打印

第一步：权限申请

在module.json5中进行如下配置；

"requestPermissions": [
  {
    "name": "ohos.permission.PRINT",
    "reason": "$string:permissionsReason",
    "usedScene": {
      "abilities": [
        "EntryAbility"
      ],
      "when":"always"
    }
  },
  {
    "name": "ohos.permission.INTERNET"
  },
],

第二步：将打印的内容保存至沙箱（这里是将网络图片下载到沙箱），并将地址转化成uri沙箱目录格式

import { fileUri } from '@kit.CoreFileKit';
import { downloadFileWithUniqueName } from './dowmload';
import { common } from '@kit.AbilityKit';
import { PrintService } from './printPage';

@Entry
@Component
struct Index {
    @State message: string = 'Hello World';
    @State uri: string = ""
    @State filePath:string = ""
    private printService: PrintService | null = new PrintService(getContext(this)); // 打印服务实例

  build() {
    Scroll() {
      Column({ space: 10 }) {
        Button("下载")
          .onClick(async () => {
            const res = await downloadFileWithUniqueName("https://pic.rmb.bdstatic.com/bjh/bb8918b3bce/241107/8b2d3382db261f701e50d6acddcb48bc.jpeg?for=bg", "test.jpg")
            let context = getContext(this) as common.UIAbilityContext
            this.filePath = `${context.filesDir}/${res.uniqueNameWithoutExt}.${res.ext}`
          })

        Text("显示")
          .fontSize(50)
          .fontWeight(FontWeight.Bold)
          .onClick(() => {
            console.log('filePath-----',this.filePath)
            this.uri = fileUri.getUriFromPath(this.filePath)
            console.log('uri-----',this.uri)
          })
        Image(this.uri)
          .width(100)
          .height(100)
        Button("打印")
          .width('90%')
          .height(50)
          .onClick(() => {
            let hostContext = this.getUIContext().getHostContext();
            if (hostContext) {
              this.printService = new PrintService(hostContext);
              this.printService.executePrint([this.uri,this.uri])
            } else {
              console.error('获取上下文失败，无法初始化打印服务');
            }
        })
      }
      .justifyContent(FlexAlign.Center)
      .constraintSize({ minHeight: '100%' })
      .width('100%')
    }
    .height('100%')
  }
}

note：其中打印需要的上下文需要用this.getUIContext().getHostContext()来获取，需要的地址格式需要用fileUri.getUriFromPath来获取。

第三步：封装打印文件需要的类

import { BusinessError, print } from '@kit.BasicServicesKit';
/**
 * 打印服务类
 */
export class PrintService {
  private context: Context;

  constructor(context: Context) {
    this.context = context;
  }

  /**
   * 执行打印操作
   */
  executePrint(files: string[],callback?: () => void): void {
    try {
      if (files.length === 0) {
        console.error('没有有效的文件可打印');
        return;
      }
      console.log("最终打印URI列表:", JSON.stringify(files));
      print.print(files, this.context).then((printTask: print.PrintTask) => {
        printTask.on('succeed', () => {
          console.info('print state is succeed');
          if (callback) {
            callback();
          }
        })
      }).catch((error: BusinessError) => {
        console.error('print err ' + JSON.stringify(error));
      })
  }catch (e){
      console.error('打印失败：' + JSON.stringify(e));
    }
  }
}

拓展：下载的工具类

import { fileIo } from '@kit.CoreFileKit';
import { request } from '@kit.BasicServicesKit';


/**
 * 将网络图片下载到沙箱
 * @param url 当前应用上下文
 * @param originalFileName 文件名（不含扩展名）
 * @returns 下载任务、唯一文件名、后缀
 */

interface DownloadTask {
  task: request.DownloadTask;
  uniqueNameWithoutExt: string;
  ext?: string;
}

// 下载文件并生成唯一文件路径，返回下载任务和唯一文件名（不含后缀）
export async function downloadFileWithUniqueName(
  url: string,
  originalFileName: string
): Promise<DownloadTask> {
  // 获取上下文和文件目录
  const context = getContext();
  const filesDir = context.filesDir;

  // 分离文件名和扩展名
  const extIndex = originalFileName.lastIndexOf('.');
  const nameWithoutExt = extIndex > 0 ? originalFileName.substring(0, extIndex) : originalFileName;
  const ext = extIndex > 0 ? originalFileName.substring(extIndex) : '';

  let newName = originalFileName;
  let counter = 1;

  // 尝试生成唯一的文件名
  while (fileIo.accessSync(`${filesDir}/${newName}`)) {
    newName = `${nameWithoutExt}(${counter})${ext}`;
    counter++;
  }

  const uniqueFilePath = `${filesDir}/${newName}`;
  const uniqueNameWithoutExt = newName.substring(0, newName.lastIndexOf('.')) || newName;

  // 下载配置
  const downFileConfig: request.DownloadConfig = {
    url: url,
    filePath: uniqueFilePath,
    background: true,
  };

  // 执行下载
  const task = await request.downloadFile(context, downFileConfig);

  return { task: task, uniqueNameWithoutExt:uniqueNameWithoutExt, ext:ext.slice(1) };
}