我对 SurfaceView 有疑问。
函数 DrawWave 由定时器间隔 5ms 调用，但实际上两次调用之间需要超过 30ms，（我尝试删除 drawColor，drawPath）。
我尝试了“模式1”和“模式2”，通过使用Dirty rect，希望它可以运行得更快。Interval是一样的，都是30ms以上，（这个宽度是800px，eScrX-sScrX<20px）
问题 1：使用 SurfaceView/SurfaceHolder 是不是我做错了什么？
问题2：如何提高绘图速度？我希望它能在 10 毫秒内完成绘图。
我的代码：
public class VS_VChannel extends SurfaceView
{//Wave Show Class
//-------------------------------------------------------------------------------
private Paint paint = new Paint();
private SurfaceHolder sHolder = null;
private Canvas cvs = null;
private Path P = new Path();
//Data source of the wave point Y
protected VSChannel Channel = null;
private float drawY;
//-------------------------------------------------------------------------------
public VS_VChannel(Context context)
{
super(context);
}
//------------------------------------------------------------------------------
public VS_VChannel(Context context, AttributeSet attrs)
{
super(context, attrs);
//Bind the wave data source whith AttributeSet name:vs_wave
String vsName = attrs.getAttributeValue(null, "vs_wave");
Channel = (VSChannel)VS.GetItem(vsName);//Find the wave data source from collection with name
//
paint.setAntiAlias(true);
paint.setDither(true);
paint.setColor(Channel.getColor());
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(2);
//
sHolder = this.getHolder();
this.setZOrderOnTop(true);
sHolder.setFormat(PixelFormat.TRANSPARENT);
}
//------------------------------------------------------------------------------
/** DrawWave is Call by a timer Interval 5ms,
* BUT actually it need more than 30ms between twice call,(tried delete drawColor, drawPath)
* I try as "Mode 1" and "Mode 2", by using Dirty rect, hope it can run faster
* The Interval is the same, both more than 30ms,
* (The width of this is 800px, and eScrX-sScrX<20px)
*/
protected void DrawWave(int sScrX, int eScrX)
{
Rect rect = new Rect(sScrX, 0, eScrX+8, getHeight()); //Mode 1
//Rect rect = new Rect(0, 0, getWidth(), getHeight()); //Mode 2
//
cvs = sHolder.lockCanvas(rect);
cvs.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
cvs.drawPath(P, paint);
sHolder.unlockCanvasAndPost(cvs);
}
//-------------------------------------------------------------------------------
protected void GetWaveY()
{
drawY = Channel.GetWaveY(getHeight());
}
//-------------------------------------------------------------------------------
protected void MoveTo(float x)
{
P.moveTo(x, drawY);
}
//-------------------------------------------------------------------------------
protected void LineTo(float x)
{
P.lineTo(x, drawY);
}
//-------------------------------------------------------------------------------
protected void DrawReturn()
{
P.reset();//Clear
P.moveTo(0, drawY);
}
//-------------------------------------------------------------------------------
}
//-------------------------------------------------------------------------------