Flutter 实现你所谓的弹窗 (对话框)

对话框介绍

Displays a Material dialog above the current contents of the app,
以安卓的样式覆盖在内容区域上的对话框,
with Material entrance and exit animations, modal barrier color, and modal
包含显示和关闭动画 , 对话框后面透明颜色 和对话框自身颜色,
barrier behavior (dialog is dismissible with a tap on the barrier).
以及对话框的一些属性 (例如: 点击可以关闭对话框)

builder 参数

This function takes a builder which typically builds a [Dialog] widget.
showDialog 函数需要通过builder来构建我们需要的对话框 ,
Content below the dialog is dimmed with a [ModalBarrier].
位于内容区域和对话框中间的透明层使用ModalBarrier .
The widget returned by the builder does not share a context with the location that showDialog is originally called from.
调用函数showDialog 传递的Context 和 builder 函数返回的Context 不属于同一个上下文 .
Use a [StatefulBuilder] or a custom [StatefulWidget] if the dialog needs
to update dynamically.
如果需要更新对话框数据，请使用 StatefulBuilder 或自定义 StatefulWidget。

StatefulBuilder 刷新对话框

  Future<void> _showMyDialog() async {
    return showDialog<void>(
      context: context,
      barrierDismissible: false, // user must tap button!
      builder: (BuildContext context) {
        String changeTextValue = "点击我就会刷新对话框";
        return AlertDialog(
          content: StatefulBuilder(
            builder: (BuildContext context, StateSetter setState) {
              return TextButton(
                  onPressed: () {
                    setState((){
                      changeTextValue = "点击后对话框Text的文本变了";
                    });
                  },
                  child:  Text(changeTextValue));
            },
          ),
        );
      },
    );
  }

透明层ModalBarrier

调用showDialog函数

Future<void> _showMyDialog() async {
    return showDialog<void>(
      context: context,
      barrierDismissible: false, // user must tap button!
      barrierColor: Colors.green,
      builder: (BuildContext context) {
        String changeTextValue = "点击我就会刷新对话框";
        return AlertDialog(
          content: StatefulBuilder(
            builder: (BuildContext context, StateSetter setState) {
              return TextButton(
                  onPressed: () {
                    setState(() {
                      changeTextValue = "点击后对话框Text的文本变了";
                    });
                  },
                  child: Text(changeTextValue));
            },
          ),
        );
      },
    );
  }

Context 参数

The context argument is used to look up the [Navigator] and [Theme] for
the dialog.
用于打开对话框 时 查找 Navigator 和 Theme 方便对话框使用 .
It is only used when the method is called.
当调用函数 showDialog 时使用 .
Its corresponding widget can be safely removed from the tree before the dialog is closed.
当需要关闭对话框时 , 可以通过Context 从对话框的父视图中移除相关子Widget .

Navigator 是管理管理具备堆栈规则的子Widget.
Theme 包括Widget 的颜色、大小、阴影等属性 .

barrierDismissible 参数

The barrierDismissible argument is used to indicate whether tapping on the
barrier will dismiss the dialog. It is true by default and can not be null.
当我们点击除开对话框内容以外的区域是否关闭对话需用用到barrierDismissible参数 . 这个参数默认值是true ,但不能为null .

barrierColor 参数

The barrierColor argument is used to specify the color of the modal barrier that darkens everything below the dialog.
barrierColor用于制定 对话框下面的背景颜色遮盖在内容的上面 .
If null, the default color Colors.black54 is used.
如果barrierColor 不设置 , 默认的颜色值是 Colors.black54 .

useSafeArea 参数

The useSafeArea argument is used to indicate if the dialog should only display in ‘safe’ areas of the screen not used by the operating system (see [SafeArea] for more details).
对话框是否显示在屏幕的安全区域 (让对话框不延伸到状态栏)
It is true by default, which means the dialog will not overlap operating system areas.
userSafeArea参数默认为true , 意味着对话框不会与状态栏重叠 .
If it is set to false the dialog will only be constrained by the screen size. It can not be null.

userSafeArea=fasle

Future<void> _showMyDialog() async {
    return showDialog<void>(
      context: context,
      barrierDismissible: true,
      barrierColor: Colors.amberAccent,
      useSafeArea: false,
      builder: (BuildContext context) {
        return AlertDialog(
          contentPadding: const EdgeInsets.all(0.0),
          content: StatefulBuilder(
            builder: (BuildContext context, StateSetter setState) {
              return Container(
                width: MediaQuery.of(context).size.width,
                height: MediaQuery.of(context).size.height,
                color: Colors.green.withOpacity(0.6),
              );
            },
          ),
        );
      },
    );
  }

userSafeArea=true

Future<void> _showMyDialog() async {
    return showDialog<void>(
      context: context,
      barrierDismissible: true,
      barrierColor: Colors.amberAccent,
      useSafeArea: true,
      builder: (BuildContext context) {
        return AlertDialog(
          contentPadding: const EdgeInsets.all(0.0),
          content: StatefulBuilder(
            builder: (BuildContext context, StateSetter setState) {
              return Container(
                width: MediaQuery.of(context).size.width,
                height: MediaQuery.of(context).size.height,
                color: Colors.green.withOpacity(0.6),
              );
            },
          ),
        );
      },
    );
  }

RouteSettings 参数

传递路由名称和参数

useRootNavigator 和barrierLabel 参数后续会将相关说明放到文章里面 ,有知道这两个参数含义可以在下面进行评论留言 !!!