Android（26） 
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新建项目，新建MusicRectangleView继承自View并重写onDraw和onSizeChanged方法，onDraw方法用于绘制矩形，onSizeChanged主要用于为矩形添加LinearGradient渐变，完整后新建变量如下：
private Paint mPaint;
public int mOffset = 10;
public int mRectWidth ;
public int mRectHeight ;
private int mRectCount = 10;
private float currentHeight;
private int mWidth;
private LinearGradient mLinearGradient;- 1
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修改onDraw方法如下：
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
for (int i=0;i<mRectCount;i++){
currentHeight = (float)(Math.random()*mRectHeight);
canvas.drawRect((float)(mWidth*0.4/2+mRectWidth*i+mOffset),currentHeight,(float)(mWidth*0.4/2+mRectWidth*(i+1)),mRectHeight,mPaint);
postInvalidateDelayed(300);
}
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修改onSizeChanged方法如下：
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
mPaint = new Paint();
mWidth = getWidth();
mRectHeight = getHeight();
mRectWidth = (int)(mWidth*0.6/mRectCount);
mLinearGradient = new LinearGradient(0,0,mRectWidth,mRectHeight, Color.YELLOW,Color.BLUE, Shader.TileMode.CLAMP);
mPaint.setShader(mLinearGradient);
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自此就完成了一个音频条形图的绘制，效果如下：
源文件下载地址：源文件