【HarmonyOS】 鸿蒙保存图片或视频到相册
前言
鸿蒙中保存图片或者视频，或者其他媒体文件到设备的媒体库，可以是相册，也可以是文件管理等。共有两种方式：
需要应用申请受限权限，获取文件读写的权限（调用需要ohos.permission.READ_IMAGEVIDEO和ohos.permission.WRITE_IMAGEVIDEO的权限），这样就可以将媒体资源（图片or视频or等等）保存到媒体库。
通过安全控件，用户触发后表示同意，可以临时授权给应用就行保存处理。
关于第二种安全控件，又分为saveButton保存按钮 和showAssetsCreationDialog授权弹框两种形式。前者的按钮样式不能自定义，所以后者以弹框的形式，让用户操作，触发入口的样式，应用就可以自定义了。后者算是前者的一种替代补充。
一、保存图片和视频授权示例
需要申请"ohos.permission.READ_IMAGEVIDEO"和"ohos.permission.WRITE_IMAGEVIDEO"权限。该权限是管制权限，需要你的应用去通过场景申请【申请使用受限权限】
配置权限READ_IMAGEVIDEO，WRITE_IMAGEVIDEO
dart
复制代码
"requestPermissions": [
{
"name": "ohos.permission.READ_IMAGEVIDEO",
"usedScene": {
"abilities": [
"EntryAbility"
],
"when": "inuse"
},
"reason": "$string:CAMERA"
},
{
"name": "ohos.permission.WRITE_IMAGEVIDEO",
"usedScene": {
"abilities": [
"EntryAbility"
],
"when": "inuse"
},
"reason": "$string:CAMERA"
}
]
向用户申请权限
dart
复制代码
// 创建申请权限明细
async reqPermissionsFromUser(): Promise
let context = getContext() as common.UIAbilityContext;
let atManager = abilityAccessCtrl.createAtManager();
let grantStatus = await atManager.requestPermissionsFromUser(context, ['ohos.permission.READ_IMAGEVIDEO','ohos.permission.WRITE_IMAGEVIDEO']);
return grantStatus.authResults;
}
// 用户申请权限
async requestPermission() {
let grantStatus = await this.reqPermissionsFromUser();
for (let i = 0; i < grantStatus.length; i++) {
if (grantStatus[i] === 0) {
// 用户授权，可以继续访问目标操作
}
}
}
保存图片到媒体库
dart
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public async savePicture(buffer: ArrayBuffer): Promise
let helper : photoAccessHelper.PhotoAccessHelper = photoAccessHelper.getPhotoAccessHelper(getContext(this) as common.UIAbilityContext);
let options: photoAccessHelper.CreateOptions = {
title: Date.now().toString()
};
let photoUri: string = await helper.createAsset(photoAccessHelper.PhotoType.IMAGE, 'jpg', options);
console.info(photoUri)
// createAsset的调用需要ohos.permission.READ_IMAGEVIDEO和ohos.permission.WRITE_IMAGEVIDEO的权限
let file: fs.File = fs.openSync(photoUri, fs.OpenMode.READ_WRITE | fs.OpenMode.CREATE);
await fs.write(file.fd, buffer);
fs.closeSync(file);
}
二、saveButton示例
dart
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import { photoAccessHelper } from '@kit.MediaLibraryKit';
@Entry
@Component
struct saveButtonExample {
saveButtonOptions: SaveButtonOptions = {
icon: SaveIconStyle.FULL_FILLED,
text: SaveDescription.SAVE_IMAGE,
buttonType: ButtonType.Capsule
} // 设置安全控件按钮属性
build() {
Row() {
Column() {
SaveButton(this.saveButtonOptions) // 创建安全控件按钮
.onClick(async (event, result: SaveButtonOnClickResult) => {
if (result == SaveButtonOnClickResult.SUCCESS) {
try {
let context = getContext();
let phAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
// 需要确保fileUri对应的资源存在
let fileUri = 'file://com.example.temptest/data/storage/el2/base/haps/entry/files/test.jpg';
let assetChangeRequest: photoAccessHelper.MediaAssetChangeRequest = photoAccessHelper.MediaAssetChangeRequest.createImageAssetRequest(context, fileUri);
await phAccessHelper.applyChanges(assetChangeRequest);
console.info('createAsset successfully, uri: ' + assetChangeRequest.getAsset().uri);
} catch (err) {
console.error(`create asset failed with error: ${err.code}, ${err.message}`);
}
} else {
console.error('SaveButtonOnClickResult create asset failed');
}
})
}
.width('100%')
}
.height('100%')
}
}
三、 showAssetsCreationDialog示例
dart
复制代码
import { photoAccessHelper } from '@kit.MediaLibraryKit';
import { fileIo } from '@kit.CoreFileKit';
let context = getContext(this);
let phAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
async function showAssetsCreationDialogExample() {
try {
// 指定待保存到媒体库的位于应用沙箱的图片uri
let srcFileUri = 'file://com.example.temptest/data/storage/el2/base/haps/entry/files/test.jpg';
let srcFileUris: Array
srcFileUri
];
// 指定待保存照片的创建选项，包括文件后缀和照片类型，标题和照片子类型可选
let photoCreationConfigs: Array
{
title: 'test', // 可选
fileNameExtension: 'jpg',
photoType: photoAccessHelper.PhotoType.IMAGE,
subtype: photoAccessHelper.PhotoSubtype.DEFAULT, // 可选
}
];
// 基于弹窗授权的方式获取媒体库的目标uri
let desFileUris: Array
// 将来源于应用沙箱的照片内容写入媒体库的目标uri
let desFile: fileIo.File = await fileIo.open(desFileUris[0], fileIo.OpenMode.WRITE_ONLY);
let srcFile: fileIo.File = await fileIo.open(srcFileUri, fileIo.OpenMode.READ_ONLY);
await fileIo.copyFile(srcFile.fd, desFile.fd);
fileIo.closeSync(srcFile);
fileIo.closeSync(desFile);
console.info('create asset by dialog successfully');
} catch (err) {
console.error(`failed to create asset by dialog successfully errCode is: ${err.code}, ${err.message}`);
}
}
注意：
1. 使用createAsset需要指定是视频还是图片， fileio.open并不校验文件内容
2. 使用createImageAssetRequest接口，如果要保存视频需要用createVideoeAssetRequest
或者还可以直接使用createAssetRequest和addResource的方式