Android编程之SurfaceView实例详解

package com.rong.activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
/**
 * 自定义SurfaceView
 * 
 * @author 徐荣
 *
 */
public class XRSurfaceView extends SurfaceView implements SurfaceHolder.Callback, Runnable {
  // SurfaceView的宽
  int surfaceWidth;
  // SurfaceView的高
  int surfaceHeight;
  // SurfaceHolder对象
  SurfaceHolder mSurfaceHolder;
  // 开关线程的标志位
  boolean isRunning = true;
  // 画笔
  Paint mPaint;
  // 圆的半径
  float radius = 0;
  // 圆是变大还是缩小的状态
  boolean status = true;
  // 圆变化的速度
  int mSpeed = 3;
  public XRSurfaceView(Context context, AttributeSet attrs) {
    super(context, attrs);
    initView();
  }
  private void initView() {
    // 获取mSurfaceHolder
    mSurfaceHolder = getHolder();
    // 添加回调
    mSurfaceHolder.addCallback(this);
  }
  @Override
  public void surfaceCreated(SurfaceHolder holder) {
    isRunning = true;
    // 初始化画笔
    mPaint = new Paint();
    mPaint.setAntiAlias(true);
    mPaint.setColor(Color.BLUE);
    // 开启绘制线程
    new Thread(this).start();
  }
  @Override
  public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
    // 获取surface的宽
    surfaceWidth = width;
    // 获取surface的高
    surfaceHeight = height;
  }
  @Override
  public void surfaceDestroyed(SurfaceHolder holder) {
    // 关闭绘制线程
    isRunning = false;
  }
  @Override
  public void run() {
    Canvas mCanvas = null;
    while (isRunning) {
      try {
        // 锁定canva进行绘制
        mCanvas = mSurfaceHolder.lockCanvas(null);
        // 这个方法很重要，相当于重绘（一定要调用不然看不到效果）
        mCanvas.drawColor(Color.BLACK);
        // 画圆
        mCanvas.drawCircle((surfaceWidth / 2), (surfaceHeight / 2), radius, mPaint);
        // 更改半径变量
        if (status) {
          radius = radius + mSpeed;
          if (radius > 200) {
            status = false;
          }
        } else {
          radius = radius - mSpeed;
          if (radius < 0) {
            status = true;
          }
        }
      } catch (Exception e) {
        e.printStackTrace();
      } finally {
        // 解除画布锁
        mSurfaceHolder.unlockCanvasAndPost(mCanvas);
      }
    }
  }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:background="#ffffff"
  android:orientation="vertical" >
  <com.rong.activity.XRSurfaceView
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:layout_centerInParent="true"
    android:orientation="vertical" />
</RelativeLayout>