Android VideoView 比例缩放

Question

在Android的VideoView中，有没有办法实现和ImageView.ScaleType.CENTER_CROP一样的效果？

也就是说，我希望我的 VideoView 播放视频，使其充满整个屏幕而不会失真。如果视频纵横比与屏幕不完全匹配，则应将其裁剪而不是扭曲。

以下解决方案将填满屏幕，但不保持视频的纵横比： https://stackoverflow.com/a/6927300/1068656

并且此解决方案保持了视频的纵横比，但不会填满整个屏幕（视频被缩放直到较长的一侧碰到屏幕的边缘，从而在侧面引入了条）： https://stackoverflow.com/a/4855315/1068656

Answer 1

虽然为时已晚，但它可能会帮助其他人寻找同样的问题。以下答案保持纵横比（videoProportion）。额外的部分 视频视图被手机的视图裁剪。

private void setDimension() {
     // Adjust the size of the video
     // so it fits on the screen
     float videoProportion = getVideoProportion();
     int screenWidth = getResources().getDisplayMetrics().widthPixels;
     int screenHeight = getResources().getDisplayMetrics().heightPixels;
     float screenProportion = (float) screenHeight / (float) screenWidth;
     android.view.ViewGroup.LayoutParams lp = videoView.getLayoutParams();

     if (videoProportion < screenProportion) {
         lp.height= screenHeight;
         lp.width = (int) ((float) screenHeight / videoProportion);
     } else {
         lp.width = screenWidth;
         lp.height = (int) ((float) screenWidth * videoProportion);
     }
     videoView.setLayoutParams(lp);
 }

// This method gets the proportion of the video that you want to display.
// I already know this ratio since my video is hardcoded, you can get the  
// height and width of your video and appropriately generate  the proportion  
//    as :height/width 
private float getVideoProportion(){
  return 1.5f;
}

Answer 2

在Android的VideoView中，这里有一个简单易行的方法，可以实现和ImageView.ScaleType.CENTER_CROP一样的效果

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">

    <VideoView
        android:id="@+id/videoView"
        android:layout_width="@dimen/dimen_0dp"
        android:layout_height="@dimen/dimen_0dp"
        android:visibility="gone"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

在 Kotlin 中：

videoView.setOnPreparedListener { mediaPlayer ->
    val videoRatio = mediaPlayer.videoWidth / mediaPlayer.videoHeight.toFloat()
    val screenRatio = videoView.width / videoView.height.toFloat()
    val scaleX = videoRatio / screenRatio
    if (scaleX >= 1f) {
        videoView.scaleX = scaleX
    } else {
        videoView.scaleY = 1f / scaleX
    }
}

在 JAVA 中：

videoView.setOnPreparedListener(new MediaPlayer.OnPreparedListener() {
@Override
public void onPrepared(MediaPlayer mp) {
      float videoRatio = mp.getVideoWidth() / (float) mp.getVideoHeight();
      float screenRatio = videoView.getWidth() / (float) 
      videoView.getHeight();
      float scaleX = videoRatio / screenRatio;
      if (scaleX >= 1f) {
          videoView.setScaleX(scaleX);
      } else {
          videoView.setScaleY(1f / scale);
      }
   }
});

这对我有用。希望这会对某人有所帮助。

Answer 3

ConstraintLayout 有一个属性 app:layout_constraintDimensionRatio 用于此目的。

<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">

    <VideoView
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintDimensionRatio="4:3" <!-- w:h -->
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</ConstraintLayout>

查看more details的官方文档