mysurfaceview.java

Android开发精典案例60个

package com.qpath;

import java.util.Random;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Path;
import android.view.KeyEvent;
import android.view.MotionEvent;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;

/**
 * 赛贝尔曲线
 * @author Himi
 * 
 */
public class MySurfaceView extends SurfaceView implements Callback, Runnable {
	private SurfaceHolder sfh;
	private Paint paint;
	private Thread th;
	private boolean flag;
	private Canvas canvas;
	public static int screenW, screenH;
	// -----------以上是SurfaceView游戏框架
	// 贝赛尔曲线成员变量(起始点，控制（操作点），终止点，3点坐标)
	private int startX, startY, controlX, controlY, endX, endY;
	// Path
	private Path path;
	// 为了不影响主画笔，这里绘制贝赛尔曲线单独用一个新画笔
	private Paint paintQ;
	// 随机库（让贝赛尔曲线更明显）
	private Random random;

	/**
	 * SurfaceView初始化函数
	 */
	public MySurfaceView(Context context) {
		super(context);
		sfh = this.getHolder();
		sfh.addCallback(this);
		paint = new Paint();
		paint.setColor(Color.WHITE);
		paint.setAntiAlias(true);
		setFocusable(true);
		// -----------以上是SurfaceView游戏框架
		//贝赛尔曲线相关初始化
		path = new Path();
		paintQ = new Paint();
		paintQ.setAntiAlias(true);
		paintQ.setStyle(Style.STROKE);
		paintQ.setStrokeWidth(5);
		paintQ.setColor(Color.WHITE);
		random = new Random();
	}

	/**
	 * SurfaceView视图创建，响应此函数
	 */
	public void surfaceCreated(SurfaceHolder holder) {
		screenW = this.getWidth();
		screenH = this.getHeight();
		flag = true;
		// 实例线程
		th = new Thread(this);
		// 启动线程
		th.start();
		// -----------以上是SurfaceView游戏框架
	}

	/**
	 * 游戏绘图
	 */
	public void myDraw() {
		try {
			canvas = sfh.lockCanvas();
			if (canvas != null) {
				canvas.drawColor(Color.BLACK);
				// -----------以上是SurfaceView游戏框架
				drawQpath(canvas);
			}
		} catch (Exception e) {
			// TODO: handle exception
		} finally {
			if (canvas != null)
				sfh.unlockCanvasAndPost(canvas);
		}
	}

	/**
	 * 绘制贝赛尔曲线
	 * 
	 * @param canvas 主画布
	 */
	public void drawQpath(Canvas canvas) {
		path.reset();// 重置path
		// 贝赛尔曲线的起始点
		path.moveTo(startX, startY);
		// 设置贝赛尔曲线的操作点以及终止点
		path.quadTo(controlX, controlY, endX, endY);
		// 绘制贝赛尔曲线（Path）
		canvas.drawPath(path, paintQ);
	}

	/**
	 * 触屏事件监听
	 */
	@Override
	public boolean onTouchEvent(MotionEvent event) {
		endX = (int) event.getX();
		endY = (int) event.getY();
		return true;
	}

	/**
	 * 游戏逻辑
	 */
	private void logic() {
		if (endX != 0 && endY != 0) {
			// 设置操作点为线段x/y的一半
			controlX = random.nextInt((endX - startX) / 2);
			controlY = random.nextInt((endY - startY) / 2);
		}
	}

	/**
	 * 按键事件监听
	 */
	@Override
	public boolean onKeyDown(int keyCode, KeyEvent event) {
		return super.onKeyDown(keyCode, event);
	}

	public void run() {
		while (flag) {
			long start = System.currentTimeMillis();
			myDraw();
			logic();
			long end = System.currentTimeMillis();
			try {
				if (end - start < 50) {
					Thread.sleep(50 - (end - start));
				}
			} catch (InterruptedException e) {
				e.printStackTrace();
			}
		}
	}

	/**
	 * SurfaceView视图状态发生改变，响应此函数
	 */
	public void surfaceChanged(SurfaceHolder holder, int format, int width,
			int height) {
	}

	/**
	 * SurfaceView视图消亡时，响应此函数
	 */
	public void surfaceDestroyed(SurfaceHolder holder) {
		flag = false;
	}
}