進(jìn)入進(jìn)階篇，相信大家通過之前的入門篇已經(jīng)有了一定的認(rèn)識(shí)了，接下來就是我們通過RecyclerView實(shí)現(xiàn)一些自己的功能
目錄
- 點(diǎn)擊事件
- 添加、刪除數(shù)據(jù)
- 更豐富的條目展示(多條目展示)
- 添加header 、footer
- 下拉刷新、上拉加載更多
進(jìn)階一：點(diǎn)擊事件、長按事件(實(shí)現(xiàn)adapter和Activity之間的通信)
RecyclerView要實(shí)現(xiàn)點(diǎn)擊事件和長按事件可以在適配器中定義接口事件回調(diào)
1、定義對(duì)象
private OnItemClickListener mOnItemClickListener;
2、寫接口，并定義方法
/**
* 通過在adapter定義接口實(shí)現(xiàn)回調(diào)
*/
public interface OnItemClickListener {
//點(diǎn)擊事件
void onItemClick(View view, int position);
//長按點(diǎn)擊事件
void onItemLongClick(View view, int position);
}
3、
public void setOnItemClickListener(OnItemClickListener mOnItemClickListener) {
this.mOnItemClickListener = mOnItemClickListener;
}
4、在adapter需要的地方調(diào)用事件
if (mOnItemClickListener != null) {
mOnItemClickListener.onItemClick(((ContentViewHolder) holder).llLayout, position - 1);
}
if (mOnItemClickListener != null) {
mOnItemClickListener.onItemLongClick(((ContentViewHolder) holder).llLayout, position - 1);
}
5、Activity調(diào)用Adapter中的事件
recyclerViewAdapter.setOnItemClickListener(new RecyclerViewAdapter.OnItemClickListener() {
@Override
public void onItemClick(View view, int position) {
Toast.makeText(RecycleActivity.this, "點(diǎn)擊了第" + position + "條", Toast.LENGTH_SHORT).show();
}
@Override
public void onItemLongClick(View view, int position) {
Toast.makeText(RecycleActivity.this, "長按了第" + position + "條", Toast.LENGTH_SHORT).show();
}
});
點(diǎn)擊事件、長按事件.gif
進(jìn)階二：添加數(shù)據(jù)、刪除某條數(shù)據(jù)
這里需要了解到刷新界面的多種方式
notifyDataSetChanged();//刷新整體布局
notifyItemChanged(position);//刷新指定position,會(huì)重新調(diào)用onBindViewHolder來進(jìn)行刷新，如果當(dāng)前position在屏幕之外，則不會(huì)調(diào)用，當(dāng)重新滾動(dòng)到屏幕內(nèi)，會(huì)重新調(diào)用
notifyItemRangeChanged(position, 10);//刷新從position開始之后10條數(shù)據(jù)
notifyItemInserted(position);//在第position處插入數(shù)據(jù)，這個(gè)插入時(shí)會(huì)有動(dòng)畫
notifyItemMoved(position,5);//將當(dāng)前position移動(dòng)到position為5的地方，并且刷新
notifyItemRangeInserted(3,10);//批量增加
notifyItemRemoved(position);//刪除第position條數(shù)據(jù)
notifyItemRangeRemoved(position, 10);//批量刪除
/**
* 刪除某條數(shù)據(jù)
*
* @param position
*/
public void removeData(int position) {
mList.remove(position);
notifyItemRemoved(position);
notifyItemRangeChanged(position, mList.size());
}
/**
* 在指定position添加數(shù)據(jù)
*
* @param position
*/
public void addData(int position, String msg) {
if (mList == null) {
mList = new ArrayList<>();
}
if (position < mList.size()) {
//說明這里是第一條
mList.add(position, msg);
} else {
mList.add(msg);
position = mList.size() - 1;
}
notifyItemInserted(position);
notifyItemRangeChanged(position, mList.size());
}
問題一：長按事件、點(diǎn)擊事件同時(shí)發(fā)生
錯(cuò)誤的添加、刪除.gif
解決思路
在public boolean onLongClick(View v) {return true}
需要消費(fèi)掉這個(gè)長按事件 返回true
正確的添加、刪除.gif
進(jìn)階三：添加header、footer
思路
1、首先要區(qū)分頭布局、中間布局、尾布局三種不同的type，通過設(shè)置一個(gè)int值來判斷不同的布局
2、通過getItemViewType來返回type
3、在onCreateViewHolder中根據(jù)不同的viewType顯示不同的布局
4、在onBindViewHolder根據(jù)不同的holder加載不同的數(shù)據(jù)
注意
1、getItemCount這里需要返回的集合的數(shù)量+header數(shù)量+footer數(shù)量
2、當(dāng)content布局中加載數(shù)據(jù)是通過position獲取數(shù)據(jù)時(shí)需要將
position-1
1、添加三種不同的type來區(qū)分不同的布局
public static final int ITEM_TYPE_CONTENT = 0;
public static final int ITEM_TYPE_FOOTER = 1;
public static final int ITEM_TYPE_HEADER = 2;
2、添加頭、尾布局?jǐn)?shù)量
private int footerCount = 1;
private int headerCount = 1;
3、根據(jù)position獲取Item的類型
@Override
public int getItemViewType(int position) {
if (isHeaderView(position)) {
return ITEM_TYPE_HEADER;
} else if (isFooterView(position)) {
return ITEM_TYPE_FOOTER;
} else {
return ITEM_TYPE_CONTENT;
}
}
4、根據(jù)不同的viewType顯示不同的布局
@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
/**
* 主要負(fù)責(zé)把加載子項(xiàng)的布局
* 將xml定義的布局實(shí)例化為view對(duì)象
*/
if (viewType == ITEM_TYPE_FOOTER) {
View view = LayoutInflater.from(mContext).inflate(R.layout.recycler_footer_item, viewGroup, false);
return new FooterViewHolder(view);
} else if (viewType == ITEM_TYPE_HEADER) {
View view = LayoutInflater.from(mContext).inflate(R.layout.recycler_header_item, viewGroup, false);
return new HeaderViewHolder(view);
} else if (viewType == ITEM_TYPE_CONTENT) {
View view = LayoutInflater.from(mContext).inflate(R.layout.recyclerview_item, viewGroup, false);
return new ContentViewHolder(view);
}
return null;
}
5、根據(jù)不同的ViewHolder加載不同的數(shù)據(jù)(注意content中通過position加載數(shù)據(jù)position需要-1)
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
//主要負(fù)責(zé)綁定數(shù)據(jù)
if (holder instanceof HeaderViewHolder) {
} else if (holder instanceof FooterViewHolder) {
} else if (holder instanceof ContentViewHolder) {
((ContentViewHolder) holder).tvItem.setText(mList.get(position - 1));
((ContentViewHolder) holder).llLayout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mOnItemClickListener != null) {
mOnItemClickListener.onItemClick(((ContentViewHolder) holder).llLayout, position - 1);
}
}
});
((ContentViewHolder) holder).llLayout.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
if (mOnItemClickListener != null) {
mOnItemClickListener.onItemLongClick(((ContentViewHolder) holder).llLayout, position - 1);
}
return true;
}
});
}
}
6、返回的集合數(shù)量(務(wù)必加上header、footer)
@Override
public int getItemCount() {
//返回集合的數(shù)量
return mList.size() + headerCount + footerCount;
}
7、判斷當(dāng)前 item 是否是 FooterView
/**
* 判斷當(dāng)前 item 是否是 FooterView
*/
public boolean isFooterView(int position) {
return footerCount != 0 && position >= (footerCount + mList.size());
}
8、判斷當(dāng)前 item 是否是 HeaderView
/**
* 判斷當(dāng)前 item 是否是 HeaderView
*/
public boolean isHeaderView(int position) {
return headerCount != 0 && position < headerCount;
}
需加
class HeaderViewHolder extends RecyclerView.ViewHolder {
public HeaderViewHolder(@NonNull View itemView) {
super(itemView);
}
}
class FooterViewHolder extends RecyclerView.ViewHolder {
public FooterViewHolder(@NonNull View itemView) {
super(itemView);
}
}
縱向添加頭布局、尾布局.jpg
問題一
當(dāng)我們?yōu)閞ecyclerView設(shè)置表格布局時(shí)，設(shè)置footer、header，如果不做任何處理就會(huì)出現(xiàn)下方錯(cuò)誤
錯(cuò)誤添加表格布局頭布局、尾布局.jpg
解決思路
1、通過setSpanSizeLookup重新設(shè)置顯示的列數(shù)
2、通過判斷當(dāng)前view是footer、header,若是footer、header則占取整列，否則占取自己列
@Override
public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
if (manager instanceof GridLayoutManager) {
//通過強(qiáng)轉(zhuǎn)將manager轉(zhuǎn)換成GridLayoutManager類型
final GridLayoutManager gridLayoutManager = (GridLayoutManager) manager;
//通過setSpanSizeLookup重新設(shè)置顯示的列數(shù)
gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
//通過判斷當(dāng)前view是否是footer、header
//若是footer、header則占取整列，否則占取自己列
return (isHeaderView(position) || isFooterView(position)) ? gridLayoutManager.getSpanCount() : 1;
}
});
}
}
表格布局正確添加頭布局、尾部居.jpg
進(jìn)階四：下拉刷新、上拉加載更多
下拉刷新：在RecyclerView布局外層添加SwipeRefreshLayout
上拉加載更多：通過RecyclerView的addOnScrollListener來判斷房前滾動(dòng)的狀態(tài)是否是最后一個(gè)Item，來進(jìn)行加載更多
1、布局
<android.support.v4.widget.SwipeRefreshLayout
android:id="@+id/swipe_refresh_layout"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.v7.widget.RecyclerView
android:id="@+id/recycleview"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</android.support.v4.widget.SwipeRefreshLayout>
2、通過swipeRefreshLayout.setOnRefreshListener來進(jìn)行下拉刷新
swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
@Override
public void run() {
/**
*要執(zhí)行的操作
*/
recyclerViewAdapter.addData(0, "我是刷新出來的數(shù)據(jù)");
swipeRefreshLayout.setRefreshing(false);
Toast.makeText(RecycleActivity.this, "下拉刷新成功", Toast.LENGTH_SHORT).show();
}
}, 1500);//3秒后執(zhí)行Runnable中的run方法
}
});
3、通過調(diào)用addOnScrollListener來進(jìn)行加載更多
onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState)//滾動(dòng)狀態(tài)變化時(shí)的回調(diào)
onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy)//滾動(dòng)時(shí)回調(diào)
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
/**
*
* @param recyclerView 當(dāng)前滾動(dòng)的recyclerView
* @param newState 當(dāng)前滾動(dòng)的狀態(tài)
*
* public static final int SCROLL_STATE_IDLE = 0;靜止沒有滾動(dòng)
* public static final int SCROLL_STATE_DRAGGING = 1;正在被外部拖拽，即用戶滑動(dòng)
* public static final int SCROLL_STATE_SETTLING = 2;//自動(dòng)滾動(dòng)
*
*
*/
@Override
public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
//滾動(dòng)狀態(tài)變化時(shí)的回調(diào)
super.onScrollStateChanged(recyclerView, newState);
//先判斷當(dāng)前狀態(tài)是否已停止
//判斷最后一條數(shù)據(jù)+1是否是集合的數(shù)據(jù)
//判斷是否滑動(dòng)到最底部
if (newState == RecyclerView.SCROLL_STATE_IDLE && (lastVisibleItem + 1 == recyclerViewAdapter.getItemCount())) {
//判斷總數(shù)>0 說明可以加載更多
if (total > 0) {
//判斷total > count 說明還可以加載數(shù)據(jù)
if (total > count) {
Toast.makeText(RecycleActivity.this, "上拉加載", Toast.LENGTH_SHORT).show();
count += 10;//每次加載10條
getData();//加載的數(shù)據(jù)
recyclerViewAdapter.notifyDataSetChanged();//刷新適配器
} else {
Toast.makeText(RecycleActivity.this, "沒有數(shù)據(jù)加載了", Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(RecycleActivity.this, "沒有數(shù)據(jù)加載了", Toast.LENGTH_SHORT).show();
}
}
}
/**
*
* @param recyclerView 當(dāng)前滾動(dòng)的recyclerView
* @param dx 水平滾動(dòng)距離
* dx > 0 時(shí)為手指向左滾動(dòng),列表滾動(dòng)顯示右面的內(nèi)容
* dx < 0 時(shí)為手指向右滾動(dòng),列表滾動(dòng)顯示左面的內(nèi)容
* @param dy 垂直滾動(dòng)距離
* dy > 0 時(shí)為手指向上滾動(dòng),列表滾動(dòng)顯示下面的內(nèi)容
* dy < 0 時(shí)為手指向下滾動(dòng),列表滾動(dòng)顯示上面的內(nèi)容
*/
@Override
public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
//滾動(dòng)時(shí)回調(diào)
//最后一個(gè)可見Item
lastVisibleItem = mLinearLayoutManager.findLastVisibleItemPosition();
}
});
下拉刷新、上拉加載更多.gif
整體代碼
為了更好的方便查，我把Activity和Adapter放在一起寫，開發(fā)中大家一定要分開邏輯來操作
package com.example.androidhightproject.module;
import android.content.Context;
import android.graphics.Rect;
import android.os.Bundle;
import android.os.Handler;
import android.support.annotation.NonNull;
import android.support.v4.widget.SwipeRefreshLayout;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.*;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.Toast;
import com.example.androidhightproject.R;
import java.util.ArrayList;
import java.util.List;
/**
* @author dongbo
*/
public class RecycleActivity extends AppCompatActivity {
private List<String> mList = new ArrayList<>();
private RecyclerView mRecyclerView;
private SwipeRefreshLayout swipeRefreshLayout;
private int lastVisibleItem;
private int total = 30;
private int count = 10;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_recycle);
mRecyclerView = (RecyclerView) findViewById(R.id.recycleview);
swipeRefreshLayout = (SwipeRefreshLayout) findViewById(R.id.swipe_refresh_layout);
/**
* 設(shè)置布局管理器
* 默認(rèn)垂直排布 LinearLayoutManager.VERTICAL垂直 LinearLayoutManager.HORIZONTAL水平
* boolean reverseLayout 默認(rèn)是false 是否反轉(zhuǎn)
*
*/
LinearLayoutManager mLinearLayoutManager = new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false);
mRecyclerView.setLayoutManager(mLinearLayoutManager);
//設(shè)置縱向默認(rèn)排列
// mRecyclerView.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));
//設(shè)置橫向默認(rèn)排列,這里需要注意改成橫向列表，分割線需要改成橫向
// mRecyclerView.setLayoutManager(new LinearLayoutManager(this,LinearLayoutManager.HORIZONTAL,false));
//設(shè)置表格布局，這里需要注意的是，有很多需求是根據(jù)返回的數(shù)據(jù)顯示表格的數(shù)量，所以分割線需要自己重新定義
// mRecyclerView.setLayoutManager(new GridLayoutManager(this, 3));
//設(shè)置瀑布流顯示
// mRecyclerView.setLayoutManager(new StaggeredGridLayoutManager(2, StaggeredGridLayoutManager.VERTICAL));
//默認(rèn)的分割線
mRecyclerView.addItemDecoration(new DividerItemDecoration(this, DividerItemDecoration.VERTICAL));
//設(shè)置自定義分割線
// mRecyclerView.addItemDecoration(new SpaceItemDecoation(3));
//設(shè)置刪除時(shí)的動(dòng)畫
mRecyclerView.setItemAnimator(new DefaultItemAnimator());
RecyclerViewAdapter recyclerViewAdapter = new RecyclerViewAdapter(getData(), this);
mRecyclerView.setAdapter(recyclerViewAdapter);
swipeRefreshLayout.setColorSchemeResources(R.color.colorAccent);
swipeRefreshLayout.setOnRefreshListener(new SwipeRefreshLayout.OnRefreshListener() {
@Override
public void onRefresh() {
Handler handler = new Handler();
handler.postDelayed(new Runnable() {
@Override
public void run() {
/**
*要執(zhí)行的操作
*/
recyclerViewAdapter.addData(0, "我是刷新出來的數(shù)據(jù)");
swipeRefreshLayout.setRefreshing(false);
Toast.makeText(RecycleActivity.this, "下拉刷新成功", Toast.LENGTH_SHORT).show();
}
}, 1500);//3秒后執(zhí)行Runnable中的run方法
}
});
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
/**
*
* @param recyclerView 當(dāng)前滾動(dòng)的recyclerView
* @param newState 當(dāng)前滾動(dòng)的狀態(tài)
*
* public static final int SCROLL_STATE_IDLE = 0;靜止沒有滾動(dòng)
* public static final int SCROLL_STATE_DRAGGING = 1;正在被外部拖拽，即用戶滑動(dòng)
* public static final int SCROLL_STATE_SETTLING = 2;//自動(dòng)滾動(dòng)
*
*
*/
@Override
public void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {
//滾動(dòng)狀態(tài)變化時(shí)的回調(diào)
super.onScrollStateChanged(recyclerView, newState);
//先判斷當(dāng)前狀態(tài)是否已停止
//判斷最后一條數(shù)據(jù)+1是否是集合的數(shù)據(jù)
//判斷是否滑動(dòng)到最底部
Log.e("newState", newState + "");
if (newState == RecyclerView.SCROLL_STATE_IDLE && (lastVisibleItem + 1 == recyclerViewAdapter.getItemCount())) {
//判斷總數(shù)>0 說明可以加載更多
if (total > 0) {
//判斷total > count 說明還可以加載數(shù)據(jù)
if (total > count) {
Toast.makeText(RecycleActivity.this, "上拉加載", Toast.LENGTH_SHORT).show();
count += 10;//每次加載10條
getData();//加載的數(shù)據(jù)
recyclerViewAdapter.notifyDataSetChanged();//刷新適配器
} else {
Toast.makeText(RecycleActivity.this, "沒有數(shù)據(jù)加載了", Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(RecycleActivity.this, "沒有數(shù)據(jù)加載了", Toast.LENGTH_SHORT).show();
}
}
}
/**
*
* @param recyclerView 當(dāng)前滾動(dòng)的recyclerView
* @param dx 水平滾動(dòng)距離
* dx > 0 時(shí)為手指向左滾動(dòng),列表滾動(dòng)顯示右面的內(nèi)容
* dx < 0 時(shí)為手指向右滾動(dòng),列表滾動(dòng)顯示左面的內(nèi)容
* @param dy 垂直滾動(dòng)距離
* dy > 0 時(shí)為手指向上滾動(dòng),列表滾動(dòng)顯示下面的內(nèi)容
* dy < 0 時(shí)為手指向下滾動(dòng),列表滾動(dòng)顯示上面的內(nèi)容
*/
@Override
public void onScrolled(@NonNull RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
//滾動(dòng)時(shí)回調(diào)
//最后一個(gè)可見Item
Log.e("dx", dx + "");
lastVisibleItem = mLinearLayoutManager.findLastVisibleItemPosition();
}
});
recyclerViewAdapter.setOnItemClickListener(new RecyclerViewAdapter.OnItemClickListener() {
@Override
public void onItemClick(View view, int position) {
Toast.makeText(RecycleActivity.this, "點(diǎn)擊了第" + position + "條", Toast.LENGTH_SHORT).show();
recyclerViewAdapter.addData(position, "我是添加的數(shù)據(jù)");
}
@Override
public void onItemLongClick(View view, int position) {
Toast.makeText(RecycleActivity.this, "長按了第" + position + "條", Toast.LENGTH_SHORT).show();
recyclerViewAdapter.removeData(position);
}
});
}
private List<String> getData() {
for (int i = 0; i < 10; i++) {
mList.add("測試數(shù)據(jù)" + i);
// mList.add("照片地址");
}
return mList;
}
}
class RecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {
/**
* 首先要區(qū)分頭布局、中間布局、尾布局三種不同的type，通過設(shè)置一個(gè)int值來判斷不同的布局
* 通過getItemViewType來返回type
* 在onCreateViewHolder中根據(jù)不同的viewType顯示不同的布局
* 在onBindViewHolder根據(jù)不同的holder加載不同的數(shù)據(jù)
* 注意：
* 1、getItemCount這里需要返回的集合的數(shù)量+header數(shù)量+footer數(shù)量
* 2、當(dāng)content布局中加載數(shù)據(jù)是通過position獲取數(shù)據(jù)時(shí)需要將position-1
*/
private List<String> mList;
private Context mContext;
private OnItemClickListener mOnItemClickListener;
public static final int ITEM_TYPE_CONTENT = 0;
public static final int ITEM_TYPE_FOOTER = 1;
public static final int ITEM_TYPE_HEADER = 2;
private int footerCount = 1;
private int headerCount = 1;
public RecyclerViewAdapter(List<String> mList, Context mContext) {
//大部分只有數(shù)據(jù)與上下文
this.mList = mList;
this.mContext = mContext;
}
public void setOnItemClickListener(OnItemClickListener mOnItemClickListener) {
this.mOnItemClickListener = mOnItemClickListener;
}
/**
* 刪除某條數(shù)據(jù)
*
* @param position
*/
public void removeData(int position) {
notifyItemRemoved(position);
mList.remove(position);
notifyItemRangeChanged(position, mList.size());
}
/**
* 在指定position添加數(shù)據(jù)
*
* @param position
*/
public void addData(int position, String msg) {
notifyItemInserted(position);
if (mList == null) {
mList = new ArrayList<>();
}
if (position < mList.size()) {
//說明這里是第一條
mList.add(position, msg);
} else {
mList.add(msg);
position = mList.size() - 1;
}
notifyItemRangeChanged(position, mList.size());
}
@Override
public int getItemViewType(int position) {
if (isHeaderView(position)) {
return ITEM_TYPE_HEADER;
} else if (isFooterView(position)) {
return ITEM_TYPE_FOOTER;
} else {
return ITEM_TYPE_CONTENT;
}
}
@Override
public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
RecyclerView.LayoutManager manager = recyclerView.getLayoutManager();
if (manager instanceof GridLayoutManager) {
//通過強(qiáng)轉(zhuǎn)將manager轉(zhuǎn)換成GridLayoutManager類型
final GridLayoutManager gridLayoutManager = (GridLayoutManager) manager;
//通過setSpanSizeLookup重新設(shè)置顯示的列數(shù)
gridLayoutManager.setSpanSizeLookup(new GridLayoutManager.SpanSizeLookup() {
@Override
public int getSpanSize(int position) {
//通過判斷當(dāng)前view是否是footer、header
//若是footer、header則占取整列，否則占取自己列
return (isHeaderView(position) || isFooterView(position)) ? gridLayoutManager.getSpanCount() : 1;
}
});
}
}
@NonNull
@Override
public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int viewType) {
/**
* 主要負(fù)責(zé)把加載子項(xiàng)的布局
* 將xml定義的布局實(shí)例化為view對(duì)象
*/
if (viewType == ITEM_TYPE_FOOTER) {
View view = LayoutInflater.from(mContext).inflate(R.layout.recycler_footer_item, viewGroup, false);
return new FooterViewHolder(view);
} else if (viewType == ITEM_TYPE_HEADER) {
View view = LayoutInflater.from(mContext).inflate(R.layout.recycler_header_item, viewGroup, false);
return new HeaderViewHolder(view);
} else if (viewType == ITEM_TYPE_CONTENT) {
View view = LayoutInflater.from(mContext).inflate(R.layout.recyclerview_item, viewGroup, false);
return new ContentViewHolder(view);
}
return null;
}
@Override
public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
//主要負(fù)責(zé)綁定數(shù)據(jù)
if (holder instanceof HeaderViewHolder) {
} else if (holder instanceof FooterViewHolder) {
} else if (holder instanceof ContentViewHolder) {
// Glide.with(mContext).load(mList.get(position-1)).into(((ContentViewHolder) holder).ivImage);
((ContentViewHolder) holder).tvItem.setText(mList.get(position - 1));
((ContentViewHolder) holder).llLayout.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (mOnItemClickListener != null) {
mOnItemClickListener.onItemClick(((ContentViewHolder) holder).llLayout, position - 1);
}
}
});
((ContentViewHolder) holder).llLayout.setOnLongClickListener(new View.OnLongClickListener() {
@Override
public boolean onLongClick(View v) {
if (mOnItemClickListener != null) {
mOnItemClickListener.onItemLongClick(((ContentViewHolder) holder).llLayout, position - 1);
}
return true;
}
});
}
}
@Override
public int getItemCount() {
//返回集合的數(shù)量
return mList.size() + headerCount + footerCount;
}
class HeaderViewHolder extends RecyclerView.ViewHolder {
public HeaderViewHolder(@NonNull View itemView) {
super(itemView);
}
}
class FooterViewHolder extends RecyclerView.ViewHolder {
public FooterViewHolder(@NonNull View itemView) {
super(itemView);
}
}
class ContentViewHolder extends RecyclerView.ViewHolder {
// private final ImageView ivImage;
private final TextView tvItem;
private final LinearLayout llLayout;
public ContentViewHolder(@NonNull View itemView) {
super(itemView);
tvItem = (TextView) itemView.findViewById(R.id.tv_item);
llLayout = (LinearLayout) itemView.findViewById(R.id.ll_layout);
// ivImage = (ImageView) itemView.findViewById(R.id.iv_image);
}
}
/**
* 通過在adapter定義接口實(shí)現(xiàn)回調(diào)
*/
public interface OnItemClickListener {
//點(diǎn)擊事件
void onItemClick(View view, int position);
//長按點(diǎn)擊事件
void onItemLongClick(View view, int position);
}
/**
* 判斷當(dāng)前 item 是否是 FooterView
*/
public boolean isFooterView(int position) {
return footerCount != 0 && position >= (footerCount + mList.size());
}
/**
* 判斷當(dāng)前 item 是否是 HeaderView
*/
public boolean isHeaderView(int position) {
return headerCount != 0 && position < headerCount;
}
}
class SpaceItemDecoation extends RecyclerView.ItemDecoration {
private int space;
public SpaceItemDecoation(int space) {
this.space = space;
}
@Override
public void getItemOffsets(@NonNull Rect outRect, @NonNull View view, @NonNull RecyclerView parent, @NonNull RecyclerView.State state) {
super.getItemOffsets(outRect, view, parent, state);
//如果不是第一個(gè)盒子設(shè)置一個(gè)居左和居下的邊距
outRect.left = space;
outRect.bottom = space;
//大部分的需求都是3個(gè) 因?yàn)榈谝粋€(gè)都是你設(shè)置個(gè)數(shù)的倍數(shù)，所以通過取余來將左邊距設(shè)置為0
if (parent.getChildLayoutPosition(view) % 3 == 0) {
outRect.left = 0;
}
}
}
最后
到此對(duì)于RecyclerView你已經(jīng)可以實(shí)現(xiàn)項(xiàng)目中的使用，還有很多需要我們來探索，比如回收復(fù)用機(jī)制、緩存機(jī)制等等，我也正在學(xué)習(xí)~
喜歡記得點(diǎn)贊或者關(guān)注我哦, 有意見或者建議評(píng)論區(qū)見~
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