关于前端:Flutter自定义弹框

在Flutter利用开发中，常常会遇到自定义弹框的开发需要，如下图所示。

对于这种款式，咱们能够抉择自定义Dialog，具体的款式能够依据本人的须要进行批改。 例如，上面是我的实现，因为文本是一个列表，所以我须要新建一个实体类，如下所示。

class IntroduceModel {

  int code;
  List<Data> data;

  IntroduceModel({this.code, this.data});

  IntroduceModel.fromJson(Map<String, dynamic> json) {
    code = json['code'];
    if (json['data'] != null) {
      data = new List<Data>();
      json['data'].forEach((v) {
        data.add(new Data.fromJson(v));
      });
    }
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['code'] = this.code;
    if (this.data != null) {
      data['data'] = this.data.map((v) => v.toJson()).toList();
    }
    return data;
  }
}

class Data {
  String itemTitle;
  String itemContent;

  Data({this.itemTitle, this.itemContent});

  Data.fromJson(Map<String, dynamic> json) {
    itemTitle = json['itemTitle'];
    itemContent = json['itemContent'];
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = new Map<String, dynamic>();
    data['itemTitle'] = this.itemTitle;
    data['itemContent'] = this.itemContent;
    return data;
  }
}

而后，咱们自定义一个Dialog，源码如下：

class IntroduceDialog extends Dialog {
  
  String des='注：以上的单⽇⽬标额从理论年⽬标额、⽉⽬标额取平均值计算⽽来。';
  String title;
  String content;
  bool isForce;
  IntroduceModel model;
  IntroduceDialog({this.title, this.content,this.isForce}){
    if(content!=null){
      model=IntroduceModel.fromJson(json.decode(content));
    }
  }


  @override
   build(BuildContext context) {
    return Material(
      type: MaterialType.transparency,
      child: Center(
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          children: [
            _buildContent(context),
            _buildClose(context)
          ],
        ),
      ),
    );
  }

  _buildContent(BuildContext context) {
    double sWidth= MediaQuery.of(context).size.width;
    return Container(
      color: Colors.white,
      width: sWidth*0.85,
      height: 420,
      padding: EdgeInsets.only(left: 15,right: 15,top: 10,bottom: 10),
      child: SingleChildScrollView(
        child: Column(
          children: [
            Text(title, style: TextStyle(fontSize: 20,color:Colors.black,fontWeight: FontWeight.bold)),
            SizedBox(height: 5),
            _buildListView(),
            Text(des, style: TextStyle(fontSize: 14)),
          ],
        ),
      ),
    );
  }

  _buildListView() {
    return Container(
      padding: EdgeInsets.only(top: 5,bottom:5,right: 0,),
      child: ListView.separated(
        shrinkWrap: true,
        physics:  NeverScrollableScrollPhysics(),
        itemCount: model.data.length,
        separatorBuilder: (BuildContext context, int index) => Container(
          child:  Divider(),
        ),
        itemBuilder: (context, index) {
          return _buildItem(context,model.data, index);
        },
      ),
    );
  }

  _buildItem(BuildContext context, list, int index) {
    Data item=list[index];
    return Column(
      mainAxisAlignment: MainAxisAlignment.start,
      crossAxisAlignment: CrossAxisAlignment.start,
      children: [
        Text(item.itemTitle, style: TextStyle(fontSize: 14)),
        Text(item.itemContent, style: TextStyle(fontSize: 14)),
      ],
    );
  }

  _buildClose(BuildContext context) {
    return GestureDetector(
      child: Offstage(
        offstage: isForce,
        child: Container(
            margin: EdgeInsets.only(top: 30),
            child: LoadAssetImage('close_icon', width: 45,height: 45,fit: BoxFit.fill,)
        ),
      ),
      onTap: (){
        Navigator.of(context).pop();
      },
    );
  }


  static showUpdateDialog(BuildContext context, String title,String content, bool isForce) {
    return showDialog(
        barrierDismissible: false,
        context: context,
        builder: (BuildContext context) {
          return WillPopScope(
              child: IntroduceDialog(title: title,content: content, isForce: isForce),onWillPop: _onWillPop);
        });
  }

  static Future<bool> _onWillPop() async{
    return false;
  }


}

须要说的是，自定义的Dialog的根组件须要应用Material，不然的话，Dialog界面的文字上面会呈现黄色的下划线，导致这种状况产生的起因是因为，Text widget 隶属于Material 格调下的组件，如果根节点不是Material 相干组件，则会应用默认带黄色下划线的格局。如果根节点是Material 容器组件，则会采纳其Material格调的款式（即不带有下换线），解决的办法有三个：

解决方案次要有三种：
1，采纳根节点为脚手架Scaffold组件：

Scaffold(body: content,);

2， 采纳根节点为Material 组件。

Material(child: content);

3， 一一批改Text 组件的style 下的decoration为TextDecoration.none。

child: Text(
                      "专栏的文章",
                      overflow: TextOverflow.ellipsis,
                      style: TextStyle(
                        decoration: TextDecoration.none,
                        color: Color(0xFF888888),
                        fontSize: 14,
                        fontWeight: FontWeight.bold,
                        fontFamily: defaultFontFamily,
                      ),
                    )

对于间距，只须要应用Offstage组件即可。最初，在须要应用的中央调用一下这个组件即可，如下所示。

 showIntroduceDialog(BuildContext context) async {
    var localData=await rootBundle.loadString('assets/flow_advertis_funnel.json');
    IntroduceDialog.showUpdateDialog(context, '数据阐明', localData, false);
  }