[Android实例] 波浪动画效果，正弦曲线绘制

该篇文章从eoeAndroid搬迁过来的，原文地址：[Android实例] 波浪动画效果，正弦曲线绘制

我们都知道正弦曲线的表达式为y=Asin(ωx+φ)+k，所以，在该demo中，我自定义一个view，在view的onDraw函数里手动绘制波浪效果的正弦函数，根据x坐标和正弦曲线表达式获取y坐标，此时y=10 * Math.sin((i + angle) * Math.PI / 180) + 20;

主要代码：

@Override
    public void onDraw(Canvas canvas) {
        // TODO Auto-generated method stub
        super.onDraw(canvas);
        setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
        int height = getHeight();
        int width = getWidth();
        paint1.setColor(Color.rgb(205, 243, 246));
        paint2.setAlpha(200);
        paint2.setColor(Color.rgb(150, 206, 231));
        paint3.setAlpha(150);
        paint3.setColor(Color.rgb(89, 186, 231));
        double lineX = 0;
        double lineY1 = 0;
        double lineY2 = 0;
        double lineY3 = 0;
        for (int i = 0; i < width; i++) {
            lineX = i;
            if (isRun) {
                lineY1 = Math.sin((i + angle) * Math.PI / 180);
                lineY2 = 10 * Math.sin((i + angle) * Math.PI / 180) + 20;
                lineY3 = 20 * Math.sin((i + angle) * Math.PI / 180) + 50;
            } else {
                lineY1 = 0;
                lineY2 = 20;
                lineY3 = 50;
            }
            canvas.drawLine((int) lineX, (int) (lineY1 + height / 1.5),
                    (int) lineX + 1, (int) (lineY2 + height / 1.5), paint1);
            canvas.drawLine((int) lineX, (int) (lineY2 + height / 1.5),
                    (int) lineX + 1, (int) (lineY3 + height / 1.5), paint2);
            canvas.drawLine((int) lineX, (int) (lineY3 + height / 1.5),
                    (int) lineX + 1, height, paint3);
        }

    }

开启线程进行每隔1毫毛angle+1，当angle为360的时候，设置angle为0：

@Override
    public void run() {
        // TODO Auto-generated method stub
        while (isRun) {
            angle++;
            if (angle == 360) {
                angle = 0;
            }
            try {
                Thread.sleep(1);
            } catch (InterruptedException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
        }
    }

    public void start() {
        isRun = true;
        new Thread(this).start();
    }

    public void stop() {
        isRun = false;
        angle = 0;
    }

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