLabel;
final String? debugLabel;

/// The behavior of the controller when [AccessibilityFeatures.disableAnimations]
/// is true.
Expand All @@ -310,24 +309,24 @@ class AnimationController extends Animation<double>
///
/// If [reverseDuration] is specified, then [duration] is only used when going
/// [forward]. Otherwise, it specifies the duration going in both directions.
Duration duration;
Duration? duration;

/// The length of time this animation should last when going in [reverse].
///
/// The value of [duration] us used if [reverseDuration] is not specified or
/// set to null.
Duration reverseDuration;
Duration? reverseDuration;

Ticker _ticker;
Ticker? _ticker;

/// Recreates the [Ticker] with the new [TickerProvider].
void resync(TickerProvider vsync) {
final Ticker oldTicker = _ticker;
final Ticker oldTicker = _ticker!;
_ticker = vsync.createTicker(_tick);
_ticker.absorbTicker(oldTicker);
_ticker!.absorbTicker(oldTicker);
}

Simulation _simulation;
Simulation? _simulation;

/// The current value of the animation.
///
Expand All @@ -339,7 +338,7 @@ class AnimationController extends Animation<double>
/// listeners.
@override
double get value => _value;
double _value;
late double _value;
/// Stops the animation controller and sets the current value of the
/// animation.
///
Expand Down Expand Up @@ -394,7 +393,7 @@ class AnimationController extends Animation<double>
double get velocity {
if (!isAnimating)
return 0.0;
return _simulation.dx(lastElapsedDuration.inMicroseconds.toDouble() / Duration.microsecondsPerSecond);
return _simulation!.dx(lastElapsedDuration!.inMicroseconds.toDouble() / Duration.microsecondsPerSecond);
}

void _internalSetValue(double newValue) {
Expand All @@ -414,22 +413,22 @@ class AnimationController extends Animation<double>
/// and the most recent tick of the animation.
///
/// If the controller is not animating, the last elapsed duration is null.
Duration get lastElapsedDuration => _lastElapsedDuration;
Duration _lastElapsedDuration;
Duration? get lastElapsedDuration => _lastElapsedDuration;
Duration? _lastElapsedDuration;

/// Whether this animation is currently animating in either the forward or reverse direction.
///
/// This is separate from whether it is actively ticking. An animation
/// controller's ticker might get muted, in which case the animation
/// controller's callbacks will no longer fire even though time is continuing
/// to pass. See [Ticker.muted] and [TickerMode].
bool get isAnimating => _ticker != null && _ticker.isActive;
bool get isAnimating => _ticker != null && _ticker!.isActive;

_AnimationDirection _direction;

@override
AnimationStatus get status => _status;
AnimationStatus _status;
late AnimationStatus _status;

/// Starts running this animation forwards (towards the end).
///
Expand All @@ -442,7 +441,7 @@ class AnimationController extends Animation<double>
/// During the animation, [status] is reported as [AnimationStatus.forward],
/// which switches to [AnimationStatus.completed] when [upperBound] is
/// reached at the end of the animation.
TickerFuture forward({ double from }) {
TickerFuture forward({ double? from }) {
assert(() {
if (duration == null) {
throw FlutterError(
Expand Down Expand Up @@ -475,7 +474,7 @@ class AnimationController extends Animation<double>
/// During the animation, [status] is reported as [AnimationStatus.reverse],
/// which switches to [AnimationStatus.dismissed] when [lowerBound] is
/// reached at the end of the animation.
TickerFuture reverse({ double from }) {
TickerFuture reverse({ double? from }) {
assert(() {
if (duration == null && reverseDuration == null) {
throw FlutterError(
Expand Down Expand Up @@ -509,7 +508,7 @@ class AnimationController extends Animation<double>
/// regardless of whether `target` > [value] or not. At the end of the
/// animation, when `target` is reached, [status] is reported as
/// [AnimationStatus.completed].
TickerFuture animateTo(double target, { Duration duration, Curve curve = Curves.linear }) {
TickerFuture animateTo(double target, { Duration? duration, Curve curve = Curves.linear }) {
assert(
_ticker != null,
'AnimationController.animateTo() called after AnimationController.dispose()\n'
Expand All @@ -531,7 +530,7 @@ class AnimationController extends Animation<double>
/// regardless of whether `target` < [value] or not. At the end of the
/// animation, when `target` is reached, [status] is reported as
/// [AnimationStatus.dismissed].
TickerFuture animateBack(double target, { Duration duration, Curve curve = Curves.linear }) {
TickerFuture animateBack(double target, { Duration? duration, Curve curve = Curves.linear }) {
assert(
_ticker != null,
'AnimationController.animateBack() called after AnimationController.dispose()\n'
Expand All @@ -541,9 +540,9 @@ class AnimationController extends Animation<double>
return _animateToInternal(target, duration: duration, curve: curve);
}

TickerFuture _animateToInternal(double target, { Duration duration, Curve curve = Curves.linear }) {
TickerFuture _animateToInternal(double target, { Duration? duration, Curve curve = Curves.linear }) {
double scale = 1.0;
if (SemanticsBinding.instance.disableAnimations) {
if (SemanticsBinding.instance!.disableAnimations) {
switch (animationBehavior) {
case AnimationBehavior.normal:
// Since the framework cannot handle zero duration animations, we run it at 5% of the normal
Expand All @@ -555,7 +554,7 @@ class AnimationController extends Animation<double>
break;
}
}
Duration simulationDuration = duration;
Duration? simulationDuration = duration;
if (simulationDuration == null) {
assert(() {
if ((this.duration == null && _direction == _AnimationDirection.reverse && reverseDuration == null) || this.duration == null) {
Expand All @@ -572,8 +571,8 @@ class AnimationController extends Animation<double>
final double remainingFraction = range.isFinite ? (target - _value).abs() / range : 1.0;
final Duration directionDuration =
(_direction == _AnimationDirection.reverse && reverseDuration != null)
? reverseDuration
: this.duration;
? reverseDuration!
: this.duration!;
simulationDuration = directionDuration * remainingFraction;
} else if (target == value) {
// Already at target, don't animate.
Expand Down Expand Up @@ -617,7 +616,7 @@ class AnimationController extends Animation<double>
/// The most recently returned [TickerFuture], if any, is marked as having been
/// canceled, meaning the future never completes and its [TickerFuture.orCancel]
/// derivative future completes with a [TickerCanceled] error.
TickerFuture repeat({ double min, double max, bool reverse = false, Duration period }) {
TickerFuture repeat({ double? min, double? max, bool reverse = false, Duration? period }) {
min ??= lowerBound;
max ??= upperBound;
period ??= duration;
Expand All @@ -636,7 +635,7 @@ class AnimationController extends Animation<double>
assert(max <= upperBound && min >= lowerBound);
assert(reverse != null);
stop();
return _startSimulation(_RepeatingSimulation(_value, min, max, reverse, period, _directionSetter));
return _startSimulation(_RepeatingSimulation(_value, min, max, reverse, period!, _directionSetter));
}

void _directionSetter(_AnimationDirection direction) {
Expand All @@ -658,13 +657,13 @@ class AnimationController extends Animation<double>
/// The most recently returned [TickerFuture], if any, is marked as having been
/// canceled, meaning the future never completes and its [TickerFuture.orCancel]
/// derivative future completes with a [TickerCanceled] error.
TickerFuture fling({ double velocity = 1.0, AnimationBehavior animationBehavior }) {
TickerFuture fling({ double velocity = 1.0, AnimationBehavior? animationBehavior }) {
_direction = velocity < 0.0 ? _AnimationDirection.reverse : _AnimationDirection.forward;
final double target = velocity < 0.0 ? lowerBound - _kFlingTolerance.distance
: upperBound + _kFlingTolerance.distance;
double scale = 1.0;
final AnimationBehavior behavior = animationBehavior ?? this.animationBehavior;
if (SemanticsBinding.instance.disableAnimations) {
if (SemanticsBinding.instance!.disableAnimations) {
switch (behavior) {
case AnimationBehavior.normal:
// TODO(jonahwilliams): determine a better process for setting velocity.
Expand Down Expand Up @@ -712,7 +711,7 @@ class AnimationController extends Animation<double>
_simulation = simulation;
_lastElapsedDuration = Duration.zero;
_value = simulation.x(0.0).clamp(lowerBound, upperBound) as double;
final TickerFuture result = _ticker.start();
final TickerFuture result = _ticker!.start();
_status = (_direction == _AnimationDirection.forward) ?
AnimationStatus.forward :
AnimationStatus.reverse;
Expand Down Expand Up @@ -745,7 +744,7 @@ class AnimationController extends Animation<double>
);
_simulation = null;
_lastElapsedDuration = null;
_ticker.stop(canceled: canceled);
_ticker!.stop(canceled: canceled);
}

/// Release the resources used by this object. The object is no longer usable
Expand All @@ -770,7 +769,7 @@ class AnimationController extends Animation<double>
}
return true;
}());
_ticker.dispose();
_ticker!.dispose();
_ticker = null;
super.dispose();
}
Expand All @@ -788,8 +787,8 @@ class AnimationController extends Animation<double>
_lastElapsedDuration = elapsed;
final double elapsedInSeconds = elapsed.inMicroseconds.toDouble() / Duration.microsecondsPerSecond;
assert(elapsedInSeconds >= 0.0);
_value = _simulation.x(elapsedInSeconds).clamp(lowerBound, upperBound) as double;
if (_simulation.isDone(elapsedInSeconds)) {
_value = _simulation!.x(elapsedInSeconds).clamp(lowerBound, upperBound) as double;
if (_simulation!.isDone(elapsedInSeconds)) {
_status = (_direction == _AnimationDirection.forward) ?
AnimationStatus.completed :
AnimationStatus.dismissed;
Expand All @@ -802,7 +801,7 @@ class AnimationController extends Animation<double>
@override
String toStringDetails() {
final String paused = isAnimating ? '' : '; paused';
final String ticker = _ticker == null ? '; DISPOSED' : (_ticker.muted ? '; silenced' : '');
final String ticker = _ticker == null ? '; DISPOSED' : (_ticker!.muted ? '; silenced' : '');
final String label = debugLabel == null ? '' : '; for $debugLabel';
final String more = '${super.toStringDetails()} ${value.toStringAsFixed(3)}';
return '$more$paused$ticker$label';
Expand Down Expand Up @@ -870,10 +869,10 @@ class _RepeatingSimulation extends Simulation {

if (reverse && _isPlayingReverse) {
directionSetter(_AnimationDirection.reverse);
return ui.lerpDouble(max, min, t);
return ui.lerpDouble(max, min, t)!;
} else {
directionSetter(_AnimationDirection.forward);
return ui.lerpDouble(min, max, t);
return ui.lerpDouble(min, max, t)!;
}
}

Expand Down

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