Android Live壁纸-为什么这么慢-如何提高速度

Question

我正在尝试创建我的第一张Live壁纸。它工作，一切都会很好，除了速度问题。它降低了桌面速度——小部件和图标的滚动速度明显比使用专业实时壁纸时慢(我正在三星note上测试它，所以速度应该不会有问题)。我开始认为我做错了——所以请看一下我的代码：

public class DemoWallpaperService extends WallpaperService {

@Override
public Engine onCreateEngine() {
return new DemoWallpaperEngine();
}
private class DemoWallpaperEngine extends Engine {
private boolean mVisible = false;
private final Handler mHandler = new Handler();
int x=0,y=0,a=255,i=-1, a1=255, i1=-1;
float r=0,rs=1;
float rx1=10, rxs=-1;
private Matrix mMatrix = new Matrix();
private Matrix mMatrix1 = new Matrix();
private Matrix mMatrixRotate1 = new Matrix();
private Matrix mMatrixRotate2 = new Matrix();
public Bitmap spaceShip = BitmapFactory.decodeResource(getResources(), R.drawable.spaceship);
public Bitmap background= BitmapFactory.decodeResource(getResources(), R.drawable.back2short2j);
public Bitmap wyspa= BitmapFactory.decodeResource(getResources(), R.drawable.wyspa22g);
public Bitmap ksiezyc = BitmapFactory.decodeResource(getResources(), R.drawable.ksiezyc);
public Bitmap reflektorfront= BitmapFactory.decodeResource(getResources(), R.drawable.reflektorwyspa);
private float mPixels;
private float mPixels1;

private final Runnable mUpdateDisplay = new Runnable() {
@Override
public void run() {
draw();
}};

private void draw() {
SurfaceHolder holder = getSurfaceHolder();
Canvas c = null;
Display d = ((WindowManager)getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
int wx= d.getWidth();
int wy= d.getHeight();

try {
Runtime.getRuntime().gc();
c = holder.lockCanvas();
c.save();
if (c != null) {
Paint paintMoon = new Paint();
if(a1<=15){
i1=1;
}
else if(a1>=255){
i1=-1;
}
a1+=5*i1;
paintMoon.setAlpha(a1);
c.translate((float)mPixels, 0f);
c.drawBitmap(background, mMatrix, null);
c.drawBitmap(ksiezyc, 1027*wx/480,15*wy/800, paintMoon);
if(rx1<=-15){
rxs=1;
}
else if(rx1>=15){
rxs=-1;
}
rx1+=rxs*0.7;
c.translate((float)mPixels1, 0f);
//reflektor wyspa back
mMatrixRotate2.setTranslate(340*wx/480,300*wy/800);
mMatrixRotate2.preRotate(rx1,reflektorfront.getWidth()/2,20);
c.drawBitmap(reflektorfront, mMatrixRotate2, null);

c.drawBitmap(wyspa, mMatrix1, null);
if(r<=-15){
rs=1;
}
else if(r>=15){
rs=-1;
}
r+=rs*0.5;

mMatrixRotate1.setTranslate(160*wx/480,380*wy/800);
mMatrixRotate1.preRotate(r,reflektorfront.getWidth()/2,20);
c.drawBitmap(reflektorfront, mMatrixRotate1, null);

if(x<c.getWidth()){
x+=3;}
else{x=0;}
if(y<c.getHeight()){
y+=3;}
else{y=0;}
Paint paint = new Paint();

if(a<=5){
i=1;
}
else if(a>=255){
i=-1;
}
a+=10*i;
paint.setAlpha(a);
c.drawBitmap(spaceShip,x,y,paint);

c.restore();
}
} finally {
if (c != null)
holder.unlockCanvasAndPost(c);
}
mHandler.removeCallbacks(mUpdateDisplay);
if (mVisible) {
mHandler.postDelayed(mUpdateDisplay, 10);
}
}
@Override
public void onOffsetsChanged(float xOffset, float yOffset,
float xStep, float yStep, int xPixels, int yPixels){
super.onOffsetsChanged(xOffset, yOffset, xStep, yStep, xPixels, yPixels);                   
mPixels = xPixels*7/4;
mPixels1 = 500+xPixels;
draw();
}

@Override
public void onVisibilityChanged(boolean visible) {
mVisible = visible;
if (visible) {
draw();
} else {
mHandler.removeCallbacks(mUpdateDisplay);
}
}
@Override
public void onSurfaceChanged(SurfaceHolder holder, int format, int width, int height) {
super.onSurfaceChanged(holder, format, width, height);
float w = background.getWidth();
float h = background.getHeight();
float s = height / (float)h;
float z = height / (float)h;
mMatrix.reset();
mMatrix1.reset();
mMatrixRotate1.reset();
mMatrixRotate2.reset();
mMatrix.setScale(s, s);
mMatrix1.setScale(z, z);
mMatrixRotate1.setScale(s, s);
draw();
}
@Override
public void onSurfaceDestroyed(SurfaceHolder holder) {
super.onSurfaceDestroyed(holder);
mVisible = false;
mHandler.removeCallbacks(mUpdateDisplay);
}

@Override
public void onCreate(SurfaceHolder surfaceHolder) {
super.onCreate(surfaceHolder);
setTouchEventsEnabled(false);
}
@Override
public void onDestroy() {
super.onDestroy();
mVisible = false;
mHandler.removeCallbacks(mUpdateDisplay);
}
}    

基本上是背景位图(850x480jpg 70kb)，滚动速度较慢，前面位图(350x400透明gif 100kb)滚动速度较快(以实现视差效果)，以及一些在前景旋转和移动的较小png位图(3x10-20kb 50x50)(灯光和太空船)。

我的问题是——我是不是错过了要点——我正在通过刷新draw()函数来设置动画，延迟设置为10。(这是我唯一知道的方法-我应该用其他方式来制作它的动画吗？位图太大了吗？或者为什么它这么慢？我应该用精灵来制作正面小效果的动画吗，让它更快吗？有其他制作生活壁纸的方法吗？我看了很多教程，我已经走了这么远，但现在我必须寻求帮助。

Answer 1

我不确定这是否是完整的答案。。。但值得一试。与其使用bitmap.decodeResources()方法引用位图，不如尝试以下操作：

pic1 = Bitmap.createScaledBitmap(background, (int)background.getWidth(), (int)background.getHeight(), true);

我制作视差壁纸已经有一段时间了，发现速度慢通常是因为屏幕上画了多少位图。