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SwipeRefreshLayout+RecyclerView实现上拉刷新和下拉刷新功能

作者:dalancon

这篇文章主要介绍了SwipeRefreshLayout+RecyclerView实现上拉刷新和下拉刷新功能,具有一定的参考价值,感兴趣的小伙伴们可以参考一下

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

源码在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的出现基本就是为了替代ListView,GridView的。

今天说一下最常见的下拉刷新  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中引用这个布局并初始化

@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);
 
 // 这句话是为了,第一次进入页面的时候显示加载进度条
 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);
 // 此处在现实项目中,请换成网络请求数据代码,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);
 
 // 此处在现实项目中,请换成网络请求数据代码,sendRequest .....
 handler.sendEmptyMessageDelayed(0, 3000);
 }

SwipeRefreshLayout里面需要注意的Api:

1、setOnRefreshListener(OnRefreshListener listener)  设置下拉监听,当用户下拉的时候会去执行回调
2、setColorSchemeColors(int... colors) 设置 进度条的颜色变化,最多可以设置4种颜色
3、setProgressViewOffset(boolean scale, int start, int end) 调整进度条距离屏幕顶部的距离
4、setRefreshing(boolean refreshing) 设置SwipeRefreshLayout当前是否处于刷新状态,一般是在请求数据的时候设置为true,在数据被加载到View中后,设置为false。

RecyclerView的实现:

第一种,下拉刷新和上拉刷新都用SwipeRefreshLayout 自带的进度条

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);
 // 此处在现实项目中,请换成网络请求数据代码,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);

第二种实现下拉刷新用SwipeRefreshLayout 自带的进度条, 上拉刷新用类似ListView的刷新 提示“加载中”等信息。

我们可以给RecyclerView 也添加一个类似FooterView的item。
我们在Adapter中实现:

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设置为数据总条数+ 1(footerView)
 @Override
 public int getItemCount() {
 return list.size() + 1;
 }
 
 @Override
 public int getItemViewType(int position) {
 // 最后一个item设置为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);
 }
 }
}

这样我们就可以针对footerview的布局做一些处理了,比如提示“加载中,”,“已经全部加载”等信息。更加灵活一点。

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。

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