开源一夏｜OpenHarmony 如何查询设备类型（eTS）

作者：坚果

2022 年 8 月 05 日
本文字数：3006 字
阅读完需：约 10 分钟

在应用开发过程中查询设备类型。

通过 js 接口查询指定系统参数（const.build.characteristics）进而确定设备类型，详见系统属性。

// @ts-nocheck
import parameter from '@ohos.systemParameter'
@Entry@Componentstruct GetDeviceTypeSample {  @State deviceType: string = 'unknown';


  build() {    Column() {      Text("获取设备类型").fontSize(24)      Text(this.deviceType).fontSize(24).onClick(()=>{        try {          this.deviceType = parameter.getSync("const.build.characteristics");        } catch(e) {          console.log("getSync unexpected error: " + e);        }
      })    }    .width('100%')    .height('100%')  }}

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通过 deviceInfo 查询设备类型，deviceInfo 中各个字段的含义请参考设备信息。

// @ts-nocheck/* * Copyright (c) 2021 JianGuo Device Co., Ltd. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * *    http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */import parameter from '@ohos.systemParameter'
@Entry@Componentstruct GetDeviceTypeSample {  @State deviceType: string = 'unknown';


  build() {    Column() {      Text("获取设备类型").fontSize(24)      //通过js接口查询指定系统参数（const.build.characteristics）进而确定设备类型      Text(this.deviceType).fontSize(24).onClick(()=>{        try {          this.deviceType = parameter.getSync("const.build.characteristics");        } catch(e) {          console.log("getSync unexpected error: " + e);        }
      })      //通过deviceInfo查询设备类型      Text(this.deviceType).fontSize(24).onClick(()=>{        try {          this.deviceType= deviceInfo.deviceType;        } catch(e) {          console.log("getSync unexpected error: " + e);        }
      })      //通过display查询显示设备的属性（包括屏幕宽、高和屏幕密度等）      Text(this.deviceType).fontSize(24).onClick(()=>{        display.getDefaultDisplay()          .then((displayInfo) => {            console.info('Display width: '+ displayInfo.width);            console.info('Display height: '+ displayInfo.height);            console.info('Display density: '+ displayInfo.densityDPI);          })          .catch((error) => {            console.error('Failed to obtain the default display size. Cause:  '+JSON.stringify(error));          })
      })    }    .width('100%')    .height('100%')  }}

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如何查询屏幕/窗口尺寸

在应用开发过程中，为了在不同的设备上取得更好的显示效果，开发者可能需要查询屏幕尺寸或应用显示窗口尺寸。

通过 display 查询显示设备的属性（包括屏幕宽、高和屏幕密度等），详见屏幕属性。

// @ts-nocheck/* * Copyright (c) 2021 JianGuo Device Co., Ltd. * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * *    http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */import deviceInfo from'@ohos.deviceInfo'import parameter from '@ohos.systemParameter'import display from '@ohos.display';
@Entry@Componentstruct GetDeviceTypeSample {  @State deviceType: string = 'deviceType';  @State device: string = 'device';  @State displayInfo: string = 'displayInfo';
  aboutToAppear() {    try {      this.deviceType = parameter.getSync("const.build.characteristics");    } catch(e) {      console.log("getSync unexpected error: " + e);    }  }  build() {    Column() {      Text("设备属性").fontSize(36)      //通过js接口查询指定系统参数（const.build.characteristics）进而确定设备类型      Text(this.deviceType).fontSize(28).onClick(() => {        try {          this.deviceType = parameter.getSync("const.build.characteristics");          console.log("坚果"          +          this.deviceType);        } catch (e) {          console.log("getSync unexpected error: " + e);        }
      })      //通过deviceInfo查询设备类型      Text(   this.device).fontSize(28).onClick(() => {        this.device= deviceInfo.deviceType;      })      //通过display查询显示设备的属性（包括屏幕宽、高和屏幕密度等）      Text(this.displayInfo).fontSize(28).onClick(() => {        display.getDefaultDisplay()          .then((displayInfo) => {            console.info('Display width: ' + displayInfo.width);            console.info('Display height: ' + displayInfo.height);            console.info('Display density: ' + displayInfo.densityDPI);            this.displayInfo=JSON.stringify(displayInfo);            console.info('Display density: ' +   JSON.stringify(displayInfo));
          })          .catch((error) => {            console.error('Failed to obtain the default display size. Cause:  ' + JSON.stringify(error));          })
      })    }    .width('100%')    .height('100%').justifyContent(FlexAlign.Center).alignItems(HorizontalAlign.Center)  }}

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运行之后，在控制台打印

{"alive":true,"densityDPI":560,"densityPixels":3.5,"height":2560,"id":0,"name":"内置屏幕","refreshRate":60.000004,"rotation":0,"scaledDensity":3.5,"state":2,"width":1440,"xDPI":560,"yDPI":560}

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下面是参数描述