##HarmonyOS Next实战##HarmonyOS SDK应用服务##教育##
参考资料：
https://developer.huawei.com/consumer/cn/doc/harmonyos-faqs/faqs-network-61
@ohos.net.connection (网络连接管理)
网络连接管理提供管理网络一些基础能力，包括WiFi/蜂窝/Ethernet等多网络连接优先级管理、网络质量评估、订阅默认/指定网络连接状态变化、查询网络连接信息、DNS解析等功能。
connection.createNetConnection
创建一个NetConnection对象，netSpecifier指定关注的网络的各项特征；timeout是超时时间(单位是毫秒)；netSpecifier是timeout的必要条件，两者都没有则表示关注默认网络。
思路：通过使用 @ohos.net.connection 的能力，在网络连接状态发生变化时，判断当前网络是否可以访问互联网，并将判断结果存储到 AppStorage 中。需要判断网络连接状态时，直接从 AppStorage 获取结果。
前提条件：
修改module.json5配置文件，增加网络权限：
"requestPermissions": [
{
"name": "ohos.permission.INTERNET"
},
{
"name": "ohos.permission.GET_NETWORK_INFO"
}
]
增加NetworkUtil 工具类：
import { connection } from "@kit.NetworkKit";
import { BusinessError } from "@kit.BasicServicesKit";
import { promptAction } from "@kit.ArkUI";
import { hilog } from "@kit.PerformanceAnalysisKit";
export class NetworkUtil {
private static netConnection: connection.NetConnection | undefined = undefined;
public static JUDGE_NET_TAG: string = 'NetworkUtil.netConnection.isUseful';
/**
* 工具注册。
* 作用：监控网络状态
*/
static register() {
if (NetworkUtil.netConnection === undefined) {
NetworkUtil.init();
}
}
/**
* 获取网络连接状态
* @returns boolean
* true: 有网络
* false: 无网络
*/
static getStatus(): boolean {
return NetworkUtil.judgeHasNet()
}
static continueWhenNetUsable(callback: () => void) {
if (NetworkUtil.getStatus()) {
callback()
} else {
promptAction.showToast({
message: 'The network is not worked, please check your network',
duration: 2000
});
}
}
private static init() {
NetworkUtil.netConnection = connection.createNetConnection();
NetworkUtil.netConnection.register(() => {
Logger.info('connection register success');
});
NetworkUtil.netConnection.on('netAvailable', (data) => {
Logger.info('NetworkUtil netAvailable ');
AppStorage.setOrCreate(NetworkUtil.JUDGE_NET_TAG, NetworkUtil.judgeHasNet());
});
NetworkUtil.netConnection.on('netUnavailable', () => {
Logger.info('NetworkUtil netUnavailable ');
AppStorage.setOrCreate(NetworkUtil.JUDGE_NET_TAG, NetworkUtil.judgeHasNet());
});
NetworkUtil.netConnection.on('netCapabilitiesChange', (data: connection.NetCapabilityInfo) => {
Logger.info('NetworkUtil netCapabilitiesChange');
AppStorage.setOrCreate(NetworkUtil.JUDGE_NET_TAG, NetworkUtil.judgeHasNet());
});
// 订阅网络连接信息变化事件。调用register后，才能接收到此事件通知
NetworkUtil.netConnection.on('netConnectionPropertiesChange', (data: connection.NetConnectionPropertyInfo) => {
Logger.info('NetworkUtil netConnectionPropertiesChange');
AppStorage.setOrCreate(NetworkUtil.JUDGE_NET_TAG, NetworkUtil.judgeHasNet());
});
NetworkUtil.netConnection.on('netLost', () => {
Logger.info('NetworkUtil netLost');
AppStorage.setOrCreate(NetworkUtil.JUDGE_NET_TAG, NetworkUtil.judgeHasNet());
});
}
private static judgeHasNet(): boolean {
try { // 获取当前网络连接
let netHandle = connection.getDefaultNetSync();
// 0-100 为系统预留的连接
if (!netHandle || netHandle.netId < 100) {
return false;
}
// 获取连接的属性
let netCapability = connection.getNetCapabilitiesSync(netHandle);
let cap = netCapability.networkCap;
if (!cap) {
return false;
}
for (let em of cap) {
if (connection.NetCap.NET_CAPABILITY_VALIDATED === em) {
return true;
}
}
} catch (e) {
let err = e as BusinessError;
Logger.info('get netInfo error ：' + JSON.stringify(err));
}
return false;
}
}
class Logger{
static info(...args: string[]){
hilog.info(0x0000, '-logger-', getFormat(args), args);
}
}
function getFormat(args: string[]) {
let format = ''
for (let i = 0; i < args.length; i++) {
if (i == 0) {
format = '%{public}s'
} else {
format += ', %{public}s'
}
}
return format
}
页面NetworkUtilPage使用示例代码：
import { NetworkUtil } from '../../utils/NetworkUtil'
import { promptAction } from '@kit.ArkUI';
@Entry
@Component
struct NetworkUtilPage {
//用法一：通过状态管理实时获取网络状态
@StorageProp(NetworkUtil.JUDGE_NET_TAG)
isNetConnectionUseful: boolean = true;
aboutToAppear(): void {
NetworkUtil.register()
}
build() {
Column({ space: 10 }) {
Text('NetworkUtil Page')
.fontSize(20)
.fontWeight(FontWeight.Bold)
Text() {
Span('watch network status is ')
Span(JSON.stringify(this.isNetConnectionUseful))
.fontColor(this.isNetConnectionUseful ? Color.Green : Color.Red)
.fontWeight(600)
}
Button('getNetworkStatus').onClick(() => {
//用法二：获取当前的网络状态
const status = NetworkUtil.getStatus()
promptAction.showToast({
message: 'The network status is ' + JSON.stringify(status),
duration: 5000
});
})
Button('continue When Net Usable').onClick(() => {
//用法三：有网络继续后续动作，无网则中断后续动作并且弹窗提示用户设置网络。
NetworkUtil.continueWhenNetUsable(() => {
//当网络中断，弹窗提示用户设置网络且不执行后续动作
//当网络可用，继续执行
promptAction.showToast({
message: 'have net, continue!',
duration: 5000
});
})
})
}
.height('100%')
.width('100%')
}
}