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如何去除Android中VideoView播放视频时的黑边区域?

问题描述

我在VideoView中加载教程视频播放,但视频无法填满整个VideoView,因为视频本身的比例和VideoView的比例不匹配,导致VideoView出现黑边。我试过用CardView包裹VideoView并设置cardCornerRadius,但没法彻底消除黑边,而且也不确定能不能给VideoView设置背景圆角。

视频黑边效果

VideoFragment.kt

private fun initVideo() {
    simpleVideoView = binding.videoViewTutorial
    simpleVideoView?.setVideoURI(
        Uri.parse("android.resource://" + requireActivity().packageName + "/" + R.raw.tutorial)
    )
    simpleVideoView?.requestFocus()
    simpleVideoView?.start()

}

fragment_video.xml

<?xml version="1.0" encoding="utf-8"?>
<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"
    xmlns:tools="http://schemas.android.com/tools">

    <androidx.fragment.app.FragmentContainerView
        android:id="@+id/tabContainerUser"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        app:defaultNavHost="true" />

    <com.google.android.material.bottomnavigation.BottomNavigationView
        android:id="@+id/bottomNavigationView"
        android:layout_width="0dp"
        android:layout_height="70dp"
        android:layout_gravity="bottom"
        android:layout_margin="30dp"
        android:background="@drawable/background_white_gray_stroke_60dp_radius"
        app:itemIconSize="27dp"
        app:labelVisibilityMode="unlabeled"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:menu="@menu/bottom_nav_menu_user" />

    <ImageView
        android:id="@+id/ivAskAdvise"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:translationZ="999dp"
        android:src="@drawable/ic_black_plus_yellow_bg"
        app:layout_constraintBottom_toBottomOf="@+id/bottomNavigationView"
        app:layout_constraintEnd_toEndOf="@+id/bottomNavigationView"
        app:layout_constraintStart_toStartOf="@+id/bottomNavigationView"
        app:layout_constraintTop_toTopOf="@+id/bottomNavigationView"
        app:layout_constraintVertical_bias="0.63"
        tools:ignore="ContentDescription" />

    <View
        android:id="@+id/viewBlackBg"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/black_0_70"
        android:visibility="gone"
        android:translationZ="999dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        tools:visibility="visible" />

<!--    <androidx.cardview.widget.CardView
        android:id="@+id/cardViewVideo"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:cardCornerRadius="70dp"
        app:cardBackgroundColor="@color/transparent"
        android:visibility="gone"
        android:translationZ="999dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHeight_percent="0.80"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintWidth_percent="0.80"
        tools:visibility="visible">-->

    <VideoView
        android:id="@+id/videoViewTutorial"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:translationZ="999dp"
        android:visibility="gone"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHeight_percent="0.80"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintWidth_percent="0.80"
        tools:visibility="visible"/>

    <!--</androidx.cardview.widget.CardView>-->

    <TextView
        android:id="@+id/tvSkipTutorial"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="20dp"
        android:fontFamily="@font/mulish_regular"
        android:text="@string/skip"
        android:textColor="@color/white"
        android:textSize="16sp"
        android:visibility="gone"
        android:translationZ="999dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/videoViewTutorial"
        tools:visibility="visible" />

</androidx.constraintlayout.widget.ConstraintLayout>
解决方案

一、消除黑边:适配视频比例

黑边本质是视频和VideoView的比例不匹配导致的,VideoView默认会保留视频原始比例,所以会留出黑边。可以通过以下两种方式解决:

1. 自定义ScalingVideoView

写一个继承自VideoView的类,重写onMeasure方法,让视频按比例填充整个View(超出部分会被裁剪):

class ScalingVideoView @JvmOverloads constructor(
    context: Context, attrs: AttributeSet? = null, defStyleAttr: Int = 0
) : VideoView(context, attrs, defStyleAttr) {

    override fun onMeasure(widthMeasureSpec: Int, heightMeasureSpec: Int) {
        val videoWidth = videoWidth
        val videoHeight = videoHeight

        if (videoWidth != 0 && videoHeight != 0) {
            val videoRatio = videoWidth.toFloat() / videoHeight.toFloat()
            val viewWidth = MeasureSpec.getSize(widthMeasureSpec)
            val viewHeight = MeasureSpec.getSize(heightMeasureSpec)
            val viewRatio = viewWidth.toFloat() / viewHeight.toFloat()

            var measuredWidth = viewWidth
            var measuredHeight = viewHeight

            // 根据比例计算适配后的尺寸
            if (videoRatio > viewRatio) {
                // 视频更宽,按宽度适配,高度超出部分裁剪
                measuredHeight = (viewWidth / videoRatio).toInt()
            } else {
                // 视频更高,按高度适配,宽度超出部分裁剪
                measuredWidth = (viewHeight * videoRatio).toInt()
            }

            setMeasuredDimension(measuredWidth, measuredHeight)
        } else {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec)
        }
    }
}

然后把xml里的VideoView替换成这个自定义类:

<your.package.name.ScalingVideoView
    android:id="@+id/videoViewTutorial"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:translationZ="999dp"
    android:visibility="gone"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHeight_percent="0.80"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintWidth_percent="0.80"
    tools:visibility="visible"/>

2. 使用MediaPlayer+SurfaceView(更灵活)

如果自定义VideoView满足不了需求,用SurfaceView配合MediaPlayer可以更精细地控制视频显示:

先在xml里把VideoView换成SurfaceView:

<SurfaceView
    android:id="@+id/surfaceViewTutorial"
    android:layout_width="0dp"
    android:layout_height="0dp"
    android:translationZ="999dp"
    android:visibility="gone"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHeight_percent="0.80"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintWidth_percent="0.80"
    tools:visibility="visible"/>

然后在代码里初始化MediaPlayer并适配比例:

private lateinit var surfaceView: SurfaceView
private lateinit var mediaPlayer: MediaPlayer

private fun initVideo() {
    surfaceView = binding.surfaceViewTutorial
    mediaPlayer = MediaPlayer()
    // 设置视频源
    mediaPlayer.setDataSource(requireContext(), Uri.parse("android.resource://" + requireActivity().packageName + "/" + R.raw.tutorial))
    
    surfaceView.holder.addCallback(object : SurfaceHolder.Callback {
        override fun surfaceCreated(holder: SurfaceHolder) {
            mediaPlayer.setDisplay(holder)
            mediaPlayer.prepareAsync()
            mediaPlayer.setOnPreparedListener { mp ->
                val videoWidth = mp.videoWidth
                val videoHeight = mp.videoHeight
                val surfaceWidth = surfaceView.width
                val surfaceHeight = surfaceView.height

                val videoRatio = videoWidth.toFloat() / videoHeight.toFloat()
                val surfaceRatio = surfaceWidth.toFloat() / surfaceHeight.toFloat()

                val layoutParams = surfaceView.layoutParams as ConstraintLayout.LayoutParams
                // 计算适配后的尺寸
                if (videoRatio > surfaceRatio) {
                    layoutParams.width = surfaceWidth
                    layoutParams.height = (surfaceWidth / videoRatio).toInt()
                } else {
                    layoutParams.height = surfaceHeight
                    layoutParams.width = (surfaceHeight * videoRatio).toInt()
                }
                surfaceView.layoutParams = layoutParams
                mp.start()
            }
        }

        override fun surfaceChanged(holder: SurfaceHolder, format: Int, width: Int, height: Int) {}
        override fun surfaceDestroyed(holder: SurfaceHolder) {
            // 释放资源
            mediaPlayer.release()
        }
    })
}

二、实现VideoView圆角效果

VideoView本身不支持直接设置圆角,但是可以通过以下两种方法实现:

1. 正确使用CardView包裹

你之前的CardView用法有问题,需要开启裁剪并关闭默认的内边距:

恢复CardView的包裹,添加以下属性:

<androidx.cardview.widget.CardView
    android:id="@+id/cardViewVideo"
    android:layout_width="0dp"
    android:layout_height="0dp"
    app:cardCornerRadius="70dp"
    app:cardBackgroundColor="@color/transparent"
    app:cardPreventCornerOverlap="false" <!-- 关闭默认的圆角重叠修正 -->
    app:cardUseCompatPadding="false" <!-- 关闭默认内边距 -->
    android:clipToOutline="true" <!-- 开启裁剪 -->
    android:visibility="gone"
    android:translationZ="999dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintHeight_percent="0.80"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent"
    app:layout_constraintWidth_percent="0.80"
    tools:visibility="visible">

    <your.package.name.ScalingVideoView
        android:id="@+id/videoViewTutorial"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:background="@color/transparent" <!-- 设置背景透明 -->
        android:translationZ="999dp"
        android:visibility="visible"/>

</androidx.cardview.widget.CardView>

2. 使用OutlineProvider(API>=21)

给VideoView设置自定义的OutlineProvider,手动创建圆角轮廓:

在代码中添加:

simpleVideoView?.clipToOutline = true
simpleVideoView?.outlineProvider = object : ViewOutlineProvider() {
    override fun getOutline(view: View, outline: Outline) {
        // 第一个参数是左偏移,第二个上偏移,第三个右边界,第四个下边界,最后一个是圆角半径
        outline.setRoundRect(0, 0, view.width, view.height, 70f)
    }
}

注意:这种方法要求系统版本在Android 5.0以上,并且VideoView的父布局不能有多余padding,否则圆角可能显示不全。


内容的提问来源于stack exchange,提问作者Ahmet Yılmaz

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最近更新时间:2026.06.24 22:54:52