android游戏开发自学笔记2 基础知识
最近迫于生存压力，不得不给人兼职打工。故在博文中加了个求点击的链接。麻烦有时间的博友们帮我点击一下。没时间的不用勉强啊。不过请放心，我是做技术的，肯定链接没病毒，就是我打工的淘宝店铺。嘻嘻。http://shop108130013.taobao.com。谢谢捧场。以后就每周写篇原创的技术博客回报大家，实在是迫于生计，无所不用其极。请谅解。
昨晚到刚才写了自学笔记1，现在给笔记2起个头，马上就要去忙工作了。起个头的原因是，提醒自己必须不断学习。不要有1无2了。嘿嘿。
今天工作忙好了，就继续学习。
第四章的开始，作者介绍如何创建一个activity等。这些都是基础的android应用知识，略过。
输入设备：touchscreen, keyboard 和 accelerometer.
Touch Events:单点触屏和多点触屏；key events这些都是基础知识。略过吧。加速器状态的读取倒是平台里我接触很少的部分，但是看了一下作者介绍，也是调用接口的实现。也略过。需要时候，再回来补补知识。
File Handing: 读取Assets,访问外部存储。
基本的图像编程包含以下几点：
使用Wake Locks, 全屏处理，UI线程的Render机制，屏幕处理，位图的使用，文字的使用。
位图处理简单实例代码：
import java.io.IOException;
import java.io.InputStream;
import android.app.Activity;
import android.content.Context;
import android.content.res.AssetManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
public class BitmapTest extends Activity {
class RenderView extends View {
Bitmap bob565;
Bitmap bob4444;
Rect dst = new Rect();
public RenderView(Context context) {
super(context);
try {
AssetManager assetManager = context.getAssets();
InputStream inputStream = assetManager.open("bobrgb888.png");
bob565 = BitmapFactory.decodeStream(inputStream);
inputStream.close();
Log.d("BitmapText","bobrgb888.png format: " + bob565.getConfig());
inputStream = assetManager.open("bobargb8888.png");
BitmapFactory.Options options = new BitmapFactory.Options();
options.inPreferredConfig = Bitmap.Config.ARGB_4444;
bob4444 = BitmapFactory.decodeStream(inputStream, null, options);
inputStream.close();
Log.d("BitmapText","bobargb8888.png format: " + bob4444.getConfig());
} catch (IOException e) {
// silently ignored, bad coder monkey, baaad!
} finally {
// we should really close our input streams here.
}
}
protected void onDraw(Canvas canvas) {
dst.set(50, 50, 350, 350);
canvas.drawBitmap(bob565, null, dst, null);
canvas.drawBitmap(bob4444, 100, 100, null);
invalidate();
}
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(new RenderView(this));
}
}
文字处理相关代码：
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.graphics.Typeface;
import android.os.Bundle;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
public class FontTest extends Activity {
class RenderView extends View {
Paint paint;
Typeface font;
Rect bounds = new Rect();
public RenderView(Context context) {
super(context);
paint = new Paint();
font = Typeface.createFromAsset(context.getAssets(), "font.ttf");
}
protected void onDraw(Canvas canvas) {
paint.setColor(Color.YELLOW);
paint.setTypeface(font);
paint.setTextSize(28);
paint.setTextAlign(Paint.Align.CENTER);
canvas.drawText("This is a test!", canvas.getWidth() / 2, 100,paint);
String text = "This is another test o_O";
paint.setColor(Color.WHITE);
paint.setTextSize(18);
paint.setTextAlign(Paint.Align.LEFT);
paint.getTextBounds(text, 0, text.length(), bounds);
canvas.drawText(text, canvas.getWidth() - bounds.width(), 140,paint);
invalidate();
}
}
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(new RenderView(this));
}
}
SurfaceView的使用：
Motivation:
SurfaceHolder and Locking:SurfaceHolder.lockCanvas()和SurfaceHolder.unlockAndPost()
Surface Creation and Validity:surfaceHolder.getSurface().isValid() 检查surface是否被创建。
The SurfaceViewTest Activity
import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.Window;
import android.view.WindowManager;
public class SurfaceViewTest extends Activity {
FastRenderView renderView;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
requestWindowFeature(Window.FEATURE_NO_TITLE);
getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
WindowManager.LayoutParams.FLAG_FULLSCREEN);
renderView = new FastRenderView(this);
setContentView(renderView);
}
protected void onResume() {
super.onResume();
renderView.resume();
}
protected void onPause() {
super.onPause();
renderView.pause();
}
class FastRenderView extends SurfaceView implements Runnable {
Thread renderThread = null;
SurfaceHolder holder;
volatile boolean running = false;
public FastRenderView(Context context) {
super(context);
holder = getHolder();
}
public void resume() {
running = true;
renderThread = new Thread(this);
renderThread.start();
}
public void run() {
while(running) {
if(!holder.getSurface().isValid()) continue;
Canvas canvas = holder.lockCanvas();
canvas.drawRGB(255, 0, 0);
holder.unlockCanvasAndPost(canvas);
}
}
public void pause() {
running = false;
while(true) {
try {
renderThread.join();
} catch (InterruptedException e) {
// retry
}
}
}
}
}