我目前正在使用RecyclerView和CardView处理Android应用。我在RecyclerView中显示了UserPosts列表(包含文本和图像)。 UserPost项目已使用CardView创建。
修改
我面临的问题是 onCreateViewHolder 方法只被调用 getItemCount 方法返回的实际计数的一半,即使我滚动到列表的末尾。例如,我有10个帖子的列表,然后 onCreateViewHolder 只调用5次。它应该首先调用10次(当我滚动到列表的末尾),然后创建视图将被回收。但事实并非如此。我访问了许多Stackoverflow帖子,但没有运气。
以下是代码 UserPostAdapter.java :
package com.adapter;
import android.content.Context;
import android.support.v7.widget.RecyclerView;
import android.text.TextUtils;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import com.model.UserPostsListItem;
import com.musomeet.R;
import com.squareup.picasso.Picasso;
import java.util.List;
import de.hdodenhof.circleimageview.CircleImageView;
/**
* Created by SI_Android on 10/21/2015 .
*
*/
public class UserPostAdapter extends RecyclerView.Adapter<UserPostAdapter.UserPostViewHolder> {
private List<UserPostsListItem> userPostList;
Context conetxt ;
LayoutInflater inflater ;
public UserPostAdapter(){
}
public UserPostAdapter(Context conetxt, List<UserPostsListItem> postlist) {
this.userPostList = postlist;
this.conetxt = conetxt ;
inflater = LayoutInflater.from(this.conetxt);
}
@Override
public int getItemCount() {
//int size = 0 ;
//if( userPostList != null )
//size = userPostList.size();
return userPostList.size();
}
@Override
public void onBindViewHolder(UserPostViewHolder videoViewHolder, int position) {
UserPostsListItem item = userPostList.get(position);
videoViewHolder.userName.setText(item.getName());
videoViewHolder.userLocation.setText(item.getCity()+", "+item.getCountry());
videoViewHolder.timeAgo.setText(item.getAgo());
videoViewHolder.likes.setText(item.getNo_of_likes());
videoViewHolder.comments.setText(item.getNo_of_comments());
videoViewHolder.userMessage.setText(item.getContent());
if(!TextUtils.isEmpty(item.getPhoto())) {
Picasso.with(conetxt).load(item.getPhoto()).into(videoViewHolder.circleImageView);
}
String url = item.getAttachment_url() ;
if (!TextUtils.isEmpty(url)) {
if ((url.endsWith(".png") || url.endsWith(".jpg"))) {
//videoViewHolder.attachment.setVisibility(View.VISIBLE);
Picasso.with(conetxt).load(url).into(videoViewHolder.attachment);
}
}
}
@Override
public UserPostViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
View itemView = inflater.inflate(R.layout.userposts_listitem_textmessage, viewGroup, false);
return new UserPostViewHolder(itemView);
}
public static class UserPostViewHolder extends RecyclerView.ViewHolder {
TextView userName, userLocation, timeAgo, likes, comments, userMessage;
ImageView attachment;
CircleImageView circleImageView;
public UserPostViewHolder(View v){
super(v);
attachment = (ImageView) v.findViewById(R.id.attachment);
circleImageView = (CircleImageView) v.findViewById(R.id.circleView);
userMessage = (TextView) v.findViewById(R.id.massage);
userName = (TextView) v.findViewById(R.id.name);
userLocation = (TextView) v.findViewById(R.id.location);
timeAgo = (TextView) v.findViewById(R.id.time);
likes = (TextView) v.findViewById(R.id.likespoints);
comments = (TextView) v.findViewById(R.id.commentspoints);
}
}
}
以下是 userposts_listitem_textmessage.xml
<?xml version="1.0" encoding="utf-8"?>
<android.support.v7.widget.CardView
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:cardView="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/userpopstcardview"
android:layout_marginTop="10dp"
android:layout_marginBottom="10dp"
android:layout_marginRight="10dp"
android:layout_marginLeft="10dp"
cardView:cardElevation="5dp"
cardView:cardCornerRadius="10dp"
cardView:cardBackgroundColor="#fff"
>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:padding="0dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<de.hdodenhof.circleimageview.CircleImageView
android:layout_width="70dp"
android:layout_height="70dp"
android:src="@drawable/contact"
android:layout_margin="10dp"
android:id="@+id/circleView"
/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical"
android:layout_gravity="center"
android:layout_marginLeft="5dp">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<TextView
android:id="@+id/name"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#000"
android:text="Jasmine"
android:textSize="20sp"
android:textStyle="bold"
/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginTop="5dp">
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<TextView
android:id="@+id/location"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#929292"
android:text="Los Angles, California"
android:textSize="14sp"
android:textStyle="normal"
/>
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="5dp"
android:layout_marginRight="5dp">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#929292"
android:text="-"
android:textSize="14sp"
android:textStyle="normal"
/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:id="@+id/time"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textColor="#929292"
android:text="2 hours ago"
android:textSize="14sp"
android:textStyle="normal"
/>
</LinearLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>
<LinearLayout
android:id="@+id/userListContentLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:padding="0dp"
android:orientation="vertical">
<TextView
android:id="@+id/massage"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/recet_text"
android:textColor="#000"
android:textSize="15sp"
android:padding="10dp"
android:scrollbars="vertical"/>
<ImageView
android:id="@+id/attachment"
android:layout_width="match_parent"
android:layout_height="200dp"
android:layout_marginTop="10dp"
android:adjustViewBounds="true"
android:scaleType="fitXY"
android:tint="#00000000"
android:src="@drawable/contact"
android:visibility="visible"
/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="10dp"
>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:id="@+id/likespoints"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="2"
android:textColor="#929292"
android:textSize="14sp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Likes"
android:textColor="#929292"
android:textSize="14sp"
android:layout_marginLeft="5dp"/>
</LinearLayout>
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:layout_marginLeft="30dp">
<TextView
android:id="@+id/commentspoints"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="3"
android:textColor="#929292"
android:textSize="14sp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Comments"
android:textColor="#929292"
android:textSize="14sp"
android:layout_marginLeft="5dp"/>
</LinearLayout>
</LinearLayout>
<LinearLayout
android:layout_height="1dp"
android:layout_width="match_parent">
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:background="#eeeeee"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="50dp"
android:orientation="horizontal"
android:weightSum="3">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1">
<TextView
android:id="@+id/like"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Like"
android:gravity="center"
android:layout_gravity="center"
android:textSize="14sp"
android:textColor="#929292"
android:padding="10dp"
android:clickable="true"
android:background="@drawable/textview_effect"/>
</LinearLayout>
<LinearLayout
android:layout_height="match_parent"
android:layout_width="1dp">
<View
android:layout_width="1dp"
android:layout_height="match_parent"
android:background="#eeeeee"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1">
<TextView
android:id="@+id/comment"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Comment"
android:gravity="center"
android:layout_gravity="center"
android:textSize="14sp"
android:textColor="#929292"
android:padding="10dp"
android:clickable="true"
android:background="@drawable/textview_effect"/>
</LinearLayout>
<LinearLayout
android:layout_height="match_parent"
android:layout_width="1dp">
<View
android:layout_width="1dp"
android:layout_height="match_parent"
android:background="#eeeeee"/>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="1">
<TextView
android:id="@+id/share"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:text="Share"
android:gravity="center"
android:layout_gravity="center"
android:textSize="14sp"
android:textColor="#929292"
android:padding="10dp"
android:clickable="true"
android:background="@drawable/textview_effect"/>
</LinearLayout>
</LinearLayout>
</LinearLayout>
</LinearLayout>
</android.support.v7.widget.CardView>
答案 0 :(得分:3)
您看到的是预期的行为。 RecylerView不会创建尽可能多的视图,因为适配器的getItemCount()返回。它创建视图,尽可能多地渲染视图。
例如,如果你的适配器包含100个元素,但是当时只显示5个元素,系统将创建5个视图(它可以创建1或2个视图作为&#34;缓冲区&#34;)并重用这些视图当用户滚动时。
答案 1 :(得分:1)
当视图被回收时,它不会被重置&#34;到它的原始状态,所以它和它的子视图仍然具有ViewHolder最后一次传递到onBindViewHolder()
时在它们上设置的属性。由于您目前仅在if
条件为true
时设置图像,因此如果其中任何一个条件为false
,则不会更新ImageView,并且仍会在其上设置图像先前。当这些条件不是true
时,您只需将ImageView的位图设置为null。此外,您可以合并两个if
语句:
@Override
public void onBindViewHolder(UserPostViewHolder videoViewHolder, int position) {
UserPostsListItem item = userPostList.get(position);
...
String url = item.getAttachment_url() ;
if (!TextUtils.isEmpty(url) && (url.endsWith(".png") || url.endsWith(".jpg"))) {
Picasso.with(conetxt).load(url).into(videoViewHolder.attachment);
}
else {
videoViewHolder.attachment.setImageBitmap(null);
}
}