Flutter拖拽小部件

缺乏、安全感 2022-10-31 04:18 22阅读 0赞

### 编写初衷 ###

> 因为项目需要浮动按钮所以我这里开发了一个拖动小部件

**这里直接上代码**

import 'dart:math';
    import 'package:flutter/gestures.dart';
    import 'package:flutter/material.dart';
    import 'package:flutter_screenutil/flutter_screenutil.dart';
    
    // ignore: must_be_immutable
    class TouchMove extends StatefulWidget { 
      TouchMove({ Key key,this.child}) : super(key: key);
      Widget child;
      @override
      _TouchMoveState createState() => _TouchMoveState();
    }
    
    class _TouchMoveState extends State<TouchMove> { 
      //静止状态下的offset
      Offset idleOffset=Offset(ScreenUtil().setWidth(600), ScreenUtil().setHeight(1100));
      // //本次移动的offset
      // Offset moveOffset=Offset(0, 0);
        //本次移动的offset
      Offset moveOffset=Offset(ScreenUtil().setWidth(600), ScreenUtil().setHeight(1100));
      //最后一次down事件的offset
      Offset lastStartOffset=Offset(ScreenUtil().setWidth(600), ScreenUtil().setHeight(1100));
    
      @override
      void initState() { 
        super.initState();
      }
      @override
      Widget build(BuildContext context) { 
        return GestureDetector(
            behavior: HitTestBehavior.deferToChild,
            onPanStart: (detail) { 
                  setState(() { 
                      lastStartOffset=detail.globalPosition;
                  });
            },
            onPanUpdate: (detail){ 
                  setState(() { 
                    moveOffset=detail.globalPosition-lastStartOffset+idleOffset;
                    moveOffset=Offset(moveOffset.dx,  moveOffset.dy);
                  });
                },
    
                onPanEnd: (detail) { 
                  setState(() { 
                    idleOffset=moveOffset*1;
                  });
                },
           child:Transform.translate(
            offset: moveOffset,
            child: Container(
             
              child:widget.child,
            
            ))
          // widget.child,
        );
      }
    }