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這篇文章主要介紹Android如何實現RecyclerView下拉刷新效果，文中介紹的非常詳細，具有一定的參考價值，感興趣的小伙伴們一定要看完！
具體內容如下
思路
RealPullRefreshView繼承了一個LinearLayout
里面放置了一個刷新頭布局，將其margin_top設置為負的刷新頭的高度的
再添加一個RecyclerView
觸摸事件分發(fā)機制，當在特定條件下讓RealPullRefreshView攔截觸摸事件，否則的話，不攔截，讓RecyclerView自己去處理觸摸事件
在手指下拉時，定義好不同的狀態(tài)STATE,在不同狀態(tài)下，處理不同的顯示，這里講不同狀態(tài)下的刷新頭如何顯示，抽象為一個接口，用戶可以實現這個接口，自定義刷新頭的布局和動畫
加載更多的功能是利用RecyclerView的多type布局實現的
難點在于觸摸事件的攔截，和認真處理各種滑動的問題
使用
xml
<com.example.apple.quickdemo.realview.view.RealPullRefreshView android:id="@+id/real_pull_refresh_view" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" app:refresh_header_view="@layout/headerview"/>
這是headerview
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="50dp" android:background="#ff0" android:orientation="horizontal" android:gravity="center"> <TextView android:layout_width="wrap_content" android:layout_height="match_parent" android:background="@color/colorAccent" android:visibility="visible" android:id="@+id/tv" android:gravity="center" android:text="下拉刷新" android:textSize="21sp"/> <ImageView android:layout_width="wrap_content" android:layout_height="wrap_content" android:src="@mipmap/ic_launcher" android:id="@+id/iv" /> </LinearLayout>
代碼
mRealPullRefreshView.setLayoutManager(mLayoutManager);
mRealPullRefreshView.setAdapter(mMyAdapte);
//用戶可以自定義自己的刷新頭布局和動畫
//mRealPullRefreshView.setOnPullShowViewListener(new GifOnPullShowViewListerner(mRealPullRefreshView));
mRealPullRefreshView.setOnPullListener(new RealPullRefreshView.OnPullListener() {
@Override
public void onRefresh() {
mHandler.postDelayed(new Runnable() {
@Override
public void run() {
mBodies.add(0, new Body("新數據"+i++,100));
mRealPullRefreshView.refreshFinish();
}
}, 3000);
}
@Override
public void onLoadMore() {
final List<Body> more=new ArrayList<Body>();
mHandler.postDelayed(new Runnable() {
@Override
public void run() {
for (int i = 0; i < 3; i++) {
more.add(new Body("more+++"+i,100));
}
mBodies.addAll(more);
mRealPullRefreshView.loadMreFinish();
}
}, 1500);
}
});自定義刷新頭布局和動畫
package com.example.apple.quickdemo.realview.show;
import android.animation.ObjectAnimator;
import android.animation.ValueAnimator;
import android.util.Log;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import com.example.apple.quickdemo.R;
import com.example.apple.quickdemo.realview.view.RealPullRefreshView;
/**
* Created by apple on 2017/7/9.
*/
public class ImplOnPullShowViewListener implements RealPullRefreshView.OnPullShowViewListener {
private TextView mTv;
private ImageView mIv;
private ObjectAnimator mAni;
View mHeaderView;
public ImplOnPullShowViewListener(RealPullRefreshView realPullRefreshView) {
mHeaderView = realPullRefreshView.getRefreshHeaderView();
mTv = (TextView) mHeaderView.findViewById(R.id.tv);
mIv = (ImageView) mHeaderView.findViewById(R.id.iv);
mAni = ObjectAnimator.ofFloat(mIv, "rotation", -15, 15).setDuration(300);
mAni.setRepeatCount(ValueAnimator.INFINITE);
mAni.setRepeatMode(ValueAnimator.REVERSE);
}
@Override
public void onPullDownRefreshState(int scrollY, int headviewHeight,int deltaY) {
mTv.setText("下拉刷新");
float f = -((float) scrollY / (float) headviewHeight);
Log.e("tag", f+ "");
Log.e("tag", -scrollY + "scrollY");
mIv.setScaleX(f);
mIv.setScaleY(f);
}
@Override
public void onReleaseRefreshState(int scrollY, int deltaY) {
mTv.setText("松手刷新");
}
@Override
public void onRefreshingState() {
mTv.setText("正在刷新");
mIv.setScaleX(1.0f);
mIv.setScaleY(1.0f);
mAni.start();
}
@Override
public void onDefaultState() {
if (mAni.isRunning()){
mAni.end();
mIv.setRotation(0);
}
}
}源碼
package com.example.apple.quickdemo.realview.view;
import android.content.Context;
import android.content.res.TypedArray;
import android.support.annotation.Nullable;
import android.support.v7.widget.GridLayoutManager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.support.v7.widget.StaggeredGridLayoutManager;
import android.util.AttributeSet;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.Scroller;
import android.widget.Toast;
import com.example.apple.quickdemo.R;
import com.example.apple.quickdemo.realview.show.ImplOnPullShowViewListener;
import static android.content.ContentValues.TAG;
/**
* Created by apple on 2017/7/7.
* 下拉刷新
*/
public class RealPullRefreshView extends LinearLayout {
private int mTouchSlop;
// 分別記錄上次滑動的坐標
private int mLastX = 0;
private int mLastY = 0;
// 分別記錄上次滑動的坐標(onInterceptTouchEnvent)
private int mLastXIntercept = 0;
private int mLastYIntercept = 0;
private Scroller mScroller;
private VelocityTracker mVelocityTracker;
private RecyclerView.Adapter mAdapter;
public RecyclerView getRecyclerView() {
return mRecyclerView;
}
private RecyclerView mRecyclerView;
private int DEFAULT = 0;
private final int PULL_DOWN_REFRESH = 1;
private final int RELEASE_REFRESH = 2;
private final int REFRESHING = 3;
private final int LOAD_MORE = 4;
private int STATE = DEFAULT;
private int rfreshHeaderWidth;
private int refreshHeadviewHeight;
private OnPullListener mOnPullListener;
private View mRefreshHeaderView;
private RecyclerView.LayoutManager mLayoutManager;
int refreshHeadviewId;
public void setLayoutManager(RecyclerView.LayoutManager manager) {
this.mLayoutManager = manager;
mRecyclerView.setLayoutManager(mLayoutManager);
}
public void setAdapter(RecyclerView.Adapter adapter) {
this.mAdapter = adapter;
mRecyclerView.setAdapter(mAdapter);
}
public View getRefreshHeaderView() {
return mRefreshHeaderView;
}
public void setOnPullShowViewListener(OnPullShowViewListener onPullShowViewListener) {
mOnPullShowViewListener = onPullShowViewListener;
}
private OnPullShowViewListener mOnPullShowViewListener;
public void setOnPullListener(OnPullListener onPullListener) {
mOnPullListener = onPullListener;
}
public RealPullRefreshView(Context context) {
super(context);
initView(context);
}
public RealPullRefreshView(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
initAttrs(context, attrs);
// ★★★★★一個坑initAttrs方法里的typedArray去獲取屬性時，第一次獲取的屬性全是0，他會馬上重走一次構造方法，再次獲取一次，才能獲得正確的值
// 如果第一次獲取的值為0，則不去initView
if (refreshHeadviewId != 0) {
initView(context);
}
}
public RealPullRefreshView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
initAttrs(context, attrs);
if (refreshHeadviewId != 0) {
initView(context);
}
}
private void initAttrs(Context context, AttributeSet attrs) {
TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.RealPullRefreshView);
try {
refreshHeadviewId = typedArray.getResourceId(R.styleable.RealPullRefreshView_refresh_header_view, 0);
} finally {
typedArray.recycle();
}
}
private void initView(Context context) {
mScroller = new Scroller(getContext());
mVelocityTracker = VelocityTracker.obtain();
// 添加headerview
// ★ ★ ★ ★ ★ 注意不要用這個方法inflate布局，會導致layout的所有屬性失效，height、width、margin
// 原因見 http://blog.csdn.net/zhaokaiqiang1992/article/details/36006467
// ★ ★ ★ ★ ★ mRefreshHeaderView = mInflater.inflate(R.layout.headerview, null);
mRefreshHeaderView = LayoutInflater.from(context).inflate(refreshHeadviewId, this, false);
addView(mRefreshHeaderView);
// }
// 以下代碼主要是為了設置頭布局的marginTop值為-headerviewHeight
// 注意必須等到一小會才會得到正確的頭布局寬高
postDelayed(new Runnable() {
@Override
public void run() {
Log.e("q11", refreshHeadviewHeight + "qqqqqqqqqq " + mRefreshHeaderView.getHeight());
rfreshHeaderWidth = mRefreshHeaderView.getWidth();
refreshHeadviewHeight = mRefreshHeaderView.getHeight();
MarginLayoutParams lp = new LinearLayout.LayoutParams(rfreshHeaderWidth, refreshHeadviewHeight);
lp.setMargins(0, -refreshHeadviewHeight, 0, 0);
mRefreshHeaderView.setLayoutParams(lp);
}
}, 100);
// 添加RecyclerView
mRecyclerView = new RecyclerView(context);
addView(mRecyclerView, LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
// 這里我提供了一個默認的顯示效果，如果用戶不使用mRealPullRefreshView.setOnPullShowViewListener的話，會默認使用這個
// 用戶可以實現OnPullShowViewListener接口，去實現自己想要的顯示效果
mOnPullShowViewListener = new ImplOnPullShowViewListener(this);
setLoadMore();
}
private void setLoadMore() {
// 當目前的可見條目是所有數據的最后一個時，開始加載新的數據
mRecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {
@Override
public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
super.onScrolled(recyclerView, dx, dy);
int lastCompletelyVisibleItemPosition = -1;
if (mLayoutManager instanceof LinearLayoutManager) {
LinearLayoutManager manager = (LinearLayoutManager) mLayoutManager;
lastCompletelyVisibleItemPosition = manager.findLastVisibleItemPosition();
} else if (mLayoutManager instanceof GridLayoutManager) {
GridLayoutManager manager = (GridLayoutManager) mLayoutManager;
lastCompletelyVisibleItemPosition = manager.findLastVisibleItemPosition();
} else if (mLayoutManager instanceof StaggeredGridLayoutManager) {
StaggeredGridLayoutManager manager = (StaggeredGridLayoutManager) mLayoutManager;
lastCompletelyVisibleItemPosition = manager.findLastVisibleItemPositions(new int[manager.getSpanCount()])[0];
}
if (lastCompletelyVisibleItemPosition + 1 == mAdapter.getItemCount()) {
if (mOnPullListener != null && STATE == DEFAULT) {
STATE = LOAD_MORE;
mOnPullListener.onLoadMore();
}
}
}
});
}
@Override
public boolean onInterceptTouchEvent(MotionEvent event) {
boolean intercepted = false;
int x = (int) event.getX();
int y = (int) event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN: {
intercepted = false;
/*if (STATE!=DEFAULT||STATE!=REFRESHING){
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}}*/
break;
}
case MotionEvent.ACTION_MOVE: {
int deltaX = x - mLastXIntercept;
int deltaY = y - mLastYIntercept;
int firstCompletelyVisibleItemPosition = -1;
if (mLayoutManager instanceof LinearLayoutManager) {
LinearLayoutManager manager = (LinearLayoutManager) mLayoutManager;
firstCompletelyVisibleItemPosition = manager.findFirstCompletelyVisibleItemPosition();
} else if (mLayoutManager instanceof GridLayoutManager) {
GridLayoutManager manager = (GridLayoutManager) mLayoutManager;
firstCompletelyVisibleItemPosition = manager.findFirstCompletelyVisibleItemPosition();
} else if (mLayoutManager instanceof StaggeredGridLayoutManager) {
StaggeredGridLayoutManager manager = (StaggeredGridLayoutManager) mLayoutManager;
firstCompletelyVisibleItemPosition = manager.findFirstCompletelyVisibleItemPositions(new int[manager.getSpanCount()])[0];
}
// ******************這里說明什么規(guī)則下，攔截，其余代碼不要動了，其余代碼指的是處理滑動沖突的代碼***************
if (firstCompletelyVisibleItemPosition == 0 && deltaY > 0 && Math.abs(deltaY) > Math.abs(deltaX)) {//拉倒最頂部，繼續(xù)往下拉，將拉出頭布局，要父布局攔截
intercepted = true;
} else if (getScrollY() < 0) {//表示頭布局已經向下拉出來，頭布局已經顯示了，要父布局攔截
intercepted = true;
} else if (deltaY < 0) {
intercepted = false;//不要父布局攔截了
} else {
intercepted = false;//不要父布局攔截了
}
// ******************什么規(guī)則下，攔截***************
break;
}
case MotionEvent.ACTION_UP: {
intercepted = false;
break;
}
default:
break;
}
Log.d(TAG, "intercepted=" + intercepted);
mLastX = x;
mLastY = y;
mLastXIntercept = x;
mLastYIntercept = y;
return intercepted;
}
/**
* 下面不同布局，不同的滑動需求
*
* @param event
* @return
*/
@Override
public boolean onTouchEvent(MotionEvent event) {
mVelocityTracker.addMovement(event);
int x = (int) event.getX();
int y = (int) event.getY();
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN: {
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
break;
}
case MotionEvent.ACTION_MOVE: {
int deltaX = x - mLastX;
int deltaY = y - mLastY;
if (getScrollY() > 0) {
//防止在正在刷新狀態(tài)下，上拉出空白
} else if (getScrollY() <= 0 && getScrollY() > -refreshHeadviewHeight * 5) {
// 最多下拉到頭布局高度5倍的距離
scrollBy(0, -deltaY / 2);
}
if (getScrollY() > -refreshHeadviewHeight && STATE != REFRESHING) {//頭布局顯示不全時，為下拉刷新PULL_DOWN_REFRESH狀態(tài)
STATE = PULL_DOWN_REFRESH;
if (mOnPullShowViewListener != null) {
mOnPullShowViewListener.onPullDownRefreshState(getScrollY(), refreshHeadviewHeight, deltaY);
}
}
if (getScrollY() < -refreshHeadviewHeight && STATE != REFRESHING) {//頭布局完全顯示時，為釋放刷新RELEASE_REFRESH狀態(tài)
STATE = RELEASE_REFRESH;
if (mOnPullShowViewListener != null) {
mOnPullShowViewListener.onReleaseRefreshState(getScrollY(), deltaY);
}
}
break;
}
case MotionEvent.ACTION_UP: {
final int scrollY = getScrollY();
//松手時，根據所處的狀態(tài)，讓布局滑動到不同的地方，做不同的操作
switch (STATE) {
case PULL_DOWN_REFRESH:
STATE = DEFAULT;
//頭布局沒有完全顯示，完全隱藏頭布局
smoothScrollBy(0, -scrollY);
break;
case RELEASE_REFRESH:
STATE = REFRESHING;
smoothScrollBy(0, -refreshHeadviewHeight - scrollY);
if (mOnPullShowViewListener != null) {
mOnPullShowViewListener.onRefreshingState();
}
if (mOnPullListener != null) {
mOnPullListener.onRefresh();
}
break;
case REFRESHING:
if (getScrollY() < -refreshHeadviewHeight) {
smoothScrollBy(0, -refreshHeadviewHeight - scrollY);
} else {
smoothScrollBy(0, -scrollY);
}
break;
}
mVelocityTracker.clear();
break;
}
default:
break;
}
mLastX = x;
mLastY = y;
return true;
}
/**
* 當用戶使用完下拉刷新回調時，需要調用此方法，將頭不去隱藏，將STATE恢復
*/
public void refreshFinish() {
smoothScrollBy(0, 0 - getScrollY());
getRecyclerView().getAdapter().notifyDataSetChanged();
STATE = DEFAULT;
if (mOnPullShowViewListener != null) {
mOnPullShowViewListener.onDefaultState();
}
Toast.makeText(getContext(), "刷新成功!", Toast.LENGTH_SHORT).show();
}
/**
* 當用戶使用完加載更多后回調時，需要調用此方法，將STATE恢復
*/
public void loadMreFinish() {
getRecyclerView().getAdapter().notifyDataSetChanged();
STATE = DEFAULT;
Toast.makeText(getContext(), "加載成功了!", Toast.LENGTH_SHORT).show();
}
/**
* 在500毫秒內平滑地滾動多少像素點
*
* @param dx
* @param dy
*/
private void smoothScrollBy(int dx, int dy) {
mScroller.startScroll(0, getScrollY(), 0, dy, 500);
invalidate();
}
@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
scrollTo(mScroller.getCurrX(), mScroller.getCurrY());
postInvalidate();
}
}
/**
* 釋放資源
*/
@Override
protected void onDetachedFromWindow() {
mVelocityTracker.recycle();
super.onDetachedFromWindow();
}
// ***************
// *****************
/**
* 回調接口
*/
public interface OnPullListener {
/**
* 當下拉刷新正在刷新時，這時候可以去請求數據，記得最后調用refreshFinish()復位
*/
void onRefresh();
/**
* 當加載更多時
*/
void onLoadMore();
}
/**
* 回調接口，可以通過下面的回調，自定義各種狀態(tài)下的顯示效果
* 可以根據下拉距離scrollY設計動畫效果
*/
public interface OnPullShowViewListener {
/**
* 當處于下拉刷新時，頭布局顯示效果
*
* @param scrollY 下拉的距離
* @param headviewHeight 頭布局高度
* @param deltaY moveY-lastMoveY,正值為向下拉
*/
void onPullDownRefreshState(int scrollY, int headviewHeight, int deltaY);
/**
* 當處于松手刷新時，頭布局顯示效果
*
* @param scrollY 下拉的距離
* @param deltaY moveY-lastMoveY,正值為向下拉
*/
void onReleaseRefreshState(int scrollY, int deltaY);
/**
* 正在刷新時，頁面的顯示效果
*/
void onRefreshingState();
/**
* 默認狀態(tài)時，頁面顯示效果，主要是為了復位各種狀態(tài)
*/
void onDefaultState();
}
}以上是“Android如何實現RecyclerView下拉刷新效果”這篇文章的所有內容，感謝各位的閱讀！希望分享的內容對大家有幫助，更多相關知識，歡迎關注億速云行業(yè)資訊頻道！
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