我需要从AWS S3下载图像并更新回收者视图中的ImageViews。我正在使用ViewModel从S3下载文件。一个文件对象正在onBindViewHolder()方法内部进行观察,一旦接收到该文件,我的目的就是更新该特定所有者所拥有的图像。 但是问题是如果有两行,则需要下载两个图像。因此,每个视图持有者都将附加到观察者。在下载第一个文件之后,回收站视图内的两个图像视图都将使用第一个图像更新,而在下载第二个图像之后,两个图像都将使用第二个图像更新。我对工作有些困惑。请帮我解决一下这个。 我不能为此使用 Glide 。因为S3有身份验证。因此,我需要使用S3库下载文件。
override fun onBindViewHolder(holder: ListViewHolder, position: Int) {
val postUrl = listData[position].postUrl
val createdAt = listData[position].createdAt
val postImage = listData[position].postImage
val postVideo = listData[position].postVideo
val postVideoThumbnail = listData[position].postVideoThumbnail
val groupId = listData[position].groupId
val postStatus = listData[position].postStatus
val postId = listData[position].postId
val userId = listData[position].userId
val postHeading = listData[position].postHeading
val postDescription = listData[position].postDescription
val updatedAt = listData[position].updatedAt
val profileName = listData[position].userName
val profileImage = listData[position].profileImage
val likeCount = listData[position].likeCount
val commentCount = listData[position].commentCount
var key = ""
if(!profileImage.isNullOrEmpty()){
Glide.with(activity).load(profileImage) to holder.imgProfile
}
holder.textName.text = profileName.substring(0, 1).toUpperCase() + profileName.substring(1).toLowerCase()
holder.textPostedDateTime.text = SimpleDateFormat(POST_LIST_DATE_FORMAT).format(Date(createdAt))
holder.textPostHeading.text = postHeading
if(postDescription.isNullOrEmpty() || postDescription == "null"){
holder.textPostDescription.visibility = View.GONE
} else{
holder.textPostDescription.visibility = View.VISIBLE
holder.textPostDescription.text = postDescription
}
if(postUrl.isNullOrEmpty() || postUrl == "null"){
holder.textPostLink.visibility = View.GONE
} else{
holder.textPostLink.visibility = View.VISIBLE
holder.textPostLink.text = postUrl
}
if(postVideoThumbnail.isNullOrEmpty() || postVideoThumbnail == "null"){
holder.imgPostVideoPreview.visibility = View.GONE
} else{
holder.imgPostVideoPreview.visibility = View.VISIBLE
loadImageToFile(holder.imgPostVideoPreview, postVideoThumbnail, position)
key = postVideoThumbnail
}
if(postImage.isNullOrEmpty() || postImage == "null"){
holder.imgPostImagePreview.visibility = View.GONE
} else{
holder.imgPostImagePreview.visibility = View.VISIBLE
loadImageToFile(holder.imgPostImagePreview, postImage, position)
key = postImage
}
holder.textLikeCount.text = likeCount.toString()
holder.textCommentCount.text = commentCount.toString()
if(!isSelfPosts){
holder.layoutCommentLikeShare.visibility = View.VISIBLE
holder.imgAddComment.setOnClickListener { }
holder.imgAddLike.setOnClickListener { }
holder.imgShare.setOnClickListener { }
}
holder.itemView.setOnClickListener {
moveTOPostDetails(postId, listData[position], Environment.getExternalStorageDirectory().path + "/" + EXTERNAL_STORAGE_FOLDER_NAME + "/" + key.substring(key.lastIndexOf("/")+1))
}
}
class ListViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
val imgProfile: ImageView = itemView.imgProfile
val textName: TextView = itemView.textName
val textPostedDateTime: TextView = itemView.textPostedDateTime
val textPostHeading: TextView = itemView.textPostHeading
val textPostDescription: TextView = itemView.textPostDescription
val textPostLink: TextView = itemView.textPostLink
val imgPostVideoPreview: ImageView = itemView.imgPostVideoPreview
val imgPostImagePreview: ImageView = itemView.imgPostImagePreview
val textCommentCount: TextView = itemView.textCommentCount
val textLikeCount: TextView = itemView.textLikeCount
val layoutCommentLikeShare: LinearLayout = itemView.layoutCommentLikeShare
val imgAddComment: ImageView = itemView.imgAddComment
val imgAddLike: ImageView = itemView.imgAddLike
val imgShare: ImageView = itemView.imgShare
}
private fun moveTOPostDetails(postId: String, fetchPostsResponseModel: FetchPostsResponseModel, imageFileName: String){
val intent = Intent(activity, PostDetails::class.java)
intent.putExtra("POST_DETAILS", fetchPostsResponseModel)
intent.putExtra("IS_SELF_POST", isSelfPosts)
intent.putExtra("IMAGE_FILE_NAME", imageFileName)
activity.startActivity(intent)
}
private fun loadImageToFile(imageView: ImageView, key: String, position: Int){
var postListAdapterViewModel: PostListAdapterViewModel = ViewModelProviders.of(fragment).get(PostListAdapterViewModel::class.java)
postListAdapterViewModel.init(activity)
postListAdapterViewModel.getMediaFile()?.observe(fragment, Observer<File>{ file ->
var a=position
imageView.setImageURI(Uri.fromFile(file))
} )
postListAdapterViewModel.performDownload(key)
}
这是我的视图模型
class PostListAdapterViewModel(application: Application):AndroidViewModel(application){
private val file = MutableLiveData<File>()
private lateinit var context: Context
fun init(context: Context) {
this.context = context
AWSMobileClient.getInstance().initialize(context).execute()
}
fun performDownload(key : String){
val credentials = BasicAWSCredentials(AMAZON_S3_ACCESS_KEY, AMAZON_S3_SECRET_KEY)
val s3Client = AmazonS3Client(credentials)
val transferUtility = TransferUtility.builder()
.context(context)
.awsConfiguration(AWSMobileClient.getInstance().configuration)
.s3Client(s3Client)
.build()
val downloadObserver = transferUtility.download (
key,
File(Environment.getExternalStorageDirectory().path + "/" + EXTERNAL_STORAGE_FOLDER_NAME + "/" + key.substring(key.lastIndexOf("/")+1)))
// Attach a listener to get state updates
downloadObserver.setTransferListener(object : TransferListener {
override fun onStateChanged(id: Int, state: TransferState) {
if (state == TransferState.COMPLETED) {
// Handle a completed upload.
file.value = File(Environment.getExternalStorageDirectory().path + "/" + EXTERNAL_STORAGE_FOLDER_NAME + "/" + key.substring(key.lastIndexOf("/")+1))
}
}
override fun onProgressChanged(id: Int, current: Long, total: Long) {
try {
val done = (((current.toDouble() / total) * 100.0).toInt()) //as Int
Log.d("PostListAdapterVM", "DOWNLOAD - - ID: $id, percent done = $done")
}
catch (e: Exception) {
Log.e("PostListAdapterVM", "Trouble calculating progress percent", e)
}
}
override fun onError(id: Int, ex: Exception) {
Log.d("PostListAdapterVM", "DOWNLOAD ERROR - - ID: $id - - EX: ${ex.message.toString()}")
}
})
// If you prefer to poll for the data, instead of attaching a
// listener, check for the state and progress in the observer.
if (downloadObserver.state == TransferState.COMPLETED) {
// Handle a completed upload.
}
Log.d("PostListAdapterVM", "Bytes Transferrred: ${downloadObserver.bytesTransferred}")
}
fun getMediaFile(): MutableLiveData<File> {
return file
}
}