您好我有这个代码，我试图通过谷歌开发者页面从Android示例中调整它。现在它被缓存但是当我进入缓存循环时，图像只显示在缓存中，而不在缓存中的图像无法显示任何想法如何解决这个问题？
由于我不熟悉编程和android API
，因此我可能缺少的东西很少public class MainActivity extends Activity {
ImageView animalView;
Animal animal;
private LruCache<String, Bitmap> mMemoryCache;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//setContentView(R.layout.activity_main);
// RelativeLayout relativeLayout = (RelativeLayout)
// findViewById(R.id.root);
// surfaceView = new OurView(this);
// relativeLayout.addView(surfaceView);
// Get max available VM memory, exceeding this amount will throw an
// OutOfMemory exception. Stored in kilobytes as LruCache takes an
// int in its constructor.
final int maxMemory = (int) (Runtime.getRuntime().maxMemory() / 1024);
// Use 1/8th of the available memory for this memory cache.
final int cacheSize = maxMemory / 8;
mMemoryCache = new LruCache<String, Bitmap>(cacheSize) {
@Override
protected int sizeOf(String key, Bitmap bitmap) {
// The cache size will be measured in kilobytes rather than
// number of items.
return bitmap.getByteCount() / 1024;
}
};
setContentView(new Animal(this));
}
public class Animal extends SurfaceView implements
SurfaceHolder.Callback, OnSharedPreferenceChangeListener {
// private Bitmap bmp;
private static final String KEY_COUNT = "count";;
private Bitmap jeepbackbmp;
private Bitmap jeepbmp;
private Canvas canvas;
private Bitmap scaled;
private Bitmap background;
private int clickCount = 0;
final int[] AnimalsArray = { R.drawable.elephants,
R.drawable.sable_antelope2560, R.drawable.wildebeest2560x1600,
R.drawable.olive_babbon2560, R.drawable.plains_zebras2560,
R.drawable.bush_pig2560, R.drawable.hippo_and_baby2560,
R.drawable.african_buffalu2560, R.drawable.black_rhinos2560,
R.drawable.giraffe_family2560, R.drawable.lessermaskedweaver,
R.drawable.alcelaphus, R.drawable.cheetah };
private SharedPreferences mPrefs;
private int pX;
private int pY;
private Region jeepbackregion;
private Region jeepgoregion;
private SurfaceHolder mSurfaceHolder;
private DisplayMetrics mDisplay;
private Thread mDrawingThread;
private int width;
private int height;
private float newWidth;
private float newHeight;
private int mDisplayWidth;
private int mDisplayHeight;
private Bitmap backgroundbmp;
private ImageView mImageView;
private Bitmap mBitmap;
public Animal(Context context) {
super(context);
mPrefs = PreferenceManager
.getDefaultSharedPreferences(getContext());
// If we are going to cache the name and gravity
// Then we better find out when they are changed
mPrefs.registerOnSharedPreferenceChangeListener(this);
// mBitmapHeightAndWidthAdj = mBitmapHeightAndWidth / 2;
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(getResources(),
AnimalsArray[clickCount], options);
mDisplay = new DisplayMetrics();
MainActivity.this.getWindowManager().getDefaultDisplay()
.getMetrics(mDisplay);
mDisplayWidth = mDisplay.widthPixels;
mDisplayHeight = mDisplay.heightPixels;
Display display = getWindowManager().getDefaultDisplay();
Point size = new Point();
display.getSize(size);
width = size.x;
height = size.y;
background = decodeSampledBitmapFromResource(getResources(),AnimalsArray[clickCount], 160, 100);
float Hscale = (float) background.getHeight() / height;
float Wscale = (float) background.getWidth() / width;
newWidth = background.getWidth() / Wscale;
newHeight = background.getHeight() / Hscale;
scaled = Bitmap.createScaledBitmap(background, (int) newWidth,
(int) newHeight, true);
jeepbackbmp = BitmapFactory.decodeResource(getResources(),
R.drawable.jeep256right);
jeepbmp = BitmapFactory.decodeResource(getResources(),
R.drawable.jeep256);
// backgroundbmp = BitmapFactory.decodeResource(getResources(),
// R.id.imageView1);
jeepbackregion = new Region(0, height - jeepbackbmp.getHeight(),
jeepbackbmp.getWidth(), height);
jeepgoregion = new Region(width - jeepbmp.getWidth(), 0, width,
height);
// RelativeLayout relativeLayout = (RelativeLayout) findViewById(R.id.frame);
// animalView = new ImageView(getApplicationContext());
// animalView.setImageDrawable(getResources().getDrawable(R.drawable.giraffe_family2560));
// relativeLayout.addView(animalView);
mSurfaceHolder = getHolder();
// mSurfaceHolder.setFixedSize(mBitmapHeightAndWidth, height);
mSurfaceHolder.addCallback(this);
}
// ***************************************
// ************* TOUCH *****************
// ***************************************
@Override
public synchronized boolean onTouchEvent(MotionEvent ev) {
pX = (int) ev.getX();
pY = (int) ev.getY();
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN: {
if (jeepbackregion.contains(pX, pY)) {
Log.d("AnimalView", "Back Touch Reached");
// jeepBack();
}
if (jeepgoregion.contains(pX, pY)) {
Log.d("AnimalView", "Go Touch Reached");
jeepGo();
}
// ballFingerMove = true;
break;
}
case MotionEvent.ACTION_MOVE: {
pX = (int) ev.getX() - jeepbackbmp.getWidth() / 2;
pY = (int) ev.getY() - jeepbackbmp.getHeight() / 2;
break;
}
case MotionEvent.ACTION_UP:
// ballFingerMove = false;
// dY = 0;
break;
}
return true;
}
// private void jeepBack() {
//
// // vb.vibrate(100);
// // anim = AnimationUtils.makeOutAnimation(MainActivity.this,
// // true);
// // jeepbackview.startAnimation(anim);
// clickCount = -1 + mPrefs.getInt("clicked", 0);
// if (clickCount < 0) {
// clickCount = AnimalsArray.length - 1;
// }
// mPrefs.edit().putInt("clicked", clickCount)
// .putBoolean("user", true).commit();
//
// if (clickCount >= 0 && clickCount <= AnimalsArray.length - 1) {
//
// background = BitmapFactory.decodeResource(getResources(),
// AnimalsArray[clickCount]);
// float Hscale = (float) background.getHeight()
// / height;
// float Wscale = (float) background.getWidth()
// / width ;
// float newWidth = background.getWidth() / Wscale;
// float newHeight = background.getHeight() / Hscale;
//
// scaled = null;
//
// scaled =
// Bitmap.createScaledBitmap(BitmapFactory.decodeResource(getResources(),
// AnimalsArray[clickCount]),
// (int) newWidth, (int) newHeight, true);
//
// }
// }
private void jeepGo() {
Log.d("AnimalView", "jeepGO() Reached");
clickCount = 1 + mPrefs.getInt("clicked", 0);
if (clickCount >= AnimalsArray.length -1) {
clickCount = 0;
}
mPrefs.edit().putInt("clicked", clickCount)
.putBoolean("user", true).commit();
Log.d("AnimalView", "Allocating new Bitmap Reached");
Log.d("AnimalView", "clicks " + clickCount);
canvas = mSurfaceHolder.lockCanvas();
if (null != canvas) {
//drawAnimal(canvas);
addBitmapToMemoryCache(String.valueOf(AnimalsArray[clickCount]), mBitmap);
loadBitmap(AnimalsArray[(clickCount + 1)], mImageView);
mSurfaceHolder.unlockCanvasAndPost(canvas);
}
}
public void drawAnimal(Canvas canvas) {
Bitmap b = decodeSampledBitmapFromResource(getResources(),AnimalsArray[clickCount], 160, 100);
float Hscale = (float) b.getHeight() / height;
float Wscale = (float) b.getWidth() / width;
newWidth = b.getWidth() / Wscale;
newHeight = b.getHeight() / Hscale;
mBitmap = Bitmap.createScaledBitmap(BitmapFactory.decodeResource(
getResources(), AnimalsArray[clickCount]), (int) newWidth,
(int) newHeight, true);
canvas.drawBitmap(mBitmap, 0, 0, null);
canvas.drawBitmap(jeepbackbmp, 10,
getHeight() - jeepbackbmp.getHeight(), null);
canvas.drawBitmap(jeepbmp, getWidth() - jeepbmp.getWidth(),
getHeight() - jeepbmp.getHeight(), null);
}
@Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2,
int arg3) {
}
@Override
public void surfaceCreated(SurfaceHolder holder) {
mDrawingThread = new Thread(new Runnable() {
public void run() {
Canvas canvas = null;
canvas = mSurfaceHolder.lockCanvas();
if (null != canvas) {
drawAnimal(canvas);
mSurfaceHolder.unlockCanvasAndPost(canvas);
}
}
});
mDrawingThread.start();
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
if (null != mDrawingThread)
mDrawingThread.interrupt();
}
@Override
public void onSharedPreferenceChanged(SharedPreferences arg0,
String arg1) {
// TODO Auto-generated method stub
}
public void loadBitmap(int resId, ImageView imageView) {
final String imageKey = String.valueOf(resId);
final Bitmap bitmap = getBitmapFromMemCache(imageKey);
if (bitmap != null) {
// setImageBitmap(bitmap);
//mBitmap = decodeSampledBitmapFromResource(getResources(),AnimalsArray[clickCount], 160, 100);
BitmapFactory.Options options = new BitmapFactory.Options();
options.inPurgeable = true;
Bitmap.createScaledBitmap(bitmap, width, height, true);
} else {
// mImageView.setImageDrawable(getResources().getDrawable(R.drawable.african_buffalu2560));
//canvas.drawBitmap(scaled, 0, 0, null);
drawAnimal(canvas);
BitmapWorkerTask task = new BitmapWorkerTask(mImageView);
task.execute(resId);
}
}
}
public static int calculateInSampleSize(BitmapFactory.Options options,
int reqWidth, int reqHeight) {
// Raw height and width of image
final int height = options.outHeight;
final int width = options.outWidth;
int inSampleSize = 1;
if (height > reqHeight || width > reqWidth) {
final int halfHeight = height / 2;
final int halfWidth = width / 2;
// Calculate the largest inSampleSize value that is a power of 2 and
// keeps both
// height and width larger than the requested height and width.
while ((halfHeight / inSampleSize) > reqHeight
&& (halfWidth / inSampleSize) > reqWidth) {
inSampleSize *= 2;
}
}
return inSampleSize;
}
public static Bitmap decodeSampledBitmapFromResource(Resources res,
int resId, int reqWidth, int reqHeight) {
// First decode with inJustDecodeBounds=true to check dimensions
final BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeResource(res, resId, options);
// Calculate inSampleSize
options.inSampleSize = calculateInSampleSize(options, reqWidth,
reqHeight);
// Decode bitmap with inSampleSize set
options.inJustDecodeBounds = false;
return BitmapFactory.decodeResource(res, resId, options);
}
class BitmapWorkerTask extends AsyncTask<Integer, Void, Bitmap> {
public BitmapWorkerTask(ImageView mImageView) {
// TODO Auto-generated constructor stub
}
// Decode image in background.
@Override
protected Bitmap doInBackground(Integer... params) {
final Bitmap bitmap = decodeSampledBitmapFromResource(
getResources(), params[0], 160, 100);
addBitmapToMemoryCache(String.valueOf(params[0]), bitmap);
return bitmap;
}
}
public void addBitmapToMemoryCache(String key, Bitmap bitmap) {
if (getBitmapFromMemCache(key) == null && bitmap != null) {
mMemoryCache.put(key, bitmap);
Log.d("AnimalView", "Bitmap added to cache" + key + bitmap);
}
}
public Bitmap getBitmapFromMemCache(String key) {
Log.d("AnimalView", "Get bitmap got as the key to" + key + mMemoryCache.get(key) );
return mMemoryCache.get(key);
}
}