SurfaceView基本使用--动态画正弦函数

package com.zzw.TestSurfaceView;

import android.content.Context;

import android.graphics.Canvas;

import android.graphics.Color;

import android.graphics.Paint;

import android.graphics.Path;

import android.util.AttributeSet;

import android.util.DisplayMetrics;

import android.view.SurfaceHolder;

import android.view.SurfaceView;

/**

 * Created by zzw on 2016/6/28.

 * 描述:

 */

public class SinSurfaceView extends SurfaceView implements SurfaceHolder.Callback, Runnable {

    private int mWidth;

    private int mHeight;

    private double angle = 0;

    private SurfaceHolder mHolder;

    /**

     * 与SurfaceHolder绑定的Canvas

     */

    private Canvas mCanvas;

    /**

     * 用于绘制的线程

     */

    private Thread t;

    /**

     * 线程的控制开关

     */

    private boolean isRunning;

    public SinSurfaceView(Context context) {

        this(context, null);

    }

    public SinSurfaceView(Context context, AttributeSet attrs) {

        this(context, attrs, 0);

    }

    public SinSurfaceView(Context context, AttributeSet attrs, int defStyleAttr) {

        super(context, attrs, defStyleAttr);

        DisplayMetrics dm = getResources().getDisplayMetrics();

        mWidth = dm.widthPixels;

        mHeight = dm.heightPixels;

        mHolder = getHolder();

        mHolder.addCallback(this);

        // setZOrderOnTop(true);// 设置画布 背景透明

        // mHolder.setFormat(PixelFormat.TRANSLUCENT);

        //设置可获得焦点

        setFocusable(true);

        setFocusableInTouchMode(true);

        //设置常亮

        this.setKeepScreenOn(true);

    }

    @Override

    public void surfaceCreated(SurfaceHolder holder) {

        isRunning = true;

        t = new Thread(this);

        t.start();

    }

    @Override

    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {

    }

    @Override

    public void surfaceDestroyed(SurfaceHolder holder) {

        // 通知关闭线程

        isRunning = false;

    }

    @Override

    public void run() {

        // 不断的进行draw

        while (isRunning) {

            draw();

        }

    }

    private void drawCoordinates() {

        Path mPath = new Path();

        Paint paint = new Paint();

        paint.setStyle(Paint.Style.FILL);//设置画笔类型

        paint.setAntiAlias(true);//抗锯齿

        paint.setStyle(Paint.Style.STROKE);//设置为空心

        mCanvas.translate(20, mHeight / 2);// 将画布坐标原点移动到中心位置

        //绘制坐标原点

        paint.setColor(Color.RED);//设置画笔颜色

        paint.setStrokeWidth(10);//为了看得清楚,设置了较大的画笔宽度

        //绘制坐标轴4个断点

        mCanvas.drawPoints(new float[]{0, 0,

                mWidth * 0.9f, 0

                , mWidth * 0.9f * 0.75f, 0

                , mWidth * 0.9f * 0.5f, 0

                , mWidth * 0.9f * 0.25f, 0}, paint);

        paint.setStrokeWidth(1);//恢复画笔默认宽度

        mCanvas.drawLine(0, 0, mWidth * 0.9f, 0, paint);

        mCanvas.drawLine(0, -mHeight / 2 * 0.9f, 0, mHeight / 2 * 0.9f, paint);

        mPath.moveTo(mWidth * 0.9f * 0.95f, -mWidth * 0.9f * 0.05f);

        mPath.lineTo(mWidth * 0.9f, 0);

        mPath.lineTo(mWidth * 0.9f * 0.95f, mWidth * 0.9f * 0.05f);

        //绘制Path

        mCanvas.drawPath(mPath, paint);

    }

    private void drawSin() {

        Paint paint = new Paint();

        paint.setStyle(Paint.Style.FILL);//设置画笔类型

        paint.setAntiAlias(true);//抗锯齿

        paint.setStyle(Paint.Style.STROKE);//设置为空心

        paint.setStrokeWidth(5);

        //绘制坐标原点

        paint.setColor(Color.RED);//设置画笔颜色

        double x = mWidth * 0.9f * (angle / 360);

//        double y = Math.sin((Math.PI / 180) * angle) * mWidth * 0.9f * 0.2;// π/180乘于角度为弧度

//        mCanvas.drawPoint((float) x, -(float) y, paint);

        for (int i = 1; i < 6; i++) {

            double y = Math.sin((Math.PI / 180) * angle) * mWidth * 0.9f * 0.15 * i;// π/180乘于角度为弧度

            mCanvas.drawPoint((float) x, -(float) y, paint);

        }

        angle += 1;

        if (angle > 360) {

            isRunning = false;

        }

    }

    private void draw() {

        try {

            Thread.sleep(1);

            // 获得canvas

            mCanvas = mHolder.lockCanvas();

            if (mCanvas != null) {

                drawCoordinates();

                drawSin();

            }

        } catch (Exception e) {

        } finally {

            if (mCanvas != null)

                mHolder.unlockCanvasAndPost(mCanvas);

        }

    }

}