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我的Android是新的，我試圖讓一個程序，它捕捉音頻的聲音，然後分析和可視化的頻率顯示存在內它的頻率。我找到了一個繪製圖形均衡器圖形部分的示例。在這個例子中，它使用了一個類型爲 AudioRecord的對象來捕捉音頻聲音。用於將音頻信號分解爲分量頻率的技術採用稱爲離散傅里葉變換（DFT）的數學變換，並且使用快速傅立葉變換（FFT）來執行DFT。這個例子使用一個實現FFT的包。包裹鏈接在這裏www.netlib.org/fftpack/jfftpack.tgz。 問題是，我運行這個例子後，我按下開始按鈕後，圖形均衡器不會出現在顯示屏上。捕獲聲音在Android的
下面是活動類的源代碼：
package com.audio.processing;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.media.AudioFormat;
import android.media.AudioRecord;
import android.media.MediaRecorder;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
import ca.uol.aig.fftpack.RealDoubleFFT;
public class AudioProcessing extends Activity implements OnClickListener{
int frequency = 8000;
int channelConfiguration = AudioFormat.CHANNEL_CONFIGURATION_MONO;
int audioEncoding = AudioFormat.ENCODING_PCM_16BIT;
private RealDoubleFFT transformer;
int blockSize = 256;
Button startStopButton;
boolean started = false;
RecordAudio recordTask;
ImageView imageView;
Bitmap bitmap;
Canvas canvas;
Paint paint;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
startStopButton = (Button) this.findViewById(R.id.StartStopButton);
startStopButton.setOnClickListener(this);
transformer = new RealDoubleFFT(blockSize);
imageView = (ImageView) this.findViewById(R.id.ImageView01);
bitmap = Bitmap.createBitmap((int)256,(int)100,Bitmap.Config.ARGB_8888);
canvas = new Canvas(bitmap);
paint = new Paint();
paint.setColor(Color.GREEN);
imageView.setImageBitmap(bitmap);
}
private class RecordAudio extends AsyncTask<Void, double[], Void> {
@Override
protected Void doInBackground(Void... params) {
try {
int bufferSize = AudioRecord.getMinBufferSize(frequency,
channelConfiguration, audioEncoding);
AudioRecord audioRecord = new AudioRecord(
MediaRecorder.AudioSource.DEFAULT, frequency,
channelConfiguration, audioEncoding, bufferSize);
short[] buffer = new short[blockSize];
double[] toTransform = new double[blockSize];
audioRecord.startRecording();
while (started) {
int bufferReadResult = audioRecord.read(buffer, 0, blockSize);
for (int i = 0; i < blockSize && i < bufferReadResult; i++) {
toTransform[i] = (double) buffer[i]/32768.0; // signed 16 bit
}
transformer.ft(toTransform);
publishProgress(toTransform);
}
audioRecord.stop();
} catch (Throwable t) {
Log.e("AudioRecord", "Recording Failed");
}
return null;
}
}
protected void onProgressUpdate(double[]... toTransform) {
canvas.drawColor(Color.BLACK);
for (int i = 0; i < toTransform[0].length; i++) {
int x = i;
int downy = (int) (100 - (toTransform[0][i] * 10));
int upy = 100;
canvas.drawLine(x, downy, x, upy, paint);
}
imageView.invalidate();
}
public void onClick(View v) {
if (started) {
started = false;
startStopButton.setText("Start");
recordTask.cancel(true);
} else {
started = true;
startStopButton.setText("Stop");
recordTask = new RecordAudio();
recordTask.execute();
}
}
}
這裏是main.xml中：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<TextView
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="@string/hello"
/>
<ImageView android:id="@+id/ImageView01" android:layout_width="wrap_content"
android:layout_height="wrap_content"></ImageView><Button android:text="Start"
android:id="@+id/StartStopButton" android:layout_width="wrap_content"
android:layout_height="wrap_content"></Button>
</LinearLayout>
在AndroidManifest.xml我設置RECORD_AUDIO權限。 在此先感謝！
其中是xml中的圖像視圖標籤？ – codeScriber 2011-04-01 09:50:03