Java - 实现Youtube Data API（API 19,4.4）

Question

所以我在Java类中遇到错误，告诉我R不是已解析的符号。我还注意到，每当我在网上浏览时，其他一些ppl的代码与其他代码略有不同，并认为这是因为更新而导致这些错误。

简而言之，我想知道如何在Java中调用布局。 R.layout.activity_main无效并返回错误。

这是整个代码，是的，我在线使用某人的代码，看看我是否可以连接我的应用程序。把它想象成一个小测试。

import android.content.Intent;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
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.YouTubePlayerView;

public class Search extends YouTubeBaseActivity implements YouTubePlayer.OnInitializedListener{

public static final String serverKey = "AIzaSyCuwJyE96NvT62erGiWbMEefVAiQptAmus";
private static final int RECOVERY_REQUEST = 1;
private YouTubePlayerView youTubeView;

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

    youTubeView = (YouTubePlayerView) findViewById(R.id.youtube_view);
    youTubeView.initialize(Config.YOUTUBE_API_KEY, this);
    playerStateChangeListener = new MyPlayerStateChangeListener();
    playbackEventListener = new MyPlaybackEventListener();
}

@Override
public void onInitializationSuccess(YouTubePlayer.Provider provider, YouTubePlayer player, boolean wasRestored) {
    player.setPlayerStateChangeListener(playerStateChangeListener);
    player.setPlaybackEventListener(playbackEventListener);

    if (!wasRestored) {
        player.cueVideo("fhWaJi1Hsfo"); // Plays https://www.youtube.com/watch?v=fhWaJi1Hsfo
    }
}

@Override
public void onInitializationFailure(YouTubePlayer.Provider provider, YouTubeInitializationResult errorReason) {
    if (errorReason.isUserRecoverableError()) {
        errorReason.getErrorDialog(this, RECOVERY_REQUEST).show();
    } else {
        String error = String.format(getString(R.string.player_error), errorReason.toString());
        Toast.makeText(this, error, Toast.LENGTH_LONG).show();
    }
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (requestCode == RECOVERY_REQUEST) {
        // Retry initialization if user performed a recovery action
        getYouTubePlayerProvider().initialize(Config.YOUTUBE_API_KEY, this);
    }
}

protected YouTubePlayer.Provider getYouTubePlayerProvider() {
    return youTubeView;
}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.menu, menu);
    return true;
}

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    // Handle action bar item clicks here. The action bar will
    // automatically handle clicks on the Home/Up button, so long
    // as you specify a parent activity in AndroidManifest.xml.
    int id = item.getItemId();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);
}

private void showMessage(String message) {
    Toast.makeText(this, message, Toast.LENGTH_LONG).show();
}

private MyPlayerStateChangeListener playerStateChangeListener;
private MyPlaybackEventListener playbackEventListener;

private final class MyPlaybackEventListener implements YouTubePlayer.PlaybackEventListener {

    @Override
    public void onPlaying() {
        // Called when playback starts, either due to user action or call to play().
        showMessage("Playing");
    }

    @Override
    public void onPaused() {
        // Called when playback is paused, either due to user action or call to pause().
        showMessage("Paused");
    }

    @Override
    public void onStopped() {
        // Called when playback stops for a reason other than being paused.
        showMessage("Stopped");
    }

    @Override
    public void onBuffering(boolean b) {
        // Called when buffering starts or ends.
    }

    @Override
    public void onSeekTo(int i) {
        // Called when a jump in playback position occurs, either
        // due to user scrubbing or call to seekRelativeMillis() or seekToMillis()
    }
}

private final class MyPlayerStateChangeListener implements YouTubePlayer.PlayerStateChangeListener {

    @Override
    public void onLoading() {
        // Called when the player is loading a video
        // At this point, it's not ready to accept commands affecting playback such as play() or pause()
    }

    @Override
    public void onLoaded(String s) {
        // Called when a video is done loading.
        // Playback methods such as play(), pause() or seekToMillis(int) may be called after this callback.
    }

    @Override
    public void onAdStarted() {
        // Called when playback of an advertisement starts.
    }

    @Override
    public void onVideoStarted() {
        // Called when playback of the video starts.
    }

    @Override
    public void onVideoEnded() {
        // Called when the video reaches its end.
    }

    @Override
    public void onError(YouTubePlayer.ErrorReason errorReason) {
        // Called when an error occurs.
    }
}
}