对于RecyclerView的使用越来越多。
首先来看效果图
recyclerView.gif
我们来进行代码的编写 ，recyclerView 添加了一个头部，底部。
首先来讲它们对应的布局创建一下。
layout_header.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">
<TextView
android:id="@+id/tv_header"
android:text="Header"
android:textSize="30sp"
android:gravity="center_horizontal|center_vertical"
android:background="@color/colorAccent"
android:layout_width="match_parent"
android:layout_height="200dp" />
</LinearLayout>
layout_footer:
<?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">
<TextView
android:id="@+id/tv_loading"
android:gravity="center"
android:text="footer"
android:layout_width="match_parent"
android:layout_height="30dp" />
</LinearLayout>
中间的item布局：
layout_item:
<?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">
<TextView
android:background="@color/colorPrimary"
android:id="@+id/tv_test"
android:textSize="20sp"
android:text="123"
android:gravity="center"
android:textColor="#000"
android:layout_width="match_parent"
android:layout_height="100dp" />
</LinearLayout>
再看activity的xml，很简单就是一个RecyclerView,做之前要依赖一下recyclerview的控件
<?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="match_parent"
android:orientation="vertical"
>
<android.support.v7.widget.RecyclerView
android:id="@+id/rv_second"
android:layout_width="match_parent"
android:layout_height="match_parent">
</android.support.v7.widget.RecyclerView>
</LinearLayout>
现在我们首先来编写RecyclerView 的适配器：
package com.example.chen.loadingtest;
import android.os.Bundle;
import android.os.Handler;
import android.support.annotation.Nullable;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.DividerItemDecoration;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
/**
* author : chen
* date : 2018/8/22 10:16
* desc :
*/
public class SecondActivity extends AppCompatActivity {
private RecyclerView rv_second;
private List<String> data = new ArrayList<>();
private SecAdapter adapter;
private GridLayoutManager manager;
private int lastVisibleItem = 0;
private final int PAGE_COUNT = 10; //模拟分页10个数据为一页
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_second);
initView();
initData();
initRecy();
}
private void initRecy() {
adapter = new SecAdapter(getDatas(0,PAGE_COUNT),this,getDatas(0,PAGE_COUNT).size()>0?true:false);
//添加头部和底部
adapter.setmHeadView(LayoutInflater.from(this).inflate(R.layout.layout_header,null));
adapter.setmFooterView(LayoutInflater.from(this).inflate(R.layout.layout_footer,null));
manager = new GridLayoutManager(this,1);
rv_second.setLayoutManager(manager);
//添加下划线
rv_second.addItemDecoration(new DividerItemDecoration(this,MyDecoration.VERTICAL_LIST));
rv_second.setAdapter(adapter);
//item的监听事件
adapter.setOnItemListener(new SecAdapter.OnItemListener() {
@Override
public void OnItemClick(View view) {
int position = rv_second.getChildAdapterPosition(view);
Toast.makeText(SecondActivity.this,data.get(position-1),Toast.LENGTH_SHORT).show();
}
});
rv_second.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
super.onScrollStateChanged(recyclerView, newState);
//对于滑动的事件操作
if(newState==RecyclerView.SCROLL_STATE_IDLE){
Log.e("tag","多少个:"+adapter.getItemCount());
Log.e("tag","现在个:"+lastVisibleItem);
Log.e("tag","fadeTip:"+adapter.isfadeTip());
//lastVisibleItem最后可看见的item
if(adapter.isfadeTip()==false&&lastVisibleItem+1==adapter.getItemCount()){
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
//减去2是因为头部和底部是增加出来的View
updateData(adapter.getItemCount()-2,adapter.getItemCount()+PAGE_COUNT-2);
}
},1000);
}else if(adapter.isfadeTip()==true){
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
updateData(adapter.getItemCount()-2,adapter.getItemCount()+PAGE_COUNT-2);
}
},1000);
}
}
}
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
//找到对吼一个可见的item
lastVisibleItem = manager.findLastVisibleItemPosition();
}
});
}
private void updateData(int fromIndex, int toIndex) {
List<String> newDatas = getDatas(fromIndex, toIndex);
Log.e("tag","数量:"+newDatas.size());
if (newDatas.size() > 0) {
adapter.updateList(newDatas, true);
} else {
adapter.updateList(null, false);
}
}
private List<String> getDatas(final int firstIndex, final int lastIndex) {
List<String> resList = new ArrayList<>();
for (int i = firstIndex; i < lastIndex; i++) {
if (i < data.size()) {
resList.add(data.get(i));
}
}
return resList;
}
private void initData() {
for(int i=1;i<=41;i++){
data.add("序号"+i);
}
}
private void initView() {
rv_second = (RecyclerView) findViewById(R.id.rv_second);
}
}
下划线：
package com.example.chen.loadingtest;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Rect;
import android.graphics.drawable.Drawable;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
/**
* author : chen
* date : 2018/8/22 11:03
* desc :
*/
public class MyDecoration extends RecyclerView.ItemDecoration{
private Context mContext;
private Drawable mDivider;
private int mOrientation;
public static final int HORIZONTAL_LIST = LinearLayoutManager.HORIZONTAL;
public static final int VERTICAL_LIST = LinearLayoutManager.VERTICAL;
//我们通过获取系统属性中的listDivider来添加，在系统中的AppTheme中设置
public static final int[] ATRRS = new int[]{
android.R.attr.listDivider
};
public MyDecoration(Context context, int orientation) {
this.mContext = context;
final TypedArray ta = context.obtainStyledAttributes(ATRRS);
this.mDivider = ta.getDrawable(0);
ta.recycle();
setOrientation(orientation);
}
//设置屏幕的方向
public void setOrientation(int orientation){
if (orientation != HORIZONTAL_LIST && orientation != VERTICAL_LIST){
throw new IllegalArgumentException("invalid orientation"); } mOrientation = orientation;
}
@Override
public void onDraw(Canvas c, RecyclerView parent, RecyclerView.State state) {
if (mOrientation == HORIZONTAL_LIST){
drawVerticalLine(c, parent, state);
}else {
drawHorizontalLine(c, parent, state);
}
}
//画横线, 这里的parent其实是显示在屏幕显示的这部分
public void drawHorizontalLine(Canvas c, RecyclerView parent, RecyclerView.State state){
int left = parent.getPaddingLeft();
int right = parent.getWidth() - parent.getPaddingRight();
final int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++){
final View child = parent.getChildAt(i);
//获得child的布局信息
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams)child.getLayoutParams();
final int top = child.getBottom() + params.bottomMargin;
final int bottom = top + mDivider.getIntrinsicHeight();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
//Log.d("wnw", left + " " + top + " "+right+" "+bottom+" "+i);
}
}
//画竖线
public void drawVerticalLine(Canvas c, RecyclerView parent, RecyclerView.State state){
int top = parent.getPaddingTop();
int bottom = parent.getHeight() - parent.getPaddingBottom();
final int childCount = parent.getChildCount();
for (int i = 0; i < childCount; i++){
final View child = parent.getChildAt(i);
//获得child的布局信息
final RecyclerView.LayoutParams params = (RecyclerView.LayoutParams)child.getLayoutParams();
final int left = child.getRight() + params.rightMargin;
final int right = left + mDivider.getIntrinsicWidth();
mDivider.setBounds(left, top, right, bottom);
mDivider.draw(c);
}
}
//由于Divider也有长宽高，每一个Item需要向下或者向右偏移
@Override
public void getItemOffsets(Rect outRect, View view, RecyclerView parent, RecyclerView.State state) {
if(mOrientation == HORIZONTAL_LIST){
//画横线，就是往下偏移一个分割线的高度
outRect.set(0, 0, 0, mDivider.getIntrinsicHeight());
}else {
//画竖线，就是往右偏移一个分割线的宽度
outRect.set(0, 0, mDivider.getIntrinsicWidth(), 0);
}
}
}
也是可以结合android.support.v4.widget.SwipeRefreshLayout控件来进行使用的：
网友评论