如何使用Glide下载图像到设备内部存储

Question

我有一个Recyclerview，它使用GLIDE显示Firebase实时数据库中的图像。在RecyClerview中，我还有一个下载按钮。当用户单击按钮时，希望将Firebase的图像下载到设备内部存储中。

适配器类

    class NatureAdapter(private val mContext: Context, private val natureList: ArrayList<Nature>) : RecyclerView.Adapter<NatureAdapter.ViewHolder>() {
    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): ViewHolder {
        val view = LayoutInflater.from(parent.context).inflate(R.layout.nature_image_view, parent, false)
        return ViewHolder(view)
    }

    override fun onBindViewHolder(holder: ViewHolder, position: Int) {
        

        Glide.with(mContext)
            .load(natureList[position].space)
            .into(holder.imageView)
    }

    override fun getItemCount(): Int {
        return natureList.size
    }

    inner class ViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        var imageView: ImageView = itemView.findViewById(R.id.NatureView)

    }

    companion object {
        private const val Tag = "RecyclerView"
    }
}

数据列表类别

   class Nature (var space: String? = null) {

}

更新

第一个错误

e: C:\Users\Khumo Kwezi Mashapa\AndroidStudioProjects\MyNotepad\app\src\main\java\com\khumomashapa\notes\fragments\NatureWallpapers.kt: (65, 17): Unresolved reference: viewModel

第二次错误

e: C:\Users\Khumo Kwezi Mashapa\AndroidStudioProjects\MyNotepad\app\src\main\java\com\khumomashapa\notes\fragments\NatureWallpapers.kt: (120, 93): No value passed for parameter 'downloadImage'

Answer 1

1. 添加OKHTTP依赖关系

首先

implementation("com.squareup.okhttp3:okhttp:4.10.0")

，您需要将OKHTTP依赖性依赖于您的应用程序gradle： 注意：如果您正在进行改造，则不需要添加Okhttp依赖关系依赖性

2. 创建下载功能

OK现在我们将添加下载逻辑在您的视图模型中，将OKHTTP实例声明和下载函数添加到您的视图模型：

注意：您可以将下载逻辑移至存储库或任何您想要的任何地方，这取决于您。

class YourViewModel : ViewModel() {

    // add okhttp instance to your view model or you inject it with hilt if your using dependency injection
    private val okHttpClient = OkHttpClient.Builder().build()

    // add this function to your view model
    fun downloadImage(imageUrl: String) {
        val request = Request.Builder()
            .url(imageUrl)
            .build()

        okHttpClient.newCall(request).enqueue(object : Callback {
            override fun onFailure(call: Call, e: IOException) {
                // Download Failed, you can show error to the user
            }

            override fun onResponse(call: Call, response: Response) {
                if (!response.isSuccessful) {
                    // Download Failed, you can show error to the user
                    return
                }

                response.body?.let { responseBody ->
                    try {
                        // Convert response body to byte array
                        val imageByteArray = responseBody.byteStream().readBytes()

                        // Split image url so we can get the image name
                        val words = imageUrl.split("/").toTypedArray()

                        // Get the image name
                        val imageName = words.last()

                        // Init pathName (Downloads Directory)
                        val pathName = "${Environment.getExternalStorageDirectory()}/${Environment.DIRECTORY_DOWNLOADS}"

                        // Create New file for the image
                        val file = File(pathName, imageName)

                        // Set byteArray To Image File
                        file.writeBytes(imageByteArray)
                    } catch(e: IOException) {
                        // Saving Image Failed, you can show error to the user
                        e.printStackTrace()
                    }
                }
            }
        })
    }

}

3. 下载函数从片段到适配器传递给

现在您需要将

val adapter = AbstractAdapter(
    context = requireContext(),
    natureList = natureList, // your list here
    downloadImage = { imageUrl ->
        viewModel.downloadImage(imageUrl)
    }
)

您的适配器，您需要将下载函数传递给lambda函数中的适配器，片段中的适配器创建应该看起来像：您的适配器构造函数看起来像这样：

class AbstractAdapter(
    private val mContext: Context, 
    private val natureList: ArrayList<Nature>,
    private val downloadImage: (imageUrl: String) -> Unit
): RecyclerView.Adapter<AbstractAdapter.ViewHolder>()

4. call downloctimage lambda lambda inslow downloctbtn inslow downloctbtn单击侦听器

现在，我们将在单击“侦听器”中添加下载图像

holder.downloadBtn.setOnClickListener {
    val imageUrl = natureList[position].space
    imageUrl?.let {
        downloadImage(it)
    }
}

5. 调用添加写入外部存储权限到androidmanifest.xml

将此许可添加到您的androidmanifest.xml文件中，以便能够将文件添加到电话存储

<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE"
        android:maxSdkVersion="28" />

注意：此权限此权限仅限SQK版本＆lt; = 28这就是为什么我们添加了android：maxSdkversion =“ 28”

我希望一切都清楚。
此代码应该给您想要的结果，请尝试一下，并告诉我是否有任何错误。

Answer 2

您也可以使用下载经理Bruv。只需创建一个OnItemClick界面，只需在主片段或类中实现此功能即可。

override fun onItemClick(item: String, pos:Int) {
    abstractData = item
    positionItem = pos

    if (checkSelfPermission(requireActivity(), Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED ){
       requestPermissions(arrayOf(Manifest.permission.WRITE_EXTERNAL_STORAGE), REQ_CODE)

    }else{

    startDownloading()
    }

    Toast.makeText(requireActivity(), "Saved to Internal storage/Pictures/AbstractWallpaper", Toast.LENGTH_LONG).show()

}

private fun startDownloading() {

    val request = DownloadManager.Request(Uri.parse(abstractData))
    request.setAllowedNetworkTypes(DownloadManager.Request.NETWORK_WIFI or DownloadManager.Request.NETWORK_MOBILE)
    request.setTitle("Abstract Wallpaper")
    request.setDescription("Your image is downloading")
    request.allowScanningByMediaScanner()
    request.setNotificationVisibility(DownloadManager.Request.VISIBILITY_VISIBLE_NOTIFY_COMPLETED)
    request.setDestinationInExternalPublicDir(Environment.DIRECTORY_PICTURES, "AbstractWallpapers")
    val manager = activity?.getSystemService(Context.DOWNLOAD_SERVICE) as DownloadManager
    manager.enqueue(request)

    Toast.makeText(requireActivity(), "Download is starting...", Toast.LENGTH_LONG).show()
}