flutterif的简单介绍

Flutter下载jar速度慢

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用Android Stduio创建Flutter项目的时候，会出现各种问题，踩了一个又一个，最后编译的时候可能会出现一直显示Running Gradle task 'assembleDebug'然后就不动了，或者会显示Could not resolve io.flutter等问题，归根结底是网络无法访问到Google服务引起的，两种解决方案：

1.具有比较良好的访问谷歌的网络环境

2.修改镜像源为国内的：

找到Flutte SDK目录下的Flutter打包配置文件flutter.gradle

路径为flutter\packages\flutter_tools\gradle\flutter.gradle

第一处配置：

buildscript {

repositories {

//注释

// google()

// jcenter()

//添加

maven { url ' ' }

maven { url ' ' }

maven { url ' ' }

}

dependencies {

classpath 'com.android.tools.build:gradle:3.5.0'

}

}

第二处配置：

class FlutterPlugin implements PluginProject {

//注释

// private static final String MAVEN_REPO = " ";

//添加这行

private static final String MAVEN_REPO = " ";

第三处配置：

void addFlutterDependencies(buildType) {

String flutterBuildMode = buildModeFor(buildType)

if (!supportsBuildMode(flutterBuildMode)) {

return

}

String repository = useLocalEngine()

? project.property('local-engine-repo')

: MAVEN_REPO

最后一处，项目中的配置，修改Flutter项目下的android下的build.gradle：

buildscript {

ext.kotlin_version = '1.3.50'

repositories {

// google()

// jcenter()

maven { url ' ' }

maven { url ' ' }

maven { url ' ' }

}

}

allprojects {

repositories {

// google()

// jcenter()

maven { url ' ' }

maven { url ' ' }

maven { url ' ' }

}

}

修改完成后，再build，就可以正常构建了！！！

flutter 带未读消息的底部导航

bottom_tab_bar,

用法和bottom_navigation_bar一样，但是新增了一些属性的用法

bottom navigation bar 里面的 icon and title.

回调，带的是tab的index

The callback that is called when a item is tapped.

The widget creating the bottom navigation bar needs to keep track of the current index and call setState to rebuild it with the newly provided index.

The index into [items] of the current active item.

当前激活的是哪一个tab

Defines the layout and behavior of a [BottomTabBar].

See documentation for [BottomTabBarType] for information on the meaning of different types.

The color of the selected item when bottom navigation bar is [BottomTabBarType.fixed].

If [fixedColor] is null then the theme's primary color, [ThemeData.primaryColor], is used. However if [BottomTabBar.type] is [BottomTabBarType.shifting] then [fixedColor] is ignored.

The size of all of the [BottomTabBarItem] icons.

See [BottomTabBarItem.icon] for more information.

动画是否开启，默认是开起的

未读消息的颜色，默认是fixedColor

按压水墨屏效果是否开启，默认是开启的，

还是带动画的，不太适合我们的正常项目

未读消息，是一个widget，可以自定义样式

未读消息

first import dependeny in pubspec.yaml

example:

Flutter判断设备类型是iPad

import 'package:device_info/device_info.dart';

///是否是ipad

static bool isIpad = false;

static checkIpadFunc() async {

if (Platform.isAndroid == false) {

DeviceInfoPlugin deviceInfo = DeviceInfoPlugin();

IosDeviceInfo info = await deviceInfo.iosInfo;

print('======a=======a=======a=======a========a======= {info.model}');

print('======a=======a=======a=======a========a======= {info.utsname.machine.toLowerCase()}');

print('======a=======a=======a=======a========a=======${info.systemName}');

isIpad = info.utsname.machine.toLowerCase().contains("ipad");

}

}

flutter 反编译

You are building a fat APK that includes binaries for android-arm, android-arm64.

If you are deploying the app to the Play Store, it's recommended to use app bundles or split the APK to reduce the APK size.

To generate an app bundle, run:

    flutter build appbundle --target-platform android-arm,android-arm64

    Learn more on:

To split the APKs per ABI, run:

    flutter build apk --target-platform android-arm,android-arm64 --split-per-abi

    Learn more on: 

Initializing gradle...                                              2.3s

Resolving dependencies...                                          14.2s

Running Gradle task 'assembleRelease'...                                                  ע: E:\work_tool\flutter\.pub-cache\hosted\pub.flutter-io.cn\connectivity-0.4.4\android\src\main\java\io\flutter\plugins\connectivity\ConnectivityPlugin.javaʹ�û????����ѹ�ʱ�� API��

ע: �й���ϸ��Ϣ, ��ʹ�� -Xlint:deprecation ���±��롣

ע: E:\work_tool\flutter\.pub-cache\hosted\pub.flutter-io.cn\url_launcher-5.1.3\android\src\main\java\io\flutter\plugins\urllauncher\WebViewActivity.javaʹ

�û????����ѹ�ʱ�� API��

ע: �й���ϸ��Ϣ, ��ʹ�� -Xlint:deprecation ���±��롣

Calling mockable JAR artifact transform to create file: C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\android.jar\baf414ed95f14e507d85c560886dfbe2\android.jar with input E:\work_tool\sdk\android-sdk-windows\platforms\android-28\android.jar

Calling mockable JAR artifact transform to create file: C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\android.jar\ab096bb3fb172ccb785acdb1058c10a9\android.jar with input E:\work_tool\sdk\android-sdk-windows\platforms\android-27\android.jar

Request to incrementing alive workforce from 0. Current workforce (dead or alive) 0

thread-pool size=4

ProGuard, version 6.0.3

Reading input...

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\flutter.jar\ab2691c929f4d2aa57a17fa551e662a6\jetified-flutter.jar] (filtered)

Reading program jar [F:\dartSpace\flutter\jiddspace\nfc\build\app\intermediates\flutter\release\libs.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\localbroadcastmanager-1.0.0.aar\7a407f962902eada026a8e241a760bac\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\work-runtime-2.1.0.aar\8e3a1e8a8ff79006a94df6c01ceeb4f5\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\fragment-1.1.0.aar\4fa7d1b49e3514cb08c8a696f9b59436\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\room-runtime-2.1.0.aar\1b8774fa39759f08defb930275652eac\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\room-runtime-2.1.0.aar\1b8774fa39759f08defb930275652eac\jars\libs\room-common-java8-2.1.0.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\viewpager-1.0.0.aar\885186e7f6f969363bc93cd607d741a5\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\loader-1.0.0.aar\f84f22ad0a97d2c689850b912fc04277\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\activity-1.0.0.aar\a46db1490fae1b9001fc672a24eb288f\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\customview-1.0.0.aar\fe8bf4a709414e884086911d2168b715\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\core-1.1.0.aar\87febb54759dd5a2c7be8e971d745644\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\versionedparcelable-1.1.0.aar\754157c6f50ca4e4cf3ac8d7cb5ced26\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\modules-2\files-2.1\androidx.collection\collection\1.1.0\1f27220b47669781457de0d600849a5de0e89909\collection-1.1.0.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\lifecycle-livedata-2.0.0.aar\de6944801d37d99b1dd0b877649fde1f\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\lifecycle-livedata-core-2.0.0.aar\e21d6663beb6faa41a30fd5a582cb4d9\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\core-runtime-2.0.1.aar\724bb0cc2ce99eaf0a23a99bb1cc5c23\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\modules-2\files-2.1\androidx.room\room-common\2.1.0\b87765704590bd992ea0d92ac50253a9df7818a0\room-common-2.1.0.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\sqlite-framework-2.0.1.aar\9cbdf82e938f7e565620a3682d2406e9\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\sqlite-2.0.1.aar\1215aa5476f752bd431fb2d8059a1a39\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\lifecycle-service-2.0.0.aar\9d24ebd4d6766d7b2cd515369a737934\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\lifecycle-runtime-2.1.0.aar\ca02c0867547ae607130bcc54a4a9ba5\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\lifecycle-viewmodel-2.1.0.aar\594e1ff6298a01d8933530bb534fa472\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\transforms-1\files-1.1\savedstate-1.0.0.aar\8a2c3791a34fc80e5d9d268bf2886f95\jars\classes.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\modules-2\files-2.1\androidx.lifecycle\lifecycle-common\2.1.0\c67e7807d9cd6c329b9d0218b2ec4e505dd340b7\lifecycle-common-2.1.0.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\modules-2\files-2.1\androidx.arch.core\core-common\2.1.0\b3152fc64428c9354344bd89848ecddc09b6f07e\core-common-2.1.0.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\modules-2\files-2.1\androidx.annotation\annotation\1.1.0\e3a6fb2f40e3a3842e6b7472628ba4ce416ea4c8\annotation-1.1.0.jar] (filtered)

Reading program jar [C:\Users\Administrator\.gradle\caches\modules-2\files-2.1\com.google.guava\listenablefuture\1.0\c949a840a6acbc5268d088e47b04177bf90b3cad\listenablefuture-1.0.jar] (filtered)

Reading program jar [F:\dartSpace\flutter\jiddspace\nfc\build\flutter_downloader\intermediates\intermediate-jars\release\classes.jar] (filtered)

Reading program jar [F:\dartSpace\flutter\jiddspace\nfc\build\shared_preferences\intermediates\intermediate-jars\release\classes.jar] (filtered)

Reading program jar [F:\dartSpace\flutter\jiddspace\nfc\build\url_launcher\intermediates\intermediate-jars\release\classes.jar] (filtered)

Reading program jar [F:\dartSpace\flutter\jiddspace\nfc\build\sqflite\intermediates\intermediate-jars\release\classes.jar] (filtered)

Reading program jar [F:\dartSpace\flutter\jiddspace\nfc\build\connectivity\intermediates\intermediate-jars\release\classes.jar] (filtered)

Reading program jar [F:\dartSpace\flutter\jiddspace\nfc\build\path_provider\intermediates\intermediate-jars\release\classes.jar] (filtered)

Reading program jar [F:\dartSpace\flutter\jiddspace\nfc\build\package_info\intermediates\intermediate-jars\release\classes.jar] (filtered)

Reading program directory [F:\dartSpace\flutter\jiddspace\nfc\build\app\intermediates\javac\release\compileReleaseJavaWithJavac\classes] (filtered)

Reading program jar [F:\dartSpace\flutter\jiddspace\nfc\build\app\intermediates\transforms\mergeJavaRes\release\0.jar] (filtered)

Reading library jar [C:\Users\Administrator\.gradle\caches\modules-2\files-2.1\androidx.annotation\annotation\1.0.0\45599f2cd5965ac05a1488fa2a5c0cdd7c499ead\annotation-1.0.0.jar] (filtered)

Reading library jar [E:\work_tool\sdk\android-sdk-windows\platforms\android-28\android.jar]

Reading library jar [E:\work_tool\sdk\android-sdk-windows\build-tools\28.0.3\core-lambda-stubs.jar]

Reading library jar [E:\work_tool\sdk\android-sdk-windows\platforms\android-28\optional\org.apache.http.legacy.jar]

Reading library jar [E:\work_tool\sdk\android-sdk-windows\platforms\android-28\optional\android.test.mock.jar]

Reading library jar [E:\work_tool\sdk\android-sdk-windows\platforms\android-28\optional\android.test.base.jar]

Reading library jar [E:\work_tool\sdk\android-sdk-windows\platforms\android-28\optional\android.test.runner.jar]

Initializing...

Warning: io.flutter.embedding.android.FlutterView: can't find referenced method 'android.graphics.Insets getSystemGestureInsets()' in library class android.view.WindowInsets

Warning: io.flutter.embedding.android.FlutterView: can't find referenced class android.graphics.Insets

Warning: io.flutter.embedding.android.FlutterView: can't find referenced class android.graphics.Insets

Warning: io.flutter.embedding.android.FlutterView: can't find referenced class android.graphics.Insets

Warning: io.flutter.embedding.android.FlutterView: can't find referenced class android.graphics.Insets

Warning: io.flutter.embedding.android.FlutterView: can't find referenced class android.graphics.Insets

Warning: io.flutter.embedding.android.FlutterView: can't find referenced class android.graphics.Insets

Warning: io.flutter.view.FlutterView: can't find referenced method 'android.graphics.Insets getSystemGestureInsets()' in library class android.view.WindowInsets

Warning: io.flutter.view.FlutterView: can't find referenced class android.graphics.Insets

Warning: io.flutter.view.FlutterView: can't find referenced class android.graphics.Insets

Note: io.flutter.view.AccessibilityViewEmbedder$ReflectionAccessors: can't find dynamically referenced class android.util.LongArray

Warning: io.flutter.view.FlutterView: can't find referenced class android.graphics.Insets

Warning: io.flutter.view.FlutterView: can't find referenced class android.graphics.Insets

Warning: io.flutter.view.FlutterView: can't find referenced class android.graphics.Insets

Warning: io.flutter.view.FlutterView: can't find referenced class android.graphics.Insets

Note: there were 1 unresolved dynamic references to classes or interfaces.

  You should check if you need to specify additional program jars.

  ()

Warning: Exception while processing task java.io.IOException: Please correct the above warnings first.

Thread(Tasks limiter_1): destruction

Warning: there were 12 unresolved references to classes or interfaces.

    You may need to add missing library jars or update their versions.

    If your code works fine without the missing classes, you can suppress

    the warnings with '-dontwarn' options.

    ()

Warning: there were 2 unresolved references to library class members.

    You probably need to update the library versions.

    ()

FAILURE: Build failed with an exception.

* What went wrong:

Execution failed for task ':app:transformClassesAndResourcesWithProguardForRelease'.

Job failed, see logs for details

* Try:

Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.

* Get more help at

BUILD FAILED in 4m 23s

Running Gradle task 'assembleRelease'...

Running Gradle task 'assembleRelease'... Done                    264.4s (!)

*******************************************************************************************

The Gradle failure may have been because of AndroidX incompatibilities in this Flutter app.

See for more information on the problem and how to fix it.

*******************************************************************************************

Gradle task assembleRelease failed with exit code 1

flutter加载h5很卡

flutter加载h5很卡的解决方法如下：

一种临时解决方案，在切换动画加载完毕后，再去构造 WebView，这样从用户角度上看，就不会有路由切换动画的卡顿了。class WebViewPage extends StatefulWidget {undefined

final String uri;

WebViewPage({undefined

@required this.uri,

}) : assert(uri != null);

@override

_WebViewPageState createState() = _WebViewPageState();

}

class _WebViewPageState extends State {undefined

WebViewController _controller;

bool _animationCompleted = false;

@override

Widget build(BuildContext context) {undefined

// 主要是下面的代码

var route = ModalRoute.of(context);

if (route != null !_animationCompleted) {undefined

void handler(status) {undefined

if (status == AnimationStatus.completed) {undefined

route.animation.removeStatusListener(handler);

setState(() {undefined

_animationCompleted = true;

});

}

}

route.animation.addStatusListener(handler);

}

return Scaffold(

title: widget.title,

backgroundColor: Colors.white,

body: _animationCompleted

? WebView(

initialUrl: 'about:blank',

onWebViewCreated: (WebViewController webViewController) {undefined

_controller = webViewController;

_loadHtmlFromAssets();

},

)

: Container(),

);

}

_loadHtmlFromAssets() async {undefined

var uri = Uri.dataFromString(

await rootBundle.loadString(widget.uri),

mimeType: 'text/html',

encoding: Encoding.getByName('utf-8'),

).toString();

_controller.loadUrl(uri);

}

}

Fluent是目前国际上比较流行的商用CFD软件包，在美国的市场占有率为60%，凡是和流体、热传递和化学反应等有关的工业均可使用。

它具有丰富的物理模型、先进的数值方法和强大的前后处理功能，在航空航天、汽车设计、石油天然气和涡轮机设计等方面都有着广泛的应用。

FLUENT软件包含基于压力的分离求解器、基于密度的隐式求解器、基于密度的显式求解器，多求解器技术使FLUENT软件可以用来模拟从不可压缩到高超音速范围内的各种复杂流场。

FLUENT软件包含非常丰富、经过工程确认的物理模型，由于采用了多种求解方法和多重网格加速收敛技术，因而FLUENT能达到最佳的收敛速度和求解精度。

灵活的非结构化网格和基于解的自适应网格技术及成熟的物理模型，可以模拟高超音速流场、传热与相变、化学反应与燃烧、多相流、旋转机械、动/变形网格、噪声、材料加工等复杂机理的流动问题。