ListView图像在滚动过程中发生变化 [英] ListView images changing During Scroll
本文介绍了ListView图像在滚动过程中发生变化的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
class ps1 extends ArrayAdapter<String> {
Context context;
String[] images1;
List mList;
String[] namearray;
String[] rating;
static class ViewHolder {
ImageView localImageView1;
ImageView localImageView2;
ImageView localImageView3;
}
ps1(Context paramContext, String[] paramArrayOfString1, String[] paramArrayOfString2, String[] paramArrayOfString3) {
super(paramContext, R.layout.list2, R.id.imageView1, paramArrayOfString1);
this.context = paramContext;
this.images1 = paramArrayOfString3;
this.namearray = paramArrayOfString1;
this.rating = paramArrayOfString2;
}
public View getView(int paramInt, View paramView, ViewGroup paramViewGroup) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(context.LAYOUT_INFLATER_SERVICE);
ViewHolder viewHolder = new ViewHolder();
if (paramView == null) {
paramView = inflater.inflate(R.layout.list2, paramViewGroup, false);
}
viewHolder.localImageView1 = (ImageView) paramView
.findViewById(R.id.imageView1);
viewHolder.localImageView2 = (ImageView) paramView
.findViewById(R.id.imageView2);
viewHolder.localImageView3 = (ImageView) paramView
.findViewById(R.id.imageView3);
viewHolder.localImageView1.setScaleType(ImageView.ScaleType.FIT_XY);
viewHolder.localImageView2.setScaleType(ImageView.ScaleType.FIT_XY);
viewHolder.localImageView3.setScaleType(ImageView.ScaleType.FIT_XY);
viewHolder.localImageView1.setTag(this.namearray[paramInt]);
new LoadImage().execute(viewHolder.localImageView1);
viewHolder.localImageView2.setTag(this.rating[paramInt]);
new LoadImage().execute(viewHolder.localImageView2);
viewHolder.localImageView3.setTag(this.images1[paramInt]);
new LoadImage().execute(viewHolder.localImageView3);
return paramView;
}
}
class LoadImage extends AsyncTask<Object, Void, Bitmap> {
private ImageView imv;
private Bitmap download_Image(String paramString) {
Bitmap localBitmap = null;
try {
Object localObject = null;
localBitmap = BitmapFactory
.decodeStream(((HttpURLConnection) new URL(paramString)
.openConnection()).getInputStream());
localObject = localBitmap;
if (localObject != null) {
return localBitmap;
}
} catch (Exception e) {
}
return localBitmap;
}
protected Bitmap doInBackground(Object... paramVarArgs) {
this.imv = ((ImageView) paramVarArgs[0]);
Log.d("fsdf", (String) this.imv.getTag());
return download_Image((String) this.imv.getTag());
}
protected void onPostExecute(Bitmap paramBitmap) {
this.imv.setImageBitmap(paramBitmap);
}
}
解决方案
我也经历过同样的事情.我也在寻找正确的解决方案.据我搜索，我知道ListView会在向下滚动时清除上一个视图，并在您向后滚动时重新加载它.因此，在上下滚动时，您的图像可能会被回收并重新对齐. (我也在等待正确的解决方案.)
但是我已经使用 SmartImageView 解决了该问题，该库是直接下载的图像并将其设置为ImageView.它将图像保存在缓存中，因此您可以获得正确的图像.
相比之下，这也更快.
im try to make listview with dynamic images, using asyntask its download image and set into listview. my problem is while scroll down images get randomly changed..
class ps1 extends ArrayAdapter<String> {
Context context;
String[] images1;
List mList;
String[] namearray;
String[] rating;
static class ViewHolder {
ImageView localImageView1;
ImageView localImageView2;
ImageView localImageView3;
}
ps1(Context paramContext, String[] paramArrayOfString1, String[] paramArrayOfString2, String[] paramArrayOfString3) {
super(paramContext, R.layout.list2, R.id.imageView1, paramArrayOfString1);
this.context = paramContext;
this.images1 = paramArrayOfString3;
this.namearray = paramArrayOfString1;
this.rating = paramArrayOfString2;
}
public View getView(int paramInt, View paramView, ViewGroup paramViewGroup) {
LayoutInflater inflater = (LayoutInflater) context
.getSystemService(context.LAYOUT_INFLATER_SERVICE);
ViewHolder viewHolder = new ViewHolder();
if (paramView == null) {
paramView = inflater.inflate(R.layout.list2, paramViewGroup, false);
}
viewHolder.localImageView1 = (ImageView) paramView
.findViewById(R.id.imageView1);
viewHolder.localImageView2 = (ImageView) paramView
.findViewById(R.id.imageView2);
viewHolder.localImageView3 = (ImageView) paramView
.findViewById(R.id.imageView3);
viewHolder.localImageView1.setScaleType(ImageView.ScaleType.FIT_XY);
viewHolder.localImageView2.setScaleType(ImageView.ScaleType.FIT_XY);
viewHolder.localImageView3.setScaleType(ImageView.ScaleType.FIT_XY);
viewHolder.localImageView1.setTag(this.namearray[paramInt]);
new LoadImage().execute(viewHolder.localImageView1);
viewHolder.localImageView2.setTag(this.rating[paramInt]);
new LoadImage().execute(viewHolder.localImageView2);
viewHolder.localImageView3.setTag(this.images1[paramInt]);
new LoadImage().execute(viewHolder.localImageView3);
return paramView;
}
}
class LoadImage extends AsyncTask<Object, Void, Bitmap> {
private ImageView imv;
private Bitmap download_Image(String paramString) {
Bitmap localBitmap = null;
try {
Object localObject = null;
localBitmap = BitmapFactory
.decodeStream(((HttpURLConnection) new URL(paramString)
.openConnection()).getInputStream());
localObject = localBitmap;
if (localObject != null) {
return localBitmap;
}
} catch (Exception e) {
}
return localBitmap;
}
protected Bitmap doInBackground(Object... paramVarArgs) {
this.imv = ((ImageView) paramVarArgs[0]);
Log.d("fsdf", (String) this.imv.getTag());
return download_Image((String) this.imv.getTag());
}
protected void onPostExecute(Bitmap paramBitmap) {
this.imv.setImageBitmap(paramBitmap);
}
}
解决方案
I have also experienced the same . I am also searching for a right solution . As far as i have searched , i came to know that ListView clears the previous view while scrolling down and re-loads it when you scroll back . So while scrolling up and down, your images may get re-cycled and mis-aligned . ( I am also waiting for the correct solution ) .
But i have tackled it using SmartImageView , which is a library that directly downloads the image and sets it to the ImageView . It will maintain the images in cache and so you could get the right images .
Comparatively this was faster too .
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