我对Android很新，并且一直在使用Canvas。我试图画一个箭头，但是我只是在运转轴上，没有箭头正常工作。

我搜索了一下，发现了一个Java示例，但Android没有GeneralPath或AffineTransform。

现在我的代码看起来像以下(箭头看起来不像箭头)：

public class DrawableView extends View {

Context mContext;

private int centerX;

private int centerY;

private int radius;

private double arrLength;

private double arrHeading;

private int margin = 10;

public DrawableView(Context context) {

super(context);

mContext = context;

}

@Override

protected void onDraw(Canvas canvas) {

//Paint Background

Paint background = new Paint();

background.setColor(getResources().getColor(R.color.background);

canvas.drawRect(0, 0, getWidth(), getHeight(), background);

//Set vars for Arrow Paint

Paint paint = new Paint();

paint.setColor(getResources().getColor(R.color.arrowColor);

centerX = getWidth() / 2;

centerY = getHeight() / 2;

arrLength = radius - 10;

if(centerX < centerY)

radius = centerX - margin;

else

radius = centerY - margin;

//Draw Shaft

int[] xy = findArrowPos(arrLength, arrHeading);

canvas.drawLine(centerX, centerY, xy[0], xy[1], paint);

//Draw ArrowHead

//This is where I'm confused

}

private int[] findArrowPos(double length, double angle) {

int[] points = new int[2];

double theta = Math.toRadians(angle);

points[0] = centerX + (int) (length * Math.cos(theta));

points[1] = centerY + (int) (length * Math.sin(theta));

return points;

}

}

我已经看了以下线索以获得指导：