flutter 长按弹出菜单,删除,分享,更多,撤回.

谁借莪１个温暖的怀抱￠ 2023-07-02 08:29 2阅读 0赞

#### 最近在开发IM软件,需要做:长按弹出菜单,删除,分享,更多,撤回. ####

#### 先看看效果是不是你想要的 ####

![format_png][]  
![format_png 1][]  
![format_png 2][]

### 使用处的代码 ###

_menuView() {
        bool isCanRecall = DateTime.now().millisecondsSinceEpoch -
                dateTime.millisecondsSinceEpoch <
            12000;
        var _data = ['复制', '转发', '删除'];
        var menuWidth = 150.0;
        if (isCanRecall && direct == 1) {
          _data.add('撤回');
          menuWidth = 200.0;
        }
        return WPopupMenu(
            menuWidth: menuWidth,
            menuHeight: 30,
            decoration: ShapeDecoration(
              shape: RoundedRectangleBorder(
                  borderRadius: BorderRadius.all(Radius.circular(5))),
            ),
            onValueChanged: (int selected) {
              switch (_data[selected]) {
                case '复制':
                  ToastUtils.toast(context, msg: '复制成功');
                  Clipboard.setData(ClipboardData(text: text));
                  break;
                case '转发':
                  _selectMemberPage();
                  break;
                case '删除':
                  _deleteMsg();
                  break;
                case '撤回':
                  _recallMsg();
                  break;
              }
            },
            pressType: PressType.longPress,
            actions: _data,
            child: _backView(context));
      }

#### WPopupMenu.dart ####

import 'package:flutter/material.dart';
    import 'package:wechat/common/view/triangle_painter.dart';
    
    const double _kMenuScreenPadding = 8.0;
    
    class WPopupMenu extends StatefulWidget {
      WPopupMenu({
        Key key,
        @required this.onValueChanged,
        @required this.actions,
        @required this.child,
        this.pressType = PressType.longPress,
        this.pageMaxChildCount = 5,
        this.backgroundColor = Colors.black,
        this.menuWidth = 250,
        this.menuHeight = 42,
        this.alignment,
        this.padding,
        Color color,
        Decoration decoration,
        this.foregroundDecoration,
        double width,
        double height,
        BoxConstraints constraints,
        this.margin,
        this.transform,
      })  : assert(onValueChanged != null),
            assert(actions != null && actions.length > 0),
            assert(child != null),
            assert(margin == null || margin.isNonNegative),
            assert(padding == null || padding.isNonNegative),
            assert(decoration == null || decoration.debugAssertIsValid()),
            assert(constraints == null || constraints.debugAssertIsValid()),
            assert(
                color == null || decoration == null,
                'Cannot provide both a color and a decoration\n'
                'The color argument is just a shorthand for "decoration: new BoxDecoration(color: color)".'),
            decoration =
                decoration ?? (color != null ? BoxDecoration(color: color) : null),
            constraints = (width != null || height != null)
                ? constraints?.tighten(width: width, height: height) ??
                    BoxConstraints.tightFor(width: width, height: height)
                : constraints,
            super(key: key);
    
      final BoxConstraints constraints;
      final Decoration decoration;
      final AlignmentGeometry alignment;
      final EdgeInsets padding;
      final Decoration foregroundDecoration;
      final EdgeInsets margin;
      final Matrix4 transform;
      final ValueChanged<int> onValueChanged;
      final List<String> actions;
      final Widget child;
      final PressType pressType; // 点击方式 长按 还是单击
      final int pageMaxChildCount;
      final Color backgroundColor;
      final double menuWidth;
      final double menuHeight;
    
      @override
      _WPopupMenuState createState() => _WPopupMenuState();
    }
    
    class _WPopupMenuState extends State<WPopupMenu> {
      @override
      Widget build(BuildContext context) {
        return GestureDetector(
          child: Container(
            key: widget.key,
            padding: widget.padding,
            margin: widget.margin,
            decoration: widget.decoration,
            constraints: widget.constraints,
            transform: widget.transform,
            alignment: widget.alignment,
            child: widget.child,
          ),
          onTap: () {
            if (widget.pressType == PressType.singleClick) {
              onTap();
            }
          },
          onLongPress: () {
            if (widget.pressType == PressType.longPress) {
              onTap();
            }
          },
        );
      }
    
      void onTap() {
        Navigator.push(
                context,
                _PopupMenuRoute(
                    context,
                    widget.actions,
                    widget.pageMaxChildCount,
                    widget.backgroundColor,
                    widget.menuWidth,
                    widget.menuHeight,
                    widget.padding,
                    widget.margin))
            .then((index) {
          widget.onValueChanged(index);
        });
      }
    }
    
    enum PressType {
      // 长按
      longPress,
      // 单击
      singleClick,
    }
    
    class _PopupMenuRoute extends PopupRoute {
      final BuildContext btnContext;
      double _height;
      double _width;
      final List<String> actions;
      final int _pageMaxChildCount;
      final Color backgroundColor;
      final double menuWidth;
      final double menuHeight;
      final EdgeInsets padding;
      final EdgeInsets margin;
    
      _PopupMenuRoute(
          this.btnContext,
          this.actions,
          this._pageMaxChildCount,
          this.backgroundColor,
          this.menuWidth,
          this.menuHeight,
          this.padding,
          this.margin) {
        _height = btnContext.size.height -
            (padding == null
                ? margin == null ? 0 : margin.vertical
                : padding.vertical);
        _width = btnContext.size.width -
            (padding == null
                ? margin == null ? 0 : margin.horizontal
                : padding.horizontal);
      }
    
      @override
      Animation<double> createAnimation() {
        return CurvedAnimation(
          parent: super.createAnimation(),
          curve: Curves.linear,
          reverseCurve: const Interval(0.0, 2.0 / 3.0),
        );
      }
    
      @override
      Color get barrierColor => null;
    
      @override
      bool get barrierDismissible => true;
    
      @override
      String get barrierLabel => null;
    
      @override
      Widget buildPage(BuildContext context, Animation<double> animation,
          Animation<double> secondaryAnimation) {
        return _MenuPopWidget(
            this.btnContext,
            _height,
            _width,
            actions,
            _pageMaxChildCount,
            backgroundColor,
            menuWidth,
            menuHeight,
            padding,
            margin);
      }
    
      @override
      Duration get transitionDuration => Duration(milliseconds: 300);
    }
    
    class _MenuPopWidget extends StatefulWidget {
      final BuildContext btnContext;
      final double _height;
      final double _width;
      final List<String> actions;
      final int _pageMaxChildCount;
      final Color backgroundColor;
      final double menuWidth;
      final double menuHeight;
      final EdgeInsets padding;
      final EdgeInsets margin;
    
      _MenuPopWidget(
        this.btnContext,
        this._height,
        this._width,
        this.actions,
        this._pageMaxChildCount,
        this.backgroundColor,
        this.menuWidth,
        this.menuHeight,
        this.padding,
        this.margin,
      );
    
      @override
      __MenuPopWidgetState createState() => __MenuPopWidgetState();
    }
    
    class __MenuPopWidgetState extends State<_MenuPopWidget> {
      int _curPage = 0;
      final double _arrowWidth = 40;
      final double _separatorWidth = 1;
      final double _triangleHeight = 10;
    
      RenderBox button;
      RenderBox overlay;
      RelativeRect position;
    
      @override
      void initState() {
        super.initState();
        button = widget.btnContext.findRenderObject();
        overlay = Overlay.of(widget.btnContext).context.findRenderObject();
        position = RelativeRect.fromRect(
          Rect.fromPoints(
            button.localToGlobal(
                Offset(
                    widget.padding == null
                        ? widget.margin == null ? 0 : widget.margin.left
                        : widget.padding.left,
                    widget.padding == null
                        ? widget.margin == null ? 0 : widget.margin.top
                        : widget.padding.top),
                ancestor: overlay),
            button.localToGlobal(
                Offset(
                    widget.padding == null
                        ? widget.margin == null ? 0 : widget.margin.left
                        : widget.padding.left,
                    widget.padding == null
                        ? widget.margin == null ? 0 : widget.margin.top
                        : widget.padding.top),
                ancestor: overlay),
          ),
          Offset.zero & overlay.size,
        );
      }
    
      @override
      Widget build(BuildContext context) {
        // 这里计算出来 当前页的 child 一共有多少个
        int _curPageChildCount =
            (_curPage + 1) * widget._pageMaxChildCount > widget.actions.length
                ? widget.actions.length % widget._pageMaxChildCount
                : widget._pageMaxChildCount;
    
        double _curArrowWidth = 0;
        int _curArrowCount = 0; // 一共几个箭头
    
        if (widget.actions.length > widget._pageMaxChildCount) {
          // 数据长度大于 widget._pageMaxChildCount
          if (_curPage == 0) {
            // 如果是第一页
            _curArrowWidth = _arrowWidth;
            _curArrowCount = 1;
          } else {
            // 如果不是第一页 则需要也显示左箭头
            _curArrowWidth = _arrowWidth * 2;
            _curArrowCount = 2;
          }
        }
    
        double _curPageWidth = widget.menuWidth +
            (_curPageChildCount - 1 + _curArrowCount) * _separatorWidth +
            _curArrowWidth;
    
        return MediaQuery.removePadding(
          context: context,
          removeTop: true,
          removeBottom: true,
          removeLeft: true,
          removeRight: true,
          child: Builder(
            builder: (BuildContext context) {
              var isInverted = (position.top +
                      (MediaQuery.of(context).size.height -
                              position.top -
                              position.bottom) /
                          2.0 -
                      (widget.menuHeight + _triangleHeight)) <
                  (widget.menuHeight + _triangleHeight) * 2;
              return CustomSingleChildLayout(
                // 这里计算偏移量
                delegate: _PopupMenuRouteLayout(
                    position,
                    widget.menuHeight + _triangleHeight,
                    Directionality.of(widget.btnContext),
                    widget._width,
                    widget.menuWidth,
                    widget._height),
                child: SizedBox(
                  height: widget.menuHeight + _triangleHeight,
                  width: _curPageWidth,
                  child: Material(
                    color: Colors.transparent,
                    child: Column(
                      mainAxisSize: MainAxisSize.min,
                      children: <Widget>[
                        isInverted
                            ? CustomPaint(
                                size: Size(_curPageWidth, _triangleHeight),
                                painter: TrianglePainter(
                                  color: widget.backgroundColor,
                                  position: position,
                                  isInverted: true,
                                  size: button.size,
                                  screenWidth: MediaQuery.of(context).size.width,
                                ),
                              )
                            : Container(),
                        Expanded(
                          child: Stack(
                            children: <Widget>[
                              ClipRRect(
                                borderRadius: BorderRadius.all(Radius.circular(5)),
                                child: Container(
                                  color: widget.backgroundColor,
                                  height: widget.menuHeight,
                                ),
                              ),
                              Row(
                                mainAxisSize: MainAxisSize.min,
                                children: <Widget>[
                                  // 左箭头：判断是否是第一页，如果是第一页则不显示
                                  _curPage == 0
                                      ? Container(
                                          height: widget.menuHeight,
                                        )
                                      : InkWell(
                                          onTap: () {
                                            setState(() {
                                              _curPage--;
                                            });
                                          },
                                          child: Container(
                                            width: _arrowWidth,
                                            height: widget.menuHeight,
                                            child: Image.asset(
                                              'images/left_white.png',
                                              fit: BoxFit.none,
                                            ),
                                          ),
                                        ),
                                  // 左箭头：判断是否是第一页，如果是第一页则不显示
                                  _curPage == 0
                                      ? Container(
                                          height: widget.menuHeight,
                                        )
                                      : Container(
                                          width: 1,
                                          height: widget.menuHeight,
                                          color: Colors.grey,
                                        ),
    
                                  // 中间是ListView
                                  _buildList(_curPageChildCount, _curPageWidth,
                                      _curArrowWidth, _curArrowCount),
    
                                  // 右箭头：判断是否有箭头，如果有就显示，没有就不显示
                                  _curArrowCount > 0
                                      ? Container(
                                          width: 1,
                                          color: Colors.grey,
                                          height: widget.menuHeight,
                                        )
                                      : Container(
                                          height: widget.menuHeight,
                                        ),
                                  _curArrowCount > 0
                                      ? InkWell(
                                          onTap: () {
                                            if ((_curPage + 1) *
                                                    widget._pageMaxChildCount <
                                                widget.actions.length)
                                              setState(() {
                                                _curPage++;
                                              });
                                          },
                                          child: Container(
                                            width: _arrowWidth,
                                            height: widget.menuHeight,
                                            child: Image.asset(
                                              (_curPage + 1) *
                                                          widget
                                                              ._pageMaxChildCount >=
                                                      widget.actions.length
                                                  ? 'images/right_gray.png'
                                                  : 'images/right_white.png',
                                              fit: BoxFit.none,
                                            ),
                                          ),
                                        )
                                      : Container(
                                          height: widget.menuHeight,
                                        ),
                                ],
                              ),
                            ],
                          ),
                        ),
                        isInverted
                            ? Container()
                            : CustomPaint(
                                size: Size(_curPageWidth, _triangleHeight),
                                painter: TrianglePainter(
                                    color: widget.backgroundColor,
                                    position: position,
                                    size: button.size,
                                  screenWidth: MediaQuery.of(context).size.width,),
                              ),
                      ],
                    ),
                  ),
                ),
              );
            },
          ),
        );
      }
    
      Widget _buildList(int _curPageChildCount, double _curPageWidth,
          double _curArrowWidth, int _curArrowCount) {
        return ListView.separated(
          shrinkWrap: true,
          physics: NeverScrollableScrollPhysics(),
          scrollDirection: Axis.horizontal,
          itemCount: _curPageChildCount,
          itemBuilder: (BuildContext context, int index) {
            return InkWell(
              onTap: () {
                Navigator.pop(
                    context, _curPage * widget._pageMaxChildCount + index);
              },
              child: SizedBox(
                width: (_curPageWidth -
                        _curArrowWidth -
                        (_curPageChildCount - 1 + _curArrowCount) *
                            _separatorWidth) /
                    _curPageChildCount,
                height: widget.menuHeight,
                child: Center(
                  child: Text(
                    widget.actions[_curPage * widget._pageMaxChildCount + index],
                    style: TextStyle(color: Colors.white, fontSize: 12),
                  ),
                ),
              ),
            );
          },
          separatorBuilder: (BuildContext context, int index) {
            return Container(
              width: 1,
              height: widget.menuHeight,
              color: Colors.grey,
            );
          },
        );
      }
    }
    
    // Positioning of the menu on the screen.
    class _PopupMenuRouteLayout extends SingleChildLayoutDelegate {
      _PopupMenuRouteLayout(this.position, this.selectedItemOffset,
          this.textDirection, this.width, this.menuWidth, this.height);
    
      // Rectangle of underlying button, relative to the overlay's dimensions.
      final RelativeRect position;
    
      // The distance from the top of the menu to the middle of selected item.
      //
      // This will be null if there's no item to position in this way.
      final double selectedItemOffset;
    
      // Whether to prefer going to the left or to the right.
      final TextDirection textDirection;
    
      final double width;
      final double height;
      final double menuWidth;
    
      // We put the child wherever position specifies, so long as it will fit within
      // the specified parent size padded (inset) by 8. If necessary, we adjust the
      // child's position so that it fits.
    
      @override
      BoxConstraints getConstraintsForChild(BoxConstraints constraints) {
        // The menu can be at most the size of the overlay minus 8.0 pixels in each
        // direction.
        return BoxConstraints.loose(constraints.biggest -
            const Offset(_kMenuScreenPadding * 2.0, _kMenuScreenPadding * 2.0));
      }
    
      @override
      Offset getPositionForChild(Size size, Size childSize) {
        // size: The size of the overlay.
        // childSize: The size of the menu, when fully open, as determined by
        // getConstraintsForChild.
    
        // Find the ideal vertical position.
        double y;
        if (selectedItemOffset == null) {
          y = position.top;
        } else {
          y = position.top +
              (size.height - position.top - position.bottom) / 2.0 -
              selectedItemOffset;
        }
    
        // Find the ideal horizontal position.
        double x;
    
        // 如果menu 的宽度 小于 child 的宽度，则直接把menu 放在 child 中间
        if (childSize.width < width) {
          x = position.left + (width - childSize.width) / 2;
        } else {
          // 如果靠右
          if (position.left > size.width - (position.left + width)) {
            if (size.width - (position.left + width) > childSize.width / 2 + _kMenuScreenPadding) {
              x = position.left - (childSize.width - width) / 2;
            } else
              x = position.left + width - childSize.width;
          } else if (position.left < size.width - (position.left + width)) {
            if (position.left > childSize.width / 2 + _kMenuScreenPadding) {
              x = position.left - (childSize.width - width) / 2;
            } else
              x = position.left;
          } else {
            x = position.right - width / 2 - childSize.width / 2;
          }
        }
    
        if (y < _kMenuScreenPadding)
          y = _kMenuScreenPadding;
        else if (y + childSize.height > size.height - _kMenuScreenPadding)
          y = size.height - childSize.height;
        else if (y < childSize.height * 2) {
          y = position.top + height;
        }
        return Offset(x, y);
      }
    
      @override
      bool shouldRelayout(_PopupMenuRouteLayout oldDelegate) {
        return position != oldDelegate.position;
      }
    }

再次感谢原文作者,在原文作者上进行的修改  
https:// juejin.im/post/5d51f543e51d4561ff6667ee

更多详解：  
喜欢可以加Q群号:913934649,点赞,评论;

简书： https://www.jianshu.com/u/88db5f15770d

csdn：https://me.csdn.net/beyondforme

掘金：https://juejin.im/user/5e09a9e86fb9a016271294a7

[format_png]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly91c2VyLWdvbGQtY2RuLnhpdHUuaW8vMjAyMC8xLzI4LzE2ZmViNDZlZDg5MWU0YWI?x-oss-process=image/format,png
[format_png 1]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly91c2VyLWdvbGQtY2RuLnhpdHUuaW8vMjAyMC8xLzI4LzE2ZmViNDcwN2M3YzhkY2M?x-oss-process=image/format,png
[format_png 2]: https://imgconvert.csdnimg.cn/aHR0cHM6Ly91c2VyLWdvbGQtY2RuLnhpdHUuaW8vMjAyMC8xLzI4LzE2ZmViNDcyNzIzN2U4NjQ?x-oss-process=image/format,png