使用 SwipeRefresh 布局获取重复的卡片视图
Getting duplicated cardviews using SwipeRefresh Layout
所以这是我的问题，我得到了一个 API，它为我提供了许多来源的最新消息。他们每个人都有一个 cardview。这里的问题是，当我使用 swipeRefresh 时，它会重复 cardViews 相同的新闻，就像如果我有 10 条新闻，它会重复 20 条相同的新闻。
这是我应用 swipeRefresh:
的代码
package com.example.newsapp4;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
import com.example.newsapp4.Model.Articles;
import com.example.newsapp4.Model.Headlines;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
public class bbcnews extends AppCompatActivity {
Adapter adapter;
Intent intencion;
RecyclerView recyclerView;
public static String source = "My Source";
public static String API_KEY = "My API Key";
SwipeRefreshLayout srl;
List<Articles> articles = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_bbcnews);
srl = findViewById(R.id.swipeRefresh);
srl.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
retrieveJson(source, API_KEY);
}
});
recyclerView = findViewById(R.id.recyclerView1);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
adapter = new Adapter(bbcnews.this,articles);
recyclerView.setAdapter(adapter);
retrieveJson(source, API_KEY);
}
public void retrieveJson(String source, String apiKey){
srl.setRefreshing(true);
Call<Headlines> call = ApiClient.getInstance().getApi().getHeadlines(source, apiKey);
call.enqueue(new Callback<Headlines>() {
@Override
public void onResponse(Call<Headlines> call, Response<Headlines> response) {
if(response.isSuccessful() && response.body().getArticles() != null){
srl.setRefreshing(false);
articles.clear();
articles = response.body().getArticles();
adapter.setArticles(articles);
}
}
@Override
public void onFailure(Call<Headlines> call, Throwable t) {
srl.setRefreshing(false);
Toast.makeText(bbcnews.this, t.getLocalizedMessage(), Toast.LENGTH_SHORT).show();
}
});
}
public String getCountry(){
Locale locale = Locale.getDefault();
String country = locale.getCountry();
return country.toLowerCase();
}
public void aPerfil(View vista){
intencion = new Intent(this, profile_activity.class);
startActivity(intencion);
}
}
我认为我不需要将 xml 代码与 progressbar 和 swipeRefresh 放在一起，但这里都有：
这是我创建 cardView:
的 Items.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto">
<androidx.cardview.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
app:cardElevation="4dp"
android:id="@+id/cardView"
app:cardCornerRadius="10dp">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="200dp">
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:id="@+id/loader"/>
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/image"
android:scaleType="centerCrop"
android:src="@drawable/img"/>
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/gradient" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TITLE"
android:textSize="20dp"
android:padding="10dp"
android:fontFamily="@font/g_bold"
android:textColor="@color/white"
android:id="@+id/tvTitle"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Source"
android:textSize="16dp"
android:padding="10dp"
android:ems="15"
android:fontFamily="@font/g_light"
android:textColor="@color/white"
android:id="@+id/tvSource"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="@font/g_light"
android:gravity="right"
android:text="Date"
android:textColor="@color/white"
android:padding="10dp"
android:textSize="16dp"
android:id="@+id/tvDate"/>
</LinearLayout>
</FrameLayout>
</androidx.cardview.widget.CardView>
</LinearLayout>
这里是 recyclerView 中带有 swipeRefresh 的那个：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@color/white"
tools:context=".bbcnews">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="DINGO BBC NEWS"
android:textColor="@color/black"
android:textSize="20sp"
android:fontFamily="@font/g_bold"
android:background="@color/white"
android:padding="10dp"
android:textAlignment="center"/>
<GridLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:paddingTop="10dp"
android:paddingBottom="10dp"
android:columnCount="2"
android:paddingLeft="20dp"
android:paddingRight="5dp"
android:background="@drawable/black_background"
android:rowCount="2">
<EditText
android:id="@+id/editTextTextPersonName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Search"
android:textColor="@color/grey"
android:textColorHint="@color/grey"
android:padding="5dp"
android:layout_column="0"
android:background="@drawable/black_background"
android:layout_row="0"
android:layout_columnWeight="1"
android:inputType="textPersonName" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingRight="20dp"
android:background="@drawable/black_background"
android:drawableRight="@drawable/ic_baseline_search_24"
android:layout_column="1"
android:layout_row="0"/>
</GridLayout>
<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/swipeRefresh">
<androidx.recyclerview.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="5dp"
android:id="@+id/recyclerView1"/>
</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>
</LinearLayout>
这也是我的 adapter.java 代码：
package com.example.newsapp4;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.cardview.widget.CardView;
import androidx.recyclerview.widget.RecyclerView;
import com.example.newsapp4.Model.Articles;
import com.squareup.picasso.Picasso;
import java.util.List;
public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {
Context context;
List<Articles> articles;
public Adapter(Context context, List<Articles> articles) {
this.context = context;
this.articles = articles;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.items, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
final Articles a = articles.get(position);
String imageUrl = a.getUrlToImage();
holder.tvTitle.setText(a.getTitle());
holder.tvSource.setText(a.getSource().getName());
holder.tvDate.setText(a.getPublishedAt());
Picasso.with(context).load(imageUrl).into(holder.imageView);
}
@Override
public int getItemCount() {
return articles.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder {
TextView tvTitle,tvSource,tvDate;
ImageView imageView;
CardView cardView;
public ViewHolder(@NonNull View itemView) {
super(itemView);
tvTitle = itemView.findViewById(R.id.tvTitle);
tvSource = itemView.findViewById(R.id.tvSource);
tvDate = itemView.findViewById(R.id.tvDate);
imageView = itemView.findViewById(R.id.image);
cardView = itemView.findViewById(R.id.cardView);
}
}
public void setArticles(List<Articles> articles) {
this.articles.addAll(articles);
int count = getItemCount();
notifyItemRangeInserted(count, count + articles.size());
}
}
感谢您的宝贵时间！
据我所知，在您的代码中，API 调用在滑动刷新后成功，这是此处的这一部分
articles.clear();
articles = response.body().getArticles();
adapter.setArticles(articles);
你在这里清除你activity里面的文章，但是你的适配器里面已经有另一个文章列表，你没有清除它们。
然后当您在以下函数中进行 adapter.setArticles(articles); 调用时，您的文章将添加到已经存在的文章列表中，从而添加到重复列表中。
public void setArticles(List<Articles> articles) {
this.articles.addAll(articles);
int count = getItemCount();
notifyItemRangeInserted(count, count + articles.size());
}
要解决此问题，您可以对函数进行以下修改。
public void setArticles(List<Articles> articles, boolean clearAll) {
if(clearAll){ this.articles.clear(); }
this.articles.addAll(articles);
notifyDataSetChanged();
}
然后修改你的函数调用如下
adapter.setArticles(articles, true);
这样当布尔为真时，它会清除现有列表。另外，我建议您将插入调用替换为数据集更改调用。否则你可以创建一个单独的函数来添加元素和清除现有元素。
// Clear adapter list before add to list.
public void setArticles(List<Articles> articles) {
if(this.articles!=null && this.articles.size()>0)
this.articles.clear();
this.articles.addAll(articles);
int count = getItemCount();
notifyItemRangeInserted(count, count + articles.size());
}
所以这是我的问题，我得到了一个 API，它为我提供了许多来源的最新消息。他们每个人都有一个 cardview。这里的问题是，当我使用 swipeRefresh 时，它会重复 cardViews 相同的新闻，就像如果我有 10 条新闻，它会重复 20 条相同的新闻。
这是我应用 swipeRefresh:
package com.example.newsapp4;
import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;
import androidx.swiperefreshlayout.widget.SwipeRefreshLayout;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Toast;
import com.example.newsapp4.Model.Articles;
import com.example.newsapp4.Model.Headlines;
import java.util.ArrayList;
import java.util.List;
import java.util.Locale;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
public class bbcnews extends AppCompatActivity {
Adapter adapter;
Intent intencion;
RecyclerView recyclerView;
public static String source = "My Source";
public static String API_KEY = "My API Key";
SwipeRefreshLayout srl;
List<Articles> articles = new ArrayList<>();
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_bbcnews);
srl = findViewById(R.id.swipeRefresh);
srl.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
retrieveJson(source, API_KEY);
}
});
recyclerView = findViewById(R.id.recyclerView1);
recyclerView.setLayoutManager(new LinearLayoutManager(this));
adapter = new Adapter(bbcnews.this,articles);
recyclerView.setAdapter(adapter);
retrieveJson(source, API_KEY);
}
public void retrieveJson(String source, String apiKey){
srl.setRefreshing(true);
Call<Headlines> call = ApiClient.getInstance().getApi().getHeadlines(source, apiKey);
call.enqueue(new Callback<Headlines>() {
@Override
public void onResponse(Call<Headlines> call, Response<Headlines> response) {
if(response.isSuccessful() && response.body().getArticles() != null){
srl.setRefreshing(false);
articles.clear();
articles = response.body().getArticles();
adapter.setArticles(articles);
}
}
@Override
public void onFailure(Call<Headlines> call, Throwable t) {
srl.setRefreshing(false);
Toast.makeText(bbcnews.this, t.getLocalizedMessage(), Toast.LENGTH_SHORT).show();
}
});
}
public String getCountry(){
Locale locale = Locale.getDefault();
String country = locale.getCountry();
return country.toLowerCase();
}
public void aPerfil(View vista){
intencion = new Intent(this, profile_activity.class);
startActivity(intencion);
}
}
我认为我不需要将 xml 代码与 progressbar 和 swipeRefresh 放在一起，但这里都有：
这是我创建 cardView:
Items.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
xmlns:app="http://schemas.android.com/apk/res-auto">
<androidx.cardview.widget.CardView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
app:cardElevation="4dp"
android:id="@+id/cardView"
app:cardCornerRadius="10dp">
<FrameLayout
android:layout_width="match_parent"
android:layout_height="200dp">
<ProgressBar
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:id="@+id/loader"/>
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/image"
android:scaleType="centerCrop"
android:src="@drawable/img"/>
<ImageView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@drawable/gradient" />
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="TITLE"
android:textSize="20dp"
android:padding="10dp"
android:fontFamily="@font/g_bold"
android:textColor="@color/white"
android:id="@+id/tvTitle"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="bottom"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Source"
android:textSize="16dp"
android:padding="10dp"
android:ems="15"
android:fontFamily="@font/g_light"
android:textColor="@color/white"
android:id="@+id/tvSource"/>
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:fontFamily="@font/g_light"
android:gravity="right"
android:text="Date"
android:textColor="@color/white"
android:padding="10dp"
android:textSize="16dp"
android:id="@+id/tvDate"/>
</LinearLayout>
</FrameLayout>
</androidx.cardview.widget.CardView>
</LinearLayout>
这里是 recyclerView 中带有 swipeRefresh 的那个：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="@color/white"
tools:context=".bbcnews">
<TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="DINGO BBC NEWS"
android:textColor="@color/black"
android:textSize="20sp"
android:fontFamily="@font/g_bold"
android:background="@color/white"
android:padding="10dp"
android:textAlignment="center"/>
<GridLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="10dp"
android:paddingTop="10dp"
android:paddingBottom="10dp"
android:columnCount="2"
android:paddingLeft="20dp"
android:paddingRight="5dp"
android:background="@drawable/black_background"
android:rowCount="2">
<EditText
android:id="@+id/editTextTextPersonName"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:ems="10"
android:hint="Search"
android:textColor="@color/grey"
android:textColorHint="@color/grey"
android:padding="5dp"
android:layout_column="0"
android:background="@drawable/black_background"
android:layout_row="0"
android:layout_columnWeight="1"
android:inputType="textPersonName" />
<Button
android:id="@+id/button2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:paddingRight="20dp"
android:background="@drawable/black_background"
android:drawableRight="@drawable/ic_baseline_search_24"
android:layout_column="1"
android:layout_row="0"/>
</GridLayout>
<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:id="@+id/swipeRefresh">
<androidx.recyclerview.widget.RecyclerView
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginTop="5dp"
android:id="@+id/recyclerView1"/>
</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>
</LinearLayout>
这也是我的 adapter.java 代码：
package com.example.newsapp4;
import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.annotation.NonNull;
import androidx.cardview.widget.CardView;
import androidx.recyclerview.widget.RecyclerView;
import com.example.newsapp4.Model.Articles;
import com.squareup.picasso.Picasso;
import java.util.List;
public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {
Context context;
List<Articles> articles;
public Adapter(Context context, List<Articles> articles) {
this.context = context;
this.articles = articles;
}
@NonNull
@Override
public ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.items, parent, false);
return new ViewHolder(view);
}
@Override
public void onBindViewHolder(@NonNull ViewHolder holder, int position) {
final Articles a = articles.get(position);
String imageUrl = a.getUrlToImage();
holder.tvTitle.setText(a.getTitle());
holder.tvSource.setText(a.getSource().getName());
holder.tvDate.setText(a.getPublishedAt());
Picasso.with(context).load(imageUrl).into(holder.imageView);
}
@Override
public int getItemCount() {
return articles.size();
}
public static class ViewHolder extends RecyclerView.ViewHolder {
TextView tvTitle,tvSource,tvDate;
ImageView imageView;
CardView cardView;
public ViewHolder(@NonNull View itemView) {
super(itemView);
tvTitle = itemView.findViewById(R.id.tvTitle);
tvSource = itemView.findViewById(R.id.tvSource);
tvDate = itemView.findViewById(R.id.tvDate);
imageView = itemView.findViewById(R.id.image);
cardView = itemView.findViewById(R.id.cardView);
}
}
public void setArticles(List<Articles> articles) {
this.articles.addAll(articles);
int count = getItemCount();
notifyItemRangeInserted(count, count + articles.size());
}
}
感谢您的宝贵时间！
据我所知，在您的代码中，API 调用在滑动刷新后成功，这是此处的这一部分
articles.clear();
articles = response.body().getArticles();
adapter.setArticles(articles);
你在这里清除你activity里面的文章，但是你的适配器里面已经有另一个文章列表，你没有清除它们。
然后当您在以下函数中进行 adapter.setArticles(articles); 调用时，您的文章将添加到已经存在的文章列表中，从而添加到重复列表中。
public void setArticles(List<Articles> articles) {
this.articles.addAll(articles);
int count = getItemCount();
notifyItemRangeInserted(count, count + articles.size());
}
要解决此问题，您可以对函数进行以下修改。
public void setArticles(List<Articles> articles, boolean clearAll) {
if(clearAll){ this.articles.clear(); }
this.articles.addAll(articles);
notifyDataSetChanged();
}
然后修改你的函数调用如下
adapter.setArticles(articles, true);
这样当布尔为真时，它会清除现有列表。另外，我建议您将插入调用替换为数据集更改调用。否则你可以创建一个单独的函数来添加元素和清除现有元素。
// Clear adapter list before add to list.
public void setArticles(List<Articles> articles) {
if(this.articles!=null && this.articles.size()>0)
this.articles.clear();
this.articles.addAll(articles);
int count = getItemCount();
notifyItemRangeInserted(count, count + articles.size());
}