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

我不是女神ヾ 2022-06-18 06:11 178阅读 0赞

**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**][http_blog.csdn.net_xiaominghimi_archive_2010_12_21_6090631.aspx]

各位童鞋请你们注意：surfaceview中确实有 onDraw这个方法，但是surfaceview不会自己去调用！！！

**  而我代码中的ondraw 也好 draw 也好，都是我自己定义的一个方法。。。放在线程中不断调用的，一定要注意！!**

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

此方法是用来响应按键！如果是自己定义一个继承自View的类,重新实现onKeyDown方法后,只有当该View获得焦点时才会调用onKeyDown方法,Actvity中的onKeyDown方法是当所有控件均没有处理该按键事件时,才会调用.

** 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

对于 canvas.save();和canvas.restore();  还有不少童鞋不懂，OK、我再补充点：

代码段1：

public void draw() { 
        Canvas canvas = sfh.lockCanvas();  
        canvas.drawColor(Color.BLACK);
        canvas.drawBitmap(bmp1, 0,0,paint);
        canvas.save(); 
        canvas.scale(1.5f, 1.5f);
        canvas.restore(); 
        canvas.drawBitmap(bmp2, 0,0,paint);
        sfh.unlockCanvasAndPost(canvas);  
      }

代码段2：

public void draw() { 
        Canvas canvas = sfh.lockCanvas();  
        canvas.drawColor(Color.BLACK);
        canvas.drawBitmap(bmp1, 0,0,paint);
        canvas.scale(1.5f, 1.5f);
        canvas.drawBitmap(bmp2, 0,0,paint);
        sfh.unlockCanvasAndPost(canvas);  
      }

上面这两个代码片段中我们都假设有两张图片 bmp1和bmp2，并且都画在画布上!

那么代码段1和代码段2的不同:

**代码段1**中我们进行画布缩放的之前保存了画布状态，做了缩放操作之后又取出之前保存的状态，这样做是为了保证bmp2正常画出来不受到缩放的影响！

**代码段2**里，画了bmp1后就执行了缩放操作，并且没有保存状态！紧接着画了bmp2，那么bmp2也会一样受到缩放的影响！！

所以我们如果单独处理一张图片的时候，而且不想影响其他部分的绘制，那么应该如下来做：

public void draw() { 
        Canvas canvas = sfh.lockCanvas();  
        canvas.drawColor(Color.BLACK);
        canvas.drawBitmap(bmp1, 0,0,paint);
        canvas.save(); 
        canvas.scale(1.5f, 1.5f);
        canvas.drawBitmap(bmp2, 0,0,paint);
        canvas.restore(); 
        sfh.unlockCanvasAndPost(canvas);  
      }

源码下载地址：  [http://download.csdn.net/source/2927823][http_download.csdn.net_source_2927823]

[http_blog.csdn.net_xiaominghimi_archive_2010_12_21_6090631.aspx]: http://blog.csdn.net/xiaominghimi/archive/2010/12/21/6090631.aspx
[http_download.csdn.net_source_2927823]: http://download.csdn.net/source/2927823