【Harmony OS】【JAVA UI】AVMetadataHelper 基本使用

 准备阶段

参考资料媒体元数据获取开发指导

准备一个视频文件，放在resources/base/rawfile/文件目录下（如下图所示）

权限

申请读写权限（ohos.permission.WRITE_USER_STORAGE，ohos.permission.READ_USER_STORAGE）在config.json（代码和图片如下所示）

 "reqPermissions": [      {"name": "ohos.permission.READ_USER_STORAGE"},      {"name": "ohos.permission.WRITE_USER_STORAGE"},    ],

在mainAbility的onstart申请动态权限，代码如下所示

package com.harmony.alliance.mydemo;import com.harmony.alliance.mydemo.slice.*;import ohos.aafwk.ability.Ability;import ohos.aafwk.content.Intent;public class MainAbility extends Ability {    @Override    public void onStart(Intent intent) { String[] permissions = {  "ohos.permission.WRITE_USER_STORAGE",  "ohos.permission.READ_USER_STORAGE" }; requestPermissionsFromUser(permissions, 0); super.onStart(intent); super.setMainRoute(AVMetadataHelperAbilitySlice.class.getName());    }}

代码实现

在resources/base/layout写av_metadata_helper.xml文件,代码如下

效果图如下所示

java代码

package com.harmony.alliance.mydemo.slice;import com.harmony.alliance.mydemo.ResourceTable;import com.harmony.alliance.mydemo.utils.HiLogUtils;import ohos.aafwk.ability.AbilitySlice;import ohos.aafwk.content.Intent;import ohos.agp.components.Component;import ohos.agp.components.Image;import ohos.global.resource.RawFileEntry;import ohos.global.resource.Resource;import ohos.media.image.PixelMap;import ohos.media.photokit.metadata.AVMetadataHelper;import java.io.File;import java.io.FileOutputStream;import java.io.IOException;public class AVMetadataHelperAbilitySlice  extends AbilitySlice {    @Override    protected void onStart(Intent intent) { super.onStart(intent); setUIContent(ResourceTable.Layout_av_metadata_helper); findComponentById(ResourceTable.Id_wite).setClickedListener(new Component.ClickedListener() {     @Override     public void onClick(Component component) {  writeToDisk();     } }); findComponentById(ResourceTable.Id_read).setClickedListener(new Component.ClickedListener() {     @Override     public void onClick(Component component) {  AVMetadataHelper avMetadataHelper = new AVMetadataHelper ();  String externalFilePath = getFilesDir() + "/video_resuorce.mp4";  avMetadataHelper.setSource(externalFilePath);  PixelMap pixelMap = avMetadataHelper.fetchVideoPixelMapByTime(0);  Image miv= (Image) findComponentById(ResourceTable.Id_mIvLogo);  miv.setPixelMap(pixelMap);  avMetadataHelper.release();     } });    }    private void writeToDisk() { String rawFilePath = "entry/resources/rawfile/video_resuorce.mp4"; String externalFilePath = getFilesDir() + "/video_resuorce.mp4"; File file = new File(externalFilePath); if (file.exists()) {     return; } RawFileEntry rawFileEntry = getResourceManager().getRawFileEntry(rawFilePath); try (FileOutputStream outputStream = new FileOutputStream(new File(externalFilePath))) {     Resource resource = rawFileEntry.openRawFile();     // cache length     byte[] cache = new byte[1024];     int len = resource.read(cache);     while (len != -1) {  outputStream.write(cache, 0, len);  len = resource.read(cache);     }     HiLogUtils.PrintLog("写入成功"+externalFilePath); } catch (IOException exception) {     HiLogUtils.PrintLog(exception.getMessage()); }    }}

运行效果

 欲了解更多更全技术文章，欢迎访问https://developer.huawei.com/consumer/cn/forum/?ha_source=zzh