如何为videoview设置mediacontroller

Question

我正在使用视频视图，我想为它设置一个媒体控制器，并且我像下面的代码那样做了它，但是当我点击播放按钮时，应用程序将会与null点异常一起崩溃。我不知道为什么，因为我确定了一切。 （当我削减'mediaC.setAnchorView（查看）;'视频将真正播放，但媒体控制器不会出现。） 谢谢你的回答。

public class VideoActivity extends Activity { 
    Button btnPaly; 
    VideoView videoPlayer; 
    MediaController mediaC; 
    String videoPath; 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_video); 

    btnPaly = (Button) findViewById(R.id.btnPlay); 
    videoPlayer = (VideoView) findViewById(R.id.videoView); 

    Bundle bundle = getIntent().getExtras(); 
    if (bundle != null) { 
     videoPath = bundle.getString(Const.VIDEO_PATH); 
    } 

    btnPaly.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 

     videoPlayer.setVideoPath(videoPath); 
     videoPlayer.setMediaController(mediaC); 
     mediaC.setAnchorView(view); // I get Null piont exception here 
     videoPlayer.start(); 
     } 
    }); 

    } 
} 

这里是我的XML：

<?xml version="1.0" encoding="utf-8"?> 
<android.support.constraint.ConstraintLayout 
    xmlns:android="http://schemas.android.com/apk/res/android" 
    xmlns:app="http://schemas.android.com/apk/res-auto" 
    xmlns:tools="http://schemas.android.com/tools" 
    android:layout_width="match_parent" 
    android:layout_height="match_parent" 
    android:id="@+id/rootLayout" 
    tools:context="simplevideoplayer.app.codenevisha.com.videoplayer.VideoActivity"> 


    <Button 
     android:id="@+id/btnPlay" 
     android:layout_width="wrap_content" 
     android:layout_height="wrap_content" 
     android:layout_marginLeft="75dp" 
     android:text="Play" 
     app:layout_constraintBottom_toBottomOf="parent" 
     app:layout_constraintLeft_toLeftOf="parent" 
     android:layout_marginStart="75dp" 
     android:layout_marginEnd="8dp" 
     android:layout_marginRight="8dp" 
     android:layout_marginBottom="-1dp" 
     app:layout_constraintRight_toRightOf="parent" 
     app:layout_constraintHorizontal_bias="0.342"/> 

    <VideoView 
     android:id="@+id/videoView" 
     android:layout_width="0dp" 
     android:layout_height="wrap_content" 
     app:layout_constraintTop_toTopOf="parent" 
     app:layout_constraintBottom_toTopOf="@+id/btnPlay" 
     app:layout_constraintLeft_toLeftOf="parent" 
     app:layout_constraintVertical_bias="1.0" 
     app:layout_constraintRight_toRightOf="parent" 
     app:layout_constraintHorizontal_bias="0.0"/> 
</android.support.constraint.ConstraintLayout> 

Answer 1

你忘了实例化MediaController，所以它的空。

在onCreate()方法试试这个（要注意的第一行）：

 MediaController mediaController = new MediaController(this); 
     mediaController.setAnchorView(videoView); 
     videoView.setMediaController(mediaController); 

Answer 2

试试这个：

public class VideoActivity extends Activity { 
    Button btnPaly; 
    VideoView videoPlayer; 
    MediaController mediaC; 
    String videoPath; 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_video); 

    btnPaly = (Button) findViewById(R.id.btnPlay); 
    videoPlayer = (VideoView) findViewById(R.id.videoView); 

    Bundle bundle = getIntent().getExtras(); 
    if (bundle != null) { 
     videoPath = bundle.getString(Const.VIDEO_PATH); 
    } 

    mediaC = new MediaController(this); 
    mediaC.setAnchorView(videoView); 
    videoView.setMediaController(mediaC); 

    btnPaly.setOnClickListener(new View.OnClickListener() { 
     @Override 
     public void onClick(View view) { 

     videoPlayer.setVideoPath(videoPath); 
     videoPlayer.setMediaController(mediaC); 
     mediaC.setAnchorView(view); // I get Null piont exception here 
     videoPlayer.start(); 
     } 
    }); 

    } 
}