音乐播放器中的跳动的平衡器

完整的音乐Demo我放在资源上，利于解析原理。地址：http://download.csdn.net/detail/zhangli_/9421671

主要用到的平衡器的工具类代码：

package com.zhangli.myapplication.custom;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Rect;import android.media.audiofx.Visualizer;import android.media.audiofx.Visualizer.OnDataCaptureListener;import android.os.Handler;import android.util.AttributeSet;import android.view.View;public class VisualizerView extends View {private final int REFRESH_TIME = 100;// 刷新间隔private final int TIMES_MAX = 10;// 刷新最大次数private final int ACCELERATION = 1;// 下落加速度(感觉最合适的一个数值)private Visualizer mVisualizer = null;private Handler mHandler = null;private int mSpectrumNum = 48;// 截取一部分private int times = 0;// 记录刷新次数private boolean error = false;// 是否初始化出错private boolean canDrawLines = false;// 是否允许画线private byte[] mBytes = null;// FFT源数组private float[] linesArray = null;// 线数组private float[] pointsArray = null;// 点数组private float[] tempArray = null;// 临时数组，用于记住点的位置private Rect mRect = null;// 矩形区域private Paint linesPaint = null;// 频谱线画笔private Paint pointsPaint = null;// 频谱点画笔private Paint errorPaint = null;// 频谱点画笔int[] colorArray = { 0xFF000000, 0xFF000000, 0xFF444444, 0xFF888888,0xFFCCCCCC, 0xFFFFFFFF, 0xFFFF0000, 0xFF00FF00, 0xFF0000FF,0xFFFFFF00, 0xFF00FFFF, 0xFFFF00FF};int colorPostion=0;public VisualizerView(Context context) {super(context);// TODO Auto-generated constructor stubinit();}public VisualizerView(Context context, AttributeSet attrs) {super(context, attrs);// TODO Auto-generated constructor stubinit();}public VisualizerView(Context context, AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);// TODO Auto-generated constructor stubinit();}/** * 生成一个VisualizerView对象，使音频频谱的波段能够反映到 VisualizerView上 * * @param audioSessionId *            MediaPlayer.getAudioSessionId() */public void setupVisualizerFx(int audioSessionId) {mHandler.removeCallbacks(runnable);canDrawLines = true;// 允许画线error = false;// 初始值未出错times = 0;if (mVisualizer != null) {mVisualizer.setEnabled(false);mVisualizer.release();mVisualizer = null;}// 4.0的模拟器肯定会报错，必须拋异常处理，可能部分手机也会出错try {mVisualizer = new Visualizer(audioSessionId);// 参数内必须是2的位数mVisualizer.setCaptureSize(Visualizer.getCaptureSizeRange()[0]);/* * 设置允许波形表示，并且捕获它，注意(true/false)， * 第一个表示是否执行onWaveFormDataCapture，第二个表示是否执行onFftDataCapture */mVisualizer.setDataCaptureListener(new OnDataCaptureListener() {@Overridepublic void onWaveFormDataCapture(Visualizer visualizer,  byte[] waveform, int samplingRate) {// TODO Auto-generated method stub//updateVisualizer(waveform);}@Overridepublic void onFftDataCapture(Visualizer visualizer, byte[] fft, int samplingRate) {// TODO Auto-generated method stubupdateVisualizer(fft);}}, Visualizer.getMaxCaptureRate() / 2, false, true);mVisualizer.setEnabled(true);} catch (Exception e) {// TODO Auto-generated catch blockerrorPaint = new Paint();errorPaint.setColor(Color.argb(230, 255, 255, 255));errorPaint.setTextSize(20);error = true;e.printStackTrace();}}/** * 释放并回收VisualizerView对象 */public void releaseVisualizerFx() {if (mVisualizer == null) {return;}canDrawLines = false;// 停止画线mVisualizer.setEnabled(false);mHandler.postDelayed(runnable, REFRESH_TIME);}// 初始化画笔private void init() {mRect = new Rect();mHandler = new Handler();linesPaint = new Paint();linesPaint.setStrokeWidth(5f);linesPaint.setAntiAlias(true);linesPaint.setColor(Color.argb(230, 134, 221, 140));pointsPaint = new Paint();pointsPaint.setStrokeWidth(5f);pointsPaint.setAntiAlias(true);pointsPaint.setColor(Color.argb(180, 218, 112, 214));int[] a = { 0, 1, 2 };initByte();}/** * 初始化FFT源数组，赋值为1的目的是能够一开始就绘制频谱，初始化的目地即重新归位 */private void initByte() {mBytes = new byte[mSpectrumNum];for (int i = 0; i < mSpectrumNum; i++) {mBytes[i] = 0;}}private void updateVisualizer(byte[] mbyte) {byte[] model = new byte[mbyte.length / 2 + 1];//Log.i("mbyte", mbyte[0]+"");model[0] = (byte) Math.abs(mbyte[0]);//Log.i("mbyte", model[0]+"");for (int i = 2, j = 1; j < mSpectrumNum;) {//返回值为sqrt(x2 +y2);model[j] = (byte) Math.hypot(mbyte[i], mbyte[i + 1]);i += 2;j++;}mBytes = model;invalidate();}/** * 自由落体运算{h=(1/2)*g*t^2} * * @param time *            时间 * @return 运动的距离 */private float freeFall(float time) {float h = ACCELERATION * time * time / 2;return h;}private Runnable runnable = new Runnable() {@Overridepublic void run() {// TODO Auto-generated method stubinvalidate();if (times < TIMES_MAX) {if (times == 1) {initByte();// 跳过一次，可能onFftDataCapture会再回调一次，初始化就没意义了}mHandler.postDelayed(this, REFRESH_TIME);}times++;}};@Overrideprotected void onDraw(Canvas canvas) {// TODO Auto-generated method stubsuper.onDraw(canvas);if (mBytes == null) {return;}if (error) {String s = "可视化效果初始化失败";canvas.drawText(s, getWidth() / 2 - errorPaint.measureText(s) / 2,getHeight() / 2, errorPaint);return;}int length = mSpectrumNum * 4;if (linesArray == null || linesArray.length < length) {linesArray = new float[length];}length = mSpectrumNum * 2;if (pointsArray == null || pointsArray.length < length) {pointsArray = new float[length];}length = mSpectrumNum * 3;if (tempArray == null || tempArray.length < length) {tempArray = new float[length];for (int l = 0; l < length; l++) {if (l % 3 == 0) {continue;// 数组指针是3的倍数初值必须为0}tempArray[l] = 1024;// 赋予一个足够大的初始值(应该够大了吧)，否则一开始点会从上面落下来}}mRect.set(0, 0, getWidth(), getHeight());/************ 绘制波形 ************///for (int i = 0; i < mBytes.length - 1; i++) {// linesArray[i * 4] = mRect.width() * i / (mBytes.length - 1);// linesArray[i * 4 + 1] = mRect.height() / 2// + ((byte) (mBytes[i] + 128)) * (mRect.height() / 2) / 128;// linesArray[i * 4 + 2] = mRect.width() * (i + 1) / (mBytes.length -// 1);// linesArray[i * 4 + 3] = mRect.height() / 2// + ((byte) (mBytes[i + 1] + 128)) * (mRect.height() / 2)// / 128;// }/************ 绘制柱状频谱 ************/final int baseX = mRect.width() / mSpectrumNum;final int height = mRect.height();for (int i = 0; i < mSpectrumNum; i++) {if (mBytes[i] < 0) {mBytes[i] = 127;}final int x = baseX * i + baseX / 2;if (canDrawLines) {// 两点构成一条直线(垂直)linesArray[i * 4] = x;// 起始点X坐标linesArray[i * 4 + 1] = height;// 起始点Y坐标linesArray[i * 4 + 2] = x;// 终点X坐标linesArray[i * 4 + 3] = height - mBytes[i];// 终点Y坐标if(colorPostion>=11)colorPostion=0;linesPaint.setColor(colorArray[colorPostion]);colorPostion++;//Log.i("height", height+"");//Log.i("height-2", height - mBytes[i]+"");canvas.drawLine(x, height, x, height - 3*mBytes[i], linesPaint);}// 线终点位置的高度减去一个数就会出现在线的上方，反之在下方int y = height - 3*mBytes[i] - 3;if (tempArray[i * 3 + 1] > y) {// 记住的位置比现在的大，也就是最新的位置更高了tempArray[i * 3] = x;tempArray[i * 3 + 1] = y;// 记住现在的最高位置tempArray[i * 3 + 2] = 0;// 一定要归0pointsArray[i * 2] = x;pointsArray[i * 2 + 1] = y;// 更高了就刷新呗} else {// 记住的位置比现在的小，说明该自由落体了tempArray[i * 3] = x;float ti = tempArray[i * 3 + 2];// 取出上次记忆的次数float temp = tempArray[i * 3 + 1] + freeFall(ti);// 加上自由落体运算tempArray[i * 3 + 2] = ++ti;// 自增一次temp = temp > y ? y : temp;// 不能跑到线下挡住了，判断一下让点归位tempArray[i * 3 + 1] = temp;pointsArray[i * 2] = x;pointsArray[i * 2 + 1] = tempArray[i * 3 + 1];// 刷新当前点}}if (canDrawLines) {if(colorPostion>=11)colorPostion=0;linesPaint.setColor(colorArray[colorPostion]);colorPostion++;canvas.drawLines(linesArray, linesPaint);}pointsPaint.setColor(colorArray[colorPostion]);canvas.drawPoints(pointsArray, pointsPaint);}@Overrideprotected void onDetachedFromWindow() {// TODO Auto-generated method stubtry {mHandler.removeCallbacks(runnable);// 确保移除线程super.onDetachedFromWindow();} catch (Exception e) {// TODO Auto-generated catch blocke.printStackTrace();}}}

记得加上权限：

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

平衡器的布局：

        <com.zhangli.myapplication.custom.VisualizerView            android:id="@+id/activity_player_visualizer"            android:layout_width="match_parent"            android:layout_height="300dp"            android:layout_below="@id/music_auther_txt"            android:layout_centerHorizontal="true"            android:layout_marginTop="55dp"/>

这是一个音乐播放器中的平衡器，所以用到这个平衡器时就要传入这个音乐资源的id，我用的是Mediaplayer，利用方法得到id后传入平衡器的setuoVisualizerFx（）方法中，平衡器开始工作。

int id=mediaPlayer.getAudioSessionId();visualizerView.setupVisualizerFx(id);

平衡器的效果图：