NullPointerException異常時，試圖在一個片段使用VideoView

Question

我試圖嵌入YouTube視頻到我的應用程序，如下所述：http://android-coffee.com/tutorial-how-to-play-youtube-videos-in-android-with-videoview/

但是，我似乎當我訪問片段會遇到NullPointerException錯誤和我似乎無法找到因果關係。

java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.VideoView.setVideoURI(android.net.Uri)' on a null object reference 

該片段的代碼如下。

import android.widget.MediaController; 
import android.net.Uri; 
import android.os.Bundle; 
import android.support.v4.app.Fragment; 
import android.view.LayoutInflater; 
import android.view.View; 
import android.view.ViewGroup; 
import android.widget.VideoView; 


public class VideosFragment extends Fragment { 


public VideosFragment() { 
    // Required empty public constructor 
} 


@Override 
public View onCreateView(LayoutInflater inflater, ViewGroup container, 
         Bundle savedInstanceState) { 
    View view = inflater.inflate(R.layout.fragment_compare, container, false); 
    VideoView videoView; 
    videoView = (VideoView)view.findViewById(R.id.videoView); 
    MediaController mediaController; 
    mediaController = new MediaController(view.getContext()); 
    mediaController.setAnchorView(videoView); 
    Uri uri= Uri.parse("rtsp://r7---sn-4g57kue6.googlevideo.com/Ck0LENy73wIaRAmk3cJBg-iaXhMYDSANFC3u0pRWMOCoAUIJbXYtZ29vZ2xlSARSBXdhdGNoYIaluaTkzciOVooBCzVxRjNraG5XcXdnDA==/D693A8E7577C3A29E60C292B42C9C87D7C25A565.762A63DC4CA0A028DA83256C6A79E5F160CBEDA3/yt6/1/video.3gp"); 
    videoView.setMediaController(mediaController); 
    videoView.setVideoURI(uri); 
    videoView.requestFocus(); 
    videoView.start(); 



    return inflater.inflate(R.layout.fragment_videos, container, false); 
} 

}

這裏是佈局文件：

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android" 
xmlns:tools="http://schemas.android.com/tools" 
android:layout_width="match_parent" 
android:layout_height="match_parent" 
tools:context="com.[left out for security].VideosFragment" 
android:background="?android:attr/colorBackground"> 

<!-- TODO: Update blank fragment layout --> 

<VideoView 
    android:id="@+id/videoView" 
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_centerVertical="true" 
    android:layout_centerHorizontal="true" /> 

感謝您的幫助！

Answer 1

您在沒有ID videoView的佈局上打電話給findViewById(R.id.videoView);。

你應該更改以下行：

View view = inflater.inflate(R.layout.fragment_compare, container, false); 

對此（假設佈局fragment_videos有ID videoView）：

View view = inflater.inflate(R.layout.fragment_videos, container, false);