Android 使用RecycleView列表实现加载更多
Android 使用RecycleView列表实现加载更多
1.界面布局
<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#f0f3f5"
tools:context=".MainActivity">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
tools:context=".MainActivity">
<ImageView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:src="@mipmap/logo"/>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="10dp"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:gravity="center">
<TextView
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:gravity="center"
android:text="电影名"/>
<LinearLayout
android:layout_width="0dp"
android:layout_weight="1"
android:gravity="center"
android:layout_height="wrap_content"
android:orientation="horizontal">
<TextView
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:text="电影评分" />
</LinearLayout>
<TextView
android:layout_width="0dp"
android:layout_weight="1"
android:gravity="center"
android:layout_height="wrap_content"
android:text="电影图片"/>
</LinearLayout>
</LinearLayout>
<androidx.swiperefreshlayout.widget.SwipeRefreshLayout
android:layout_height="wrap_content"
android:layout_width="wrap_content"
android:id="@+id/s1">
<androidx.recyclerview.widget.RecyclerView
android:id="@+id/r1"
android:layout_width="match_parent"
android:layout_height="wrap_content" />
</androidx.swiperefreshlayout.widget.SwipeRefreshLayout>
</LinearLayout>
</FrameLayout>
列表布局list.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="match_parent"
android:layout_height="160dp">
<TextView
android:id="@+id/t2"
android:layout_width="0dp"
android:layout_weight="1.5"
android:gravity="center"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:text="我不是药神"/>
<TextView
android:id="@+id/t3"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:gravity="center"
android:text="9.0"/>
<ImageView
android:id="@+id/i1"
android:layout_width="0dp"
android:layout_weight="1.5"
android:layout_height="150dp"
android:padding="20dp"
android:src="@mipmap/ic_launcher"/>
</LinearLayout>
加载更多布局foot_view.xml
<?xml version="1.0" encoding="utf-8"?>
<TextView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/tv_foot"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:padding="10dp"
android:gravity="center"
tools:text="下拉刷新"
android:orientation="vertical"/>
2.功能实现
(1)添加网络权限
<uses-permission android:name="android.permission.INTERNET"/>
(2)添加使用到的第三方库
implementation 'com.android.support:design:28.0.0'
implementation 'com.android.support:support-v4:28.0.0'
implementation 'com.android.support:appcompat-v7:28.0.0'
implementation 'com.squareup.okhttp3:okhttp:3.12.1'
debugImplementation 'com.squareup.okhttp3:logging-interceptor:3.12.1'
implementation 'com.google.code.gson:gson:2.8.5'
implementation 'com.github.bumptech.glide:glide:4.9.0'
annotationProcessor 'com.github.bumptech.glide:compiler:4.9.0'
(3)数据解析
使用GsonFormat插件，快速将json字符串转换成一个Java Bean，免去我们根据json字符串手写对应Java Bean的过程。
定义一个类OneModel.class
public class OneModel implements Serializable {
}
使用快捷键（Alt+s）粘贴全部过去数据，之后一直点击OK
(4)绑定控件ID
private RecyclerView r1;
private SwipeRefreshLayout s1;
private LinearLayoutManager linearLayoutManager;
private Adapter adapter;
(5)定义一个Adapter类
package com.example.note4;
import android.content.Context;
import android.graphics.Color;
import android.os.Handler;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.TextView;
import androidx.recyclerview.widget.RecyclerView;
import com.bumptech.glide.Glide;
import java.util.List;
public class Adapter extends RecyclerView.Adapter<Adapter.ViewHolder> {
private Context mContext;
private List<DateModel.SubjectsBean> mData;//数据
private int max_count = 6;//最大显示数
private Boolean isFootView = false;//是否添加了FootView
private String footViewText = "";//FootView的内容
//两个final int类型表示ViewType的两种类型
private final int NORMAL_TYPE = 0;
private final int FOOT_TYPE = 1111;
public Adapter(Context context, List<DateModel.SubjectsBean> data) {
this.mContext = context;
this.mData = data;
}
public class ViewHolder extends RecyclerView.ViewHolder {
public TextView t3,t2;
public ImageView i1;
private TextView tvFootView;
//初始化viewHolder，此处绑定后在onBindViewHolder中可以直接使用
public ViewHolder(View itemView, int viewType) {
super(itemView);
if (viewType == NORMAL_TYPE) {
t3 = (TextView) itemView.findViewById(R.id.t3);
t2 = (TextView) itemView.findViewById(R.id.t2);
i1=(ImageView)itemView.findViewById(R.id.i1);
} else if (viewType == FOOT_TYPE) {
tvFootView = (TextView) itemView.findViewById(R.id.tv_foot);
}
}
}
@Override
public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
View normal_views = LayoutInflater.from(parent.getContext()).inflate(
R.layout.list, parent, false);
View foot_view = LayoutInflater.from(parent.getContext()).inflate(
R.layout.foot_view, parent, false);
if (viewType == FOOT_TYPE)
return new ViewHolder(foot_view, FOOT_TYPE);
return new ViewHolder(normal_views, NORMAL_TYPE);
}
@Override
public int getItemViewType(int position) {
if (position == max_count - 1) {
return FOOT_TYPE;
}
return NORMAL_TYPE;
}
@Override
public void onBindViewHolder(ViewHolder holder, int position) {
DateModel.SubjectsBean subjectsBean=mData.get(position);
//如果footview存在，并且当前位置ViewType是FOOT_TYPE
if (isFootView && (getItemViewType(position) == FOOT_TYPE)) {
holder.tvFootView.setText(footViewText);
// 刷新太快 所以使用Hanlder延迟两秒
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
@Override
public void run() {
max_count += 5;
notifyDataSetChanged();
}
}, 1000);
} else {
holder.t2.setText(subjectsBean.getTitle());
holder.t3.setText(subjectsBean.getRate());
Glide.with(mContext).load(subjectsBean.getCover()).into(holder.i1);
}
}
@Override
public int getItemCount() {
if (mData.size() <= max_count) {
return mData.size();
}
return max_count;
}
//创建一个方法来设置footView中的文字
public void setFootViewText(String footViewText) {
isFootView = true;
this.footViewText = footViewText;
}
}
(6)网络请求
public void getDate(DateModel dateModel)
{
if(dateModel==null||dateModel.getSubjects()==null)
{
Toast.makeText(MainActivity.this,"失败",Toast.LENGTH_SHORT).show();
return;
}
Toast.makeText(MainActivity.this,"成功",Toast.LENGTH_SHORT).show();
adapter=new Adapter(MainActivity.this,dateModel.getSubjects());
adapter.setFootViewText("加载中...");
r1.setAdapter(adapter);
s1.setRefreshing(false);
}
public void requestDate() {
String url = "https://movie.douban.com/j/search_subjects?type=movie&tag=%E8%B1%86%E7%93%A3%E9%AB%98%E5%88%86&sort=recommend&page_limit=200&page_start=0";
OkHttpClient okHttpClient = new OkHttpClient();
final Request request = new Request.Builder()
.url(url)
.get()
.build();
Call call = okHttpClient.newCall(request);
call.enqueue(new Callback() {
@Override
public void onFailure(Call call, IOException e) {
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this, "网络连接失败", Toast.LENGTH_SHORT).show();
}
});
}
@Override
public void onResponse(Call call, Response response) throws IOException {
String result = response.body().string();
Gson gson = new Gson();
final DateModel dateModel = gson.fromJson(result, DateModel.class);
runOnUiThread(new Runnable() {
@Override
public void run() {
Toast.makeText(MainActivity.this, "网络连接成功", Toast.LENGTH_SHORT).show();
getDate(dateModel);
}
});
}
});
}
(7)功能实现
linearLayoutManager=new LinearLayoutManager(MainActivity.this);
linearLayoutManager.setOrientation(LinearLayoutManager.VERTICAL);
r1.setLayoutManager(linearLayoutManager);
requestDate();
s1.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
requestDate();
}
},1000);
}
});
(8)源代码
点击下载