[Android实例] 波浪动画效果，正弦曲线绘制

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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;    }

这里写图片描述

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