Android Visualizer 实现崩溃答案

【问题标题】：Android Visualizer implementation crashAndroid Visualizer 实现崩溃
【发布时间】：2012-01-25 14:40:37
【问题描述】：

我正在尝试实现 Android Visualizer 类。我查找了其他问题线程，但仍然遇到致命错误。在我看来，这一切都应该正常工作，无论出于何种原因，AVD 不断崩溃。

首先，我正在使用权限：

<uses-permission android:name="android.permission.RECORD_AUDIO" />
<uses-permission android:name="android.permission.MODIFY_AUDIO_SETTINGS"/>

这是我的日志：

12-21 15:10:46.983: D/dalvikvm(642): Not late-enabling CheckJNI (already on)
12-21 15:10:48.823: D/MediaPlayer(642): Couldn't open file on client side, trying server     side  
12-21 15:10:53.603: E/AudioEffect(642): set(): AudioFlinger could not create effect,    status: -22
12-21 15:10:53.603: E/visualizers-JNI(642): Visualizer initCheck failed -4
12-21 15:10:53.613: E/Visualizer-JAVA(642): Error code -4 when initializing Visualizer.
12-21 15:10:53.613: E/Visual Ex(642): Cannot initialize Visualizer engine, error: -4
12-21 15:10:53.964: D/gralloc_goldfish(642): Emulator without GPU emulation detected.

还有我的代码：

package MediaPlayer.namespace;

import java.io.IOException;

import android.app.Activity;
import android.media.MediaPlayer;
import android.media.MediaRecorder;
import android.media.audiofx.Visualizer;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;

public class MediaPlayerActivity extends Activity 
{
Visualizer      visual;
int             formattedVizData[];
byte            rawWaveForm[];
int             cont = 0xFF;

public void onCreate(Bundle savedInstanceState) 
{
    //start
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);


    ///start media player & visualizer.
    MediaPlayer mediaPlayer = new MediaPlayer();
    mediaPlayer = MediaPlayer.create(this, Uri.parse("http://vprbbc.streamguys.net:80/vprbbc24.mp3"));
    mediaPlayer.start();
    // Create the Visualizer object and attach it to our media player.
    try{
        visual = new Visualizer(mediaPlayer.getAudioSessionId()); // this line causing Exception 
        visual.setEnabled(true);
        visual.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
        }
        catch(Exception ex)
        {
            Log.e("Visual Ex", ex.getMessage());
        }
    }
}

【问题讨论】：

你解决了吗？我有同样的问题，我自己的代码和 SDK 的 ApiDemos 中的示例。我已经在我的 2.3 手机和 4.0.3 模拟器上试过了。

标签： android visualizer

【解决方案1】：

我有同样的问题，所以尝试添加 AndroidManifest.xml 文件中的权限

另外，如果你不想看到那个 audi wave，你应该在画布或其他东西上展示它......

工作示例：

//android.permission.MODIFY_AUDIO_SETTINGS for audio settings and also
//android.permission.INTERNET for internet streaming

package com.janilemy;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.media.audiofx.Visualizer;
import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.SeekBar;
import android.widget.TextView;

import java.io.IOException;

public class AudioFxDemoActivity extends Activity {

    //Here is your URL defined
String url = "http://vprbbc.streamguys.net/vprbbc24.mp3";

    //Constants for vizualizator - HEIGHT 50dip
private static final float VISUALIZER_HEIGHT_DIP = 50f;

    //Your MediaPlayer
MediaPlayer mp;

//Vizualization
private Visualizer mVisualizer;

    private LinearLayout mLinearLayout;
    private VisualizerView mVisualizerView;
    private TextView mStatusTextView;


/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    //Info textView
    mStatusTextView = new TextView(this);

    //Create new LinearLayout ( because main.xml is empty )
    mLinearLayout = new LinearLayout(this);
    mLinearLayout.setOrientation(LinearLayout.VERTICAL);
    mLinearLayout.addView(mStatusTextView);

    //set content view to new Layout that we create
    setContentView(mLinearLayout);

    //start media player - like normal
    mp = new MediaPlayer();
    mp.setAudioStreamType(AudioManager.STREAM_MUSIC);

    try {
        mp.setDataSource(url); // set data source our URL defined
    } catch (IllegalArgumentException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IllegalStateException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }       

    try {   //tell your player to go to prepare state
        mp.prepare(); 
    } catch (IllegalStateException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
            //Start your stream / player
    mp.start();

    //setup your Vizualizer - call method
    setupVisualizerFxAndUI();        

            //enable vizualizer
            mVisualizer.setEnabled(true);

            //Info text
    mStatusTextView.setText("Playing audio...");
}

    //Our method that sets Vizualizer
private void setupVisualizerFxAndUI() {
    // Create a VisualizerView (defined below), which will render the simplified audio
    // wave form to a Canvas.

    //You need to have something where to show Audio WAVE - in this case Canvas
    mVisualizerView = new VisualizerView(this);
    mVisualizerView.setLayoutParams(new ViewGroup.LayoutParams(
            ViewGroup.LayoutParams.FILL_PARENT,
            (int)(VISUALIZER_HEIGHT_DIP * getResources().getDisplayMetrics().density)));
    mLinearLayout.addView(mVisualizerView);

    // Create the Visualizer object and attach it to our media player.
    //YOU NEED android.permission.RECORD_AUDIO for that in AndroidManifest.xml
    mVisualizer = new Visualizer(mp.getAudioSessionId());
    mVisualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
    mVisualizer.setDataCaptureListener(new Visualizer.OnDataCaptureListener() {
        public void onWaveFormDataCapture(Visualizer visualizer, byte[] bytes,
                int samplingRate) {
            mVisualizerView.updateVisualizer(bytes);
        }

        public void onFftDataCapture(Visualizer visualizer, byte[] bytes, int samplingRate) {}
    }, Visualizer.getMaxCaptureRate() / 2, true, false); 
}

@Override
protected void onPause() {
    super.onPause();

    if (isFinishing() && mp != null) {
        mVisualizer.release();
        mEqualizer.release();
        mp.release();
        mp = null;
    }
}

/**
 * A simple class that draws waveform data received from a
 * {@link Visualizer.OnDataCaptureListener#onWaveFormDataCapture }
 */
class VisualizerView extends View {
    private byte[] mBytes;
    private float[] mPoints;
    private Rect mRect = new Rect();

    private Paint mForePaint = new Paint();

    public VisualizerView(Context context) {
        super(context);
        init();
    }

    private void init() {
        mBytes = null;

        mForePaint.setStrokeWidth(1f);
        mForePaint.setAntiAlias(true);
        mForePaint.setColor(Color.rgb(0, 128, 255));
    }

    public void updateVisualizer(byte[] bytes) {
        mBytes = bytes;
        invalidate();
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        if (mBytes == null) {
            return;
        }

        if (mPoints == null || mPoints.length < mBytes.length * 4) {
            mPoints = new float[mBytes.length * 4];
        }

        mRect.set(0, 0, getWidth(), getHeight());

        for (int i = 0; i < mBytes.length - 1; i++) {
            mPoints[i * 4] = mRect.width() * i / (mBytes.length - 1);
            mPoints[i * 4 + 1] = mRect.height() / 2
                    + ((byte) (mBytes[i] + 128)) * (mRect.height() / 2) / 128;
            mPoints[i * 4 + 2] = mRect.width() * (i + 1) / (mBytes.length - 1);
            mPoints[i * 4 + 3] = mRect.height() / 2
                    + ((byte) (mBytes[i + 1] + 128)) * (mRect.height() / 2) / 128;
        }

        canvas.drawLines(mPoints, mForePaint);
    }
}

}

这是一个完整的 android 媒体播放器音频波形可视化示例......我希望它对您的解决方案有所帮助......

贾尼·L

【讨论】：

谢谢，但我已经将这些权限添加到 XML 文件中。就可视化器而言，我几乎拥有您所拥有的东西，尽管我不需要显示它，我只是使用该类从正在播放的音乐中获取一些原始数据。我感谢您的努力。
@janilemy 你能帮我吗？我想用波形播放音频。我阅读了可视化器类信息并按照您的代码实现，但我在日志猫中收到错误，例如“可视化器类不是”。
@janilemy 你能帮帮我吗..我想添加图像和按钮以及可视化工具，我该怎么做？通过编码..我试过这么膨胀，但我初始化失败了..请帮助我

【解决方案2】：

使用 Visualizer 有一些重要事项。

最小api level 必须等于或大于9。
Visualizer engine，错误：-1 表示 RECORD_AUDIO permission 是不见了。
Visualizer engine，错误：-4 表示 Operation failed due to bad parameter。价值。 Visualizer 的配置有问题，您没有正确设置 Visualizer。

还可以查看我的answer here。

注意

参数（audioSession）系统范围内唯一的音频会话标识符。如果audioSession 不为0，则visualizer 将附加到同一音频会话中的MediaPlayer 或AudioTrack。否则，Visualizer 将应用于输出组合。

【讨论】：

后期评论但是：我发现添加权限后可能需要重新启动。看看我的回答stackoverflow.com/questions/6971567/…
@Kaushal28 你好，我也遇到-3错误代码，这个代码是什么意思？你有没有解决过这个错误？请给我一些建议
@ihsan,gaozp 我也收到了-3的错误代码，我还没有找到解决方案。你们中的任何一个都有吗？

【解决方案3】：

@Kaushal28、@ihsan、gaozp、@大钱

-3 错误代码表示 ERROR_NO_INIT 注：https://developer.android.com/reference/kotlin/android/media/audiofx/Visualizer

我也有同样的经历，使用了 AudioRecorder 的 audioSesstionId。

如果查看 Visualizer 的文档，则只能使用 MediaPlayer 和 AudioTrack，如下所示。

If audioSession is not 0, the visualizer will be attached to the 
MediaPlayer or AudioTrack in the same audio session. Otherwise, 
the Visualizer will apply to the output mix.

【讨论】：

【解决方案4】：

您缺少 Internet 权限

<uses-permission android:name="android.permission.INTERNET" />

【讨论】：

【解决方案5】：

启用后，您无法对 visulizer 的对象进行任何更改。所以只需像 belove 代码中所示的那样交换行。

public class MediaPlayerActivity extends Activity {

    Visualizer visual;
    int formattedVizData[];
    byte rawWaveForm[];
    int cont = 0xFF;

    public void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        // Start media player & visualizer.
        MediaPlayer mediaPlayer = new MediaPlayer();
        mediaPlayer = MediaPlayer.create(this, Uri.parse("http://vprbbc.streamguys.net:80/vprbbc24.mp3"));
        mediaPlayer.start();

        // Create the Visualizer object and attach it to our media player.
        try {

            // this line is not actually causing Exception ,It is because u are
            // enabling the visulizer to capture data & and after that setting
            // the capture size of buffer. U can't make any changes after
            // enabling it. I tried this same code and it's working fine for me
            visual = new Visualizer(mediaPlayer.getAudioSessionId());

            visual.setCaptureSize(Visualizer.getCaptureSizeRange()[1]);
            visual.setEnabled(true);
        } 
        catch (Exception ex) {
            Log.e("Visual Ex", ex.getMessage());
        }

    }

}

请参阅此链接以获取最佳示例https://github.com/felixpalmer/android-visualizer

【讨论】：

【解决方案6】：

完成所有操作后，如果没有开始可视化，请尝试visualizationview.startRendering()

【讨论】：