默认高度为半屏，设置isScrollControlled为true是全屏，不想全屏，使用BoxConstraints组件限制最大高度
- 键盘溢出
首先使用SingleChildScrollView作为根组件让其可以滚动，然后获取键盘高度MediaQuery.of(context).viewInsets.bottom作为padding的bottom，因为这不在scaffold工作范围内，flutter不会为我们上推界面。
- 状态更新
showModalBottomSheet等其他dialog组件，相当于跳转的一个新的路由页面，在这个页面setState(() {}); 更新上个页面的状态没有用。
解决办法有许多，其中一个是使用Builder组件包裹要更新的组件，在更新时调用 (context as Element).markNeedsBuild();
contentPadding: EdgeInsets.all(0.0),
去除水波纹默认情况下，可滚动组件滑到顶部和尾部会有水波纹效果，如图所示，那么怎么去掉呢？
全局去掉如下：
MaterialApp(
builder: (context, child) {
child= ScrollConfiguration(
child: child,
behavior: RefreshScrollBehavior(),
);
return child;
},
)
class RefreshScrollBehavior extends ScrollBehavior {
@override
Widget buildViewportChrome(
BuildContext context, Widget child, AxisDirection axisDirection) {
switch (getPlatform(context)) {
case TargetPlatform.iOS:
return child;
case TargetPlatform.macOS:
case TargetPlatform.android:
return GlowingOverscrollIndicator(
child: child,
showLeading: false, //顶部水波纹是否展示
showTrailing: false, //底部水波纹是否展示
axisDirection: axisDirection,
notificationPredicate: (notification) {
if (notification.depth == 0) {
// 越界是否展示水波纹
if (notification.metrics.outOfRange) {
return false;
}
return true;
}
return false;
},
color: Theme.of(context).primaryColor,
);
case TargetPlatform.fuchsia:
}
return null;
}
}
通过设置AppBar的flexibleSpace属性
flexibleSpace: Container(
decoration: BoxDecoration(
gradient: LinearGradient(
colors: [Colors.cyan, Colors.blue, Colors.blueAccent],
),
),
),
使用NotificationListener监听页面滚动，动态改变appbar透明值。
body: NotificationListener(
onNotification: (scrollNotification) {
if (scrollNotification is ScrollUpdateNotification) {
if (scrollNotification.metrics.axis == Axis.vertical) _onScroll(scrollNotification.metrics.pixels);
}
return false;
},
_onScroll(offset) {
//print(offset);
if (offset > 200) return;
double alpha = offset / 200;
if (alpha < 0) {
alpha = 0;
} else if (alpha > 1) {
alpha = 1;
}
setState(() {
appBarAlpha = alpha;
});
}
使用FittedBox组件可自动调节内容，超出宽高会自动调节字体大小
自定义底部导航如图所示，这种导航条官方没有提供，只能靠我们自定义了。 通过自定义Scaffold的bottomNavigationBar属性来实现，其中bottomAppBarItem是一个自定义方法，生成一个个导航按钮，红点使用stack相对定位，中间是一个播放进度按钮，类似喜马拉雅，思路是CircularProgressIndicator组件作为进度条，Container组件形状指定为圆 shape: BoxShape.circle,子组件是图片，然后相对定位于CircularProgressIndicator
bottomNavigationBar: BottomAppBar(
child: Consumer(
builder: (context,_imNotice,child){
return Row(
children: [
bottomAppBarItem(0, Icons.home, ‘首页’, badge: badge1),
bottomAppBarItem(1, Icons.email, ‘消息’, badge: _imNotice.unreadMsgCount),
bottomAppBarItem(-1, Icons.store, ‘商店’, badge: badge1),
bottomAppBarItem(2, Icons.store, ‘商店’, badge: 101),
bottomAppBarItem(3, Icons.person, ‘我的’, badge: 1, type: ‘q’),
],
mainAxisAlignment: MainAxisAlignment.spaceAround, //均分底部导航栏横向空间
mainAxisSize: MainAxisSize.max,
);
},
)
)
popupMenu 弹出菜单 滑动关闭
官方的弹出菜单，需要点击空白才能关闭，如何才能滑动屏幕就能关闭呢？参照微信长按聊天会话。
官方没有提供，只能我们自定义了。
复制showMenu函数源码到项目文件夹下，并更名为customShowMenu，防止与官方冲突，用法不变。
大约在770行，添加GestureDetector组件，我们自己处理滑动事件。
return MediaQuery.removePadding(
context: context,
removeTop: true,
removeBottom: true,
removeLeft: true,
removeRight: true,
child: GestureDetector(
behavior: HitTestBehavior.translucent,
onPanStart: (DragStartDetails details) {
Navigator.of(context).maybePop();
},
child: Builder(
builder: (BuildContext context) {
return CustomSingleChildLayout(
delegate: _PopupMenuRouteLayout(
默认情况下，tabbar切换，上一个页面滚动的位置会销毁， 解决办法：使用key保存位置
var _tab1 = PageStorageKey(’_tab1’);
自定义搜索如图所示 ，官方自带搜索组件showSearch，需要实现一个SearchDelegate，为了实现底部tabbar，我们需要修改源码。
复制SearchDelegate 源码到我们项目文件夹下，并更名为myShowSearchGoods和MySearchDelegateGoods，名字随意防止与官方冲突，这个一个抽象类，后面我们实现它。
GestureDetector(
behavior: HitTestBehavior.opaque,
onTap: () => myShowSearchGoods(con
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text: context, delegate: GoodsSearchBarDelegate()),
child: Container(
class GoodsSearchBarDelegate extends MySearchDelegateGoods {
List recentSuggest = List.from(MySheetSearch.getData().reversed.toList());
int id = 0;
//List tabTitle = [‘单曲’, ‘专辑’, ‘歌手’, ‘歌单’];
List songList = [];
List albumList = [];
List artistList = [];
List sheetList = [];
int page1,page2,page3,page4=0;
List tabTitle = [
{“name”: “单曲”, “type”: 1},
{“name”: “专辑”, “type”: 10},
{“name”: “歌手”, “type”: 100},
{“name”: “歌单”, “type”: 1000},
];
String oldQuery;
RefreshController _controllerR1 =RefreshController(initialRefresh: false);
RefreshController _controllerR2 =RefreshController(initialRefresh: false);
RefreshController _controllerR3 =RefreshController(initialRefresh: false);
RefreshController _controllerR4 =RefreshController(initialRefresh: false);
GoodsSearchBarDelegate();
@override
String get searchFieldLabel => ‘搜点什么’;
@override
loadData(BuildContext context) async { //加载数据
if(query.isEmpty){
Utils.showToast(‘请输入搜索内容’);
return false;
}
if (oldQuery != query) {
oldQuery = query;
songList = [];
albumList = [];
artistList = [];
sheetList = [];
page1=0;
page2=0;
page3=0;
page4=0;
}
else
showResults(context);
if (tabController.index == 0 && (songListnull || songList.isNotEmpty))
return false;
else if (tabController.index == 1 && (albumListnull || albumList.isNotEmpty)) return false;
else if (tabController.index == 2 && (artistListnull || artistList.isNotEmpty)) return false;
else if (tabController.index == 3 && (sheetListnull || sheetList.isNotEmpty)) return false;
var cancel = Utils.showLoading();
List data = await GoodsSearch().getSearchRes(query, type: tabTitle[tabController.index][‘type’]);
cancel();
if (tabController.index == 0) songList = data;
else if (tabController.index == 1) albumList = data;
else if (tabController.index == 2) artistList = data;
else if (tabController.index == 3) sheetList = data;
showResults(context);
}
loadMoreData(int page) async{
// var cancel = Utils.showLoading();
List data = await GoodsSearch().getSearchRes(query, type: tabTitle[tabController.index][‘type’],page: page);
// cancel();
return data;
}
@override
Widget buildAppBarBottom(BuildContext context) { //tabbar
return PreferredSize(
preferredSize: Size.fromHeight(40.0),
child: Container(
height: 40,
child: TabBar(
controller: tabController,
indicatorSize: TabBarIndicatorSize.label,
labelColor: Theme.of(context).primaryColor,
tabs: List.generate(
tabTitle.length,
(index) => Tab(
text: tabTitle[index][‘name’],
)),
)));
}
下面代码与官方类似，重写相应方法
父子组件相互调用方法
- 子组件调用父组件
方法少的话，直接传方法名到子组件，子组件调用即可。
方法多的话，使用抽象类。父组件实现抽象类，然后将this作为参数传到子组件。
abstract class BottomInputBarDelegate {
String userIdOrGroupId;
int chatType=0;
void insertNewMessage(EMMessage msg);
void scrollBottom();
}
@override // 父组件
void scrollBottom() {
if (_msgListController.offset != 0.0)
//_msgListController.jumpTo(0.0);
_msgListController.animateTo(
0.0,
curve: Curves.easeInOut,
duration: const Duration(milliseconds: 200),
);
}
…
ChatBottomInputTool(
this,
childController: childController,
)
class ChatBottomInputTool extends StatefulWidget{ // 子组件
final ChildPageController childController;
final BottomInputBarDelegate delegate;
ChatBottomInputTool(this.delegate,{@required this.childController});
@override
State createState() {
// TODO: implement createState
return _ChatBottomInputToolState(childController);
}
}
…
widget.delegate.scrollBottom();
- 父组件调用子组件
借助Controller控制器思想来实现。
class ChildPageController{
bool Function() closeBottom;
}
class ChatBottomInputTool extends StatefulWidget{ // 子组件
final ChildPageController childController;
final BottomInputBarDelegate delegate;
ChatBottomInputTool(this.delegate,{@required this.childController});
@override
State createState() {
// TODO: implement createState
return _ChatBottomInputToolState(childController);
}
}
class _ChatBottomInputToolState extends State with WidgetsBindingObserver,TickerProviderStateMixin{
_ChatBottomInputToolState( ChildPageController _childController){
_childController.closeBottom=closeBottom;
}
bool closeBottom() {
bool update = false;
faceH = 0;
moreToolH = 0.0;
showFaceA = true;
showToolA = true;
if (showMoreTool) {
update = true;
}
if (showFace) {
update = true;
}
if (_focusNode.hasFocus && curKeyboardH > 0) {
_focusNode.unfocus();
SystemChannels.textInput.invokeMethod(‘TextInput.hide’);
return true;
}
if (update) {
setState(() {});
Future.delayed(Duration(milliseconds: 100)).then((value) {
showFace = false;
showMoreTool = false;
});
return true;
}
return false;
}
class _ChatRoomPageState extends State with TickerProviderStateMixin
implements EMMessageListener,BottomInputBarDelegate { // 父组件
final ChildPageController childController = ChildPageController();
return true;
}
if (update) {
setState(() {});
Future.delayed(Duration(milliseconds: 100)).then((value) {
showFace = false;
showMoreTool = false;
});
return true;
}
return false;
}
class _ChatRoomPageState extends State with TickerProviderStateMixin
implements EMMessageListener,BottomInputBarDelegate { // 父组件
final ChildPageController childController = ChildPageController();
