【ANDROID游戏开发之四】基础的ANDROID 游戏框架（一个游戏角色在屏幕行走的DEMO）-阿里云开发者社区

本站文章均为李华明Himi 原创,转载务必在明显处注明：

转载自【黑米GameDev街区】原文链接: http://www.himigame.com/android-game/298.html

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『很多童鞋说我的代码运行后，点击home或者back后会程序异常，如果你也这样遇到过，那么你肯定没有仔细读完Himi的博文，第十九篇Himi专门写了关于这些错误的原因和解决方法，这里我在博客都补充说明下，省的童鞋们总疑惑这一块；请点击下面联系进入阅读：

【Android游戏开发十九】(必看篇)SurfaceView运行机制详解—剖析Back与Home按键及切入后台等异常处理！』

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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，以不要高手们不要乱喷哦 :kl: ~

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~

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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 &lt; 2) {

                frame_count++;

            } else {

                frame_count = 0;

            }

        }

        if (DOWN == false &amp;&amp; UP == false &amp;&amp; LEFT == false &amp;&amp; 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：

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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：

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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：

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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);

  }

本章源码下载： “Himi-Android游戏框架源码.rar” 下载地址： http://vdisk.weibo.com/s/hq1dQ