【Android2D游戏开发之四】Android 游戏框架（一个游戏角色在屏幕行走的demo）

        其实上一篇分析surfaceview的文章就是一个简单的游戏框架了，当然这里再强调一下，简单的游戏框架，所以不要高手们不要乱喷~

 这个Demo是给群里一童鞋写的一个对图片操作以及按键处理，游戏简单框架的一个demo，这里放出给大家分享~

package com.himi; import android.content.Context; import android.content.res.Resources; import android.graphics.Bitmap; import android.graphics.BitmapFactory; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.util.Log; import android.view.KeyEvent; import android.view.SurfaceHolder; import android.view.SurfaceView; import android.view.SurfaceHolder.Callback; public class MySurfaceView extends SurfaceView implements Callback, Runnable { private Thread th = new Thread(this); private SurfaceHolder sfh; private int SH, SW; private Canvas canvas; private Paint p; private Paint p2; private Resources res; private Bitmap bmp; private int bmp_x = 100, bmp_y = 100; private boolean UP, DOWN, LEFT, RIGHT; private int animation_up[] = { 3, 4, 5 }; private int animation_down[] = { 0, 1, 2 }; private int animation_left[] = { 6, 7, 8 }; private int animation_right[] = { 9, 10, 11 }; private int animation_init[] = animation_down; private int frame_count; public MySurfaceView(Context context) { super(context); this.setKeepScreenOn(true); res = this.getResources(); bmp = BitmapFactory.decodeResource(res, R.drawable.enemy1); sfh = this.getHolder(); sfh.addCallback(this); p = new Paint(); p.setColor(Color.YELLOW); p2 = new Paint(); p2.setColor(Color.RED); p.setAntiAlias(true); setFocusable(true); //备注1 } public void surfaceCreated(SurfaceHolder holder) { SH = this.getHeight(); SW = this.getWidth(); th.start(); } public void draw() { canvas = sfh.lockCanvas(); canvas.drawRect(0, 0, SW, SH, p); //备注2 canvas.save(); //备注3 canvas.drawText("Himi", bmp_x-2, bmp_y-10, p2); canvas.clipRect(bmp_x, bmp_y, bmp_x + bmp.getWidth() / 13, bmp_y+bmp.getHeight()); if (animation_init == animation_up) { canvas.drawBitmap(bmp, bmp_x - animation_up[frame_count] * (bmp.getWidth() / 13), bmp_y, p); } else if (animation_init == animation_down) { canvas.drawBitmap(bmp, bmp_x - animation_down[frame_count] * (bmp.getWidth() / 13), bmp_y, p); } else if (animation_init == animation_left) { canvas.drawBitmap(bmp, bmp_x - animation_left[frame_count] * (bmp.getWidth() / 13), bmp_y, p); } else if (animation_init == animation_right) { canvas.drawBitmap(bmp, bmp_x - animation_right[frame_count] * (bmp.getWidth() / 13), bmp_y, p); } canvas.restore(); //备注3 sfh.unlockCanvasAndPost(canvas); } public void cycle() { if (DOWN) { bmp_y += 5; } else if (UP) { bmp_y -= 5; } else if (LEFT) { bmp_x -= 5; } else if (RIGHT) { bmp_x += 5; } if (DOWN || UP || LEFT || RIGHT) { if (frame_count < 2) { frame_count++; } else { frame_count = 0; } } if (DOWN == false && UP == false && LEFT == false && RIGHT == false) { frame_count = 0; } } @Override public boolean onKeyDown(int key, KeyEvent event) { if (key == KeyEvent.KEYCODE_DPAD_UP) { if (UP == false) { animation_init = animation_up; } UP = true; } else if (key == KeyEvent.KEYCODE_DPAD_DOWN) { if (DOWN == false) { animation_init = animation_down; } DOWN = true; } else if (key == KeyEvent.KEYCODE_DPAD_LEFT) { if (LEFT == false) { animation_init = animation_left; } LEFT = true; } else if (key == KeyEvent.KEYCODE_DPAD_RIGHT) { if (RIGHT == false) { animation_init = animation_right; } RIGHT = true; } return super.onKeyDown(key, event); } /* (non-Javadoc) * @see android.view.View#onKeyUp(int, android.view.KeyEvent) */ @Override public boolean onKeyUp(int keyCode, KeyEvent event) { if (DOWN) { DOWN = false; } else if (UP) { UP = false; } else if (LEFT) { LEFT = false; } else if (RIGHT) { RIGHT = false; } return super.onKeyUp(keyCode, event); } @Override public void run() { // TODO Auto-generated method stub while (true) { draw(); cycle(); try { Thread.sleep(100); } catch (Exception ex) { } } } @Override public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) { // TODO Auto-generated method stub } @Override public void surfaceDestroyed(SurfaceHolder holder) { // TODO Auto-generated method stub } }

 备注1

   此方法是用来绑定按键，这里不同于继承view，如果是继承view的画是不需要绑定按键也能自响应事件

 备注2

   这里也是对屏幕进行刷屏操作，其实这也只是一种，之前文章里我也用到drawRGB的方法同样实现，当然也可以用fillRect等来刷屏。

    那么这里我想说下，在继承view中，因为onDraw方法是系统自动调用的，不像在surfaceview这里这样去在run里面自己去不断调用，在view中我们可以抵用 invalidate()/postInvalidate() 这两种方法实现让系统调用onDraw方法，这里也是和surfaceview中的不同之一！

 备注3

   这里canvas.save();和canvas.restore();是两个相互匹配出现的，作用是用来保存画布的状态和取出保存的状态的。这里稍微解释一下，

   当我们对画布进行旋转，缩放，平移等操作的时候其实我们是想对特定的元素进行操作，比如图片，一个矩形等，但是当你用canvas的方法来进行这些操作的时候，其实是对整个画布进行了操作，那么之后在画布上的元素都会受到影响，所以我们在操作之前调用canvas.save()来保存画布当前的状态，当操作之后取出之前保存过的状态，这样就不会对其他的元素进行影响

源码下载地址：  http://download.csdn.net/source/2927823

Himi  原创， 转载请注明！ 谢谢。

  原文地址： http://blog.csdn.net/xiaominghimi/archive/2010/12/21/6090631.aspx