Flutter assembly

Set the background color

Container(
decoration: new BoxDecoration(color: Colors.pink),
child: Column(
children: [
title(‘3D Interaction ’),
title(‘ Start training mode ’),
title(‘ The background music ’),
title(‘ common problem ’),
],
),

appBar: AppBar(
backgroundColor: Colors.redAccent,
title: Text(‘ motion ’),
leading: Icon(Icons.ac_unit, color: Colors.white),
)

Container

1. The function is all ready
2. Set up text Inside and outside the margin
   EdgeInsets.fromLTRB(10,10,10,10) ,L It means the left margin (left abbreviation ),T Indicates the top margin (top abbreviation ),R Indicates the right margin (right abbreviation ),B Indicates the bottom margin (bottom abbreviation ), The four values can be written separately ;
   EdgeInsets.all(10), The top, bottom, left and right margins are 10;
   EdgeInsets.only(left: 10, right: 5, top: 10, bottom: 10), Can be specified separately 4 The margin value in each direction , If you only need the top margin , It can be written. EdgeInsets.only( top: 10);
   EdgeInsets.symmetric(vertical: 20, horizontal: 10) , You can specify the vertical and horizontal margins , You can also specify the vertical or horizontal margins separately . For example, only the vertical margin is required , Can be written as EdgeInsets.symmetric(vertical: 20);
   EdgeInsets.fromWindowPadding(), Create a that matches the given window fill insets. The specific usage is still unknown , The first parameter is given widget Of windowpadding, The second is the screen resolution
   3. Interval use SizedBox(width: 10),
   Here are some Inline code slice .

new Container(
  constraints: new BoxConstraints.expand(
    height:Theme.of(context).textTheme.display1.fontSize * 1.1 + 200.0,
  ),
  decoration: new BoxDecoration(
    border: new Border.all(width: 2.0, color: Colors.red),
    color: Colors.grey,
    borderRadius: new BorderRadius.all(new Radius.circular(20.0)),
    image: new DecorationImage(
      image: new NetworkImage('http://h.hiphotos.baidu.com/zhidao/wh%3D450%2C600/sign=0d023672312ac65c67506e77cec29e27/9f2f070828381f30dea167bbad014c086e06f06c.jpg'),
      centerSlice: new Rect.fromLTRB(270.0, 180.0, 1360.0, 730.0),
    ),
  ),
  padding: const EdgeInsets.all(8.0),
  alignment: Alignment.center,
  child: new Text('Hello World',
    style: Theme.of(context).textTheme.display1.copyWith(color: Colors.black)),
  transform: new Matrix4.rotationZ(0.3),
)

Container Of alignment Didn't work , Because Container The size of is not set , Or the size just wraps around the child elements

appbar attribute

1. Common properties Insert the code slice description here
.leading left Element customization , It's a widget parts
leadingWidth AppBar Of leading Width , If leading If there are words in , If you don't set this property , When you have a lot of words , It will change lines
title AppBar The title of the , Also a widget
titleSpacing Set up AppBar The title of the Open the left and right On both sides distance
centerTitle control AppBar Whether the title of is centered , Boolean value , Default false,
actins AppBar Additional part on the right , Like a button , A word, etc , Need to pass in a List（ Array ）
backgroundColor AppBar Background color of , Pass in a Color The color of the type , Such as Colors.red, Color(0xff45ff41)
elevation AppBar Bottom of Shadow size , The default is 4.0, Set to 0.0 Hui He body The elements in are linked together
shadowColor AppBar Bottom of Shadow color , Same as backgroundColor Parameter usage
toolbarHeight Set up AppBar Of components Height , Pass in double Type of value , Such as 25, 40.2
2.
appbar Of title Centering centerTitle: true, Don't need to use margin: const EdgeInsets.only(left: 100, right: 0, top: 10, bottom: 10)
3.
appbar How to set the height of ：
In the AppBar Before to add appBar: PreferredSize(preferredSize: Size.fromHeight(10),child: AppBar( But in general ,appbar The height is the same

row The two ends of the sub assembly are aligned

Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Text(value),
Icon(Icons.arrow_forward_ios)
],
)
4. There are setState Method , To write to a class
5.color: Colors.#F6F6F6-----color: Color(0xffF6F6F6)
6.ClipRRect No cutting container,contanner Set rounded border
Cannot provide both a color and a decoration
7. Picture set click event and jump
InkWell(
child: Icon(Icons.arrow_forward_ios,size: 15,),
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => MyHomePage2(),
),
);

listview

scrollDirection: Axis.horizontal,
1. Implement roughly the same list ,ListTile yes cell( Each one item) Is a fixed row height . adopt scrollDirection Property can be set to horizontal list
2. children Parameters , It accepts a Widget list （List）. This approach is suitable for situations where only a small number of subcomponents are known and relatively small , On the contrary, you should use ListView.builder Dynamically build list items on demand .
3. ListView.builder Of itemCount Is a must
4.listviw To give length , Otherwise... Cannot be displayed
5. All attributes ：
leading, cell Icon on the left
title, cell Main title
subtitle, cell Subtitle
trailing, cell Right icon
isThreeLine = false, cell Whether to display in three lines
dense, cell Intuitive feeling is the overall size
contentPadding, cell Content margins
enabled = true, cell Can I respond to
onTap, cell onTap cell Click event
onLongPress, cell onLongPress Long press event
selected = false, cell Check the status
6.
listview Do not fix the height , Just use expand
7.
listview It contains listview. In it list view It contains a container, And specify the height .

ListTile

  const ListTile({
    Key key, 
    this.leading, //title Previous widget
    this.title, // The main contents of the list block 
    this.subtitle, //title The contents shown below 
    this.trailing, // After the title widget, It's usually a [Icon]widget
    this.isThreeLine = false, // Are you going to display three lines of text 
    this.dense, // Whether this list block is part of a vertically dense list , If it is true The text will be smaller 
    this.visualDensity, 
    this.shape,
    this.contentPadding, // Margin between content and border , The default is 16
    this.enabled = true, // Whether the list block is interactive 
    this.onTap, // When the user clicks this list block, call 
    this.onLongPress, // When the user presses and holds this list block, call 
    this.mouseCursor,
    this.selected = false, // If the list block... Is selected , The color of the text and icon will become the main color of the theme 
    this.focusColor,
    this.hoverColor,
    this.focusNode,
    this.autofocus = false,
  })

Text

Text(value,style: TextStyle(
      fontSize: 14,
      color: Color(0xff4F6770),
      fontFamily: "PingFang SC",)),
  )

Click event

  InkWell(
            child: buildButtonColum(Icons.call, 'CALL'),
            onTap:(){
              print('CALL');
              },
          ),

Image

'image/one.png', height: 10,
                  width: 10,

Two centered

Container(
              height: 32,
              width: 109,
              alignment: Alignment.center,
              decoration: new BoxDecoration(
                color: Color(articlecolor),
                borderRadius: new BorderRadius.all(new Radius.circular(10.0)),
              ),
              child: Text(' article ',
                  textAlign: TextAlign.center,
                  style: TextStyle(
                    fontSize: 14,
                    color: Color(0xff4F6770),
                    fontFamily: "PingFang SC",
                  )),
            ),

textAlign: TextAlign.center, Just center the text , Because it only occupies one line , So it doesn't center vertically in the container

Wrap

Wrap The child controls can be laid out horizontally or vertically , And when the space runs out ,Wrap It will wrap itself , It is also often said that streaming ​ Layout .

wheel

https://zhuanlan.zhihu.com/p/90035192
Name of wheel ：percent_indicator
Wheel overview ：flutter A circular and linear progress bar .

Stack

CustomPaint

It can be called the originator of animation , It can achieve any cool animation and effects .CustomPaint It has no animation properties , Just draw attributes , In general ,CustomPaint Can be used with animation control , Achieve the desired results .

TabBar、TabBarView,TabController

Provides common multi Tab Switching function , For example, the clothes marked horizontally above the e-commerce website 、 furniture 、 Electronic products, … Wait to switch pages , Then click on the corresponding tab Switch to different special sessions .

Integrated monitoring App Crash function

import ‘package:flutter_bugly/flutter_bugly.dart’;

flustars

Depend on Dart Common tool class library common_utils, And encapsulating other third-party libraries , We are committed to sharing simple and easy-to-use tools
1、SpUtil : Single case " Sync "SharedPreferences Tool class . Support get Pass in the default value , Support storage objects , Supports storing object arrays .
2、ScreenUtil : Screen adaptation , Get screen width 、 high 、 density ,AppBar high , Status bar height , Screen orientation .
3、WidgetUtil : monitor Widget Render states , obtain Widget Wide and high , Coordinates on the screen , Get network / Local picture size .
4、DioUtil : Single case Dio Network tools ( Migrated here DioUtil).
5、ImageUtil : Get network / Local picture size .

Bidirectional data binding code

TextField(
                style: const TextStyle(color: Color(0xFFA7ABBB),fontSize: 15),
                inputFormatters: [DecimalInputFormat(decimalRange: 4)],
                keyboardType: TextInputType.numberWithOptions(signed: true),
                controller: TextEditingController.fromValue(TextEditingValue(
                    text: item['number'],
                    selection: TextSelection.fromPosition(TextPosition(
                        affinity: TextAffinity.downstream,
                        offset: item['number'].length)
                    ))
                ),
                decoration: InputDecoration(
                  counterText: '',
                  filled: true,
                  fillColor: Color(0xFF1A1A1A),
                  hintStyle: const TextStyle(color: Color(0xFFA7ABBB),fontSize: 15),
                  hintText: ' Please enter the quantity ',
                  contentPadding: EdgeInsets.symmetric(horizontal: 15,vertical: 10),
                  enabledBorder: OutlineInputBorder(borderRadius: BorderRadius.circular(6),borderSide: BorderSide.none),
                  focusedBorder: OutlineInputBorder(borderRadius: BorderRadius.circular(6),borderSide: BorderSide.none),
                  suffixIcon: Container(alignment: Alignment.centerRight,child: Text('XBIT',style: const TextStyle(color: Color(0xFFA7ABBB),fontSize: 15),),margin: EdgeInsets.only(right: 15),),
                  suffixIconConstraints: BoxConstraints(maxWidth: 80)
                ),
                onChanged: (v){undefined
                  item['number'] = v;
                  setState(() { });
                },
              )

text field

Realization text field The inner string is cleared , First, two-way data binding ,
2.
Click again on the textfield The cursor will go to the front , To be in contraner Set cursor in
controller: TextEditingController.fromValue(
TextEditingValue(
selection: TextSelection.fromPosition(
TextPosition(offset: _controller.length)),
text: _controller,
)),
3.

controller: TextEditingController.fromValue(TextEditingValue(
text: controller,
// selection: TextSelection.fromPosition(TextPosition(
// affinity: TextAffinity.downstream,
// offset: item[‘number’].length)
)),

Historical record

bug: //searchHistory.add(str); // Can't add in Unsupported operation: Cannot add to an unmodifiable list
SpUtil.putStringList(‘search_history_list’, […searchHistory, str]);// Direct use ... Syntax addition generates an array

Delete the contents of the hard disk with SpUtil.remove(‘search_history_list’); But the memory value is not deleted , So it won't disappear immediately ,final Can't change the direction , But you can use an array of clear Method empty

Interface

The data format returned by the interface is json, It needs to be serialized to be rendered
json Convert to module class , because sdk The problem of high version leads to the risk that null values are not allowed
Methods for parent-child components to pass values , no need provider, Instead, the parent and child components get variables , because provider, After killing the process, the history is gone

Scloolbar

Add a slider to use , This must be a rollable component of the package , Other components do not work ; The direction of the slider cannot be set ,
The direction of the slider is in the direction of scrolling , So set the scrolling direction of the scrolling component

debug, Algorithm

Common problems in algorithms ： Traversal array , But in the process of changing the number of array elements
RangeError (index): Invalid value: Not in inclusive range 0…12: 13 #0 List.[] (dart:core-patch/array.dart:268:52)
List searchedData; searchedData.add(initData[“problem”][“list”][i]); Unable to add ; should List searchedData = [];

sp_util

import ‘package:sp_util/sp_util.dart’;
bool isLooked = SpUtil.getBool(‘is_looked’);
SpUtil.putBool(‘is_looked’, true);
SpUtil.remove(‘search_history_list’);