SwipeRefreshLayout + RecyclerView 实现 上拉刷新 和 下拉刷新
2015-11-06 23:08
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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:
[html] view
plaincopy
<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
[java] view
plaincopy
@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
[java] view
plaincopy
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:
[java] view
plaincopy
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
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:
[html] view
plaincopy
<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
[java] view
plaincopy
@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
[java] view
plaincopy
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:
[java] view
plaincopy
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
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