Flutter-flutter_screenutil screen adaptation

Source: https://www.cnblogs.com/joe235/p/11262530.html

flutter_screenutil plug

flutter screen adaptation scheme, so you can show reasonable layout of the UI on different screen sizes!

Note : This plugin is still in the development stage, some API might not be available.

Installation depends:

Check out the latest version before installing

# Add rely 
  flutter_screenutil: ^ 0.5.3

In place of use of each import packages:

import 'package:flutter_screenutil/flutter_screenutil.dart';

Attributes

Attributes	Types of	Defaults	description
width	double	1080px	The width of the device design draft units px
height	double	1920px	The height of the apparatus design draft units px
allowFontScaling	bool	false	Whether to set the font size is scaled to the "font size" accessibility system

Initialization and set adaptation size and font size to be scaled according to whether the "font size" accessibility system

Before using, please set the width and height of good design draft, passing design draft of the width and height (in px) certain page setup (ie import documents, can be set once) in MaterialApp the home in order to ensure that each using the previously set a good adaptation size:

// fill in the design draft device screen size 

// Default width: 1080px, height: 1920px, allowFontScaling: to false 
ScreenUtil.instance = ScreenUtil.getInstance () .. the init (context); 

// if the draft design is based iPhone6 the sized (750 * 1334 of iPhone6) 
ScreenUtil.instance ScreenUtil = (width: 750, height: 1334 of) the init .. (context); 

// set the font size is scaled to the "font size" accessibility system defaults to false 
ScreenUtil.instance ScreenUtil = (width: 750, height: 1334 of, allowFontScaling: to true) .. the init (context);

use:

Adaptation size:

Incoming design draft px Size:

The screen width is adapted  width: ScreenUtil.getInstance().setWidth(540),

According to the height of the screen adaptation  height: ScreenUtil.getInstance().setHeight(200),

It may be used  ScreenUtil() alternatively  ScreenUtil.getInstance(), for example:ScreenUtil().setHeight(200)

note

According setWidth height adaptation can do to ensure that no deformation (when you want a square of the time)

setHeight method is to be adapted in height, at the same time you want to control the use of the actual height of the display on a screen in the UI.

// Initialization sized 
ScreenUtil.instance ScreenUtil = (width: 750, height: 1334 of) the init .. (context); 

Print ( 'pixel density devices: $ {} ScreenUtil.pixelRatio'); 
Print ( 'high equipment: ScreenUtil.screenHeight} {$ '); 
Print (' the device width: $ {ScreenUtil.screenWidth} ');

Adaptation font:

Incoming design draft px Size:

// passed font size, default is not scaled according to "font size" option auxiliary systems (allowFontScaling can be set at initialization ScreenUtil) 
ScreenUtil.getInstance (). SetSp (28)          
 
// Incoming font size, according to the system "font size" option to zoom in aid (if one does not follow the global allowFontScaling place settings)      
ScreenUtil (allowFontScaling: to true) .setSp (28)         
     
// for Example: 

Column ( 
              crossAxisAlignment: CrossAxisAlignment.start, 
              Children: <Widget> [ 
                text ( 'my text size is in the design draft 25px, will not change with the scale text system', 
                    style: TextStyle ( 
                        Color: Colors.black, fontSize:. ScreenUtil.getInstance () setSp (24-)) ), 
                text ( 'my text size is in the design draft 25px, will change with the scale text system', 
                    style: TextStyle (
                        color: Colors.black, fontSize: ScreenUtil(allowFontScaling: true).setSp(24))),
              ],
  )

Other related api:

ScreenUtil.pixelRatio       //设备的像素密度
ScreenUtil.screenWidth //设备宽度 ScreenUtil.screenHeight //设备高度 ScreenUtil.bottomBarHeight //底部安全区距离，适用于全面屏下面有按键的 ScreenUtil.statusBarHeight //状态栏高度 刘海屏会更高 单位px ScreenUtil.textScaleFactory //系统字体缩放比例 ScreenUtil.getInstance().scaleWidth // 实际宽度的dp与设计稿px的比例 ScreenUtil.getInstance().scaleHeight // 实际高度的dp与设计稿px的比例

Complete demo sample code:

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

void main() => runApp(new MyApp());

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return new MaterialApp(
      debugShowCheckedModeBanner: false,
      title: 'Flutter_ScreenUtil',
      theme: new ThemeData(
        primarySwatch: Colors.blue,
      ),
      home: new MyHomePage(title: 'FlutterScreenUtil Demo'),
    );
  }
}

class MyHomePage extends StatefulWidget {
  MyHomePage ({Key Key, this.title}): Super (Key: Key); 
    Print (

  final String title;

  @override 
  _MyHomePageState createState () => _MyHomePageState new new (); 
} 

class _MyHomePageState the extends State <MyHomePage> { 
  @override 
  the Widget Build (BuildContext context) { 
    // set adaptation size (fill the screen size of the device design draft) Should the design of draft is designed iPhone6 sized (750 * 1334 of iPhone6) 
    ScreenUtil.instance ScreenUtil = (width: 750, height: 1334 of) the init .. (context); 
    Print ( 'width of the device: $ {ScreenUtil.screenWidth}'); device width // 
    Print ( 'height of the device: ScreenUtil.screenHeight $ {}'); // device height 
    Print ( 'pixel density devices: $ {} ScreenUtil.pixelRatio'); // device pixel density 
        'safe zone from the bottom : $ {} ScreenUtil.bottomBarHeight DP '); // Bottom Zone Distance Safe, Suitable for Buttons with Full Screen 
    Print (
        'Status Bar Height: $ {} ScreenUtil.statusBarHeight dp'); // the Status bar height, Will BE IN AREAS OF COMMUNICAITIONS Unit of Notch px 

    Print (px design draft ratio dp and the actual width ': $ {ScreenUtil.getInstance () scaleWidth . } ';) 
    . (the actual height ratio dp px and the design draft: $ {ScreenUtil.getInstance () Print' ScaleHeight} '); 

    Print ( 
        ' with respect to the ratio of the width and font design draft amplification: $ {ScreenUtil.getInstance ()} ScreenUtil.pixelRatio .scaleWidth * '); 
    Print ( 
        .' with respect to the design draft highly enlarged scale: $ {ScreenUtil.getInstance ()} ScreenUtil.pixelRatio ScaleHeight * '); 
    Print (' system Font scaling: ScreenUtil.textScaleFactory} {$ '); 

    return the Scaffold ( 
      appbar: the appBar ( AppBar(
        title: Text(widget.title),
      ), 
      floatingActionButton: FloatingActionButton ( 
        onPressed: () { 
          Print (
              'ScreenUtil.getInstance().width：${ScreenUtil.getInstance().width}');
          print('ScreenUtil().width：${ScreenUtil().width}');
        },
        child: Icon(Icons.accessible_forward),
      ),
      body: new Center(
        child: Column(
          crossAxisAlignment: CrossAxisAlignment.center,
          children: <Widget>[
            Row(
              children: <Widget>[
                Container(
                  width: ScreenUtil.getInstance().setWidth(375),
                  height: ScreenUtil.getInstance().setHeight(200),
                  color: Colors.red,
                  child: Text(
                    '我的宽度:${ScreenUtil.getInstance().setWidth(375)}dp',
                    style: TextStyle(
                      color: Colors.white,
                      fontSize: ScreenUtil.getInstance().setSp(24),
                    ),
                  ),
                ),
                Container(
                  width: ScreenUtil.getInstance().setWidth(375),
                  height: ScreenUtil.getInstance().setHeight(200),
                  color: Colors.blue,
                  child:
                      Text('我的宽度:${ScreenUtil.getInstance().setWidth(375)}dp',
                          style: TextStyle(
                            Color: Colors.white, 
                            the fontSize:. ScreenUtil.getInstance () setSp (24), 
                          )), 
                ), 
              ], 
            ), 
            the Text ( 'width of the device: $ {} ScreenUtil.screenWidth PX'), 
            the Text ( 'height of the equipment: PX ScreenUtil.screenHeight} {$ '), 
            the Text (' width of the device: $ {} ScreenUtil.screenWidthDp DP '), 
            the Text (' height of the device: $ {} ScreenUtil.screenHeightDp DP '), 
            the Text (' draft design width: $ {ScreenUtil.getInstance () width.} ' ), 
            pixel density Text (' equipment: ScreenUtil.pixelRatio $ {} '), 
            Text (' safe zone from the bottom: $ {} ScreenUtil.bottomBarHeight DP '), 
            Text (' status bar height: $ {ScreenUtil.statusBarHeight}dp'),
            The Text ( 
                    style: the TextStyle ( 
              ' design and the actual width of DP draft ratio px of: $ {ScreenUtil.getInstance ().scaleWidth}',
              textAlign: TextAlign.center, 
            ), 
            (the Text 
              'dp ratio of the actual height of the design draft px: $ {ScreenUtil.getInstance (ScaleHeight.)}', 
              textAlign: TextAlign.center, 
            ), 
            SizedBox ( 
              height: ScreenUtil.getInstance ( ) .setHeight (100), 
            ), 
            the text ( 'font scaling system: $ {} ScreenUtil.textScaleFactory'), 
            the Column ( 
              crossAxisAlignment: CrossAxisAlignment.start, 
              Children: <the Widget> [ 
                the text ( 'my design text size is 24px, does not change the scaling 'system on the document with text, 
                        Color: Colors.black,
                        fontSize:. ScreenUtil.getInstance () setSp (24-))), 
                Text ( 'My text size is in the design draft 24px, will change with the scale text system', 
                    style: TextStyle ( 
                        Color: Colors.black, 
                        the fontSize: 
                            ScreenUtil (allowFontScaling: to true) .setSp (24))), 
              ], 
            ) 
          ], 
        ), 
      ), 
    ); 
  } 
}

 

Summary: The study of the use flutter_ScreenUtilto adapt Flutter of APP application, should be noted that this plug-in again escalating, so use the time to use the latest version.

github Address: https://github.com/OpenFlutter/flutter_screenutil