【发布时间】:2019-11-18 22:10:54
【问题描述】:
我在自己的片段中而不是在活动中实现了 YouTubePlayerSupportFragment API。视频确实可以正常播放,但是当用户从 YouTube 提供的媒体控件中选择全屏观看视频时,应用程序会转向横向,显示黑色加载屏幕,然后立即崩溃。
ExpandedItem.layout
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical">
<LinearLayout
android:id="@+id/youtube_layout_container"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:visibility="gone"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@id/close_button">
<fragment
android:id="@+id/youtube_player_fragment"
android:name="com.google.android.youtube.player.YouTubePlayerSupportFragment"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginStart="10dp"
android:layout_marginEnd="10dp"
android:layout_marginTop="15dp"/>
</LinearLayout>
</androidx.constraintlayout.widget.ConstraintLayout>
ExpandedItemFragment.kt
import android.os.Bundle
import android.text.SpannableString
import android.text.style.BulletSpan
import android.view.LayoutInflater
import android.view.View
import android.view.ViewGroup
import android.widget.ImageView
import android.widget.LinearLayout
import android.widget.TextView
import android.widget.Toast
import androidx.fragment.app.Fragment
import com.google.android.youtube.player.YouTubeInitializationResult
import com.google.android.youtube.player.YouTubePlayer
import com.google.android.youtube.player.YouTubePlayerSupportFragment
class ExpandedItemFragment(private val hasVideo: Boolean) : Fragment(), YouTubePlayer.OnInitializedListener {
private lateinit var mosquitoVideo: YouTubePlayerSupportFragment
override fun onCreateView(
inflater: LayoutInflater, container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
return inflater.inflate(
R.layout.expanded_item, container, false
)
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
initializeLayout()
}
private fun initializeLayout() {
if (hasVideo) {
youTubeLayoutContainer.visibility = View.VISIBLE
mosquitoVideo =
childFragmentManager.findFragmentById(R.id.youtube_player_fragment) as YouTubePlayerSupportFragment
mosquitoVideo.initialize(getString(R.string.google_api_key), this)
}
}
override fun onInitializationSuccess(
provider: YouTubePlayer.Provider,
youTubePlayer: YouTubePlayer,
b: Boolean
) {
if (!b) {
youTubePlayer.cueVideo("rD8SmacBUcU")
}
}
override fun onInitializationFailure(
provider: YouTubePlayer.Provider,
youTubeInitializationResult: YouTubeInitializationResult
) {
Toast.makeText(activity, "Youtube video failed to play", Toast.LENGTH_SHORT).show()
}
当视频尚未全屏时,ExpandedItemFragment 会正常膨胀,但在用户选择全屏后,应用会崩溃。抛出的异常是:
Caused by: androidx.fragment.app.Fragment$InstantiationException: Unable to instantiate fragment com.example.mosquitotracker.ExpandedItemFragment: could not find Fragment constructor
异常位于我的 MainActivity.kt 中
super.onCreate(savedInstanceState)
【问题讨论】:
-
错误信息是说你需要有一个默认的非参数构造函数——这就是 FragmentManager 在配置更改或进程死亡和重新创建后创建 Fragments 的方式。
标签: android kotlin android-youtube-api android-fullscreen