ConstrainedBox

Author: DIVINER-only

docs/widget/regular/constrainedbox/index.md

@@ -0,0 +1,20 @@
+## **ConstrainedBox**
+
+>
+一个基础布局控件，添加额外的限制条件(constraints)到child上
+
+### 构造方法
+``` dart
+ConstrainedBox({
+  Key key,
+  @required this.constraints,
+  Widget child
+})
+```
+
+### 属性介绍
+* constraints: 添加到child上的额外限制条件，其类型为BoxConstraints，限制各种最大最小宽高
+* child: ConstrainedBox中的内容Widget
+
+### 其他用法
+* constraints值为BoxConstraints.expand时，提供width或者height，那么限制（Constraints）将严格使用给出的width或者height值

lib/widget/regular/constrainedbox/demo.dart

@@ -0,0 +1,63 @@
+import 'package:flutter/material.dart';
+
+class Index extends StatefulWidget {
+  @override
+  _IndexState createState() => _IndexState();
+}
+
+class _IndexState extends State<Index> {
+  var maxWidth = 200.0;
+  var maxHeight = 200.0;
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: Text('ConstrainedBox'),),
+      body: ListView(
+        children: <Widget>[
+          SizedBox(
+            child: Text('修改maxWidth maxHeight 值'),
+          ),
+          Row(
+            children: <Widget>[
+              FlatButton(
+                child: Text('maxWidth: $maxWidth', style: TextStyle(fontSize: 14.0),),
+                onPressed: (){
+                  setState(() {
+                    maxWidth == 200.0 ? maxWidth = 150.0 : maxWidth = 200.0;
+                  });
+                },
+              ),
+              FlatButton(
+                child: Text('maxHeight: $maxHeight', style: TextStyle(fontSize: 14.0),),
+                onPressed: (){
+                  setState(() {
+                    maxHeight == 200.0 ? maxHeight = 150.0 : maxHeight = 200.0;
+                  });
+                },
+              )
+            ],
+          ),
+          Center(
+            child: ConstrainedBox(
+              constraints: BoxConstraints(
+                minWidth: 100.0,
+                minHeight: 100.0,
+                maxWidth: maxWidth,
+                maxHeight: maxHeight
+              ),
+              child: Container(
+                margin: EdgeInsets.all(10.0),
+                decoration: BoxDecoration(
+                  image: DecorationImage(
+                    image: NetworkImage('http://sucimg.itc.cn/avatarimg/55d21fdc4b8d4838bef0da94ada78cab_1501139484387')
+                  ),
+                  color: Theme.of(context).primaryColor,
+                ),
+              ),
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+}

lib/widget/regular/constrainedbox/demo_expand.dart

@@ -0,0 +1,26 @@
+import 'package:flutter/material.dart';
+
+class Index extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: Text('Expand'),),
+      body: Center(
+        child: ConstrainedBox(
+          constraints: BoxConstraints.expand(
+            width: 150.0,
+            height: 150.0
+          ),
+          child: Container(
+            alignment: Alignment.center,
+            color: Theme.of(context).primaryColor,
+            child: Text(
+              'Hello World',
+              style: TextStyle(fontSize: 20.0, color: Colors.white, fontWeight: FontWeight.bold)
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+}

lib/widget/regular/constrainedbox/index.dart

@@ -0,0 +1,27 @@
+import 'package:flutter/material.dart';
+import 'package:efox_flutter/components/widgetComp.dart' as WidgetComp;
+import 'demo.dart' as Demo;
+import 'demo_expand.dart' as DemoExpand;
+
+class Index extends StatefulWidget {
+  static String title = 'ConstrainedBox';
+  static String originCodeUrl = '';
+  static String mdUrl = 'docs/widget/regular/constrainedbox/index.md';
+  @override
+  _IndexState createState() => _IndexState();
+}
+
+class _IndexState extends State<Index> {
+  @override
+  Widget build(BuildContext context) {
+    return WidgetComp.Index(
+      title: Index.title,
+      originCodeUrl: Index.originCodeUrl,
+      mdUrl: Index.mdUrl,
+      demoChild: <Widget>[
+        Demo.Index(),
+        DemoExpand.Index()
+      ],
+    );
+  }
+}

lib/widget/regular/index.dart

@@ -7,6 +7,7 @@ import 'align/index.dart' as Align;
 import 'center/index.dart' as Center;
 import 'fittedbox/index.dart' as FittedBox;
 import 'aspectratio/index.dart' as AspectRatio;
+import 'constrainedbox/index.dart' as ConstrainedBox;
 
 const nameSpaces = '/regular_';
 
@@ -50,6 +51,11 @@ List widgets = [
     widget: AspectRatio.Index(),
     code: 58688, // local_bar
     title: AspectRatio.Index.title
+  ),
+  ItemInfo(
+    widget: ConstrainedBox.Index(),
+    code: 57709, // low_priority 
+    title: ConstrainedBox.Index.title
   )
 ];
 

pubspec.yaml

@@ -64,6 +64,7 @@ flutter:
       - docs/widget/regular/center/
       - docs/widget/regular/fittedbox/
       - docs/widget/regular/aspectratio/
+      - docs/widget/regular/constrainedbox/
   # An image asset can refer to one or more resolution-specific "variants", see
   # https://flutter.io/assets-and-images/#resolution-aware.