我在 Activity 中有一个 ListView ，它的每个项目都被定制为有一些TextViews以及一个DropDownList项目和一个ImageView。在OnScrollListener()实现中，listView 的每个项目都使用 ArrayAdapter 填充文本视图，该文本视图的值取自 arrayList 和 ImageView 以及存储在 SD 卡上的.jpeg文件。以下是 listView Item 的 screenSHot
当 sdCard 中的 .jpeg 文件转换为位图（即BitmapFactory.decodeFile(fileName)）然后使用setImageBitmap(Bitmap bmp)分配给图像视图时，就会出现问题. 由于将位图图像设置为图像视图是一个漫长的过程，因此它无法跟上滚动侦听器实现的步伐，并且不同 ListView 行的 ImageView 会填充它分配给上面任何行的图像。任何人都可以建议一些锻炼来解决这个问题，特别是将图像从 SD 卡分配到 imageView。它不像我的 listView 项目过度加载控件，这就是我面临这个问题的原因。我也尝试过在每行内使用单个 ImageView 项目，它的行为方式相同。欢迎您提出即兴创作的建议，并且肯定会有很大帮助。谢谢 ：-）
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row = convertView;
AssetDetailHolder assetDetailholder = null;
try {
if (row == null) {
LayoutInflater inflator = ((Activity) context)
.getLayoutInflater();
row = inflator.inflate(layoutResourceID, parent, false);
assetDetailholder = new AssetDetailHolder();
assetDetailholder.itemPosition = position;
assetDetailholder.txtVwlineCOde = (TextView) row
.findViewById(R.id.lineCodeValue_ad);
assetDetailholder.txtvwLocation = (TextView) row
.findViewById(R.id.locationValue_ad);
assetDetailholder.txtvwLocationDetail = (TextView) row
.findViewById(R.id.detailLocationValue_ad);
assetDetailholder.txtvwInventoryNo = (TextView) row
.findViewById(R.id.InventoryNoValue_ad);
assetDetailholder.spnrconditionCode = (Spinner) row
.findViewById(R.id.spinner_ad);
assetDetailholder.txtvwAssetName = (TextView) row
.findViewById(R.id.AssetNameValue_ad);
assetDetailholder.subNoThumbnail = (ImageView) row
.findViewById(R.id.IV_subNoThumbnail);
row.setTag(assetDetailholder);
} else {
assetDetailholder = (AssetDetailHolder) row.getTag();
assetDetailholder.itemPosition = position;
}
AssetDetail assetDetail = assetsDetailList[position];
new ThumbnailTask(position, assetDetailholder, assetDetail, context)
.execute();
if (assetDetail.assetLineCodeDesc.equals("")) {
assetDetailholder.txtVwlineCOde
.setText(assetDetail.strLineCOde);
} else {
assetDetailholder.txtVwlineCOde.setText(assetDetail.strLineCOde
+ "(" + assetDetail.assetLineCodeDesc + ")");
}
if (assetDetail.assetLocationNameDesc.equals("")) {
assetDetailholder.txtvwLocation
.setText(assetDetail.strLocationName);
} else {
assetDetailholder.txtvwLocation
.setText(assetDetail.strLocationName + "("
+ assetDetail.assetLocationNameDesc + ")");
}
assetDetailholder.txtvwLocationDetail
.setText(assetDetail.strLocationDetail);
if (assetDetail.strInventoryNumber.contains("-")) {
assetDetailholder.txtvwInventoryNo
.setText(assetDetail.strInventoryNumber.split("-")[0]);
} else {
assetDetailholder.txtvwInventoryNo
.setText(assetDetail.strInventoryNumber);
}
assetDetailholder.txtvwAssetName.setText(assetDetail.assetName);
String conditionCodeString = assetDetail.assetConditionCode;
if (conditionCodeString != "" || conditionCodeString != null) {
try {
int conditionCodeInteger = Integer
.parseInt(conditionCodeString);
assetDetailholder.spnrconditionCode
.setSelection(conditionCodeInteger);
} catch (Exception e) {
assetDetailholder.spnrconditionCode.setSelection(0);
}
} else {
assetDetailholder.spnrconditionCode.setSelection(0);
}
// String thumbnailDir = Common
// .getSubNoDirectory(context, assetDetail);
// if (new File(thumbnailDir).isDirectory()) {
//
// File thumbnailFile = new File(Common.getSubNoImgFilePath(
// thumbnailDir, assetDetail, SubNo_ImageSample.A));
//
// if (thumbnailFile.exists()) {
// assetDetailholder.subNoThumbnail
// .setImageBitmap(BitmapFactory
// .decodeFile(thumbnailFile.getAbsolutePath()));
// }
// }
} catch (Exception e) {
e.printStackTrace();
}
return row;
}
static class AssetDetailHolder {
TextView txtVwlineCOde;
TextView txtvwLocation;
TextView txtvwLocationDetail;
TextView txtvwInventoryNo;
TextView txtvwAssetName;
Spinner spnrconditionCode;
ImageView subNoThumbnail;
public int itemPosition;
}
private static class ThumbnailTask extends AsyncTask<Void, Void, Void> {
private int mPosition;
private AssetDetailHolder mHolder;
private Context cntxt;
private AssetDetail assetItem;
private Bitmap thumbnailBmp;
public ThumbnailTask(int position, AssetDetailHolder holder,
AssetDetail asset, Context context) {
mPosition = position;
mHolder = holder;
assetItem = asset;
cntxt = context;
}
@Override
protected Void doInBackground(Void... params) {
String thumbnailDir = Common.getSubNoDirectory(cntxt, assetItem);
if (new File(thumbnailDir).isDirectory()) {
File thumbnailFile = new File(Common.getSubNoImgFilePath(
thumbnailDir, assetItem, SubNo_ImageSample.A));
if (thumbnailFile.exists()) {
thumbnailBmp = BitmapFactory.decodeFile(thumbnailFile
.getAbsolutePath());
}
}
return null;
}
@Override
protected void onPostExecute(Void result) {
if (mHolder.itemPosition == mPosition && thumbnailBmp != null) {
mHolder.subNoThumbnail.setImageBitmap(thumbnailBmp);
}
// super.onPostExecute(result);
}
}