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SwipeRefreshLayout+RecyclerView實(shí)現(xiàn)上拉刷新和下拉刷新功能

 更新時間:2019年01月16日 10:17:03   作者:dalancon  
這篇文章主要介紹了SwipeRefreshLayout+RecyclerView實(shí)現(xiàn)上拉刷新和下拉刷新功能,具有一定的參考價值,感興趣的小伙伴們可以參考一下

SwipeRefreshLayout 是谷歌公司推出的用于下拉刷新的控件,SwipeRefreshLayout已經(jīng)被放到了sdk中,在Version 19.1之后SwipeRefreshLayout 被放到support v4中。

源碼在SDK\sdk\extras\android\support\v4\src\java\android\support\v4\widget\SwipeRefreshLayout.java

谷歌公司只提供了下拉刷新的功能,RecyclerView的出現(xiàn)基本就是為了替代ListView,GridView的。

今天說一下最常見的下拉刷新  和 上拉刷新的功能。

布局文件:

<android.support.v4.widget.SwipeRefreshLayout
 xmlns:android="http://schemas.android.com/apk/res/android"
 xmlns:tools="http://schemas.android.com/tools"
 android:id="@+id/swipe_refresh_widget"
 android:layout_width="match_parent"
 android:layout_height="match_parent" >
 
 <android.support.v7.widget.RecyclerView
 android:id="@android:id/list"
 android:layout_width="match_parent"
 android:layout_height="match_parent"
 android:cacheColorHint="@null"
 android:scrollbars="vertical" />
 
</android.support.v4.widget.SwipeRefreshLayout>

在Activity中引用這個布局并初始化

@Override
 protected void onCreate(Bundle savedInstanceState) {
 super.onCreate(savedInstanceState);
 setContentView(R.layout.activity_main);
 
 mSwipeRefreshWidget = (SwipeRefreshLayout) findViewById(R.id.swipe_refresh_widget);
 mRecyclerView = (RecyclerView) findViewById(android.R.id.list);
 
 mSwipeRefreshWidget.setColorScheme(R.color.color1, R.color.color2,
 R.color.color3, R.color.color4);
 mSwipeRefreshWidget.setOnRefreshListener(this);
 
 // 這句話是為了,第一次進(jìn)入頁面的時候顯示加載進(jìn)度條
 mSwipeRefreshWidget.setProgressViewOffset(false, 0, (int) TypedValue
 .applyDimension(TypedValue.COMPLEX_UNIT_DIP, 24, getResources()
 .getDisplayMetrics()));
 
 mRecyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
 
 @Override
 public void onScrollStateChanged(RecyclerView recyclerView,
 int newState) {
 super.onScrollStateChanged(recyclerView, newState);
 if (newState == RecyclerView.SCROLL_STATE_IDLE
 && lastVisibleItem + 1 == adapter.getItemCount()) {
 mSwipeRefreshWidget.setRefreshing(true);
 // 此處在現(xiàn)實(shí)項目中,請換成網(wǎng)絡(luò)請求數(shù)據(jù)代碼,sendRequest .....
 handler.sendEmptyMessageDelayed(0, 3000);
 }
 }
 
 @Override
 public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
 super.onScrolled(recyclerView, dx, dy);
 lastVisibleItem = mLayoutManager.findLastVisibleItemPosition();
 }
 
 });
 
 mRecyclerView.setHasFixedSize(true);
 mLayoutManager = new LinearLayoutManager(this);
 mRecyclerView.setLayoutManager(mLayoutManager);
 mRecyclerView.setItemAnimator(new DefaultItemAnimator());
 
 adapter = new SampleAdapter();
 mRecyclerView.setAdapter(adapter);
 
 // 此處在現(xiàn)實(shí)項目中,請換成網(wǎng)絡(luò)請求數(shù)據(jù)代碼,sendRequest .....
 handler.sendEmptyMessageDelayed(0, 3000);
 }

SwipeRefreshLayout里面需要注意的Api:

1、setOnRefreshListener(OnRefreshListener listener)  設(shè)置下拉監(jiān)聽,當(dāng)用戶下拉的時候會去執(zhí)行回調(diào)
2、setColorSchemeColors(int... colors) 設(shè)置 進(jìn)度條的顏色變化,最多可以設(shè)置4種顏色
3、setProgressViewOffset(boolean scale, int start, int end) 調(diào)整進(jìn)度條距離屏幕頂部的距離
4、setRefreshing(boolean refreshing) 設(shè)置SwipeRefreshLayout當(dāng)前是否處于刷新狀態(tài),一般是在請求數(shù)據(jù)的時候設(shè)置為true,在數(shù)據(jù)被加載到View中后,設(shè)置為false。

RecyclerView的實(shí)現(xiàn):

第一種,下拉刷新和上拉刷新都用SwipeRefreshLayout 自帶的進(jìn)度條

mRecyclerView = (RecyclerView) findViewById(android.R.id.list);
mRecyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() {
 
 @Override
 public void onScrollStateChanged(RecyclerView recyclerView,
 int newState) {
 super.onScrollStateChanged(recyclerView, newState);
 if (newState == RecyclerView.SCROLL_STATE_IDLE
 && lastVisibleItem + 1 == adapter.getItemCount()) {
 mSwipeRefreshWidget.setRefreshing(true);
 // 此處在現(xiàn)實(shí)項目中,請換成網(wǎng)絡(luò)請求數(shù)據(jù)代碼,sendRequest .....
 handler.sendEmptyMessageDelayed(0, 3000);
 }
 }
 
 @Override
 public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
 super.onScrolled(recyclerView, dx, dy);
 lastVisibleItem = mLayoutManager.findLastVisibleItemPosition();
 }
 });
 
 mRecyclerView.setHasFixedSize(true);
 mLayoutManager = new LinearLayoutManager(this);
 mRecyclerView.setLayoutManager(mLayoutManager);
 mRecyclerView.setItemAnimator(new DefaultItemAnimator());
 
 adapter = new SampleAdapter();
 mRecyclerView.setAdapter(adapter);

第二種實(shí)現(xiàn)下拉刷新用SwipeRefreshLayout 自帶的進(jìn)度條, 上拉刷新用類似ListView的刷新 提示“加載中”等信息。

我們可以給RecyclerView 也添加一個類似FooterView的item。
我們在Adapter中實(shí)現(xiàn):

public class SampleAdapter extends RecyclerView.Adapter<ViewHolder> {
 private List<Integer> list;
 
 private static final int TYPE_ITEM = 0;
 private static final int TYPE_FOOTER = 1;
 
 public List<Integer> getList() {
 return list;
 }
 
 public SampleAdapter() {
 list = new ArrayList<Integer>();
 }
 
 // RecyclerView的count設(shè)置為數(shù)據(jù)總條數(shù)+ 1(footerView)
 @Override
 public int getItemCount() {
 return list.size() + 1;
 }
 
 @Override
 public int getItemViewType(int position) {
 // 最后一個item設(shè)置為footerView
 if (position + 1 == getItemCount()) {
 return TYPE_FOOTER;
 } else {
 return TYPE_ITEM;
 }
 }
 
 @Override
 public void onBindViewHolder(ViewHolder holder, final int position) {
 if (holder instanceof ItemViewHolder) {
 ((ItemViewHolder) holder).textView.setText(String.valueOf(list
 .get(position)));
 }
 }
 
 @Override
 public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
 if (viewType == TYPE_ITEM) {
 View view = LayoutInflater.from(parent.getContext()).inflate(
 R.layout.list_item_text, null);
 view.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
 LayoutParams.WRAP_CONTENT));
 return new ItemViewHolder(view);
 }
 // type == TYPE_FOOTER 返回footerView
 else if (viewType == TYPE_FOOTER) {
 View view = LayoutInflater.from(parent.getContext()).inflate(
 R.layout.footerview, null);
 view.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,
 LayoutParams.WRAP_CONTENT));
 return new FooterViewHolder(view);
 }
 
 return null;
 }
 
 class FooterViewHolder extends ViewHolder {
 
 public FooterViewHolder(View view) {
 super(view);
 }
 
 }
 
 class ItemViewHolder extends ViewHolder {
 TextView textView;
 
 public ItemViewHolder(View view) {
 super(view);
 textView = (TextView) view.findViewById(R.id.text);
 }
 }
}

這樣我們就可以針對footerview的布局做一些處理了,比如提示“加載中,”,“已經(jīng)全部加載”等信息。更加靈活一點(diǎn)。

以上就是本文的全部內(nèi)容,希望對大家的學(xué)習(xí)有所幫助,也希望大家多多支持腳本之家。

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