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Posted on Jun 29

PreviewUtil, file preview tool class

#harmony #harmonyos #arkts

Introduction and description of harmony-utils

harmony-utils A HarmonyOS tool library with rich features and extremely easy to use, with the help of many practical tools, is committed to helping developers quickly build Hongmeng applications. Its encapsulated tools cover APP, device, screen, authorization, notification, inter-thread communication, pop-up frames, toast, biometric authentication, user preferences, taking photos, albums, scanning codes, files, logs, exception capture, characters, strings, numbers, collections, dates, random, base64, encryption, decryption, JSON and other functions, which can meet various development needs.

picker_utils It is a sub-store split by harmony-utils, including PickerUtil, PhotoHelper, and ScanUtil.

Download and install

ohpm i @pura/harmony-utils

ohpm i @pura/picker_utils

  //Global initialization method, initialized in the onCreate method of UIAbility AppUtil.init()
  onCreate(want: Want, launchParam: AbilityConstant.LaunchParam): void {
    AppUtil.init(this.context);
  }

API methods and usage

generatePreviewInfo build PreviewInfo based on file uri

 let docPath = FileUtil.getFilesDirPath("download/wps/doc', "测试DOC文件.doc");
 FileUtil.writeEasy(docPath, "harmony-utils 一款高效的OpenHarmony/HarmonyOS工具包。帮助开发者快速构建鸿蒙应用。");
 let uri = FileUtil.getUriFromPath(docPath);
 let info = PreviewUtil.generatePreviewInfo(uri);
 let infoStr = JSON.stringify(info, null, 2);
 LogUtil.error(infoStr);

openPreview opens the preview window by passing in file preview information. Repeated calls within 1 second are invalid

 let docPath = FileUtil.getFilesDirPath("download/wps/doc', "测试DOC文件.doc");
 let uri = FileUtil.getUriFromPath(docPath);
 let info = PreviewUtil.generatePreviewInfo(uri);
 PreviewUtil.openPreview(info).catch((error: BusinessError) => {
  LogUtil.error(`onSharePreview-异常 ~ code: ${error.code} -·- message: ${error.message}`);
 });

openPreviewEasy opens the preview window through the uri of the file. Repeated calls within 1 second are invalid

 let docPath = FileUtil.getFilesDirPath("download/wps/doc', "测试DOC文件.doc");
 let uri = FileUtil.getUriFromPath(docPath);
 PreviewUtil.openPreviewEasy(uri);

canPreview determines whether the file can be previewed based on the uri of the file

 let docPath = FileUtil.getFilesDirPath("download/wps/doc', "测试DOC文件.doc");
 let uri = FileUtil.getUriFromPath(docPath);
 let canPreview = await PreviewUtil.canPreview(uri);
 ToastUtil.showToast(`canPreview: ${canPreview}`);

hasDisplayed determines whether the preview window already exists

 let hasDisplayed = await PreviewUtil.hasDisplayed();
 ToastUtil.showToast(`hasDisplayed: ${hasDisplayed}`);

closePreview Closes the preview window, only effective if the preview window exists

PreviewUtil.closePreview().then(() => {
  ToastUtil.showToast("已关闭预览");
});

loadData Loads preview file information. Only effective if the preview window exists

let docPath = FileUtil.getFilesDirPath("download/wps/doc', "测试DOC文件.doc");
let uri = FileUtil.getUriFromPath(docPath);
let info = PreviewUtil.generatePreviewInfo(uri);
let hasDisplayed = await PreviewUtil.hasDisplayed();
if (hasDisplayed) {
  PreviewUtil.loadData(info);
} else {
  PreviewUtil.openPreview(info);
}

loadDataEasy Loads preview file information. Only effective if the preview window exists

let docPath = FileUtil.getFilesDirPath("download/wps/doc', "测试DOC文件.doc");
let uri = FileUtil.getUriFromPath(docPath);
let hasDisplayed = await PreviewUtil.hasDisplayed();
if (hasDisplayed) {
  PreviewUtil.loadDataEasy(uri);
} else {
  PreviewUtil.openPreviewEasy(uri);
}

onSharePreview Calls other application preview files

let docPath = FileUtil.getFilesDirPath("download/wps/doc', "测试DOC文件.doc");
let uri = FileUtil.getUriFromPath(docPath);
PreviewUtil.onSharePreview(uri).catch((error: BusinessError) => {
  ToastUtil.showToast("打开文件失败，" + error.message);
  LogUtil.error(`onSharePreview-异常 ~ code: ${error.code} -·- message: ${error.message}`);
});

getTypeDescriptor Get TypeDescriptor (a description class for standardized data type)

let typeDescriptor = PreviewUtil.getTypeDescriptor("png");
ToastUtil.showToast(`${typeDescriptor.mimeTypes}`);

getMimeType Get file mimeType according to file suffix name

let mimeType = PreviewUtil.getMimeType("png");
let mimeType2 = PreviewUtil.getMimeType("txt");
ToastUtil.showToast(`${mimeType} --- ${mimeType2}`);

getIconFileStr Get the icon of the corresponding file type according to the file suffix name

let iconFileStr = PreviewUtil.getIconFileStr("doc");
let iconRes: Resource = $r(iconFileStr);

canIUsePreview determines whether the current device supports file preview capabilities

 let bl = PreviewUtil.canIUsePreview();
 ToastUtil.showToast(`当前设备是否支持文件预览能力:${bl}`);

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