編輯:關於Android編程
ListView已經用了很多年了,後來又有了RecyclerView,基本可以代替ListView/GridView了,還有瀑布流的模式,加上各種特效,於是就嘗試用RecyclerView替代listview。實際使用過之後發現,確實不錯,但是還存在一些問題(比如卡頓)
如果UI要求不嚴格,那麼有一個很簡單的方式實現下拉刷新:SwipeRefreshLayout ,然後基本你就可以開開心心做完了。
但是如果你們的UI或者產品說,我們要一個什麼什麼樣的功能(反正就是不造輪子不行的需求),那只能自己做了。
先看一下效果:
簡單說一下思路:
下拉刷新:
1.自定義一個線性布局linearlayout,裡面先添加一個header,然後添加recycclerview。
2.計算出header的高度h1,然後設置linearlayout布局的的padding為-h1(也可以設置margin為-h,都可以實現,本文采用的是padding)
3.利用消息傳遞機制及對recyclerview的滾動監聽來判斷是否可以下拉刷新。
4.根據用戶的手勢移動來設置padding值,再加上一些回滾效果就ok了。
加載更多:
1.首先寫一個BaseAdapter抽象類繼承
import android.support.v7.widget.RecyclerView.Adapter;
2.在BaseAdapter中添加一個footerViewHolder,並設置開關,如果有加載更多的時候,就顯示。如果沒有,則不顯示。
3.監聽RecyclerView的滾動,如果滾動到末尾並且有加載更多,則調用加載更多的方法。
有了上面的思路寫起來就簡單多了。
接下來分析代碼:
下拉刷新:
public class RefreshRecyclerView extends LinearLayout{ public static final long ONE_MINUTE = 60 * 1000;//一分鐘的毫秒值,用於判斷上次的更新時間 public static final long ONE_HOUR = 60 * ONE_MINUTE;//一小時的毫秒值,用於判斷上次的更新時間 public static final long ONE_DAY = 24 * ONE_HOUR;//一天的毫秒值,用於判斷上次的更新時間 public static final long ONE_MONTH = 30 * ONE_DAY;//一月的毫秒值,用於判斷上次的更新時間 public static final long ONE_YEAR = 12 * ONE_MONTH;//一年的毫秒值,用於判斷上次的更新時間 private String MYRECYCLERVIEW = "MyRecyclerView";//保存用的 private int id;//用來區分不同頁面 private LinearLayout headerView;//刷新頭部布局 public static final int SCROLL_SPEED = -10;//下拉頭部回滾的速度 private int topPadding;//距離頂部的padding值 private RecyclerView mRecyclerView;//列表控件 private LinearLayoutManager mLayoutManager;//RecyclerView布局管理器 private int firstVisibleItemPostion;//第一個可見item的position private int mHeaderHeight;//頭部高度 private boolean hasMore;//設置是否有加載更多(用戶設置) private boolean hasRefresh;//設置是否有下拉刷新(用戶設置) private boolean canRefresh;//是否可以下拉刷新(邏輯判斷) private boolean isLoading;//列表是否正在刷新或加載更多中 private boolean canScroll;//列表是否可以滾動(刷新加載中禁止用戶進行列表操作) private LoadLinsteners loadLinsteners;//加載監聽器 private ScrollLinsteners scrollLinsteners;//滾動監聽器 private BaseAdapter mAdapter;//Item適配器 //頭部相關 private TextView description, updated_at;//描述 private Long lastUpdateTime;//上次更新時間 private ImageView arrow;//箭頭 private ProgressBar progress_bar; private ImageView iv_head;//頭部圖片 private Context context; private int readCount;//判斷當前列表最大滾動位置 public RefreshRecyclerView(Context context) { this(context, null); } public RefreshRecyclerView(Context context, AttributeSet attrs) { super(context, attrs); this.context = context; initContents(); } /** * 初始化 */ private void initContents() { //默認可下拉刷新,無加載更多 canRefresh = true; hasMore = false; hasRefresh = true; isLoading = false; canScroll = true; //頭部 headerView = (LinearLayout) LayoutInflater.from(context).inflate(R.layout.item_recyler_header, null); iv_head = (ImageView)headerView.findViewById(R.id.iv_head); description = (TextView)headerView.findViewById(R.id.description); updated_at = (TextView)headerView.findViewById(R.id.updated_at); arrow = (ImageView)headerView.findViewById(R.id.arrow); progress_bar = (ProgressBar)headerView.findViewById(R.id.progress_bar); //測量並獲取頭部高度 measureView(headerView); mHeaderHeight = headerView.getMeasuredHeight(); //列表 mRecyclerView = new RecyclerView(context); mRecyclerView.setOverScrollMode(View.OVER_SCROLL_NEVER); //創建默認的線性LayoutManager mLayoutManager = new LinearLayoutManager(getContext()); mRecyclerView.setLayoutManager(mLayoutManager); //添加布局 setOrientation(VERTICAL); addView(headerView, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT)); addView(mRecyclerView, new LayoutParams(LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT, 1)); //隱藏頭部 setTopPadding(-mHeaderHeight); setLinsteners(); /** * 添加旋轉動畫 */ Animation animation= AnimationUtils.loadAnimation(context, R.anim.anim_rotate_earth); LinearInterpolator lin = new LinearInterpolator(); animation.setInterpolator(lin); iv_head.startAnimation(animation); } /** * 設置布局管理器 * @param layoutManager */ public void setmLayoutManager(LinearLayoutManager layoutManager){ this.mLayoutManager = layoutManager; mRecyclerView.setLayoutManager(mLayoutManager); } /** * 獲取布局管理器 * @return */ public RecyclerView.LayoutManager getmLayoutManager(){ return mLayoutManager; } /** * 設置adapter * @param mAdapter */ public void setAdapter(BaseAdapter mAdapter){ this.mAdapter = mAdapter; mRecyclerView.setAdapter(mAdapter); } /** * 獲取recyclerview * @return */ public RecyclerView getmRecyclerView(){ return mRecyclerView; } /** * 加載監聽器 */ public interface LoadLinsteners{ void onLoadMore(); void onRefresh(); } /** * 設置監聽器 * @param loadLinsteners * @param id */ public void setLoadLinsteners(LoadLinsteners loadLinsteners, int id){ this.loadLinsteners = loadLinsteners; this.id = id; refreshUpdatedAtValue(); } /** * 設置監聽器 * @param loadLinsteners */ public void setLoadLinsteners(LoadLinsteners loadLinsteners){ this.loadLinsteners = loadLinsteners; this.id = -1; refreshUpdatedAtValue(); } /** * 滾動監聽接口 */ public interface ScrollLinsteners{ void onScrolled(int firstVisibleItem, int dx, int dy); } /** * 設置滾動監聽 * @param scrollLinsteners */ public void setScrollLinsteners(ScrollLinsteners scrollLinsteners){ this.scrollLinsteners = scrollLinsteners; } /** * 獲取最大滾動位置 * @return */ public int getReadCount(){ return readCount; } @Override public boolean onInterceptTouchEvent(MotionEvent ev) { if(!canScroll) {//禁止事件傳遞 return true; }else { return false; } } private float moveY, startY = -1, dY; private void setLinsteners() { /** * 添加觸摸監聽,實現下拉效果 */ mRecyclerView.setOnTouchListener(new OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { if (canRefresh && firstVisibleItemPostion == 0 && !isLoading && hasRefresh) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: startY = -1; Log.i("move---", "down:-1"); break; case MotionEvent.ACTION_MOVE: moveY = event.getRawY(); Log.i("move----1", "startY:"+ startY + " moveY:" + moveY + " dY:" + dY + " headerHeight:" + mHeaderHeight); if(startY == -1) { startY = moveY; } dY = moveY - startY; Log.i("move----2", "startY:"+ startY + " moveY:" + moveY + " dY:" + dY + " headerHeight:" + mHeaderHeight); if (dY > 30) { dY = dY - 30; int maxLength = mHeaderHeight * 6; if (dY < maxLength && dY >= 30) { description.setText(R.string.pull_to_refresh); } else if (dY >= maxLength) { description.setText(R.string.release_to_refresh); dY = maxLength; } if(dY > mHeaderHeight){ dY = (dY + mHeaderHeight)/2; } setTopPadding((int)(dY - mHeaderHeight)); } else { Log.i("move---", "reset"); setTopPadding(- mHeaderHeight); return false; } break; case MotionEvent.ACTION_UP: Log.i("move---", "up:-1"); if (dY > mHeaderHeight / 2) { isLoading = true; canScroll = false; canRefresh = false; description.setText(R.string.refreshing); arrow.setVisibility(View.GONE); progress_bar.setVisibility(View.VISIBLE); new RefreshingTask().execute(); if(loadLinsteners != null) { loadLinsteners.onRefresh(); } } else { startY = -1; new HideHeaderTask().execute(); return false; } dY = 0; startY = -1; moveY = 0; break; } return true; } return false; } }); /** * 添加滾動監聽,判斷加載更多 */ mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() { @Override public void onScrolled(RecyclerView recyclerView, int dx, int dy) { super.onScrolled(recyclerView, dx, dy); firstVisibleItemPostion = mLayoutManager.findFirstVisibleItemPosition(); int lastVisibleItem = mLayoutManager.findLastVisibleItemPosition(); int totalItemCount = mLayoutManager.getItemCount(); if (readCount <= lastVisibleItem) { readCount = lastVisibleItem; } //lastVisibleItem >= totalItemCount - 4 表示剩下4個item自動加載 // dy > 0 表示向下滑動 if (lastVisibleItem >= totalItemCount - 4 && dy >= 0) { if (hasMore && !isLoading) {//可以下拉刷新並且沒有加載中 isLoading = true; canScroll = true; if (loadLinsteners != null) { loadLinsteners.onLoadMore(); } } } //如果列表在頭部 if (firstVisibleItemPostion == 0 && mLayoutManager.getChildAt(0).getTop() == 0 && hasRefresh) { Log.i("move---", "recyclerview:reset:-1"); canRefresh = true; startY = -1; } else { canRefresh = false; } if (scrollLinsteners != null) { scrollLinsteners.onScrolled(firstVisibleItemPostion, dx, dy); } } @Override public void onScrollStateChanged(RecyclerView recyclerView, int newState) { super.onScrollStateChanged(recyclerView, newState); } }); } /** * 設置頂部padding值 */ public void setTopPadding(int top){ topPadding = top; setPadding(0, top, 0, 0); } /** * 停止下拉刷新 */ public void onStopRefresh(){ new HideHeaderTask().execute(); canRefresh = true; isLoading = false; canScroll = true; arrow.setVisibility(View.GONE); progress_bar.setVisibility(View.GONE); saveTv_refresh_time(); } /** * 停止加載更多 */ public void onStopMore(){ isLoading = false; } /** * 保存刷新時間 */ public void saveTv_refresh_time(){ if(id == -1)return; saveSPLongData(MYRECYCLERVIEW + id, System.currentTimeMillis()); refreshUpdatedAtValue(); } public void setId(int id){ this.id = id; } /** * 是否可以加載更多 * @param hasMore */ public void setHasMore(boolean hasMore){ this.hasMore = hasMore; if(mAdapter != null) { mAdapter.setHasMore(hasMore); } } /** * 是否可以下拉刷新 * @param hasRefresh */ public void setHasRefresh(boolean hasRefresh){ this.hasRefresh = hasRefresh; } /** * 測量布局 */ private void measureView(View child) { ViewGroup.LayoutParams params = child.getLayoutParams(); if (params == null) { params = new ViewGroup.LayoutParams( ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT); } int childWidthSpec = ViewGroup.getChildMeasureSpec(0, 0, params.width); int lpHeight = params.height; int childHeightSpec; if (lpHeight > 0) { childHeightSpec = MeasureSpec.makeMeasureSpec(lpHeight, MeasureSpec.EXACTLY); } else { childHeightSpec = MeasureSpec.makeMeasureSpec(0, MeasureSpec.UNSPECIFIED); } child.measure(childWidthSpec, childHeightSpec); } /** * 刷新下拉頭中上次更新時間的文字描述。 */ private void refreshUpdatedAtValue() { if(id == -1)return; lastUpdateTime = getSPLongData(MYRECYCLERVIEW + id); long currentTime = System.currentTimeMillis(); long timePassed = currentTime - lastUpdateTime; long timeIntoFormat; String updateAtValue; if (lastUpdateTime == -1) { updateAtValue = getResources().getString(R.string.not_updated_yet); } else if (timePassed < 0) { updateAtValue = getResources().getString(R.string.time_error); } else if (timePassed < ONE_MINUTE) { updateAtValue = getResources().getString(R.string.updated_just_now); } else if (timePassed < ONE_HOUR) { timeIntoFormat = timePassed / ONE_MINUTE; String value = timeIntoFormat + "分鐘"; updateAtValue = String.format(getResources().getString(R.string.updated_at), value); } else if (timePassed < ONE_DAY) { timeIntoFormat = timePassed / ONE_HOUR; String value = timeIntoFormat + "小時"; updateAtValue = String.format(getResources().getString(R.string.updated_at), value); } else if (timePassed < ONE_MONTH) { timeIntoFormat = timePassed / ONE_DAY; String value = timeIntoFormat + "天"; updateAtValue = String.format(getResources().getString(R.string.updated_at), value); } else if (timePassed < ONE_YEAR) { timeIntoFormat = timePassed / ONE_MONTH; String value = timeIntoFormat + "個月"; updateAtValue = String.format(getResources().getString(R.string.updated_at), value); } else { timeIntoFormat = timePassed / ONE_YEAR; String value = timeIntoFormat + "年"; updateAtValue = String.format(getResources().getString(R.string.updated_at), value); } updated_at.setText(updateAtValue); } /** * 正在刷新的任務,在此任務中會去回調注冊進來的下拉刷新監聽器。 */ class RefreshingTask extends AsyncTask{ @Override protected Integer doInBackground(Void... params) { int tp = topPadding; long curMills = System.currentTimeMillis(); while (true) { long nowMills = System.currentTimeMillis(); if(nowMills - curMills >= 10){ curMills = nowMills; tp = tp + SCROLL_SPEED * 2; if (tp <= 0) { tp = 0; break; } publishProgress(tp); } } return tp; } @Override protected void onProgressUpdate(Integer... tp) { setTopPadding(tp[0]); } @Override protected void onPostExecute(Integer tp) { setTopPadding(tp); } } /** * 隱藏下拉頭的任務,當未進行下拉刷新或下拉刷新完成後,此任務將會使下拉頭重新隱藏。 */ class HideHeaderTask extends AsyncTask { @Override protected Integer doInBackground(Void... params) { int tp = topPadding; long curMills = System.currentTimeMillis(); while (true) { long nowMills = System.currentTimeMillis(); if(nowMills - curMills >= 10) { curMills = nowMills; tp = tp + SCROLL_SPEED; if (tp <= -mHeaderHeight) { tp = -mHeaderHeight; break; } publishProgress(tp); } } return tp; } @Override protected void onProgressUpdate(Integer... tp) { setTopPadding(tp[0]); } @Override protected void onPostExecute(Integer tp) { setTopPadding(tp); } } /** * 獲取賬戶管理sp * @return */ private SharedPreferences getAccountSP() { return context.getSharedPreferences("account", Context.MODE_PRIVATE); } /** * 保存Long值 * @param key * @param value */ public void saveSPLongData(String key, long value) { getAccountSP().edit().putLong(key, value).commit(); } /** * 獲取存儲的Long值 * @param key * @return */ public Long getSPLongData(String key) { return getAccountSP().getLong(key, -1); } }
(已經很詳細的注釋了,就不多說了,這裡有一個注意點就是:
dependencies { compile fileTree(dir: 'libs', include: ['*.jar']) testCompile 'junit:junit:4.12' compile 'com.android.support:appcompat-v7:23.3.0' compile 'com.android.support:design:23.2.0' }紅色區域是需要注意的,如果你用的是23.3.0會有問題。。。原因未知。。。其它版本未測試)
加載更多:
public abstract class BaseAdapterextends Adapter { protected final LayoutInflater layoutInflater; public List mMessages; private static final int TYPE_FOOTER = -2; public boolean hasMore; public Context context; private int mResources; private ItemOnclickLinstener itemOnclickLinstener; public BaseAdapter(Context context, List mMessages, int mResources) { this.mMessages = mMessages; this.context = context; this.mResources = mResources; layoutInflater = LayoutInflater.from(context); hasMore = false; } @Override public K onCreateViewHolder(ViewGroup parent, int viewType) { // type == TYPE_FOOTER 返回footerView if (viewType == TYPE_FOOTER) { View view = layoutInflater.inflate(R.layout.item_footer, null); view.setLayoutParams(new ViewGroup.LayoutParams( ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)); return (K)new FooterViewHolder(view); }else { final K vh = createViewHolder(viewType, parent); vh.itemView.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { if(itemOnclickLinstener != null) { itemOnclickLinstener.setItemOnclickLinsteners(v, vh.getLayoutPosition(), vh.getItemViewType()); } } }); return vh; } } @Override public void onBindViewHolder(final K viewHolder, final int position) { if(!(hasMore && position == getItemCount() -1)){ setOnBindViewHolder(viewHolder, position); } } @Override public int getItemCount() { int size = 0; if(mMessages != null){ size = mMessages.size(); } return hasMore ? size + 1 : size; } @Override public int getItemViewType(int position) { if (position + 1 == getItemCount() && hasMore) { return TYPE_FOOTER; } else { return setItemViewType(position); } } /** * footer ViewHolder */ class FooterViewHolder extends ViewHolder { public FooterViewHolder(View view) { super(view); } } /** * 是否顯示加載更多 * @param hasMore */ public void setHasMore(boolean hasMore){ this.hasMore = hasMore; } /** * 創建ViewHolder * @param viewType * @return */ protected abstract K createViewHolder(int viewType, ViewGroup parent); /** * 設置ViewHolder類型 * @param position * @return */ protected abstract int setItemViewType(int position); /** * 數據填充 */ protected abstract void setOnBindViewHolder(K viewHolder, int position); /** * Item點擊事件 * @param * @return */ public void setItemOnClickLinsteners(ItemOnclickLinstener itemOnclickLinstener){ this.itemOnclickLinstener = itemOnclickLinstener; } /** * item點擊接口 */ public interface ItemOnclickLinstener{ void setItemOnclickLinsteners(View v, int postion, int type); } protected View getView(int resource){ View view = layoutInflater.inflate(resource, null); view.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)); return view; } protected View getView(){ View view = layoutInflater.inflate(mResources, null); view.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)); return view; } protected View getView(ViewGroup parent){ View view = layoutInflater.inflate(mResources, parent, false); view.setLayoutParams(new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.WRAP_CONTENT)); return view; } }
源碼地址:https://github.com/736791050/RefreshRecyclerView
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