鸿蒙跳转到图库或者文件选择图片并显示到Image控件中

今天有个坛友问跳转到文件和图库如何将选择的图片读取出来在Image控件中显示，我这里分享一下解决思路。

首先当然是建个布局页面，页面上放个按钮和图片控件，如下代码

<?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">

    <Button
        ohos:id="$+id:btnChooseImg"
        ohos:height="match_content"
        ohos:width="match_content"
        ohos:text="选择图片"
        ohos:text_size="40vp"
        ohos:background_element="gray"></Button>
    <Image
        ohos:id="$+id:showChooseImg"
        ohos:height="match_content"
        ohos:width="match_content"
        ></Image>

</DirectionalLayout>

然后看一下后台代码，后代主要用到DataAbility去访问图片，访问图片我们需要申请ohos.permission.READ_USER_STORAGE权限，代码如下

package com.example.phonetest.slice;

import com.example.phonetest.ResourceTable;
import ohos.aafwk.ability.AbilitySlice;
import ohos.aafwk.ability.DataAbilityHelper;
import ohos.aafwk.content.Intent;
import ohos.aafwk.content.Operation;
import ohos.agp.components.Button;
import ohos.agp.components.Image;
import ohos.hiviewdfx.HiLog;
import ohos.hiviewdfx.HiLogLabel;
import ohos.media.image.ImageSource;
import ohos.media.image.PixelMap;
import ohos.media.photokit.metadata.AVStorage;
import ohos.utils.net.Uri;

import java.io.File;
import java.io.FileDescriptor;

public class ChooseImageTestSlice extends AbilitySlice {
    static final HiLogLabel label = new HiLogLabel(HiLog.LOG_APP, 0x0001, "选择图片测试");
    private final int imgRequestCode=1123;
    Image showChooseImg=null;
    @Override
    public void onStart(Intent intent) {
        super.onStart(intent);
        super.setUIContent(ResourceTable.Layout_ability_choose_image_test);
        //获取存储权限
        requestPermissionsFromUser(new String[]{"ohos.permission.READ_USER_STORAGE"},imgRequestCode);
        Button btnChooseImg=(Button)findComponentById(ResourceTable.Id_btnChooseImg);
        btnChooseImg.setClickedListener(c->{
            //选择图片
            selectPic();
        });
        showChooseImg=(Image)findComponentById(ResourceTable.Id_showChooseImg);
    }
    private void selectPic() {
        Intent intent = new Intent();
        Operation opt=new Intent.OperationBuilder().withAction("android.intent.action.GET_CONTENT").build();
        intent.setOperation(opt);
        intent.addFlags(Intent.FLAG_NOT_OHOS_COMPONENT);
        intent.setType("image/*");
        startAbilityForResult(intent, imgRequestCode);
    }
    @Override
    protected void onAbilityResult(int requestCode, int resultCode, Intent resultData) {
        if(requestCode==imgRequestCode)
        {
            HiLog.info(label,"选择图片getUriString:"+resultData.getUriString());
            //选择的Img对应的Uri
            String chooseImgUri=resultData.getUriString();
            HiLog.info(label,"选择图片getScheme:"+chooseImgUri.substring(chooseImgUri.lastIndexOf('/')));

            //定义数据能力帮助对象
            DataAbilityHelper helper=DataAbilityHelper.creator(getContext());
            //定义图片来源对象
            ImageSource imageSource = null;
            //获取选择的Img对应的Id
            String chooseImgId=null;
            //如果是选择文件则getUriString结果为content://com.android.providers.media.documents/document/image%3A30，其中%3A是":"的URL编码结果，后面的数字就是image对应的Id
            //如果选择的是图库则getUriString结果为content://media/external/images/media/30，最后就是image对应的Id
            //这里需要判断是选择了文件还是图库
            if(chooseImgUri.lastIndexOf("%3A")!=-1){
                chooseImgId = chooseImgUri.substring(chooseImgUri.lastIndexOf("%3A")+3);
            }
            else {
                chooseImgId = chooseImgUri.substring(chooseImgUri.lastIndexOf('/')+1);
            }
            //获取图片对应的uri，由于获取到的前缀是content，我们替换成对应的dataability前缀
            Uri uri=Uri.appendEncodedPathToUri(AVStorage.Images.Media.EXTERNAL_DATA_ABILITY_URI,chooseImgId);
            HiLog.info(label,"选择图片dataability路径:"+uri.toString());
            try {
                //读取图片
                FileDescriptor fd = helper.openFile(uri, "r");
                imageSource = ImageSource.create(fd, null);
                //创建位图
                PixelMap pixelMap = imageSource.createPixelmap(null);
                //设置图片控件对应的位图
                showChooseImg.setPixelMap(pixelMap);
            } catch (Exception e) {
                e.printStackTrace();
            } finally {
                if (imageSource != null) {
                    imageSource.release();
                }
            }
        }
    }

    @Override
    public void onActive() {
        super.onActive();
    }

    @Override
    public void onForeground(Intent intent) {
        super.onForeground(intent);
    }
}

这里要注意下在弹出的选择有让我们选择图库还是文件，这两种方式处理方式不一样，判断一下就可以了，代码中已经注释。

我看一下运行结果