android开发分享Android提高之SurfaceView的基本用法实例分析

  <?xml version="1.0" encoding="utf-8"?>  <linearlayout xmlns:android="https://schemas.android.com/apk/res/android"   android:layout_width="fill_parent" android:layout_height="fill_parent"   android:orientation="vertical">     <linearlayout android:id="@+id/linearlayout01"   android:layout_width="wrap_content" android:layout_height="wrap_content">   <button android:id="@+id/button01" android:layout_width="wrap_content"   android:layout_height="wrap_content" android:text="简单绘画"></button>   <button android:id="@+id/button02" android:layout_width="wrap_content"   android:layout_height="wrap_content" android:text="定时器绘画"></button>   </linearlayout>   <surfaceview android:id="@+id/surfaceview01"   android:layout_width="fill_parent" android:layout_height="fill_parent"></surfaceview>  </linearlayout>    

  package com.testsurfaceview;  import java.util.timer;  import java.util.timertask;  import android.app.activity;  import android.graphics.canvas;  import android.graphics.color;  import android.graphics.paint;  import android.graphics.rect;  import android.os.bundle;  import android.util.log;  import android.view.surfaceholder;  import android.view.surfaceview;  import android.view.view;  import android.widget.button;    public class testsurfaceview extends activity {   /** called when the activity is first created. */   button btnsimpledraw, btntimerdraw;   surfaceview sfv;   surfaceholder sfh;     private timer mtimer;   private mytimertask mtimertask;   int y_axis[],//保存正弦波的y轴上的点   centery,//中心线   oldx,oldy,//上一个xy点    currentx;//当前绘制到的x轴上的点     @override   public void oncreate(bundle savedinstancestate) {   super.oncreate(savedinstancestate);   setcontentview(r.layout.main);   btnsimpledraw = (button) this.findviewbyid(r.id.button01);   btntimerdraw = (button) this.findviewbyid(r.id.button02);   btnsimpledraw.setonclicklistener(new clickevent());   btntimerdraw.setonclicklistener(new clickevent());   sfv = (surfaceview) this.findviewbyid(r.id.surfaceview01);   sfh = sfv.getholder();     //动态绘制正弦波的定时器   mtimer = new timer();   mtimertask = new mytimertask();     // 初始化y轴数据   centery = (getwindowmanager().getdefaultdisplay().getheight() - sfv   .gettop()) / 2;   y_axis = new int[getwindowmanager().getdefaultdisplay().getwidth()];   for (int i = 1; i < y_axis.length; i++) {// 计算正弦波   y_axis[i - 1] = centery   - (int) (100 * math.sin(i * 2 * math.pi / 180));   }   }   class clickevent implements view.onclicklistener {     @override   public void onclick(view v) {     if (v == btnsimpledraw) {   simpledraw(y_axis.length-1);//直接绘制正弦波   } else if (v == btntimerdraw) {   oldy = centery;   mtimer.schedule(mtimertask, 0, 5);//动态绘制正弦波   }   }   }   class mytimertask extends timertask {   @override   public void run() {     simpledraw(currentx);   currentx++;//往前进   if (currentx == y_axis.length - 1) {//如果到了终点，则清屏重来   cleardraw();   currentx = 0;   oldy = centery;   }   }   }   /*   * 绘制指定区域   */   void simpledraw(int length) {   if (length == 0)   oldx = 0;   canvas canvas = sfh.lockcanvas(new rect(oldx, 0, oldx + length,   getwindowmanager().getdefaultdisplay().getheight()));// 关键:获取画布   log.i("canvas:",   string.valueof(oldx) + "," + string.valueof(oldx + length));   paint mpaint = new paint();   mpaint.setcolor(color.green);// 画笔为绿色   mpaint.setstrokewidth(2);// 设置画笔粗细   int y;   for (int i = oldx + 1; i < length; i++) {// 绘画正弦波   y = y_axis[i - 1];   canvas.drawline(oldx, oldy, i, y, mpaint);   oldx = i;   oldy = y;   }   sfh.unlockcanvasandpost(canvas);// 解锁画布，提交画好的图像   }   void cleardraw() {   canvas canvas = sfh.lockcanvas(null);   canvas.drawcolor(color.black);// 清除画布   sfh.unlockcanvasandpost(canvas);   }  }