如何在Android中生成围绕圆的动态线

Question

我想在一个圆形的动态图片周围创建动态线条。线条的大小取决于总的回合数，如果总回合数为10，则10个线条适合该整体。

我尝试了下面的for循环中的代码，动态创建了线，但它们不是圆形的。请帮助我解决此问题。谢谢。

这是您可以在其中看到红色的图像。月球周围的黄绿线：

代码如下：

int Stages = 10;
int circleCircumfarence = 785;
int spaceBetweenLine = 10;
int allspacesSize = 785 - (spaceBetweenLine * Stages);
int onelinesize = allspacesSize / 10; //250 is the width of circle
int x1 = (int) imgCatfill.getWidth() / 2;//image of globe 
int y1 = 10;
int x2 = (int) x1 + onelinesize;
int y2 = x2 / 10;
int curveRadius = 5;
int midX = x1 + ((x2 - x1) / 2);
int midY = y1 + ((y2 - y1) / 2);
float xDiff = midX - x1;
float yDiff = midY - y1;
double angle = (Math.atan2(yDiff, xDiff) * (180 / Math.PI)) - 45;
double angleRadians = Math.toRadians(angle);
float pointX = (float) (midX + curveRadius * Math.cos(angleRadians));
float pointY = (float) (midY + curveRadius * Math.sin(angleRadians));
path.moveTo(x1, y1);
path.cubicTo(x1, y1, pointX, pointY, x2, y2);
canvas.drawPath(path, paint);

Answer 1

这可以通过使用方法canvas.drawTextOnPath并根据文本宽度更改x和y位置来完成

参考代码

private String QUOTE = "123456789123456789";
private Path circle;
private Paint mCirlcePaint;
private Paint tPaint;
private Rect textBounds;
private int mTextWidth, mTextHeight, centerX, centerY;

private float radius;

public GraphicsView(Context context) {
    super(context);
    circle = new Path();

    tPaint = new Paint(Paint.ANTI_ALIAS_FLAG);
    tPaint.setStyle(Paint.Style.FILL_AND_STROKE);
    tPaint.setColor(Color.RED);
    tPaint.setTextSize(80f);
    textBounds = new Rect();

    tPaint.getTextBounds(QUOTE, 0, QUOTE.length(), textBounds);
    mTextWidth = Math.round(tPaint.measureText(QUOTE.toString())); // Use measureText to calculate width
    mTextHeight = textBounds.height(); // Use height from getTextBounds()

    mCirlcePaint = new Paint();
    mCirlcePaint.setStyle(Paint.Style.FILL);
    mCirlcePaint.setColor(Color.BLUE);

    radius = (float) ((mTextWidth) / (Math.PI));

}

@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
    centerX = w / 2;
    centerY = h / 2;

}

@Override
protected void onDraw(Canvas canvas) {

    canvas.rotate(180, getWidth() / 2, getHeight() / 2);
    canvas.drawCircle(centerX, centerY, radius, mCirlcePaint);
    circle.addCircle(centerX, centerY, radius, Path.Direction.CW);
    canvas.drawTextOnPath(QUOTE, circle, 0, 0, tPaint);

   }

}

如果文本长度大于画布，则需要减小文本大小或使用完整的圆圈。 replace radius = (float) ((mTextWidth) / (Math.PI))与radius = (float) ((mTextWidth) / (2*(Math.PI)))