我正在尝试绘制由细线组成的心电图，但是当我调用该Canvas drawLine方法时，该方法会像形状一样填充线条的顶部
这是绘制图表的类：
public class ECGView extends View{
private Bitmap mBitmap;
private Paint mPaint = new Paint();
private Canvas mCanvas = new Canvas();
private final float MAX_MILISECONDS = 5000f;
private final float INTERVAL = 4;
private float maxValue = 0;
private float minValue = 1023;
private float maxX;
private float deltaX;
private float lastX;
private float maxY;
private float deltaY;
private float lastY;
private int lineColor = Color.argb(192, 0, 0, 128);
public ECGView(Context context) {
super(context);
mPaint.setFlags(Paint.ANTI_ALIAS_FLAG);
mPaint.setColor(lineColor);
mPaint.setStyle(Style.STROKE);
//mPaint.setStrokeWidth(0.5f);
lastX = 0;
lastY = 0;
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
mBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.RGB_565);
mCanvas.setBitmap(mBitmap);
mCanvas.drawColor(0xFFFFFFFF);
maxY = h;
maxX = w;
deltaX = maxX/(MAX_MILISECONDS/INTERVAL);
lastX = maxX;
super.onSizeChanged(w, h, oldw, oldh);
}
@Override
protected void onDraw(Canvas canvas) {
if(mBitmap != null){
final Canvas cavas = mCanvas;
if(lastX >= maxX){
lastX = 0;
cavas.drawColor(0xFFFFFFFF);
}
canvas.drawBitmap(mBitmap, 0, 0, null);
}
super.onDraw(canvas);
}
public synchronized void addData(short[] values){
if(mBitmap != null){
final Canvas canvas = mCanvas;
final Paint paint = mPaint;
for(short value : values){
if(value > maxValue) maxValue = value;
if(value < minValue) minValue = value;
if(minValue == maxValue)
deltaY = maxY/1023.0f;
else{
deltaY =maxY/(maxValue-minValue);
value -= minValue;
}
final float newX = lastX+deltaX;
final float newY = deltaY*value;
canvas.drawLine(lastX, lastY, newX, newY, paint);
lastX += deltaX;
invalidate();
}
}
}
}
我错过了什么吗？