AndroidのアクティビティでYoutubeプレーヤーの初期化を指定する方法は？

Question

私はAndroidアプリを開発しています。私の活動の1つにはYoutubeプレーヤーが含まれています。ここでは、提供されたリンクが "null"と等しくない場合にのみ、プレーヤーを表示したいと考えていますが、私は以下のように試しましたが、YouTubeプレーヤーはエラーで初期化されています。

package com.example.acer.videoapp; 

import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.support.v7.widget.Toolbar; 
import android.util.Log; 
import android.view.View; 
import android.widget.TextView; 
import android.widget.Toast; 

import com.google.android.youtube.player.YouTubeBaseActivity; 
import com.google.android.youtube.player.YouTubeInitializationResult; 
import com.google.android.youtube.player.YouTubePlayer; 
import com.google.android.youtube.player.YouTubePlayer.ErrorReason; 
import com.google.android.youtube.player.YouTubePlayer.PlaybackEventListener; 
import com.google.android.youtube.player.YouTubePlayer.PlayerStateChangeListener; 
import com.google.android.youtube.player.YouTubePlayer.Provider; 
import com.google.android.youtube.player.YouTubePlayerView; 

public class FourthActivity extends YouTubeBaseActivity implements YouTubePlayer.OnInitializedListener { 
    public static final String API_KEY = "key"; 
    public static String VIDEO_ID = ""; 
    Toolbar toolbar3; 


    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     setContentView(R.layout.activity_fourth); 

     //setting title to toolbar 
     toolbar3 = (Toolbar) findViewById(R.id.toolbar3); 
     toolbar3.setTitleTextColor(getColor(R.color.white)); 

     //set back button on toolbar 
     toolbar3.setNavigationIcon(R.drawable.back); 
     toolbar3.setNavigationOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
       onBackPressed(); 
      } 
     }); 

     Bundle bundle = getIntent().getExtras(); 
     if(bundle!=null) { 
      TextView textView = (TextView) findViewById(R.id.text); 
      textView.setText(bundle.getString("name")); 
      TextView textView1 = (TextView) findViewById(R.id.text1); 
      textView1.setText(bundle.getString("engname")); 
      TextView textView2 = (TextView) findViewById(R.id.text2); 
      textView2.setText(bundle.getString("desc")); 
      VIDEO_ID=bundle.getString("link"); 
      //Log.d("link",VIDEO_ID); 
     } 

     //initializing youtube player view 
     if(VIDEO_ID!="null") { 
      YouTubePlayerView youTubePlayerView = (YouTubePlayerView) findViewById(R.id.youtube_player); 
      youTubePlayerView.initialize(API_KEY, this); 
     } 
    } 

    @Override 
    public void onInitializationFailure(Provider provider, YouTubeInitializationResult result){ 
     Toast.makeText(this,"Failed to Initialize",Toast.LENGTH_LONG).show(); 
    } 

    @Override 
    public void onInitializationSuccess(Provider provider, YouTubePlayer player, boolean wasRestored){ 
     if(VIDEO_ID!="null") { 
      //add listeners to YouTubePlayer instance 
      player.setPlayerStateChangeListener(playerStateChangeListener); 
      player.setPlaybackEventListener(playbackEventListner); 

      //start buffering 
      if (!wasRestored) { 
       player.cueVideo(VIDEO_ID); 
      } 
     } 
    } 

    private PlaybackEventListener playbackEventListner = new PlaybackEventListener() { 
     @Override 
     public void onPlaying() { 

     } 

     @Override 
     public void onPaused() { 

     } 

     @Override 
     public void onStopped() { 

     } 

     @Override 
     public void onBuffering(boolean arg0) { 

     } 

     @Override 
     public void onSeekTo(int arg0) { 

     } 
    }; 

    private PlayerStateChangeListener playerStateChangeListener = new PlayerStateChangeListener() { 
     @Override 
     public void onLoading() { 

     } 

     @Override 
     public void onLoaded(String arg0) { 

     } 

     @Override 
     public void onAdStarted() { 

     } 

     @Override 
     public void onVideoStarted() { 

     } 

     @Override 
     public void onVideoEnded() { 

     } 

     @Override 
     public void onError(ErrorReason arg0) { 

     } 
    }; 

} 

Answer 1

使用してみてください、

if(VIDEO_ID.equals("")){ /* do the initialization */ }