之前一直做的是应用类，这次抽时间，参考网上资料实践了下SurfaceView。目标是在页面上画一个科赫曲线的分形图。

代码如下：

package com.example.fredric.demo02;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Rect;import android.os.Bundle;import android.support.design.widget.FloatingActionButton;import android.support.design.widget.Snackbar;import android.support.v7.app.AppCompatActivity;import android.support.v7.widget.Toolbar;import android.view.Surface;import android.view.SurfaceHolder;import android.view.SurfaceView;import android.view.View;import android.view.Menu;import android.view.MenuItem;import android.view.WindowManager;public class MainActivity extends AppCompatActivity {    private int width;    private int height;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);        width = wm.getDefaultDisplay().getWidth();        height = wm.getDefaultDisplay().getHeight();        setContentView(new MyView(this));    }    //知识点备注：    //1、Surface:原始图像缓冲区的句柄，通过该接口可以获取原始缓冲区中的数据；    //Surface 中包含canvas对象    //2、SurfaceView:继承至View，    // 2.1 提供了一个运行在渲染线程的surface    // 2.2 SurfaceView 和 SurfaceHolder.Callback的方法都应该在主线程（UI线程）里面调用    //3、SurfaceHolder:控制surface的一个抽象接口    //4、SurfaceHolder.Callback: 监听Surface改变的接口    class MyView extends SurfaceView implements SurfaceHolder.Callback {        private SurfaceHolder holder;        private MyThread myThread;        public MyView(Context context) {            super(context);            // TODO Auto-generated constructor stub            holder = this.getHolder();            holder.addCallback(this);            myThread = new MyThread(holder);        }        @Override        public void surfaceCreated(SurfaceHolder holder) {            myThread.isRun = true;            myThread.start();        }        @Override        public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {        }        @Override        public void surfaceDestroyed(SurfaceHolder holder) {            myThread.isRun = false;        }        class MyThread extends Thread {            private SurfaceHolder holder;            public boolean isRun;            public MyThread(SurfaceHolder holder) {                this.holder = holder;                isRun = true;            }            @Override            public void run() {                int count = 0;                while (isRun) {                    Canvas c = null;                    c = this.holder.lockCanvas();                    try {                        synchronized (holder) {                            if (null != c){                                c.drawColor(Color.WHITE);                                Paint p = new Paint();                                p.setColor(Color.BLUE);                                p.setStrokeWidth((float) 5.0);                                draw(c, p, 0, 0, width, height, 6);                                Thread.sleep(1000);                                isRun = false;                            }                        }                    } catch (Exception e) {                        e.printStackTrace();                    } finally {                        if (c != null) {                            // 此时才提交绘画结果                            holder.unlockCanvasAndPost(c);                        }                    }                }            }        }//class MyThread extends Thread {
            public void draw(Canvas c, Paint p, int x1, int y1, int x2, int y2,int depth) {            c.drawLine(x1, y1, x2, y2, p);            if (depth <= 1) {                return;            }            else {
   //得到三等分点                double x11 = (x1 * 2  + x2)  / 3;                double y11 = (y1 * 2  + y2)  / 3;                double x22 = (x1 + x2 * 2) / 3;                double y22 = (y1 + y2 * 2) / 3;                double x33 = (x11 + x22) / 2 - (y11 - y22) * Math.sqrt(3) / 2;                double y33 = (y11 + y22) / 2 - (x22 - x11) * Math.sqrt(3) / 2;                c.drawLine(x1, y1, x2, y2, p);                draw(c, p, x1, y1, (int) x11, (int) y11, depth - 1);                draw(c, p, (int) x11, (int) y11, (int) x33, (int) y33, depth - 1);                draw(c, p, (int) x22, (int) y22, x2, y2, depth - 1);                draw(c, p, (int) x33, (int) y33, (int) x22, (int) y22, depth - 1);            }        }    }}

结果：