我正在寫一個圖庫應用程序。 它使用androidstudio模板列表片段和AbsList。ListView在lrucache中沒有注意地回收位圖
我重寫getView以使用任務和lrucache來緩存一些位圖。
來自listview的每個視圖都是一個帶有一個ImageView上的TextView的RelativeLayout。 如果緩存中沒有位圖,則AsyncTask加載它並將其放入緩存,getView在ImageView上繪製資源。 加載後,onPostExecute將位圖放入ImageView中。
如果在高速緩存中的相應的位圖,將它設置成ImageView的
我設置對象持有的TextView和ImageView的隨着一個id進入getView的convertView參數標籤來跟蹤的正確的位圖繪製。
我有兩個問題,雖然:
當我第一次向下滾動,新形象的看法似乎與以前的位圖瞬間任務完成後設置正確的位圖(甚至前儘管我在適配器的getView上繪製資源位圖)但我不明白爲什麼。
當我向後滾動時,大多數時候應用程序崩潰,因爲緩存上的位圖原來被回收,儘管我不知道是誰回收了它。
任何人都可以幫我理解這裏會發生什麼嗎?
public View getView(int position, View convertView, ViewGroup parent) {
Log.i(TAG, "getView: Asking for view " + position);
GalleryItemViewHolder lViewHolder;
if (convertView == null) {
convertView = getActivity().getLayoutInflater().inflate(R.layout
.gallery_item, null);
lViewHolder = new GalleryItemViewHolder();
convertView.setTag(lViewHolder);
} else {
lViewHolder = (GalleryItemViewHolder) convertView.getTag();
}
lViewHolder.setId(position);
lViewHolder.setTextView((TextView) convertView.findViewById(R.id.gallery_infoTextView));
lViewHolder.setImageView((ImageView) convertView.findViewById(R.id.gallery_imageView));
lViewHolder.getTextView().setText(getItem(position).getName() + ": (" + getItem
(position).getCount() + ")");
if (!getItem(position).paintCover(lViewHolder.getImageView())) {
Log.i(TAG,"getView: task");
new GalleryItemTask(position, lViewHolder)
.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, null);
}
Log.i(TAG,"getView: return");
return convertView;
}
封面類有此paintCover方法,其中MID是URI /流至圖像
public boolean paintCover(ImageView imageView) {
Bitmap lBitmap;
if (mId == null || (lBitmap = BitmapCacheManager.getInstance().get(mId)) == null) {
i(TAG, "paintCover: Sin Cache ");
imageView.getHeight();
imageView.getWidth();
imageView.setImageResource(android.R.drawable.alert_dark_frame);
return false;
} else
{
i(TAG, "paintCover: En Cache "+lBitmap.isRecycled());
imageView.setImageBitmap(lBitmap);
return true;
}
}
的更多細節。 在片段的onCreate,我跑這個方法:
private void prepareGalleryLoaders() {
LoaderManager lm = getLoaderManager();
Log.i(TAG, "prepareGalleryLoaders: Iniciando loader");
lm.initLoader(IdConstants.GALLERY_LOADER, null, new GalleryLoaderCallbacks());
}
/**
* Callbacks para cargar los datos de las galerías
* Al terminar de cargarlas, se crea el nuevo arreglo
*/
private class GalleryLoaderCallbacks implements LoaderManager.LoaderCallbacks<List<Gallery>> {
@Override
public Loader<List<Gallery>> onCreateLoader(int id, Bundle args) {
return new GalleriesLoader(getActivity());
}private class GalleryItemTask extends AsyncTask<Void, Void, Gallery> {
private static final String TAG = "GalleryItemTask";
private int mId;
private String mCoverId;
private GalleryItemViewHolder mViewHolder;
private Bitmap mBitmap;
GalleryItemTask(int id, GalleryItemViewHolder galleryItemViewHolder) {
mViewHolder = galleryItemViewHolder;
mId = id;
}
@Override
protected void onPostExecute(Gallery galleries) {
if (mId != mViewHolder.getId()) {
Log.i(TAG, "onPostExecute: IDs difieren!!! "+mId+" - "+mViewHolder.getId());
mBitmap.recycle();
mBitmap=null;
return;
}
// Validar y actualizar bitmap
mViewHolder.getImageView().setImageBitmap(mBitmap);
//mGalleries.get(mId).setBitmap(mBitmap);
super.onPostExecute(galleries);
}
@Override
protected Gallery doInBackground(Void... params) {
// generar bitmap (y posiblemente agregarlo a algún cache)
String[] queryProjection = {
MediaStore.Images.ImageColumns.DATA, MediaStore.Images.ImageColumns.TITLE};
String[] selectionArgs = new String[]{String.valueOf(mGalleries.get(mId).getId())};
Cursor lCursor = getView().getContext().getContentResolver().query(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
queryProjection, MediaStore.Images.ImageColumns.BUCKET_ID + "= ?",
selectionArgs, MediaStore.Images.ImageColumns.TITLE);
lCursor.moveToFirst();
while (!lCursor.isAfterLast()) {
//Log.i(TAG,"doInBackground: "+mGalleries.get(mId).getName()+" - "+lCursor.getString
// (1)+" - "+ lCursor.getString(0));
lCursor.moveToNext();
}
lCursor.moveToFirst();
Log.i(TAG, "doInBackground: " + mId + " - " + mViewHolder.getId());
BitmapFactory.Options lOptions = new BitmapFactory.Options();
lOptions.inJustDecodeBounds = true;
mBitmap = BitmapFactory.decodeFile(lCursor.getString(0), lOptions);
lOptions.inSampleSize = ImageUtils.calculateInSampleSize(lOptions, 256, 256);
lOptions.inJustDecodeBounds = false;
mBitmap = BitmapFactory.decodeFile(lCursor.getString(0), lOptions);
BitmapCacheManager.getInstance().put(lCursor.getString(0), mBitmap);
//if(mGalleries.get(mId).getBitmap()!=null)
// mGalleries.get(mId).getBitmap().recycle();
//mGalleries.get(mId).setBitmap(mBitmap);
if(!mGalleries.get(mId).hasCover()) {
SimpleCover lSimpleCover=new SimpleCover(getActivity(),lCursor.getString(0));
mGalleries.get(mId).setCover(lSimpleCover);
}
lCursor.close();
return null;
}
}
@Override
public void onLoadFinished(Loader<List<Gallery>> loader, List<Gallery> data) {
if (mGalleries != null) {
mGalleries.clear();
} else
mGalleries = new ArrayList<Gallery>();
mGalleries.addAll(data);
for (Gallery lGallery : data) {
Log.i(TAG, "onLoadFinished: " + lGallery.getName());
}
mAdapter.notifyDataSetChanged();
}
在這一點上,目前還沒有定義封面,只是加載了冠軍和總含量和id數據畫廊名單。圖像(封面)從列表適配器的getView中加載。
的GalleryItemTask類:
private class GalleryItemTask extends AsyncTask<Void, Void, Gallery> {
private static final String TAG = "GalleryItemTask";
private int mId;
private String mCoverId;
private GalleryItemViewHolder mViewHolder;
private Bitmap mBitmap;
GalleryItemTask(int id, GalleryItemViewHolder galleryItemViewHolder) {
mViewHolder = galleryItemViewHolder;
mId = id;
}
@Override
protected void onPostExecute(Gallery galleries) {
if (mId != mViewHolder.getId()) {
Log.i(TAG, "onPostExecute: IDs difieren!!! "+mId+" - "+mViewHolder.getId());
mBitmap.recycle();
mBitmap=null;
return;
}
// Validar y actualizar bitmap
mViewHolder.getImageView().setImageBitmap(mBitmap);
//mGalleries.get(mId).setBitmap(mBitmap);
super.onPostExecute(galleries);
}
@Override
protected Gallery doInBackground(Void... params) {
// generar bitmap (y posiblemente agregarlo a algún cache)
String[] queryProjection = {
MediaStore.Images.ImageColumns.DATA, MediaStore.Images.ImageColumns.TITLE};
String[] selectionArgs = new String[]{String.valueOf(mGalleries.get(mId).getId())};
Cursor lCursor = getView().getContext().getContentResolver().query(
MediaStore.Images.Media.EXTERNAL_CONTENT_URI,
queryProjection, MediaStore.Images.ImageColumns.BUCKET_ID + "= ?",
selectionArgs, MediaStore.Images.ImageColumns.TITLE);
lCursor.moveToFirst();
while (!lCursor.isAfterLast()) {
//Log.i(TAG,"doInBackground: "+mGalleries.get(mId).getName()+" - "+lCursor.getString
// (1)+" - "+ lCursor.getString(0));
lCursor.moveToNext();
}
lCursor.moveToFirst();
Log.i(TAG, "doInBackground: " + mId + " - " + mViewHolder.getId());
BitmapFactory.Options lOptions = new BitmapFactory.Options();
lOptions.inJustDecodeBounds = true;
mBitmap = BitmapFactory.decodeFile(lCursor.getString(0), lOptions);
lOptions.inSampleSize = ImageUtils.calculateInSampleSize(lOptions, 256, 256);
lOptions.inJustDecodeBounds = false;
mBitmap = BitmapFactory.decodeFile(lCursor.getString(0), lOptions);
BitmapCacheManager.getInstance().put(lCursor.getString(0), mBitmap);
//if(mGalleries.get(mId).getBitmap()!=null)
// mGalleries.get(mId).getBitmap().recycle();
//mGalleries.get(mId).setBitmap(mBitmap);
if(!mGalleries.get(mId).hasCover()) {
SimpleCover lSimpleCover=new SimpleCover(getActivity(),lCursor.getString(0));
mGalleries.get(mId).setCover(lSimpleCover);
}
lCursor.close();
return null;
}
}
如果paintCover返回false,則表示它在ImageView上繪製了一個模板,然後線程運行以創建Bitmap並將其放入緩存中,並在稍後將其繪製在ImageView上。如果它返回true,則表示圖像在緩存中找到,並放入ImageView中,因此沒有任何操作。然而,在試圖找出之後,我發現緩存中的圖像被回收了,但我不知道是誰做的或者它是如何發生的。 – dabicho 2014-11-04 07:03:26
如果paintCover爲真,你想要做什麼? – 2014-11-04 07:07:21
謝謝,我剛剛發現我做錯了什麼......如果ID不同,我錯誤地回收了位圖,因爲我已經將它放入緩存。我的錯。但不知何故,觀看/討論這裏的代碼對我來說很清楚。如果paintCover爲true,則意味着封面已經塗上了最終的Bitmap(因爲它在緩存中找到),所以暫時沒有。 – dabicho 2014-11-04 07:10:47