Flutter学习笔记（20）--FloatingActionButton、PopupMenuButton、SimpleDialog、AlertDialog、SnackBar

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• floatingactionbutton

floatingactionbutton对应一个圆形图标按钮，悬停在内容之上，以展示对应程序中的主要动作，所以非常醒目，类似于ios系统里的小白点按钮。

floatingactionbutton组件属性及描述如下：

1. child：child一般为icon，不推荐使用文字
2. tooltip：按钮提示文字
3. foregroundcolor：前景色
4. backgroundcolor：背景色
5. elevation：未点击时阴影值，默认6.0
6. hignlightelevation：点击时阴影值
7. onpressed：点击事件回调
8. shape：定义按钮的shape，设置shape时，默认的elevation将会失效，默认为circleborder

import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';

void main() => runapp(demoapp());

class demoapp extends statelesswidget{
  @override
  widget build(buildcontext context) {
    // todo: implement build
    return new materialapp(
      title: 'floatingbutton demo',
      debugshowcheckedmodebanner: false,
      home: new scaffold(
        appbar: appbar(
          title: new text('floatingbutton demo'),
        ),
        drawer: drawer(
          child: listview(
            children: <widget>[
              useraccountsdrawerheader(
                  accountname: new text('floatingbutton demo'),
                  accountemail: new text('www.baidu.com'),
                  currentaccountpicture: new circleavatar(
                    backgroundimage: assetimage('images/user.jpeg'),
                  ),
              ),
              listtile(
                title: new text('我是主标题'),
                leading: icon(icons.add_circle_outline),
                subtitle: new text('我是副标题'),
              ),
              listtile(
                title: new text('我是主标题'),
                leading: icon(icons.add_circle_outline),
                subtitle: new text('我是副标题'),
              ),
              listtile(
                title: new text('我是主标题'),
                leading: icon(icons.add_circle_outline),
                subtitle: new text('我是副标题'),
              ),
              listtile(
                title: new text('我是主标题'),
                leading: icon(icons.add_circle_outline),
                subtitle: new text('我是副标题'),
              )
            ],
          ),
        ),
        floatingactionbutton: new builder(builder: (buildcontext context){
          return new floatingactionbutton(
              child: icon(icons.album),
              foregroundcolor: colors.amberaccent,
              backgroundcolor: colors.deeppurple,
              elevation: 10.0,
              highlightelevation: 20.0,
              mini: false,
              onpressed: (){
                scaffold.of(context).showsnackbar(new snackbar(content: new text('点击了floatingbutton')));
              }
          );
        }),
        floatingactionbuttonlocation: floatingactionbuttonlocation.centerfloat,
      ),
    );
  }

}

 

 

• popupmenubutton

构造方法：

  const popupmenubutton({
    key key,
    @required this.itembuilder,//item子项，可以为任意类型
    this.initialvalue,//初始值
    this.onselected,//选中其中一项时回调
    this.oncanceled,//点击空白处，不选择时回调
    this.tooltip,//提示
    this.elevation = 8.0,//阴影大小
    this.padding = const edgeinsets.all(8.0),//padding
    this.child,
    this.icon,
    this.offset = offset.zero,
  }) : assert(itembuilder != null),
        assert(offset != null),
        assert(!(child != null && icon != null)), // fails if passed both parameters
        super(key: key);

 

demo示例：

import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';

void main() => runapp(demoapp());

class demoapp extends statelesswidget{
  @override
  widget build(buildcontext context) {
    // todo: implement build
    return new materialapp(
      title: 'floatingbutton demo',
      debugshowcheckedmodebanner: false,
      home: new scaffold(
        body: new center(
          child: _showpopupmenubutton(),
        ),
        appbar: appbar(
          title: new text('floatingbutton demo'),
        ),
        drawer: drawer(
          child: listview(
            children: <widget>[
              useraccountsdrawerheader(
                  accountname: new text('floatingbutton demo'),
                  accountemail: new text('www.baidu.com'),
                  currentaccountpicture: new circleavatar(
                    backgroundimage: assetimage('images/user.jpeg'),
                  ),
              ),
              listtile(
                title: new text('我是主标题'),
                leading: icon(icons.add_circle_outline),
                subtitle: new text('我是副标题'),
              ),
              listtile(
                title: new text('我是主标题'),
                leading: icon(icons.add_circle_outline),
                subtitle: new text('我是副标题'),
              ),
              listtile(
                title: new text('我是主标题'),
                leading: icon(icons.add_circle_outline),
                subtitle: new text('我是副标题'),
              ),
              listtile(
                title: new text('我是主标题'),
                leading: icon(icons.add_circle_outline),
                subtitle: new text('我是副标题'),
              )
            ],
          ),
        ),
        floatingactionbutton: new builder(builder: (buildcontext context){
          return new floatingactionbutton(
              child: icon(icons.album),
              foregroundcolor: colors.amberaccent,
              backgroundcolor: colors.deeppurple,
              elevation: 10.0,
              highlightelevation: 20.0,
              mini: false,
              onpressed: (){
              },
          );
        }),
        floatingactionbuttonlocation: floatingactionbuttonlocation.centerfloat,
      ),
    );
  }

  popupmenubutton _showpopupmenubutton() {
    return popupmenubutton(
      icon: icon(icons.menu),
        itembuilder: (buildcontext context) => <popupmenuentry>[
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton1"),
            ),
          ),
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton2"),
            ),
          ),
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton3"),
            ),
          ),
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton4"),
            ),
          ),
        ]
    );
  }
}

 

效果截图：

   

• simpledialog

 

import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';

void main() => runapp(demoapp());

class demoapp extends statelesswidget{
  @override
  widget build(buildcontext context) {
    return new materialapp(
      title: 'floatingbutton demo',
      debugshowcheckedmodebanner: false,
      home: mhomepage(),
    );
  }
}

class mhomepage extends statefulwidget{
  @override
  state<statefulwidget> createstate() {
    // todo: implement createstate
    return _mhomepage();
  }
}

class _mhomepage extends state {
  @override
  widget build(buildcontext context) {
    // todo: implement build
    return new scaffold(
      body: new center(
        child: _showpopupmenubutton(),
      ),
      appbar: appbar(
        title: new text('floatingbutton demo'),
      ),
      drawer: drawer(
        child: listview(
          children: <widget>[
            useraccountsdrawerheader(
              accountname: new text('floatingbutton demo'),
              accountemail: new text('www.baidu.com'),
              currentaccountpicture: new circleavatar(
                backgroundimage: assetimage('images/user.jpeg'),
              ),
            ),
            listtile(
              title: new text('我是主标题'),
              leading: icon(icons.add_circle_outline),
              subtitle: new text('我是副标题'),
            ),
            listtile(
              title: new text('我是主标题'),
              leading: icon(icons.add_circle_outline),
              subtitle: new text('我是副标题'),
            ),
            listtile(
              title: new text('我是主标题'),
              leading: icon(icons.add_circle_outline),
              subtitle: new text('我是副标题'),
            ),
            listtile(
              title: new text('我是主标题'),
              leading: icon(icons.add_circle_outline),
              subtitle: new text('我是副标题'),
            )
          ],
        ),
      ),
      floatingactionbutton: new floatingactionbutton(
        child: icon(icons.album),
        foregroundcolor: colors.amberaccent,
        backgroundcolor: colors.deeppurple,
        elevation: 10.0,
        highlightelevation: 20.0,
        mini: false,
        onpressed: (){
            _showsimpledialog(context);
        },
      ),
      floatingactionbuttonlocation: floatingactionbuttonlocation.centerfloat,
    );
  }

  popupmenubutton _showpopupmenubutton() {
    return popupmenubutton(
        icon: icon(icons.menu),
        itembuilder: (buildcontext context) => <popupmenuentry>[
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton1"),
            ),
          ),
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton2"),
            ),
          ),
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton3"),
            ),
          ),
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton4"),
            ),
          ),
        ]
    );
  }

  void _showsimpledialog(buildcontext context) {
    showdialog(
        context: context,
        builder: (buildcontext context){
          return simpledialog(
            title: new text('simpledialog demo'),
            children: <widget>[
              simpledialogoption(
                child: text('选项1'),
              ),
              simpledialogoption(
                child: text('选项2'),
                onpressed: (){
                  navigator.pop(context);
                },
              ),
            ],
          );
        }
    );
  }
}

 

效果截图：

• alertdialog

alertdialog常用属性：

  const alertdialog({
    key key,
    this.title,//对话框顶部提示文案
    this.titlepadding,
    this.titletextstyle,//对话框顶部提示文案字体样式
    this.content,//内容部分，对话框的提示内容，通常为文字
    this.contentpadding = const edgeinsets.fromltrb(24.0, 20.0, 24.0, 24.0),
    this.contenttextstyle,//对话框提示内容的字体样式
    this.actions,//对话框底部操作按钮
    this.backgroundcolor,//对话框背景色
    this.elevation,
    this.semanticlabel,
    this.shape,
  }) : assert(contentpadding != null),
       super(key: key);

 

import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';

void main() => runapp(demoapp());

class demoapp extends statelesswidget{
  @override
  widget build(buildcontext context) {
    return new materialapp(
      title: 'floatingbutton demo',
      debugshowcheckedmodebanner: false,
      home: mhomepage(),
    );
  }
}

class mhomepage extends statefulwidget{
  @override
  state<statefulwidget> createstate() {
    // todo: implement createstate
    return _mhomepage();
  }
}

class _mhomepage extends state {
  @override
  widget build(buildcontext context) {
    // todo: implement build
    return new scaffold(
      body: new center(
        child: _showpopupmenubutton(),
      ),
      appbar: appbar(
        title: new text('floatingbutton demo'),
      ),
      drawer: drawer(
        child: listview(
          children: <widget>[
            useraccountsdrawerheader(
              accountname: new text('floatingbutton demo'),
              accountemail: new text('www.baidu.com'),
              currentaccountpicture: new circleavatar(
                backgroundimage: assetimage('images/user.jpeg'),
              ),
            ),
            listtile(
              title: new text('我是主标题'),
              leading: icon(icons.add_circle_outline),
              subtitle: new text('我是副标题'),
            ),
            listtile(
              title: new text('我是主标题'),
              leading: icon(icons.add_circle_outline),
              subtitle: new text('我是副标题'),
            ),
            listtile(
              title: new text('我是主标题'),
              leading: icon(icons.add_circle_outline),
              subtitle: new text('我是副标题'),
            ),
            listtile(
              title: new text('我是主标题'),
              leading: icon(icons.add_circle_outline),
              subtitle: new text('我是副标题'),
            )
          ],
        ),
      ),
      floatingactionbutton: new floatingactionbutton(
        child: icon(icons.album),
        foregroundcolor: colors.amberaccent,
        backgroundcolor: colors.deeppurple,
        elevation: 10.0,
        highlightelevation: 20.0,
        mini: false,
        onpressed: (){
//            _showsimpledialog(context);
          _showalertdialog(context);
        },
      ),
      floatingactionbuttonlocation: floatingactionbuttonlocation.centerfloat,
    );
  }

  popupmenubutton _showpopupmenubutton() {
    return popupmenubutton(
        icon: icon(icons.menu),
        itembuilder: (buildcontext context) => <popupmenuentry>[
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton1"),
            ),
          ),
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton2"),
            ),
          ),
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton3"),
            ),
          ),
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton4"),
            ),
          ),
        ]
    );
  }

  void _showsimpledialog(buildcontext context) {
    showdialog(
        context: context,
        builder: (buildcontext context){
          return simpledialog(
            title: new text('simpledialog demo'),
            children: <widget>[
              simpledialogoption(
                child: text('选项1'),
              ),
              simpledialogoption(
                child: text('选项2'),
                onpressed: (){
                  navigator.pop(context);
                },
              ),
            ],
          );
        }
    );
  }

  void _showalertdialog(buildcontext context) {
    showdialog(
      context: context,
      builder: (buildcontext context){
        return alertdialog(
          title: new text('提示'),
          content: new text('这是提示框的内容'),
          actions: <widget>[
            flatbutton(onpressed: null, child: new text('确定'),disabledtextcolor: colors.blueaccent,),
            flatbutton(onpressed: null, child: new text('取消'),disabledcolor: colors.deeppurple,),
          ],
        );
      }
    );
  }
}

 

效果截图：

• snackbar

snackbar是一个轻量级消息提示组件，在屏幕的底部显示，snackbar常用属性如下：

  const snackbar({
    key key,
    @required this.content,//提示内容
    this.backgroundcolor,//背景色
    this.action,
    this.duration = _ksnackbardisplayduration,//提示时常
    this.animation,//弹出动画
  }) : assert(content != null),
       assert(duration != null),
       super(key: key);

 

import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';

void main() => runapp(demoapp());

class demoapp extends statelesswidget{
  @override
  widget build(buildcontext context) {
    return new materialapp(
      title: 'floatingbutton demo',
      debugshowcheckedmodebanner: false,
      home: mhomepage(),
    );
  }
}

class mhomepage extends statefulwidget{
  @override
  state<statefulwidget> createstate() {
    // todo: implement createstate
    return _mhomepage();
  }
}

class _mhomepage extends state {
  @override
  widget build(buildcontext context) {
    // todo: implement build
    return new scaffold(
      body: new center(
        child: _showpopupmenubutton(),
      ),
      appbar: appbar(
        title: new text('floatingbutton demo'),
        actions: <widget>[
          iconbutton(icon: icon(icons.search), onpressed: (){
            scaffold.of(context).showsnackbar(new snackbar(content: new text('snackbar')));
          })
        ],
      ),
      drawer: drawer(
        child: listview(
          children: <widget>[
            useraccountsdrawerheader(
              accountname: new text('floatingbutton demo'),
              accountemail: new text('www.baidu.com'),
              currentaccountpicture: new circleavatar(
                backgroundimage: assetimage('images/user.jpeg'),
              ),
            ),
            listtile(
              title: new text('我是主标题'),
              leading: icon(icons.add_circle_outline),
              subtitle: new text('我是副标题'),
            ),
            listtile(
              title: new text('我是主标题'),
              leading: icon(icons.add_circle_outline),
              subtitle: new text('我是副标题'),
            ),
            listtile(
              title: new text('我是主标题'),
              leading: icon(icons.add_circle_outline),
              subtitle: new text('我是副标题'),
            ),
            listtile(
              title: new text('我是主标题'),
              leading: icon(icons.add_circle_outline),
              subtitle: new text('我是副标题'),
            )
          ],
        ),
      ),
      floatingactionbutton: new floatingactionbutton(
        child: icon(icons.album),
        foregroundcolor: colors.amberaccent,
        backgroundcolor: colors.deeppurple,
        elevation: 10.0,
        highlightelevation: 20.0,
        mini: false,
        onpressed: (){
//            _showsimpledialog(context);
          _showalertdialog(context);
        },
      ),
      floatingactionbuttonlocation: floatingactionbuttonlocation.centerfloat,
    );
  }

  popupmenubutton _showpopupmenubutton() {
    return popupmenubutton(
        icon: icon(icons.menu),
        itembuilder: (buildcontext context) => <popupmenuentry>[
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton1"),
            ),
          ),
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton2"),
            ),
          ),
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton3"),
            ),
          ),
          const popupmenuitem(
            child: listtile(
              leading: icon(icons.add_circle_outline),
              title: text("popupmenubutton4"),
            ),
          ),
        ]
    );
  }

  void _showsimpledialog(buildcontext context) {
    showdialog(
        context: context,
        builder: (buildcontext context){
          return simpledialog(
            title: new text('simpledialog demo'),
            children: <widget>[
              simpledialogoption(
                child: text('选项1'),
              ),
              simpledialogoption(
                child: text('选项2'),
                onpressed: (){
                  navigator.pop(context);
                },
              ),
            ],
          );
        }
    );
  }

  void _showalertdialog(buildcontext context) {
    showdialog(
      context: context,
      builder: (buildcontext context){
        return alertdialog(
          title: new text('提示'),
          content: new text('这是提示框的内容'),
          actions: <widget>[
            flatbutton(onpressed: null, child: new text('确定'),disabledtextcolor: colors.blueaccent,),
            flatbutton(
              onpressed: (){
                navigator.pop(context);
                scaffold.of(context).showsnackbar(new snackbar(content: new text('snackbar')));
              },
              child: new text('取消'),disabledcolor: colors.deeppurple,),
          ],
          backgroundcolor: colors.amberaccent,
        );
      }
    );
  }
}