访问和管理动态照片资源
动态照片是一种结合了图片和视频的照片形式，可以显示一小段时间的动态画面和声音。可以帮助用户捕捉精彩的动态瞬间，提升创作空间，同时令拍照的容错率更高。
媒体库提供访问和管理动态照片资源的能力，包括：
拍摄动态照片的能力由Camera Kit提供，可参考动态照片拍摄(ArkTS)。
保存动态照片资源
使用安全控件保存动态照片资源后，可用于获取MovingPhoto对象，从而完成播放动态照片等操作。
使用安全控件保存动态照片资源，无需申请相册管理模块权限'ohos.permission.WRITE_IMAGEVIDEO'，允许用户通过点击按钮临时获取存储权限，并将资源直接保存到指定的媒体库路径，使得操作更为便捷。
详情请参考SaveButton。
开发步骤
-
设置安全控件按钮属性。
-
创建安全控件按钮。
-
调用MediaAssetChangeRequest.createAssetRequest接口新建一个创建资产的变更请求，指定待创建资产的子类型为动态照片。
-
调用MediaAssetChangeRequest.addResource接口指定动态照片的图片和视频内容，动态照片的视频时长不能超过10s。
以下示例以从应用沙箱的应用文件fileUri指定动态照片的图片和视频内容为例。
开发者可根据实际情况，通过ArrayBuffer的方式指定资源内容，参考MediaAssetChangeRequest.addResource(type: ResourceType, data: ArrayBuffer)。
-
调用PhotoAccessHelper.applyChanges接口提交创建资产的变更请求。
import { photoAccessHelper } from '@kit.MediaLibraryKit';
import { common } from '@kit.AbilityKit';
// ...
@Entry({ routeName : 'Scene1' })
@Component
export struct Scene1 {
@State statusMessage: string = '';
@State imageSource: string = '';
saveButtonOptions: SaveButtonOptions = {
icon: SaveIconStyle.FULL_FILLED,
text: SaveDescription.SAVE_IMAGE,
buttonType: ButtonType.Capsule
}// Set properties of SaveButton.
// ...
build() {
NavDestination() {
Column({ space: 20 }) {
// ...
SaveButton(this.saveButtonOptions) // Create a button with SaveButton.
.onClick(async (event, result: SaveButtonOnClickResult) => {
if (result == SaveButtonOnClickResult.SUCCESS) {
try {
let context: Context = this.getUIContext().getHostContext() as common.UIAbilityContext;
let phAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
// Ensure that the assets specified by imageFileUri and videoFileUri exist.
let imageFileUri = 'file://' + context.filesDir + '/create_moving_photo.jpg';
let videoFileUri = 'file://' + context.filesDir + '/create_moving_photo.mp4';
let assetChangeRequest: photoAccessHelper.MediaAssetChangeRequest =
photoAccessHelper.MediaAssetChangeRequest.createAssetRequest(context,
photoAccessHelper.PhotoType.IMAGE, 'jpg', {
title: 'moving_photo',
subtype: photoAccessHelper.PhotoSubtype.MOVING_PHOTO
});
assetChangeRequest.addResource(photoAccessHelper.ResourceType.IMAGE_RESOURCE, imageFileUri);
assetChangeRequest.addResource(photoAccessHelper.ResourceType.VIDEO_RESOURCE, videoFileUri);
await phAccessHelper.applyChanges(assetChangeRequest);
this.statusMessage = 'create moving photo successfully, uri: ' + assetChangeRequest.getAsset().uri;
console.info('create moving photo successfully, uri: ' + assetChangeRequest.getAsset().uri);
} catch (err) {
this.statusMessage = `create moving photo failed with error: ${err.code}, ${err.message}`;
console.error(`create moving photo failed with error: ${err.code}, ${err.message}`);
}
} else {
this.statusMessage = 'SaveButtonOnClickResult create moving photo failed';
console.error('SaveButtonOnClickResult create moving photo failed');
}
})
// ...
}
.width('100%')
.height('100%')
}
.title('Save Moving Photo')
}
}
获取动态照片对象
-
应用可以通过Picker的方式获取用户媒体库里的动态照片对象，后续可用于在应用内播放动态照片，或是读取动态照片资源进行其他操作（如上传到应用共享给他人浏览等）。
-
应用也可以通过传入应用沙箱的应用文件图片和视频fileUri的方式构造应用本地的动态照片对象。
获取到动态照片对象后，如需播放动态照片请参考使用MovingPhotoView播放动态照片。
获取媒体库动态照片对象
- 通过Picker选择动态照片的媒体文件URI。
- 调用PhotoAccessHelper.getAssets和FetchResult.getFirstObject接口获取URI对应的PhotoAsset资产。
- 调用MediaAssetManager.requestMovingPhoto获取PhotoAsset对应的动态照片对象（MovingPhoto）。
import { photoAccessHelper } from '@kit.MediaLibraryKit';
import { dataSharePredicates } from '@kit.ArkData';
import { common } from '@kit.AbilityKit';
@Entry({ routeName : 'Scene2' })
@Component
export struct Scene2 {
@State statusMessage: string = '';
build() {
NavDestination() {
Column({ space: 20 }) {
Button('example')
.width('80%')
.height(50)
.fontSize(16)
.onClick(async () => {
let context: Context = this.getUIContext().getHostContext() as common.UIAbilityContext;
let phAccessHelper = photoAccessHelper.getPhotoAccessHelper(context);
this.statusMessage = await example(phAccessHelper, context);
})
// ...
}
.width('100%')
.height('100%')
}
.title('Get from Media Library')
}
}
async function example(phAccessHelper: photoAccessHelper.PhotoAccessHelper, context: Context): Promise<string> {
try {
// Use Picker to select the URI of the moving photo.
let photoSelectOptions = new photoAccessHelper.PhotoSelectOptions();
photoSelectOptions.MIMEType = photoAccessHelper.PhotoViewMIMETypes.MOVING_PHOTO_IMAGE_TYPE;
photoSelectOptions.maxSelectNumber = 9;
let photoViewPicker = new photoAccessHelper.PhotoViewPicker();
let photoSelectResult = await photoViewPicker.select(photoSelectOptions);
let uris = photoSelectResult.photoUris;
let resultMessage = 'Selected ' + uris.length + ' moving photo(s)\n\n';
for (let i = 0; i < uris.length; i++) {
// Obtain the photo asset corresponding to the URI.
let predicates: dataSharePredicates.DataSharePredicates = new dataSharePredicates.DataSharePredicates();
predicates.equalTo(photoAccessHelper.PhotoKeys.URI, uris[i]);
let fetchOption: photoAccessHelper.FetchOptions = {
fetchColumns: [],
predicates: predicates
};
let fetchResult: photoAccessHelper.FetchResult<photoAccessHelper.PhotoAsset> =
await phAccessHelper.getAssets(fetchOption);
let photoAsset: photoAccessHelper.PhotoAsset = await fetchResult.getFirstObject();
let movingPhotoUri = await new Promise<string>((resolve) => {
// Obtain the moving photo object corresponding to the photo asset.
photoAccessHelper.MediaAssetManager.requestMovingPhoto(context, photoAsset, {
deliveryMode: photoAccessHelper.DeliveryMode.FAST_MODE
}, {
async onDataPrepared(movingPhoto: photoAccessHelper.MovingPhoto) {
if (movingPhoto !== undefined) {
// Customize the logic for processing the moving photo.
console.info('request moving photo successfully, uri: ' + movingPhoto.getUri());
resolve(movingPhoto.getUri());
}
}
})
});
resultMessage += (i + 1) + '. request moving photo successfully, uri: ' + movingPhotoUri + '\n';
}
return resultMessage;
} catch (err) {
console.error(`request moving photo failed with error: ${err.code}, ${err.message}`);
return `request moving photo failed with error: ${err.code}, ${err.message}`;
}
}
获取应用沙箱动态照片对象
调用MediaAssetManager.loadMovingPhoto加载应用沙箱的动态照片对象（MovingPhoto）。
import { photoAccessHelper } from '@kit.MediaLibraryKit';
import { common } from '@kit.AbilityKit';
// ...
@Entry({ routeName : 'Scene3' })
@Component
export struct Scene3 {
@State statusMessage: string = '';
@State imageSource: string = '';
// ...
build() {
NavDestination() {
Column({ space: 20 }) {
// ...
Button('example')
.width('80%')
.height(50)
.fontSize(16)
.onClick(async () => {
let context: Context = this.getUIContext().getHostContext() as common.UIAbilityContext;
this.statusMessage = await example(context);
})
// ...
}
.width('100%')
.height('100%')
}
.title('Load from Sandbox')
}
}
async function example(context: Context): Promise<string> {
try {
let imageFileUri = 'file://' + context.filesDir + '/local_moving_photo.jpg';
let videoFileUri = 'file://' + context.filesDir + '/local_moving_photo.mp4';
let movingPhoto = await photoAccessHelper.MediaAssetManager.loadMovingPhoto(context, imageFileUri, videoFileUri);
console.info('load moving photo successfully');
return 'load moving photo successfully';
} catch (err) {
console.error(`load moving photo failed with error: ${err.code}, ${err.message}`);
return `load moving photo failed with error: ${err.code}, ${err.message}`;
}
}
读取动态照片资源
对于一个动态照片对象，应用可以通过MovingPhoto.requestContent导出图片和视频到应用沙箱，或者读取图片或视频的ArrayBuffer内容。
import { photoAccessHelper } from '@kit.MediaLibraryKit';
import { common } from '@kit.AbilityKit';
// ...
@Entry({ routeName : 'Scene4' })
@Component
export struct Scene4 {
@State movingPhotoObj: photoAccessHelper.MovingPhoto | null = null;
@State statusMessage: string = '';
// ...
build() {
NavDestination() {
Column({ space: 20 }) {
// ...
Button('example')
.width('80%')
.height(50)
.fontSize(16)
.onClick(async () => {
if (this.movingPhotoObj) {
let context: Context = this.getUIContext().getHostContext() as common.UIAbilityContext;
this.statusMessage = await example(this.movingPhotoObj, context);
} else {
this.statusMessage = 'Please prepare and load moving photo first!';
}
})
// ...
}
.width('100%')
.height('100%')
}
// ...
}
}
async function example(movingPhoto: photoAccessHelper.MovingPhoto, context: Context): Promise<string> {
try {
let imageFileUri = context.filesDir + '/request_moving_photo.jpg';
let videoFileUri = context.filesDir + '/request_moving_photo.mp4';
await movingPhoto.requestContent(imageFileUri, videoFileUri);
let imageData = await movingPhoto.requestContent(photoAccessHelper.ResourceType.IMAGE_RESOURCE);
let videoData = await movingPhoto.requestContent(photoAccessHelper.ResourceType.VIDEO_RESOURCE);
return 'Exported to:\n' + imageFileUri + '\n' + videoFileUri + '\n\nImage data size: ' + imageData.byteLength + ' bytes\nVideo data size: ' + videoData.byteLength + ' bytes';
} catch (err) {
console.error(`request content of moving photo failed with error: ${err.code}, ${err.message}`);
return `request content of moving photo failed with error: ${err.code}, ${err.message}`;
}
}