Flutter悬浮按钮FloatingActionButton使用详解

来源：jb51　　时间：2021/7/12 13:14:04　　对本文有异议

1、普通用法

floatingActionButton: FloatingActionButton(
    child: Icon(Icons.add),
      onPressed: (){
         print('不要啊~');
      },
 ),

2、修改悬浮按钮位置

继承FloatingActionButtonLocation类，重写对应方法自定义位置

import 'package:flutter/material.dart';
 
class CustomFloatingActionButtonLocation extends FloatingActionButtonLocation {
  FloatingActionButtonLocation location;
  double offsetX;    // X方向的偏移量
  double offsetY;    // Y方向的偏移量
  CustomFloatingActionButtonLocation(this.location, this.offsetX, this.offsetY);
 
  @override
  Offset getOffset(ScaffoldPrelayoutGeometry scaffoldGeometry) {
    Offset offset = location.getOffset(scaffoldGeometry);
    return Offset(offset.dx + offsetX, offset.dy + offsetY);
  }
}

使用

floatingActionButtonLocation:CustomFloatingActionButtonLocation(
             FloatingActionButtonLocation.endFloat, 0, -DpUtils.setWidth(20)),

3、修改悬浮按钮大小

floatingActionButton: SizedBox(
  height: 100.0,
  width: 100.0,
  child:FloatingActionButton(
    child: Icon(Icons.add),
    onPressed: () {},
  ),
),

4、去除悬浮按钮切换动画

继承FloatingActionButtonAnimator类并重写对应的方法

import 'package:flutter/material.dart';
 
class NoScalingAnimation extends FloatingActionButtonAnimator{
  double _x;
  double _y;
  @override
  Offset getOffset({Offset begin, Offset end, double progress}) {
    _x = begin.dx +(end.dx - begin.dx)*progress ;
    _y = begin.dy +(end.dy - begin.dy)*progress;
    return Offset(_x,_y);
  }
 
  @override
  Animation<double> getRotationAnimation({Animation<double> parent}) {
    return Tween<double>(begin: 1.0, end: 1.0).animate(parent);
  }
 
  @override
  Animation<double> getScaleAnimation({Animation<double> parent}) {
    return Tween<double>(begin: 1.0, end: 1.0).animate(parent);
  }
}

使用

floatingActionButtonAnimator: NoScalingAnimation(),

5、一般的自定义悬浮按钮样式

@override
  Widget build(BuildContext context) {
    return Scaffold(
       floatingActionButton: FloatingActionButton(
          child: Container(
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              crossAxisAlignment: CrossAxisAlignment.center,
              children: <Widget>[
                Image.asset(
                  "images/float_button.png",
                  width: DpUtils.setWidth(32),
                  height: DpUtils.setWidth(32),
                ),
                Text(
                  "悬浮按钮",
                  style: TextStyle(fontWeight: FontWeight.bold, 
                        fontSize: DpUtils.setSp(20), color: Colors.white),
                ),
              ],
            ),
          ),
          elevation: 0,
          onPressed: () {
            _doSome();
          },
          backgroundColor: Colors.black,
          heroTag: "floatHome",
        ),
    )
)}

6、彻底的自定义悬浮按钮样式

其实，floatingActionButton 可以直接传入普通的widget。所以该干嘛干嘛咯

@override
  Widget build(BuildContext context) {
    return Scaffold(
        floatingActionButton: Container(
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            crossAxisAlignment: CrossAxisAlignment.center,
            children: <Widget>[
              Image.asset(
                "images/home_icon_publishing.png",
                width: DpUtils.setWidth(32),
                height: DpUtils.setWidth(32),
              ),
              Text(
                "发主题",
                style: TextStyle(fontWeight: FontWeight.bold, 
                     fontSize: DpUtils.setSp(20), color: Colors.white),
              ),
            ],
          ),
        ),
    );
  }