我已编辑this code以将Rect实例化移出onDraw方法。我在几台设备上测试过它。
public class BallBouncesActivity extends Activity {
BallBounces ball;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ball = new BallBounces(this);
setContentView(ball);
}
}
class BallBounces extends SurfaceView implements SurfaceHolder.Callback {
GameThread thread;
int screenW; //Device's screen width.
int screenH; //Devices's screen height.
int ballX; //Ball x position.
int ballY; //Ball y position.
int initialY ;
float dY; //Ball vertical speed.
int ballW;
int ballH;
int bgrW;
int bgrH;
int angle;
int bgrScroll;
int dBgrY; //Background scroll speed.
float acc;
Bitmap ball, bgr, bgrReverse;
boolean reverseBackroundFirst;
boolean ballFingerMove;
Rect toRect1, fromRect1;
Rect toRect2, fromRect2;
//Measure frames per second.
long now;
int framesCount=0;
int framesCountAvg=0;
long framesTimer=0;
Paint fpsPaint=new Paint();
//Frame speed
long timeNow;
long timePrev = 0;
long timePrevFrame = 0;
long timeDelta;
public BallBounces(Context context) {
super(context);
ball = BitmapFactory.decodeResource(getResources(), R.drawable.rocket); //Load a ball image.
bgr = BitmapFactory.decodeResource(getResources(), R.drawable.sky_bgr); //Load a background.
ballW = ball.getWidth();
ballH = ball.getHeight();
toRect1 = new Rect(0, 0, bgr.getWidth(), bgr.getHeight());
fromRect1 = new Rect(0, 0, bgr.getWidth(), bgr.getHeight());
toRect2 = new Rect(0, 0, bgr.getWidth(), bgr.getHeight());
fromRect2 = new Rect(0, 0, bgr.getWidth(), bgr.getHeight());
//Create a flag for the onDraw method to alternate background with its mirror image.
reverseBackroundFirst = false;
//Initialise animation variables.
acc = 0.2f; //Acceleration
dY = 0; //vertical speed
initialY = 100; //Initial vertical position
angle = 0; //Start value for the rotation angle
bgrScroll = 0; //Background scroll position
dBgrY = 1; //Scrolling background speed
fpsPaint.setTextSize(30);
//Set thread
getHolder().addCallback(this);
setFocusable(true);
}
@Override
public void onSizeChanged (int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
//This event-method provides the real dimensions of this custom view.
screenW = w;
screenH = h;
bgr = Bitmap.createScaledBitmap(bgr, w, h, true); //Scale background to fit the screen.
bgrW = bgr.getWidth();
bgrH = bgr.getHeight();
//Create a mirror image of the background (horizontal flip) - for a more circular background.
Matrix matrix = new Matrix(); //Like a frame or mould for an image.
matrix.setScale(-1, 1); //Horizontal mirror effect.
bgrReverse = Bitmap.createBitmap(bgr, 0, 0, bgrW, bgrH, matrix, true); //Create a new mirrored bitmap by applying the matrix.
ballX = (int) (screenW /2) - (ballW / 2) ; //Centre ball X into the centre of the screen.
ballY = -50; //Centre ball height above the screen.
}
//***************************************
//************* TOUCH *****************
//***************************************
@Override
public synchronized boolean onTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN: {
ballX = (int) ev.getX() - ballW/2;
ballY = (int) ev.getY() - ballH/2;
ballFingerMove = true;
break;
}
case MotionEvent.ACTION_MOVE: {
ballX = (int) ev.getX() - ballW/2;
ballY = (int) ev.getY() - ballH/2;
break;
}
case MotionEvent.ACTION_UP:
ballFingerMove = false;
dY = 0;
break;
}
return true;
}
@Override
public void onDraw(Canvas canvas) {
super.onDraw(canvas);
//Draw scrolling background.
fromRect1.set(0, 0, bgrW - bgrScroll, bgrH);
toRect1.set(bgrScroll, 0, bgrW, bgrH);
fromRect2.set(bgrW - bgrScroll, 0, bgrW, bgrH);
toRect2.set(0, 0, bgrScroll, bgrH);
// Rect fromRect1 = new Rect(0, 0, bgrW - bgrScroll, bgrH);
// Rect toRect1 = new Rect(bgrScroll, 0, bgrW, bgrH);
//
// Rect fromRect2 = new Rect(bgrW - bgrScroll, 0, bgrW, bgrH);
// Rect toRect2 = new Rect(0, 0, bgrScroll, bgrH);
if (!reverseBackroundFirst) {
canvas.drawBitmap(bgr, fromRect1, toRect1, null);
canvas.drawBitmap(bgrReverse, fromRect2, toRect2, null);
}
else{
canvas.drawBitmap(bgr, fromRect2, toRect2, null);
canvas.drawBitmap(bgrReverse, fromRect1, toRect1, null);
}
//Next value for the background's position.
if ( (bgrScroll += dBgrY) >= bgrW) {
bgrScroll = 0;
reverseBackroundFirst = !reverseBackroundFirst;
}
//Compute roughly the ball's speed and location.
if (!ballFingerMove) {
ballY += (int) dY; //Increase or decrease vertical position.
if (ballY > (screenH - ballH)) {
dY=(-1)*dY; //Reverse speed when bottom hit.
}
dY+= acc; //Increase or decrease speed.
}
//Increase rotating angle
if (angle++ >360)
angle =0;
//DRAW BALL
//Rotate method one
/*
Matrix matrix = new Matrix();
matrix.postRotate(angle, (ballW / 2), (ballH / 2)); //Rotate it.
matrix.postTranslate(ballX, ballY); //Move it into x, y position.
canvas.drawBitmap(ball, matrix, null); //Draw the ball with applied matrix.
*/// Rotate method two
canvas.save(); //Save the position of the canvas matrix.
canvas.rotate(angle, ballX + (ballW / 2), ballY + (ballH / 2)); //Rotate the canvas matrix.
canvas.drawBitmap(ball, ballX, ballY, null); //Draw the ball by applying the canvas rotated matrix.
canvas.restore(); //Rotate the canvas matrix back to its saved position - only the ball bitmap was rotated not all canvas.
//*/
//Measure frame rate (unit: frames per second).
now=System.currentTimeMillis();
canvas.drawText(framesCountAvg+" fps", 40, 70, fpsPaint);
framesCount++;
if(now-framesTimer>1000) {
framesTimer=now;
framesCountAvg=framesCount;
framesCount=0;
}
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
thread = new GameThread(getHolder(), this);
thread.setRunning(true);
thread.start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
boolean retry = true;
thread.setRunning(false);
while (retry) {
try {
thread.join();
retry = false;
} catch (InterruptedException e) {
}
}
}
class GameThread extends Thread {
private SurfaceHolder surfaceHolder;
private BallBounces gameView;
private boolean run = false;
public GameThread(SurfaceHolder surfaceHolder, BallBounces gameView) {
this.surfaceHolder = surfaceHolder;
this.gameView = gameView;
}
public void setRunning(boolean run) {
this.run = run;
}
public SurfaceHolder getSurfaceHolder() {
return surfaceHolder;
}
@Override
public void run() {
Canvas c;
while (run) {
c = null;
//limit frame rate to max 60fps
timeNow = System.currentTimeMillis();
timeDelta = timeNow - timePrevFrame;
if ( timeDelta < 16) {
try {
Thread.sleep(16 - timeDelta);
}
catch(InterruptedException e) {
}
}
timePrevFrame = System.currentTimeMillis();
try {
c = surfaceHolder.lockCanvas(null);
synchronized (surfaceHolder) {
//call methods to draw and process next fame
gameView.onDraw(c);
}
} finally {
if (c != null) {
surfaceHolder.unlockCanvasAndPost(c);
}
}
}
}
}
}
如果您注意到，则有测量帧速率的代码：
now=System.currentTimeMillis();
canvas.drawText(framesCountAvg+" fps", 40, 70, fpsPaint);
framesCount++;
if(now-framesTimer>1000) {
framesTimer=now;
framesCountAvg=framesCount;
framesCount=0;
}
我在我的两款Galaxy Nexus设备上都看到了这一点，运行Android 4.0和4.2，它大约是22-24fps。在我的HTC Desire上，运行Android 2.2，它更像是60fps。
您还会注意到我没有在onDraw方法中分配任何内容。我也没有创建新的Paint对象。我真的不知道这是怎么运行的，所以，所以在我的Galaxy Nexus设备上慢得多。有很多口吃，球移动得很慢。
是否有人知道我可以撤消的设置或重新绘制Galaxy Nexus的已知问题？我的Galaxy Nexus正在运行4.0 和正在运行4.2的那个，所以我不确定它是特定于操作系统的。我已关闭窗口并在“开发者选项”中转换动画。我是否强制进行2D加速并没有什么区别。
答案 0 :(得分：1)
您是否在应用程序中测试了android：hardwareAccelerated =“true | false”标志？
Android Dev Doc：http://developer.android.com/guide/topics/graphics/hardware-accel.html
您可以在setContentView之前添加：
if (android.os.Build.VERSION.SDK_INT >= 11) {
getWindow().setFlags(WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED, WindowManager.LayoutParams.FLAG_HARDWARE_ACCELERATED);
}
答案 1 :(得分：0)
你的targetSdk设置为什么？
如果targetSdk设置为8（2.2），但您在4.x设备（15+）上运行它，则4.x设备将以兼容模式运行，这意味着它将虚拟化所有呼叫，它们的返回方式与它们在版本8设备上运行完全相同。
这种虚拟化可能解释了一些缓慢的问题。尝试将targetSdk更改为17（对于您的4.2设备）并查看它是否有所作为。
答案 2 :(得分：0)
我一直在考虑这个问题，因为我的Nexus 10仍然存在表面问题，就像我之前所说的那样，我的性能提升了很多我去除了油漆对象的使用，这是一个很长的镜头你只使用一个，但你可以尝试从onDraw（）中删除文本绘图部分，看它是否对你的绘图速度有任何影响。
除此之外，我认为这是一个试图确定问题的案例。
我注意到即使我从方程中完全删除了我的onDraw和逻辑更新方法，它仍然需要长达25ms来锁定和解锁/发布画布！所以问题可能实际上并不在于onDraw方法 - 给它一个去，从Run（）方法中注释出来的对象，然后看看你得到的速度（使用Loglog来查看数字，记住具有讽刺意味的是，在屏幕上显示一个帧/时间计数可能会影响你正在测量的东西。 ： - ）
答案 3 :(得分：0)
我在Kindle Fire，Sony Xperia Z和Samsung S4（都是用android 4.2）上经历了同样的事情。
修复方法是：在App Manifest文件中删除“android：supportsRtl =”true“”。
希望它能节省您的时间。在我拿到它之前，我花了4个小时进行测试和合并。