mirror of
https://github.com/flutter/flutter.git
synced 2026-02-20 02:29:02 +08:00
e8318f65a7
This patch removes the mutable API to event handling (Nodes no longer have a events object with which to add listeners). Instead, a new (non-Render) Node is introduced: EventTarget. This node represents a location in the Effen tree which can handle events as they bubble. Note that this also changes the implementation to use event delegation (one set of listeners at the sky.document level) rather than direct listeners on leaf nodes. R=abarth@chromium.org Review URL: https://codereview.chromium.org/1019633004
88 lines
2.5 KiB
Dart
88 lines
2.5 KiB
Dart
// Copyright 2015 The Chromium Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style license that can be
|
|
// found in the LICENSE file.
|
|
|
|
import '../animation/scroll_behavior.dart';
|
|
import '../fn.dart';
|
|
import 'dart:math' as math;
|
|
import 'dart:sky' as sky;
|
|
import 'scrollable.dart';
|
|
|
|
abstract class FixedHeightScrollable extends Scrollable {
|
|
// TODO(rafaelw): This component really shouldn't have an opinion
|
|
// about how it is sized. The owning component should decide whether
|
|
// it's explicitly sized or flexible or whatever...
|
|
static final Style _style = new Style('''
|
|
overflow: hidden;
|
|
position: relative;
|
|
flex: 1;
|
|
will-change: transform;'''
|
|
);
|
|
|
|
static final Style _scrollAreaStyle = new Style('''
|
|
position:relative;
|
|
will-change: transform;'''
|
|
);
|
|
|
|
double _height = 0.0;
|
|
double _itemHeight;
|
|
|
|
FixedHeightScrollable({
|
|
Object key,
|
|
ScrollBehavior scrollBehavior
|
|
}) : super(key: key, scrollBehavior: scrollBehavior);
|
|
|
|
void didMount() {
|
|
super.didMount();
|
|
var root = getRoot();
|
|
var item = root.firstChild.firstChild;
|
|
sky.ClientRect scrollRect = root.getBoundingClientRect();
|
|
sky.ClientRect itemRect = item.getBoundingClientRect();
|
|
assert(scrollRect.height > 0);
|
|
assert(itemRect.height > 0);
|
|
|
|
setState(() {
|
|
_height = scrollRect.height;
|
|
_itemHeight = itemRect.height;
|
|
});
|
|
}
|
|
|
|
Node buildContent() {
|
|
var itemNumber = 0;
|
|
var drawCount = 1;
|
|
var transformStyle = '';
|
|
|
|
if (_height > 0.0) {
|
|
if (scrollOffset < 0.0) {
|
|
double visibleHeight = _height + scrollOffset;
|
|
drawCount = (visibleHeight / _itemHeight).round() + 1;
|
|
transformStyle =
|
|
'transform: translateY(${(-scrollOffset).toStringAsFixed(2)}px)';
|
|
} else {
|
|
drawCount = (_height / _itemHeight).round() + 1;
|
|
double alignmentOffset = math.max(0.0, scrollOffset);
|
|
double alignmentDelta = -scrollOffset % _itemHeight;
|
|
if (alignmentDelta != 0.0)
|
|
alignmentDelta -= _itemHeight;
|
|
|
|
double drawStart = scrollOffset + alignmentDelta;
|
|
itemNumber = math.max(0, (drawStart / _itemHeight).floor());
|
|
|
|
transformStyle =
|
|
'transform: translateY(${(alignmentDelta).toStringAsFixed(2)}px)';
|
|
}
|
|
}
|
|
|
|
return new Container(
|
|
style: _style,
|
|
children: [
|
|
new Container(
|
|
style: _scrollAreaStyle,
|
|
inlineStyle: transformStyle,
|
|
children: buildItems(itemNumber, drawCount)
|
|
)
|
|
]
|
|
);
|
|
}
|
|
}
|