问题描述
我创建一个自定义联系人应用程序..我用ViewHolder设计模式ArrayAdapter优化......既然花了很多时间来加载缩略图图片，我使用的加载图像的AsyncTask类，第一套在我的屏幕接触时，图片加载很好，但是当我向下滚动，相同的一组照片被随意用于其他联系人重新循环......我已搜查这个forumn，发现了几个解决方案，但没有为我工作。我现在就把我下面的code ..有人请告诉我什么是错在code，而不是将其标记为正，副本QN ...
公共类CustomList扩展ArrayAdapter＆LT;串GT; { 私人最终活动范围内;
私人最终的ArrayList＆LT;串GT;显示名，demoteValue，突发事件;
ArrayList的＆LT;龙＆GT;的ContactID; 公共CustomList（Activity上下文，ArrayList的＆LT;龙＆GT;的ContactID，ArrayList的＆LT;串GT;显示名，ArrayList的＆LT;串GT; demoteValue，
ArrayList的＆LT;串GT;应急）{
超（背景下，R.layout.list_single，显示名）;
this.context =背景;
this.displayName =显示名;
this.demoteValue = demoteValue;
this.emergency =紧急情况;
this.contactId =的ContactID; } 类MyViewHolder
{
公共QuickContactBadge ImageView的;
公众的TextView txtTitle;
INT位置; MyViewHolder（视图V）{
txtTitle =（TextView中）v.findViewById（R.id.txt）;
ImageView的=（QuickContactBadge）v.findViewById（R.id.contactimageentry）;
}
}
@覆盖
公共查看getView（INT位置，查看convertView，父母的ViewGroup）{
查看rowView = convertView;
MyViewHolder支架=无效; 如果（rowView == NULL）
{
LayoutInflater吹气=（LayoutInflater）context.getSystemService（Context.LAYOUT_INFLATER_SERVICE）;
rowView = inflater.inflate（R.layout.list_single，父母，假）;
持有人=新MyViewHolder（rowView）;
rowView.setTag（保持器）; }其他{
支架=（MyViewHolder）rowView.getTag（）;
} holder.txtTitle.setText（displayName.get（位置））;
holder.txtTitle.setPadding（5,5，5,5）;
//有些唧唧歪歪的工作。
如果（emergency.get（位置）.equals（1））{ holder.txtTitle.setTextSize（TypedValue.COMPLEX_UNIT_SP，25）;
。holder.imageView.getLayoutParams（）宽度=的getPixels（TypedValue.COMPLEX_UNIT_DIP，50）;}
//获取和设置光这里谎言到问题的CALL
holder.position =位置;
新LoadContactImage（的getContext（），持有人，位置，contactId.get（位置））
.executeOnExecutor（AsyncTask.THREAD_POOL_EXECUTOR，NULL）;
返回rowView;
}
}
这是我的任务异步的code加载基于ID，同时调用它，我已经通过了图像
公共类LoadContactImage扩展的AsyncTask＆LT;对象，太虚，位图＆GT; {私人长期路径;
私人MyViewHolder mHolder;
私人诠释mposition;
上下文CTX;公共LoadContactImage（上下文的背景下，MyViewHolder架，INT位置，长ID）{
this.mHolder =持有人;
this.Path = ID;
this.mposition =位置;
this.ctx =背景;
}@覆盖
保护位图doInBackground（对象... PARAMS）{
乌里my_uri = getPhotoUri（路径）;
ContentResolver的CR = ctx.getContentResolver（）;
在的InputStream = NULL;
尝试{
在= cr.openInputStream（my_uri）;
}赶上（FileNotFoundException异常五）{
// TODO自动生成catch块
e.printStackTrace（）;
}
位图位图= BitmapFactory.de codeStream（中）;
返回位图;
}@覆盖
保护无效onPostExecute（位图结果）{ super.onPostExecute（结果）;
如果（结果=空＆安培;！＆安培; mposition == mHolder.position）{
//imv.setImageBitmap(result）;
mHolder.imageView.setImageBitmap（结果）;
}
}
}
想通了......现在，它在评论由西蒙·迈尔给working..Soln是correct..I必要的初始化的ImageView在getView位图（）之前，我可以调用异步Task..Here是code修改
holder.position =位置;holder.imageView.setImageURI（Uri.parse（android.resource：//com.vishnu.demotingprototype/drawable/ic_contact_picture））;新LoadContactImage（的getContext（），持有人，位置，contactId.get（位置））执行（）;
I am creating a custom contact app.. I use a ArrayAdapter with ViewHolder design pattern for optimization...Since it took a lot of time to load the thumbnail pics, I use AsyncTask class for loading images, for the first set of contacts in my screen, the pics are loading well but when I scroll down, the same set of pictures are being re-cycled at random for other contacts...I have searched this forumn and found a few solutions but none worked for me. I shall put my code below.. Someone pls tell me what is wrong in the code instead of marking it as duplicate qn...
public class CustomList extends ArrayAdapter<String>{
private final Activity context;
private final ArrayList<String> displayName,demoteValue,emergency;
ArrayList<Long> contactId;
public CustomList(Activity context,ArrayList<Long> contactId,ArrayList<String> displayName,ArrayList<String> demoteValue ,
ArrayList<String> emergency) {
super(context, R.layout.list_single, displayName);
this.context = context;
this.displayName = displayName;
this.demoteValue = demoteValue;
this.emergency = emergency;
this.contactId=contactId;
}
class MyViewHolder
{
public QuickContactBadge imageView;
public TextView txtTitle;
int position;
MyViewHolder(View v){
txtTitle = (TextView) v.findViewById(R.id.txt);
imageView = (QuickContactBadge) v.findViewById(R.id.contactimageentry);
}
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View rowView=convertView;
MyViewHolder holder=null;
if(rowView==null)
{
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
rowView = inflater.inflate(R.layout.list_single, parent, false);
holder=new MyViewHolder(rowView);
rowView.setTag(holder);
}else{
holder= (MyViewHolder) rowView.getTag();
}
holder.txtTitle.setText(displayName.get(position));
holder.txtTitle.setPadding(5, 5, 5, 5);
//Some BLA BLA BLA work.
if(emergency.get(position).equals("1")){
holder.txtTitle.setTextSize(TypedValue.COMPLEX_UNIT_SP,25);
holder.imageView.getLayoutParams().width=getPixels(TypedValue.COMPLEX_UNIT_DIP,50);
}
//Get and set the photo-HERE LIES THE CALL TO THE PROBLEM
holder.position = position;
new LoadContactImage(getContext(),holder,position,contactId.get(position))
.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, null);
return rowView;
}
}
And here is the code for my Async Task that loads the images based on the ID which I have passed while calling it
public class LoadContactImage extends AsyncTask<Object, Void, Bitmap> {
private long Path;
private MyViewHolder mHolder;
private int mposition;
Context ctx;
public LoadContactImage(Context context,MyViewHolder holder,int position,Long id) {
this.mHolder= holder;
this.Path = id;
this.mposition=position;
this.ctx= context;
}
@Override
protected Bitmap doInBackground(Object... params) {
Uri my_uri = getPhotoUri(Path);
ContentResolver cr = ctx.getContentResolver();
InputStream in = null;
try {
in = cr.openInputStream(my_uri);
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
Bitmap bitmap = BitmapFactory.decodeStream(in);
return bitmap;
}
@Override
protected void onPostExecute(Bitmap result) {
super.onPostExecute(result);
if (result != null && mposition == mHolder.position) {
//imv.setImageBitmap(result);
mHolder.imageView.setImageBitmap(result);
}
}
}
Figured it out...Now its working..Soln given by Simon Meyer in Comments is correct..I need to initialize the imageView to a bitmap in getView() before I could call Async Task..Here is the change in code
holder.position = position;
holder.imageView.setImageURI( Uri.parse("android.resource://com.vishnu.demotingprototype/drawable/ic_contact_picture"));
new LoadContactImage(getContext(),holder,position,contactId.get(position)).execute();
这篇关于Android-加载通讯录与ViewHolder和AsyncTask-缩略图问题的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！