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Refresh Indicator fine tuning (#4800)

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This commit is contained in:
Hans Muller 2016-06-30 15:36:06 -07:00 committed by GitHub
parent 6298a1aeb1
commit 107cbd3185
2 changed files with 114 additions and 55 deletions
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24
packages/flutter/lib/src/material/progress_indicator.dart
View File

@ -381,7 +381,8 @@ class _RefreshProgressIndicatorPainter extends _CircularProgressIndicatorPainter
double tailValue,
int stepValue,
double rotationValue,
double strokeWidth
double strokeWidth,
this.arrowheadScale
}) : super(
valueColor: valueColor,
value: value,
@ -392,23 +393,27 @@ class _RefreshProgressIndicatorPainter extends _CircularProgressIndicatorPainter
strokeWidth: strokeWidth
);
final double arrowheadScale;
void paintArrowhead(Canvas canvas, Size size) {
// ux, uy: a unit vector whose direction parallels the base of the arrowhead.
// Note that -ux, uy points in the direction the arrowhead points.
// Note that ux, -uy points in the direction the arrowhead points.
final double arcEnd = arcStart + arcSweep;
final double ux = math.cos(arcEnd);
final double uy = math.sin(arcEnd);
assert(size.width == size.height);
final double radius = size.width / 2.0;
final double arrowHeadRadius = strokeWidth * 1.5;
final double innerRadius = radius - arrowHeadRadius;
final double outerRadius = radius + arrowHeadRadius;
final double arrowheadPointX = radius + ux * radius + -uy * strokeWidth * 2.0 * arrowheadScale;
final double arrowheadPointY = radius + uy * radius + ux * strokeWidth * 2.0 * arrowheadScale;
final double arrowheadRadius = strokeWidth * 1.5 * arrowheadScale;
final double innerRadius = radius - arrowheadRadius;
final double outerRadius = radius + arrowheadRadius;
Path path = new Path()
..moveTo(radius + ux * innerRadius, radius + uy * innerRadius)
..lineTo(radius + ux * outerRadius, radius + uy * outerRadius)
..lineTo(radius + ux * radius + -uy * strokeWidth * 2.0, radius + uy * radius + ux * strokeWidth * 2.0)
..lineTo(arrowheadPointX, arrowheadPointY)
..close();
Paint paint = new Paint()
..color = valueColor
@ -420,7 +425,8 @@ class _RefreshProgressIndicatorPainter extends _CircularProgressIndicatorPainter
@override
void paint(Canvas canvas, Size size) {
super.paint(canvas, size);
paintArrowhead(canvas, size);
if (arrowheadScale > 0.0)
paintArrowhead(canvas, size);
}
}
@ -472,6 +478,7 @@ class _RefreshProgressIndicatorState extends _CircularProgressIndicatorState {
@override
Widget _buildIndicator(BuildContext context, double headValue, double tailValue, int stepValue, double rotationValue) {
final double arrowheadScale = config.value == null ? 0.0 : (config.value * 2.0).clamp(0.0, 1.0);
return new Container(
width: _kIndicatorSize,
height: _kIndicatorSize,
@ -490,7 +497,8 @@ class _RefreshProgressIndicatorState extends _CircularProgressIndicatorState {
tailValue: tailValue,
stepValue: stepValue,
rotationValue: rotationValue,
strokeWidth: 2.0
strokeWidth: 2.0,
arrowheadScale: arrowheadScale
)
)
)

145
packages/flutter/lib/src/material/refresh_indicator.dart
View File

@ -37,19 +37,24 @@ typedef Future<Null> RefreshCallback();
/// Where the refresh indicator appears: top for over-scrolls at the
/// start of the scrollable, bottom for over-scrolls at the end.
enum RefreshIndicatorLocation {
/// The refresh indicator should appear at the top of the scrollable.
/// The refresh indicator will appear at the top of the scrollable.
top,
/// The refresh indicator should appear at the bottom of the scrollable.
/// The refresh indicator will appear at the bottom of the scrollable.
bottom,
/// The refresh indicator will appear at both ends of the scrollable.
both
}
// The state machine moves through these modes only when the scrollable
// identified by scrollableKey has been scrolled to its min or max limit.
enum _RefreshIndicatorMode {
drag,
armed,
snap,
refresh,
dimiss
drag, // Pointer is down.
armed, // Dragged far enough that an up event will run the refresh callback.
snap, // Animating to the indicator's final "displacement".
refresh, // Running the refresh callback.
dismiss // Animating the indicator's fade-out.
}
/// A widget that supports the Material "swipe to refresh" idiom.
@ -62,6 +67,11 @@ enum _RefreshIndicatorMode {
/// returns. The refresh indicator disappears after the callback's
/// Future has completed.
///
/// The required [scrollableKey] parameter identifies the scrollable widget
/// whose scrollOffset is monitored by this RefreshIndicator. The same
/// scrollableKey must also be set on the scrollable. See [Block.scrollableKey]
/// [ScrollableList.scrollableKey], etc.
///
/// See also:
///
/// * <https://www.google.com/design/spec/patterns/swipe-to-refresh.html>
@ -75,17 +85,22 @@ class RefreshIndicator extends StatefulWidget {
this.scrollableKey,
this.child,
this.displacement: 40.0,
this.refresh
this.refresh,
this.location: RefreshIndicatorLocation.top
}) : super(key: key) {
assert(child != null);
assert(refresh != null);
assert(location != null);
}
/// Identifies the [Scrollable] descendant of child that will cause the
/// refresh indicator to appear. Can be null if there's only one
/// [Scrollable] descendant.
/// refresh indicator to appear.
final GlobalKey<ScrollableState> scrollableKey;
/// The refresh indicator will be stacked on top of this child. The indicator
/// will appear when child's Scrollable descendant is over-scrolled.
final Widget child;
/// The distance from the child's top or bottom edge to where the refresh indicator
/// will settle. During the drag that exposes the refresh indicator, its actual
/// displacement may significantly exceed this value.
@ -96,9 +111,9 @@ class RefreshIndicator extends StatefulWidget {
/// Future must complete when the refresh operation is finished.
final RefreshCallback refresh;
/// The refresh indicator will be stacked on top of this child. The indicator
/// will appear when child's Scrollable descendant is over-scrolled.
final Widget child;
/// Where the refresh indicator should appear, RefreshIndicatorLocation.top
/// by default.
final RefreshIndicatorLocation location;
@override
_RefreshIndicatorState createState() => new _RefreshIndicatorState();
@ -116,7 +131,7 @@ class _RefreshIndicatorState extends State<RefreshIndicator> {
double _containerExtent;
double _minScrollOffset;
double _maxScrollOffset;
RefreshIndicatorLocation _location = RefreshIndicatorLocation.top;
bool _isIndicatorAtTop = true;
_RefreshIndicatorMode _mode;
Future<Null> _pendingRefreshFuture;
@ -165,12 +180,6 @@ class _RefreshIndicatorState extends State<RefreshIndicator> {
_maxScrollOffset = scrollBehavior.maxScrollOffset;
}
RefreshIndicatorLocation get _locationForScrollOffset {
return _scrollOffset < _minScrollOffset
? RefreshIndicatorLocation.top
: RefreshIndicatorLocation.bottom;
}
void _handlePointerDown(PointerDownEvent event) {
final ScrollableState scrollable = config.scrollableKey?.currentState;
if (scrollable == null)
@ -179,27 +188,70 @@ class _RefreshIndicatorState extends State<RefreshIndicator> {
_updateState(scrollable);
_scaleController.value = 0.0;
_sizeController.value = 0.0;
_mode = _RefreshIndicatorMode.drag;
setState(() {
_mode = _RefreshIndicatorMode.drag;
});
}
double _overscrollDistance() {
final ScrollableState scrollable = config.scrollableKey?.currentState;
if (scrollable == null)
return 0.0;
final double oldOffset = _scrollOffset;
final double newOffset = scrollable.scrollOffset;
_updateState(scrollable);
if ((newOffset - oldOffset).abs() < kPixelScrollTolerance.distance)
return 0.0;
switch (config.location) {
case RefreshIndicatorLocation.top:
return newOffset < _minScrollOffset ? _minScrollOffset - newOffset : 0.0;
case RefreshIndicatorLocation.bottom:
return newOffset > _maxScrollOffset ? newOffset - _maxScrollOffset : 0.0;
case RefreshIndicatorLocation.both: {
if (newOffset < _minScrollOffset)
return _minScrollOffset - newOffset;
else if (newOffset > _maxScrollOffset)
return newOffset - _maxScrollOffset;
else
return 0.0;
}
}
return 0.0;
}
void _handlePointerMove(PointerMoveEvent event) {
final ScrollableState scrollable = config.scrollableKey?.currentState;
if (scrollable == null)
return;
final double value = scrollable.scrollOffset;
if ((value < _minScrollOffset || value > _maxScrollOffset) &&
((value - _scrollOffset).abs() > kPixelScrollTolerance.distance)) {
final double overScroll = value < _minScrollOffset ? _minScrollOffset - value : value - _maxScrollOffset;
final double newValue = overScroll / (_containerExtent * _kDragContainerExtentPercentage);
final double overscroll = _overscrollDistance();
if (overscroll > 0.0) {
final double newValue = overscroll / (_containerExtent * _kDragContainerExtentPercentage);
_sizeController.value = newValue.clamp(0.0, 1.0);
if (_location != _locationForScrollOffset) {
final bool newIsAtTop = _scrollOffset < _minScrollOffset;
if (_isIndicatorAtTop != newIsAtTop) {
setState(() {
_location = _locationForScrollOffset;
_isIndicatorAtTop = newIsAtTop;
});
}
}
// No setState() here because this doesn't cause a visual change.
_mode = _valueColor.value.alpha == 0xFF ? _RefreshIndicatorMode.armed : _RefreshIndicatorMode.drag;
_updateState(scrollable);
}
// Stop showing the refresh indicator
Future<Null> _dismiss() async {
setState(() {
_mode = _RefreshIndicatorMode.dismiss;
});
await _scaleController.animateTo(1.0, duration: _kIndicatorScaleDuration);
if (mounted && _mode == _RefreshIndicatorMode.dismiss) {
setState(() {
_mode = null;
});
}
}
Future<Null> _doHandlePointerUp(PointerUpEvent event) async {
@ -220,15 +272,11 @@ class _RefreshIndicatorState extends State<RefreshIndicator> {
bool completed = _pendingRefreshFuture != null;
_pendingRefreshFuture = null;
if (mounted && completed && _mode == _RefreshIndicatorMode.refresh) {
setState(() {
_mode = null; // Stop showing the indeterminate progress indicator.
});
_scaleController.animateTo(1.0, duration: _kIndicatorScaleDuration);
}
if (mounted && completed && _mode == _RefreshIndicatorMode.refresh)
_dismiss();
}
} else {
_scaleController.animateTo(1.0, duration: _kIndicatorScaleDuration);
} else if (_mode == _RefreshIndicatorMode.drag) {
_dismiss();
}
}
@ -238,7 +286,8 @@ class _RefreshIndicatorState extends State<RefreshIndicator> {
@override
Widget build(BuildContext context) {
final bool isAtTop = _location == RefreshIndicatorLocation.top;
final bool showIndeterminateIndicator =
_mode == _RefreshIndicatorMode.refresh || _mode == _RefreshIndicatorMode.dismiss;
return new Listener(
onPointerDown: _handlePointerDown,
onPointerMove: _handlePointerMove,
@ -250,26 +299,28 @@ class _RefreshIndicatorState extends State<RefreshIndicator> {
value: true
),
new Positioned(
top: isAtTop ? 0.0 : null,
bottom: isAtTop ? null : 0.0,
top: _isIndicatorAtTop ? 0.0 : null,
bottom: _isIndicatorAtTop ? null : 0.0,
left: 0.0,
right: 0.0,
child: new SizeTransition(
axisAlignment: isAtTop ? 1.0 : 0.0,
axisAlignment: _isIndicatorAtTop ? 1.0 : 0.0,
sizeFactor: _sizeFactor,
child: new Container(
padding: isAtTop
padding: _isIndicatorAtTop
? new EdgeInsets.only(top: config.displacement)
: new EdgeInsets.only(bottom: config.displacement),
child: new Align(
alignment: isAtTop ? FractionalOffset.bottomCenter : FractionalOffset.topCenter,
alignment: _isIndicatorAtTop
? FractionalOffset.bottomCenter
: FractionalOffset.topCenter,
child: new ScaleTransition(
scale: _scaleFactor,
child: new AnimatedBuilder(
animation: _sizeController,
builder: (BuildContext context, Widget child) {
return new RefreshProgressIndicator(
value: _mode == _RefreshIndicatorMode.refresh ? null : _value.value,
value: showIndeterminateIndicator ? null : _value.value,
valueColor: _valueColor
);
}