How to do Visualizer while recording audio in android

Two important things:

• you need to convert live bytes (from mic) to numeric values inorder to plot them.

• Since you use a real-time graph, to plot those points use SurfaceView.

  Convert recording bytes to numeric values refer: Android: Listener to record sound if any sound occurs where you will see the variable "temp" holds the numerical value of your audio.

  Plot points These numeric values which indicates your Y values is plotted against increasing X (time interval) values (0,1,2..) as graph. Using SurfaceView eg..,

//canvas.drawLine(previous X value,previous Y value,X,Y, paint);
canvas.drawPoint(X,Y,paint);
SurfaceHolder.unlockCanvasAndPost(canvas);

You need not plot all values, for efficiency you can filter those values with your conditions and plot for certain intervals of time.

Hope this helps :)