在Android中利用动画效果绘制正弦波

来源：互联网发布：路易斯·蒙巴顿知乎编辑：程序博客网时间：2024/05/29 03:26

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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