适配器的getView方法中的毛刺 [英] Glitches in adapter's getView method
问题描述
我正在显示联系人列表.除了设备有1620个联系人外，其他都很好，因此列表滚动速度非常慢，甚至有时会挂起.
I am showing the list of contacts .All good except that device has 1620 contacts so list is scrolling very slow and even sometimes get hangs.
I tried using a check in getView method for ConvertView!=null but it alwayz inflate same view many times. thanks in advance..
My code for getView method:-
if(ConvertView==null)
{ view= mInflater.inflate(R.layout.facebookfriend, null);
TextView name=(TextView)view.findViewById(R.id.textView1);
ImageView image=(ImageView)view.findViewById(R.id.imageView1);
name.setText(mlist.get(position).get("name"));
String Id=mlist.get(position).get("contactId");
Log.e("Id",""+Id);
CheckBox chkbox= (CheckBox)view.findViewById(R.id.checkBox1);
chkbox.setOnCheckedChangeListener(new OnCheckedChangeListener() {
@Override
public void onCheckedChanged(
CompoundButton buttonView, boolean isChecked) {
isSelected.set(position, isChecked);
}
});
String photoid=mlist.get(position).get("photoId");
Log.e("photoid",""+photoid);
if(mlist.get(position).get("photoId")!=null){
Log.e("photoid",""+"photoid");
image.setImageBitmap(loadContactPhoto(Id, mlist.get(position).get("photoId")));
}
}
}
有人告诉我使listview根据要求动态加载数据，还使用ViewHolder使其效率更高.我已经使用视图持有器尝试过它，但是每次它一次又一次地放大单个视图时，我的列表滚动得非常平稳，但真的不知道为什么它一次又一次地膨胀相同的视图.请帮忙 .我的代码与viewHolder:-
somebody told me to make the listview to load the data dynamically as per the requirement,also to use ViewHolder to make it more efficient. I have already tried it using view holder but it every time it inflates the single view again and again.My list is scrolling very smoothly but really do not know why it inflate the same view again and again. Please Help . My code with viewHolder :-
if (ConvertView == null) {
holder = new ViewHolder();
ConvertView= mInflater.inflate(R.layout.facebookfriend, null);
holder.name = (TextView)ConvertView.findViewById(R.id.textView1);
holder.imageView = (ImageView)ConvertView.findViewById(R.id.imageView1);
holder.chkbox= (CheckBox)ConvertView.findViewById(R.id.checkBox1);
ConvertView.setTag(holder);
} else {
holder = (ViewHolder) ConvertView.getTag();
}
holder.name.setText(mlist.get(position).get("Name").toString());
holder. chkbox.setOnCheckedChangeListener(new OnCheckedChangeListener() {
@Override
public void onCheckedChanged(
CompoundButton buttonView, boolean isChecked) {
isSelected.set(position, isChecked);
Log.e("position"+position,""+isChecked);
}
});
String Id=mlist.get(position).get("Contactid").toString();
Log.e("Id","--------------"+Id);
if(mlist.get(position).get("Photoid")!=null){
Log.e("photoid",""+"photoid");
holder.imageView.setImageBitmap(loadContactPhoto(Id, mlist.get(position).get("Photoid")));
Log.e("position position",""+position);
}
}
static class ViewHolder {
TextView name;
ImageView imageView;
CheckBox chkbox;
}
我的Imagefrom接触方法代码，我确定该代码是
My code for Imagefrom contact method,I am damn sure for this code
private Bitmap loadContactPhoto(String id, String photoId) {
Long _id=Long.parseLong(id);
Long _photoId=0l;
if(photoId!=null){
_photoId=Long.parseLong(photoId);
}
ContentResolver cr = Setting.this.getContentResolver();
Uri uri = ContentUris.withAppendedId(ContactsContract.Contacts.CONTENT_URI, _id);
InputStream input = ContactsContract.Contacts.openContactPhotoInputStream(cr, uri);
if (input != null) {
return BitmapFactory.decodeStream(input);
} else {
Log.d("PHOTO", "first try failed to load photo");
}
byte[] photoBytes = null;
Uri photoUri = ContentUris.withAppendedId(ContactsContract.Data.CONTENT_URI, _photoId);
Cursor c = cr.query(photoUri,new String[] { ContactsContract.CommonDataKinds.Photo.PHOTO },
null, null, null);
try {
if (c.moveToFirst())
photoBytes = c.getBlob(0);
} catch (Exception e) {
e.printStackTrace();
} finally {
c.close();
}
if (photoBytes != null)
return BitmapFactory.decodeByteArray(photoBytes, 0,
photoBytes.length);
else
Log.d("PHOTO", "second try also failed");
Bitmap icon = BitmapFactory.decodeResource(this.getResources(),
R.drawable.default_image);
return icon;
}
推荐答案
我认为您的问题出在 loadContactPhoto()中.每次使用 loadContactPhoto()时，您都在运行查询并通过解码数组获取位图.这就是滚动变慢的原因.
Your problem is in loadContactPhoto() I think. Each time with loadContactPhoto() you are running query and get the Bitmap by decoding array. That's why the scrolling is getting slow.
在加载 ListView 之前尝试加载所有联系人图像，然后让我们知道发生了什么.
Try to load all the contact images before loading the ListView and let us know what happened.
您还可以按照本教程使用 SimpleCursorAdapter 加载照片联系人.
You can also follow this tutorial to load contact with photo using SimpleCursorAdapter.
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