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

准备阶段

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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）

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权限

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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"},

    ],

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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

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

<?xml version="1.0" encoding="utf-8"?>
<DirectionalLayout
    xmlns:ohos="http://schemas.huawei.com/res/ohos"
    ohos:height="match_parent"
    ohos:width="match_parent"
    ohos:orientation="vertical">
    <Text
        ohos:height="200fp"
        ohos:width="match_parent"
        ohos:text="写入"
        ohos:text_color="#ed6262"
        ohos:text_size="20fp"
        ohos:id="$+id:wite"
        ohos:text_alignment="center"
        ohos:background_element="#80ffffff"/>

    <Text
        ohos:height="200fp"
        ohos:width="match_parent"
        ohos:text="读取"
        ohos:text_color="#ffffff"
        ohos:text_size="20fp"
        ohos:id="$+id:read"
        ohos:text_alignment="center"
        ohos:background_element="#ed6262"/>


    <Image
        ohos:scale_mode="clip_center"
        ohos:image_src="#ed6200"
        ohos:height="400fp"
        ohos:width="400fp"
        ohos:id="$+id:mIvLogo"/>

</DirectionalLayout>

效果图如下所示

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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

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