我正在我的应用程序中构建一个 MP3 播放器，但我收到一条错误消息，指出“raw cannot be resolved or is not a field”在线:mMediaPlayer = MediaPlayer.create(this, R.raw.test_cbr) ;

我不确定 R.raw.test_cbr 到底是什么(我没有写这段代码)有人可以解释一下 R.raw.test_cbr 是什么以及如何解决这个问题吗？

Java:

import android.app.Activity;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
import android.widget.Toast;

import com.idg.omv.R;

public class MediaPlayerDemo extends Activity {

    private static final String TAG = "MediaPlayerDemo";
    private MediaPlayer mMediaPlayer;
    private static final String MEDIA = "media";
    private static final int LOCAL_AUDIO = 1;
    private static final int STREAM_AUDIO = 2;
    private static final int RESOURCES_AUDIO = 3;
    private static final int LOCAL_VIDEO = 4;
    private static final int STREAM_VIDEO = 5;
    private String path;

    private TextView tx;

    public void onCreate(Bundle icicle) {
        super.onCreate(icicle);
        tx = new TextView(this);
        setContentView(tx);
        Bundle extras = getIntent().getExtras();
        playAudio(extras.getInt(MEDIA));
    }

    private void playAudio(Integer media) {
        try {
            switch (media) {
                case LOCAL_AUDIO:
                    /**
                     * TODO: Set the path variable to a local audio file path.
                     */
                    path = "";
                    if (path == "") {
                        // Tell the user to provide an audio file URL.
                        Toast
                                .makeText(
                                        MediaPlayerDemo.this,
                                        "Please edit MediaPlayer_Audio Activity, "
                                                + "and set the path variable to your audio file path."
                                                + " Your audio file must be stored on sdcard.",
                                        Toast.LENGTH_LONG).show();

                    }
                    mMediaPlayer = new MediaPlayer();
                    mMediaPlayer.setDataSource(path);
                    mMediaPlayer.prepare();
                    mMediaPlayer.start();
                    break;
                case RESOURCES_AUDIO:
                    /**
                     * TODO: Upload a audio file to res/raw folder and provide
                     * its resid in MediaPlayer.create() method.
                     */
                    mMediaPlayer = MediaPlayer.create(this, R.raw.test_cbr);
                    mMediaPlayer.start();

            }
            tx.setText("Playing audio...");

        } catch (Exception e) {
            Log.e(TAG, "error: " + e.getMessage(), e);
        }

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        // TODO Auto-generated method stub
        if (mMediaPlayer != null) {
            mMediaPlayer.release();
            mMediaPlayer = null;
        }

    }
}

最佳答案

I'm not sure exactly what R.raw.test_cbr is (I did not write this code) can someone explain what R.raw.test_cbr is as well as how this can be resolved?

R.raw 是指放置在res/raw 中的“原始”资源。 “原始”意味着资源文件按原样包含在应用程序包中，没有任何编译时修改。

(至少在理论上是这样。我遇到过工具链修改我的原始资源的问题，但这超出了这个问题的范围。)

你得到这个编译时错误是因为你没有 res/raw 文件夹并且 R.raw 嵌套类没有在 R 中生成。 java.

R.raw.test_cbr指的是res/raw文件夹下的一个文件test_cbr.ext，其中ext 只是一些文件扩展名。

因为你正在喂 MediaPlayer，你应该放置一些音频媒体文件 test_cbr 例如res/raw 中的 text_cbr.mp3 并重建您的应用程序。

关于java - raw 无法解析或不是字段，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/20644230/