我正在开发一款适用于平板电脑的Android应用程序，该应用程序将用作许多产品的目录（大约10 000个）。
我在gridview中显示它们，我只显示250个，如果我到达这些250的末尾，我会再加载250个。
我的问题是图片。我的应用程序似乎工作时，我不快速滚动，它是顺利的，没有问题，但它可以使用300或400 MB的RAM，所以我想我做得很糟糕。我听说我应该使用WeakReferences但我不确定如何使用它们......这是第一个“问题”。 （这不是很重要，因为用户可能只使用这个应用程序，如果它运行得很好......但是，如果我可以改进它，我会尝试）
这里的另一个大问题是，当我做类似的事情时：
“底部”的一些图片显示在“顶部”的图片上（而不是临时性的，只有当我滚动并回到它们时它们才会再次改变。）
我真正了解的是：
当快速向上滚动然后快速向上滚动时，我会显示错误的图片。在其他情况下可能会发生这种情况。
public class ProduitsAdapter extends ArrayAdapter<Article> {
private final Activity context;
private ArrayList<Article> params;
private Resources res;
static class ViewHolder {
public TextView numero;
public TextView design;
public ImageView image;
public ImageSwitcher imgSwitcher;
public ImageView codeBarre;
public TextView codeBarreText;
public TextView colisage;
public TextView col3;
public TextView col4;
public TextView col5;
public String image_string = "";
public boolean found = true;
public ImageView nouveaute;
}
public ProduitsAdapter(Activity context, ArrayList<Article> params) {
super(context, R.layout.list_single, params);
res = Catalogue.activity.getResources();
this.context = context;
this.params = params;
}
public int getCount() {
return params.size();
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View rowView = convertView;
if (rowView == null) {
LayoutInflater inflater = context.getLayoutInflater();
ViewHolder viewHolder = new ViewHolder();
if (Catalogue.type_aff.equals("list")) {
rowView = inflater.inflate(R.layout.list_single, null);
viewHolder.numero = (TextView) rowView
.findViewById(R.id.numero);
viewHolder.design = (TextView) rowView
.findViewById(R.id.designation);
viewHolder.col3 = (TextView) rowView.findViewById(R.id.col3);
viewHolder.col4 = (TextView) rowView.findViewById(R.id.col4);
viewHolder.col5 = (TextView) rowView.findViewById(R.id.col5);
} else {
rowView = inflater.inflate(R.layout.fragment_grid_item, null);
viewHolder.numero = (TextView) rowView
.findViewById(R.id.numero);
viewHolder.design = (TextView) rowView
.findViewById(R.id.designation);
viewHolder.colisage = (TextView) rowView
.findViewById(R.id.grid_colisage);
viewHolder.codeBarre = (ImageView) rowView
.findViewById(R.id.code_barre);
viewHolder.codeBarreText = (TextView) rowView
.findViewById(R.id.code_barre_text);
viewHolder.nouveaute = (ImageView) rowView
.findViewById(R.id.img_nouveaute);
}
viewHolder.image = (ImageView) rowView.findViewById(R.id.img);
rowView.setTag(viewHolder);
}
ViewHolder holder = (ViewHolder) rowView.getTag();
if (Catalogue.type_aff.equals("list")) {
holder.col3.setText(params.get(position).getColonne_pref(3));
holder.col4.setText(params.get(position).getColonne_pref(4));
holder.col5.setText(params.get(position).getColonne_pref(5));
} else {
if (params.get(position).isNouveaute()) {
holder.nouveaute.setImageResource(R.drawable.nouveaute);
holder.nouveaute.setVisibility(ImageView.VISIBLE);
} else
holder.nouveaute.setVisibility(ImageView.GONE);
holder.colisage.setText(params.get(position).getColisage());
if (ProduitsFragment.barcodeVisible) {
holder.codeBarreText.setText(params.get(position)
.getGencodNegoce());
}
}
holder.numero.setText(params.get(position).getCodeArt());
holder.design.setText(params.get(position).getDesignation_pref());
// This is how I store my pictures, because finding one picture in a folder of 10 000 pictures takes too much time
String pattern_deb = holder.numero.getText() + "";
String chemin = Environment.getExternalStorageDirectory().getPath()
+ res.getString(R.string.chemin_app_data)
+ MainActivity.listDossiersSocietes
.get(MainActivity.societeSelected)
+ res.getString(R.string.chemin_dossier_photos);
for (int i = 0; i < pattern_deb.length() - 2; i++) {
chemin += "/" + pattern_deb.charAt(i);
}
chemin += "/";
File f = new File(chemin + params.get(position).getFichierPhoto());
if (f.exists()) {
holder.image_string = f.getAbsolutePath();
new loadImagesFromFileThread(holder, position).execute();
if (!Catalogue.type_aff.equals("list")
&& ProduitsFragment.barcodeVisible)
new loadBarCodeThread(holder, position).execute();
} else {
holder.image.setImageResource(R.drawable.notfound300);
}
return rowView;
}
private BitmapDrawable loadImagesFromFile(ViewHolder holder, int position) {
holder.found = true;
File bmp = new File(holder.image_string);
if (bmp.exists() && !bmp.isDirectory()) {
if (position < ProduitsFragment.gridView.getFirstVisiblePosition()
&& position > ProduitsFragment.gridView
.getLastVisiblePosition()) {
holder.found = false;
return null;
} else {
if (holder.image.getVisibility() == ImageView.VISIBLE) {
holder.found = false;
return null;
}
}
Bitmap myBitmap = BitmapFactory.decodeFile(bmp.getAbsolutePath());
int width = myBitmap.getWidth();
int height = myBitmap.getHeight();
int newWidth = 200;
int newHeight = 200;
if (Catalogue.type_aff.equals("list")) {
newWidth = 40;
newHeight = 40;
} else {
if (Catalogue.nbGrid == 5) {
newWidth = 200;
newHeight = 200;
}
if (Catalogue.nbGrid == 3) {
newWidth = 300;
newHeight = 300;
}
}
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
Matrix matrix = new Matrix();
matrix.postScale(scaleWidth, scaleHeight);
Bitmap resizedBitmap = Bitmap.createBitmap(myBitmap, 0, 0, width,
height, matrix, true);
BitmapDrawable bmd = new BitmapDrawable(context.getResources(),
resizedBitmap);
return bmd;
} else {
holder.found = false;
return null;
}
}
private class loadImagesFromFileThread extends
AsyncTask<Void, Void, BitmapDrawable> {
ViewHolder holder;
int position;
public loadImagesFromFileThread(ViewHolder holder, int position) {
this.holder = holder;
this.position = position;
this.holder.image.setVisibility(ImageView.INVISIBLE);
}
@Override
protected BitmapDrawable doInBackground(Void... params) {
return loadImagesFromFile(holder, position);
}
@Override
protected void onPostExecute(BitmapDrawable bmd) {
if (ProduitsFragment.isNotScrolling) {
if (bmd != null) {
holder.image.setImageDrawable(bmd);
if (holder.image.getVisibility() != ImageView.VISIBLE
&& !(position < ProduitsFragment.gridView
.getFirstVisiblePosition() && position > ProduitsFragment.gridView
.getLastVisiblePosition())) {
Animation fadeIn = new AlphaAnimation(0, 1);
fadeIn.setInterpolator(new DecelerateInterpolator());
fadeIn.setDuration(500);
fadeIn.setStartOffset(500);
holder.image.startAnimation(fadeIn);
holder.image.setVisibility(ImageView.VISIBLE);
}
} else {
if (position < ProduitsFragment.gridView
.getFirstVisiblePosition()
&& position > ProduitsFragment.gridView
.getLastVisiblePosition()) {
Log.e("DEBUG", "...");
} else {
if (holder.image.getVisibility() != ImageView.VISIBLE) {
if (!holder.found) {
if (Catalogue.type_aff.equals("list")) {
holder.image
.setImageResource(R.drawable.notfound40);
} else {
if (Catalogue.nbGrid == 5) {
holder.image
.setImageResource(R.drawable.notfound200);
}
if (Catalogue.nbGrid == 3) {
holder.image
.setImageResource(R.drawable.notfound300);
}
}
Animation fadeIn = new AlphaAnimation(0, 1);
fadeIn.setInterpolator(new DecelerateInterpolator());
fadeIn.setDuration(500);
holder.image.startAnimation(fadeIn);
holder.image.setVisibility(ImageView.VISIBLE);
} else {
Animation fadeIn = new AlphaAnimation(0, 1);
fadeIn.setInterpolator(new DecelerateInterpolator());
fadeIn.setDuration(500);
holder.image.startAnimation(fadeIn);
}
holder.image.setVisibility(ImageView.VISIBLE);
}
}
}
}
}
}
}
我很感激任何帮助来纠正错误图片的问题，如果有人能解释我如何使用一些代码正确加载它们（如果可能的话，不使用300 MB的RAM）那将是非常好的。