Android Kotlin中Firebase Storage视频仅显URL无法播放求助

问题描述 #

开发一款时间胶囊类App，支持存储文本、图片和视频，内容仅在指定时间展示。目前文本和图片功能正常，但视频消息仅显示URL而非实际播放。已尝试使用VideoView等方法，问题仍未解决，需要实现Android Kotlin中流式播放Firebase Storage视频的功能。

现有Adapter代码 #

import android.net.Uri
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.TextView
import androidx.recyclerview.widget.RecyclerView
import com.example.timescape.Messages
import com.example.timescape.R
import com.google.android.exoplayer2.ExoPlayer
import com.google.android.exoplayer2.MediaItem
import com.google.android.exoplayer2.ui.PlayerView
import com.squareup.picasso.Picasso
import java.text.SimpleDateFormat
import java.util.*

class MessageAdapter(private val messages: List<Messages>) : RecyclerView.Adapter<RecyclerView.ViewHolder>() {

    private val TYPE_TEXT = 0
    private val TYPE_IMAGE = 1
    private val TYPE_VIDEO = 2

    override fun getItemViewType(position: Int): Int {
        val message = messages[position]
        return when {
            message.mediaUrls.isNotEmpty() && message.mediaUrls[0].endsWith(".mp4") -> TYPE_VIDEO
            message.mediaUrls.isNotEmpty() -> TYPE_IMAGE
            else -> TYPE_TEXT
        }
    }

    override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): RecyclerView.ViewHolder {
        return when (viewType) {
            TYPE_IMAGE -> {
                val view = LayoutInflater.from(parent.context).inflate(R.layout.item_imgmsg, parent, false)
                ImageViewHolder(view)
            }
            TYPE_VIDEO -> {
                val view = LayoutInflater.from(parent.context).inflate(R.layout.item_vidmsg, parent, false)
                VideoViewHolder(view)
            }
            else -> {
                val view = LayoutInflater.from(parent.context).inflate(R.layout.item_textmsg, parent, false)
                TextViewHolder(view)
            }
        }
    }

    override fun onBindViewHolder(holder: RecyclerView.ViewHolder, position: Int) {
        val message = messages[position]
        val displayDateTime = Date(message.openDateTime)
        val currentDateTime = Date()

        if (currentDateTime.after(displayDateTime)) {
            when (holder) {
                is ImageViewHolder -> {
                    Picasso.get().load(message.mediaUrls[0]).into(holder.imageView)
                    holder.dateTimeView.text = SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault()).format(Date(message.storedDateTime))
                }
                is VideoViewHolder -> {
                    holder.bind(message.mediaUrls[0])
                    holder.dateTimeView.text = SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault()).format(Date(message.storedDateTime))
                }
                is TextViewHolder -> {
                    holder.textView.text = message.content
                    holder.dateTimeView.text = SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault()).format(Date(message.storedDateTime))
                }
            }
        } else {
            val futureMessageText = "This message will be displayed on ${SimpleDateFormat("yyyy-MM-dd HH:mm:ss", Locale.getDefault()).format(displayDateTime)}"
            when (holder) {
                is ImageViewHolder -> {
                    holder.imageView.setImageResource(R.drawable.baseline_image_24)
                    holder.dateTimeView.text = futureMessageText
                }
                is VideoViewHolder -> {
                    holder.itemView.setBackgroundResource(R.drawable.baseline_videocam_24)
                    holder.dateTimeView.text = futureMessageText
                }
                is TextViewHolder -> {
                    holder.textView.text = futureMessageText
                }
            }
        }
    }

    override fun getItemCount() = messages.size

    class ImageViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val imageView: ImageView = itemView.findViewById(R.id.message_image)
        val dateTimeView: TextView = itemView.findViewById(R.id.message_date_time)
    }

    class VideoViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        private val playerView: PlayerView = itemView.findViewById(R.id.player_view)
        val dateTimeView: TextView = itemView.findViewById(R.id.message_date_time)
        private var exoPlayer: ExoPlayer? = null

        fun bind(videoUrl: String) {
            if (exoPlayer == null) {
                exoPlayer = ExoPlayer.Builder(itemView.context).build()
                playerView.player = exoPlayer
            }

            val mediaItem = MediaItem.fromUri(Uri.parse(videoUrl))
            exoPlayer?.setMediaItem(mediaItem)
            exoPlayer?.prepare()
            exoPlayer?.playWhenReady = true
        }

        fun releasePlayer() {
            exoPlayer?.release()
            exoPlayer = null
        }
    }

    class TextViewHolder(itemView: View) : RecyclerView.ViewHolder(itemView) {
        val textView: TextView = itemView.findViewById(R.id.message_text)
        val dateTimeView: TextView = itemView.findViewById(R.id.message_date_time)
    }

    override fun onViewRecycled(holder: RecyclerView.ViewHolder) {
        if (holder is VideoViewHolder) {
            holder.releasePlayer()
        }
        super.onViewRecycled(holder)
    }
}

数据类代码 #

package com.example.timescape

data class Messages(
    val id: String="",
    val content: String="",
    val openDateTime: Long=0L,
    val mediaUrls: List<String> = listOf(),
    var isRead: Boolean = false,
    var type: String = "text",
    val storedDateTime: Long = 0L
)

解决方案 #

1. 确认Firebase Storage视频URL有效性 #

Firebase Storage的存储路径（如gs://bucket-name/path/video.mp4）无法直接用于播放，必须获取临时HTTPS下载URL：

val storageRef = FirebaseStorage.getInstance().getReferenceFromUrl("gs://your-bucket-name/video-path.mp4")
storageRef.downloadUrl.addOnSuccessListener { uri ->
    val validDownloadUrl = uri.toString()
    // 将此URL存入Messages的mediaUrls字段
}

检查当前mediaUrls中的值是否为有效的HTTPS URL，而非存储路径或相对路径。

2. 修复VideoViewHolder绑定逻辑 #

优化播放器复用逻辑，避免状态残留：

fun bind(videoUrl: String) {
    if (exoPlayer == null) {
        exoPlayer = ExoPlayer.Builder(itemView.context).build()
        playerView.player = exoPlayer
    } else {
        exoPlayer?.stop()
        exoPlayer?.clearMediaItems()
    }

    val mediaItem = MediaItem.fromUri(Uri.parse(videoUrl))
    exoPlayer?.addMediaItem(mediaItem)
    exoPlayer?.prepare()
    exoPlayer?.playWhenReady = true
}

3. 检查视频项布局文件 #

确保item_vidmsg.xml中PlayerView布局正确，无遮挡且宽高合理：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:orientation="vertical"
    android:padding="8dp">

    <com.google.android.exoplayer2.ui.PlayerView
        android:id="@+id/player_view"
        android:layout_width="match_parent"
        android:layout_height="200dp" />

    <TextView
        android:id="@+id/message_date_time"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="8dp"
        android:textSize="12sp" />
</LinearLayout>

确认布局中没有额外显示URL的TextView组件。

4. 添加必要权限 #

在AndroidManifest.xml中添加网络权限：

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" /> <!-- 可选，用于检测网络状态 -->

5. 优化未到展示时间的处理逻辑 #

在onBindViewHolder的else分支中，确保释放播放器并清除状态：

is VideoViewHolder -> {
    holder.releasePlayer()
    holder.playerView.setDefaultArtwork(null)
    holder.itemView.setBackgroundResource(R.drawable.baseline_videocam_24)
    holder.dateTimeView.text = futureMessageText
}

内容的提问来源于stack exchange，提问作者Muskan Bandri