Flutter 解决ExpansionTile上下分割线问题，以及title撑满问题
文章目录
- 前言
- 一、解决上下分割线问题
- 二、使ExpansionTile的title撑满
- 总结
前言
最近在做flutter项目，其中的一个功能用到了ExpansionTile的效果，奈何我们的设计师要求很高，展开的时候不能有上下一根线，而且我们是不需要展开的按钮，也就是说，让title横向撑满显示组件的信息。
一、解决上下分割线问题
1、使用Theme，然后把dividerColor的颜色改为透明或者白色，就能解决问题。
Theme(
data: Theme.of(context).copyWith(dividerColor: Colors.transparent),
child: BSExpansionTile(
trailing: null,
title: _buildTitle(model),
onExpansionChanged: (value) {
setState(() {
isExpanded = value;
});
},
initiallyExpanded: isExpanded,
children: _buildWalletItemList(),
),
);
二、使ExpansionTile的title撑满
1、查看它的源码发现都会有一个默认展开的箭头问题，只能把它的源码拷贝出来重新写了，把名字改为：BSExpansionTile
// Copyright 2014 The Flutter 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 'package:flutter/material.dart';
const Duration _kExpand = Duration(milliseconds: 200);
/// Enables control over a single [ExpansionTile]'s expanded/collapsed state.
///
/// It can be useful to expand or collapse an [ExpansionTile]
/// programatically, for example to reconfigure an existing expansion
/// tile based on a system event. To do so, create an [ExpansionTile]
/// with an [ExpansionTileController] that's owned by a stateful widget
/// or look up the tile's automatically created [ExpansionTileController]
/// with [ExpansionTileController.of]
///
/// The controller's [expand] and [collapse] methods cause the
/// the [ExpansionTile] to rebuild, so they may not be called from
/// a build method.
class ExpansionTileController {
/// Create a controller to be used with [ExpansionTile.controller].
ExpansionTileController();
_BSExpansionTileState? _state;
/// Whether the [ExpansionTile] built with this controller is in expanded state.
///
/// This property doesn't take the animation into account. It reports `true`
/// even if the expansion animation is not completed.
///
/// See also:
///
/// * [expand], which expands the [ExpansionTile].
/// * [collapse], which collapses the [ExpansionTile].
/// * [ExpansionTile.controller] to create an ExpansionTile with a controller.
bool get isExpanded {
assert(_state != null);
return _state!._isExpanded;
}
/// Expands the [ExpansionTile] that was built with this controller;
///
/// Normally the tile is expanded automatically when the user taps on the header.
/// It is sometimes useful to trigger the expansion programmatically due
/// to external changes.
///
/// If the tile is already in the expanded state (see [isExpanded]), calling
/// this method has no effect.
///
/// Calling this method may cause the [ExpansionTile] to rebuild, so it may
/// not be called from a build method.
///
/// Calling this method will trigger an [ExpansionTile.onExpansionChanged] callback.
///
/// See also:
///
/// * [collapse], which collapses the tile.
/// * [isExpanded] to check whether the tile is expanded.
/// * [ExpansionTile.controller] to create an ExpansionTile with a controller.
void expand() {
assert(_state != null);
if (!isExpanded) {
_state!._toggleExpansion();
}
}
/// Collapses the [ExpansionTile] that was built with this controller.
///
/// Normally the tile is collapsed automatically when the user taps on the header.
/// It can be useful sometimes to trigger the collapse programmatically due
/// to some external changes.
///
/// If the tile is already in the collapsed state (see [isExpanded]), calling
/// this method has no effect.
///
/// Calling this method may cause the [ExpansionTile] to rebuild, so it may
/// not be called from a build method.
///
/// Calling this method will trigger an [ExpansionTile.onExpansionChanged] callback.
///
/// See also:
///
/// * [expand], which expands the tile.
/// * [isExpanded] to check whether the tile is expanded.
/// * [ExpansionTile.controller] to create an ExpansionTile with a controller.
void collapse() {
assert(_state != null);
if (isExpanded) {
_state!._toggleExpansion();
}
}
/// Finds the [ExpansionTileController] for the closest [ExpansionTile] instance
/// that encloses the given context.
///
/// If no [ExpansionTile] encloses the given context, calling this
/// method will cause an assert in debug mode, and throw an
/// exception in release mode.
///
/// To return null if there is no [ExpansionTile] use [maybeOf] instead.
///
/// {@tool dartpad}
/// Typical usage of the [ExpansionTileController.of] function is to call it from within the
/// `build` method of a descendant of an [ExpansionTile].
///
/// When the [ExpansionTile] is actually created in the same `build`
/// function as the callback that refers to the controller, then the
/// `context` argument to the `build` function can't be used to find
/// the [ExpansionTileController] (since it's "above" the widget
/// being returned in the widget tree). In cases like that you can
/// add a [Builder] widget, which provides a new scope with a
/// [BuildContext] that is "under" the [ExpansionTile]:
///
/// ** See code in examples/api/lib/material/expansion_tile/expansion_tile.1.dart **
/// {@end-tool}
///
/// A more efficient solution is to split your build function into
/// several widgets. This introduces a new context from which you
/// can obtain the [ExpansionTileController]. With this approach you
/// would have an outer widget that creates the [ExpansionTile]
/// populated by instances of your new inner widgets, and then in
/// these inner widgets you would use [ExpansionTileController.of].
static ExpansionTileController of(BuildContext context) {
final _BSExpansionTileState? result = context.findAncestorStateOfType<_BSExpansionTileState>();
if (result != null) {
return result._tileController;
}
throw FlutterError.fromParts(<DiagnosticsNode>[
ErrorSummary(
'ExpansionTileController.of() called with a context that does not contain a ExpansionTile.',
),
ErrorDescription(
'No ExpansionTile ancestor could be found starting from the context that was passed to ExpansionTileController.of(). '
'This usually happens when the context provided is from the same StatefulWidget as that '
'whose build function actually creates the ExpansionTile widget being sought.',
),
ErrorHint(
'There are several ways to avoid this problem. The simplest is to use a Builder to get a '
'context that is "under" the ExpansionTile. For an example of this, please see the '
'documentation for ExpansionTileController.of():\n'
' https://api.flutter.dev/flutter/material/ExpansionTile/of.html',
),
ErrorHint(
'A more efficient solution is to split your build function into several widgets. This '
'introduces a new context from which you can obtain the ExpansionTile. In this solution, '
'you would have an outer widget that creates the ExpansionTile populated by instances of '
'your new inner widgets, and then in these inner widgets you would use ExpansionTileController.of().\n'
'An other solution is assign a GlobalKey to the ExpansionTile, '
'then use the key.currentState property to obtain the ExpansionTile rather than '
'using the ExpansionTileController.of() function.',
),
context.describeElement('The context used was'),
]);
}
/// Finds the [ExpansionTile] from the closest instance of this class that
/// encloses the given context and returns its [ExpansionTileController].
///
/// If no [ExpansionTile] encloses the given context then return null.
/// To throw an exception instead, use [of] instead of this function.
///
/// See also:
///
/// * [of], a similar function to this one that throws if no [ExpansionTile]
/// encloses the given context. Also includes some sample code in its
/// documentation.
static ExpansionTileController? maybeOf(BuildContext context) {
return context.findAncestorStateOfType<_BSExpansionTileState>()?._tileController;
}
}
/// A single-line [ListTile] with an expansion arrow icon that expands or collapses
/// the tile to reveal or hide the [children].
///
/// This widget is typically used with [ListView] to create an
/// "expand / collapse" list entry. When used with scrolling widgets like
/// [ListView], a unique [PageStorageKey] must be specified to enable the
/// [ExpansionTile] to save and restore its expanded state when it is scrolled
/// in and out of view.
///
/// This class overrides the [ListTileThemeData.iconColor] and [ListTileThemeData.textColor]
/// theme properties for its [ListTile]. These colors animate between values when
/// the tile is expanded and collapsed: between [iconColor], [collapsedIconColor] and
/// between [textColor] and [collapsedTextColor].
///
/// The expansion arrow icon is shown on the right by default in left-to-right languages
/// (i.e. the trailing edge). This can be changed using [controlAffinity]. This maps
/// to the [leading] and [trailing] properties of [ExpansionTile].
///
/// {@tool dartpad}
/// This example demonstrates how the [ExpansionTile] icon's location and appearance
/// can be customized.
///
/// ** See code in examples/api/lib/material/expansion_tile/expansion_tile.0.dart **
/// {@end-tool}
///
/// {@tool dartpad}
/// This example demonstrates how an [ExpansionTileController] can be used to
/// programatically expand or collapse an [ExpansionTile].
///
/// ** See code in examples/api/lib/material/expansion_tile/expansion_tile.1.dart **
/// {@end-tool}
///
/// See also:
///
/// * [ListTile], useful for creating expansion tile [children] when the
/// expansion tile represents a sublist.
/// * The "Expand and collapse" section of
/// 总结
这就是解决ExpansionTile上下分割线问题，以及title撑满问题，希望能够帮到你，谢谢。