下拉刷新完成之后，接下来当然是加载更多，加载更多也是在下拉刷新的基础上封装的。具体逻辑差不多，下面直接上代码
一、RecyclerView封装类
public class LoadRefreshRecyclerView extends RefreshRecyclerView {
// 上拉加载更多的辅助类
private LoadViewCreator mLoadCreator;
// 上拉加载更多头部的高度
private int mLoadViewHeight = 0;
// 上拉加载更多的头部View
private View mLoadView;
// 手指按下的Y位置
private int mFingerDownY;
// 当前是否正在拖动
private boolean mCurrentDrag = false;
// 当前的状态
private int mCurrentLoadStatus;
// 默认状态
public int LOAD_STATUS_NORMAL = 0x0011;
// 上拉加载更多状态
public static int LOAD_STATUS_PULL_DOWN_REFRESH = 0x0022;
// 松开加载更多状态
public static int LOAD_STATUS_LOOSEN_LOADING = 0x0033;
// 正在加载更多状态
public int LOAD_STATUS_LOADING = 0x0044;
public LoadRefreshRecyclerView(Context context) {
super(context);
}
public LoadRefreshRecyclerView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
}
public LoadRefreshRecyclerView(Context context, @Nullable AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
// 先处理上拉加载更多，同时考虑加载列表的不同风格样式，确保这个项目还是下一个项目都能用
// 所以我们不能直接添加View，需要利用辅助类
public void addLoadViewCreator(LoadViewCreator loadCreator) {
this.mLoadCreator = loadCreator;
addRefreshView();
}
@Override
public void setAdapter(Adapter adapter) {
super.setAdapter(adapter);
addRefreshView();
}
@Override
public boolean dispatchTouchEvent(MotionEvent ev) {
switch (ev.getAction()) {
case MotionEvent.ACTION_DOWN:
// 记录手指按下的位置 ,之所以写在dispatchTouchEvent那是因为如果我们处理了条目点击事件，
// 那么就不会进入onTouchEvent里面，所以只能在这里获取
mFingerDownY = (int) ev.getRawY();
break;
case MotionEvent.ACTION_UP:
if (mCurrentDrag) {
restoreLoadView();
}
break;
}
return super.dispatchTouchEvent(ev);
}
/**
* 重置当前加载更多状态
*/
private void restoreLoadView() {
int currentBottomMargin = ((MarginLayoutParams) mLoadView.getLayoutParams()).bottomMargin;
int finalBottomMargin = 0;
if (mCurrentLoadStatus == LOAD_STATUS_LOOSEN_LOADING) {
mCurrentLoadStatus = LOAD_STATUS_LOADING;
if (mLoadCreator != null) {
mLoadCreator.onLoading();
}
if (mListener != null) {
mListener.onLoad();
}
}
int distance = currentBottomMargin - finalBottomMargin;
// 回弹到指定位置
ValueAnimator animator = ObjectAnimator.ofFloat(currentBottomMargin, finalBottomMargin).setDuration(distance);
animator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
@Override
public void onAnimationUpdate(ValueAnimator animation) {
float currentTopMargin = (float) animation.getAnimatedValue();
setLoadViewMarginBottom((int) currentTopMargin);
}
});
animator.start();
mCurrentDrag = false;
}
@Override
public boolean onTouchEvent(MotionEvent e) {
switch (e.getAction()) {
case MotionEvent.ACTION_MOVE:
// 如果是在最底部才处理，否则不需要处理
if (canScrollDown() || mCurrentLoadStatus == LOAD_STATUS_LOADING
|| mLoadCreator == null || mLoadView == null) {
// 如果没有到达最顶端，也就是说还可以向上滚动就什么都不处理
return super.onTouchEvent(e);
}
if (mLoadCreator != null) {
mLoadViewHeight = mLoadView.getMeasuredHeight();
}
// 解决上拉加载更多自动滚动问题
if (mCurrentDrag) {
scrollToPosition(getAdapter().getItemCount() - 1);
}
// 获取手指触摸拖拽的距离
int distanceY = (int) ((e.getRawY() - mFingerDownY) * mDragIndex);
// 如果是已经到达头部，并且不断的向下拉，那么不断的改变refreshView的marginTop的值
if (distanceY < 0) {
setLoadViewMarginBottom(-distanceY);
updateLoadStatus(-distanceY);
mCurrentDrag = true;
return true;
}
break;
}
return super.onTouchEvent(e);
}
/**
* 更新加载的状态
*/
private void updateLoadStatus(int distanceY) {
if (distanceY <= 0) {
mCurrentLoadStatus = LOAD_STATUS_NORMAL;
} else if (distanceY < mLoadViewHeight) {
mCurrentLoadStatus = LOAD_STATUS_PULL_DOWN_REFRESH;
} else {
mCurrentLoadStatus = LOAD_STATUS_LOOSEN_LOADING;
}
if (mLoadCreator != null) {
mLoadCreator.onPull(distanceY, mLoadViewHeight, mCurrentLoadStatus);
}
}
/**
* 添加底部加载更多View
*/
private void addRefreshView() {
Adapter adapter = getAdapter();
if (adapter != null && mLoadCreator != null) {
// 添加底部加载更多View
View loadView = mLoadCreator.getLoadView(getContext(), this);
if (loadView != null) {
addFooterView(loadView);
this.mLoadView = loadView;
}
}
}
/**
* 设置加载View的marginBottom
*/
public void setLoadViewMarginBottom(int marginBottom) {
MarginLayoutParams params = (MarginLayoutParams) mLoadView.getLayoutParams();
if (marginBottom < 0) {
marginBottom = 0;
}
params.bottomMargin = marginBottom;
mLoadView.setLayoutParams(params);
}
/**
* @return Whether it is possible for the child view of this layout to
* scroll up. Override this if the child view is a custom view.
* 判断是不是滚动到了最顶部，这个是从SwipeRefreshLayout里面copy过来的源代码
*/
public boolean canScrollDown() {
return ViewCompat.canScrollVertically(this, 1);
}
/**
* 停止加载更多
*/
public void onStopLoad() {
mCurrentLoadStatus = LOAD_STATUS_NORMAL;
restoreLoadView();
if (mLoadCreator != null) {
mLoadCreator.onStopLoad();
}
}
// 处理加载更多回调监听
private OnLoadMoreListener mListener;
public void setOnLoadMoreListener(OnLoadMoreListener listener) {
this.mListener = listener;
}
public interface OnLoadMoreListener {
void onLoad();
}}
二、辅助类
public abstract class LoadViewCreator {
/**
* 获取上拉加载更多的View
*
* @param context 上下文
* @param parent RecyclerView
*/
public abstract View getLoadView(Context context, ViewGroup parent);
/**
* 正在上拉
*
* @param currentDragHeight 当前拖动的高度
* @param loadViewHeight 总的加载高度
* @param currentLoadStatus 当前状态
*/
public abstract void onPull(int currentDragHeight, int loadViewHeight, int currentLoadStatus);
/**
* 正在加载中
*/
public abstract void onLoading();
/**
* 停止加载
*/
public abstract void onStopLoad();
}
使用和下来加载差不多
三、下拉刷新和上拉加载更多使用
// 添加头部和底部刷新效果
mRecyclerView.addRefreshViewCreator(new DefaultRefreshCreator());
mRecyclerView.addLoadViewCreator(new DefaultLoadCreator());
mRecyclerView.setOnRefreshListener(this);
mRecyclerView.setOnLoadMoreListener(this);
@Override
public void onRefresh() {
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
mRecyclerView.onStopRefresh();
}
}, 2000);
}
@Override
public void onLoad() {
new Handler().postDelayed(new Runnable() {
@Override
public void run() {
initData();
mRecyclerView.onStopLoad();
mAdapter.notifyDataSetChanged();
}
}, 2000);
}
