RecyclerView 下拉刷新和上拉加载

小灰灰 2022-07-24 04:05 521阅读 0赞

## RecyclerView 下拉刷新和上拉加载 ##

RecyclerView已经出来很久了，许许多多的项目都开始从ListView转战RecyclerView，那么，上拉加载和下拉刷新是一件很有必要的事情。

在ListView上，我们可以通过自己添加`addHeadView`和`addFootView`去添加头布局和底部局实现自定义的上拉和下拉，或者使用一些第三方库来简单的集成，例如`android-pulltorefresh`或者`android-Ultra-Pull-to-Refresh`，后者的自定义更强，但需要自己实现上拉加载。

而在下面我们将用两种方式来实现上拉加载和下拉刷新

*  `SwipeRefreshLayout`\+滑动底部自动加载
 *  使用第三方库`SwipeToLoadLayout`实现上拉加载和下拉刷新。

### **`SwipeRefreshLayout`\+滑动底部自动加载** ###

SwipeRefreshLayout实现很简单，重点是滑动到底部自动加载应该如何实现，其实其实现的方式类似于`ListView`的实现方式。

看一下`activity_recycle_swiperefresh.xml`文件：

<android.support.v4.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:id="@+id/swipe_refresh"
        android:orientation="vertical" android:layout_width="match_parent"
        android:layout_height="match_parent">
    
        <android.support.v7.widget.RecyclerView
            android:id="@+id/swipe_target"
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:scrollbars="none" />
    
    </android.support.v4.widget.SwipeRefreshLayout>

布局文件就两个控件，`SwipeRefreshLayout`中嵌套`RecyclerView`。

在代码中初始化`RecyclerView`以及实现`adapter`等，这不是重点，不再贴代码。

在`RecyclerView`中有方法`addOnScrollListener`，该方法类似于`ListView`的`setOnScrollListener`方法，`OnScrollListener`中有两个方法的回调

*  `onScrolled(RecyclerView recyclerView, int dx, int dy)` ：滚动的回调，dx和dy表示手指滑动水平和垂直的偏移量。
 *  `onScrollStateChanged(RecyclerView recyclerView, int newState)`：滑动状态的回调。

那么，我们的着重点就在这个两个方法上了。

对于向上加载更多，我们需要有如下判断

*  是否是向上滑动
 *  是否滑动到底部
 *  当前是否正在加载数据
 *  当前状态是否是滑动停止的状态

实现比较复杂，定义一个类`LoadDataScrollController`，继承类`RecyclerView.OnScrollListener`，

因为`onScrollStateChanged`实在状态改变时的回调，无法时时的获取显示的条目以及位置，所以我们在`onScrolled`中获取相应位置，

@Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
    
            /** * 获取布局参数 */
            RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
    
            //如果为null，第一次运行，确定布局类型
            if (mLayoutManagerType == null) {
                if (layoutManager instanceof LinearLayoutManager) {
                    mLayoutManagerType = LayoutManagerType.LINEAR_LAYOUT;
                } else if (layoutManager instanceof GridLayoutManager) {
                    mLayoutManagerType = LayoutManagerType.GRID_LAYOUT;
                } else if (layoutManager instanceof StaggeredGridLayoutManager) {
                    mLayoutManagerType = LayoutManagerType.STAGGERED_GRID_LAYOUT;
                } else {
                    throw new RuntimeException("LayoutManager should be LinearLayoutManager,GridLayoutManager,StaggeredGridLayoutManager");
                }
            }
    
            //对于不太能够的布局参数，不同的方法获取到当前显示的最后一个条目数
            switch (mLayoutManagerType) {
                case LINEAR_LAYOUT:
                    mLastVisibleItemPosition = ((LinearLayoutManager) layoutManager).findLastVisibleItemPosition();
                    break;
                case GRID_LAYOUT:
                    mLastVisibleItemPosition = ((GridLayoutManager) layoutManager).findLastVisibleItemPosition();
                    break;
                case STAGGERED_GRID_LAYOUT:
                    StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;
                    if (mLastPostions == null) {
                        mLastPostions = new int[staggeredGridLayoutManager.getSpanCount()];
                    }
                    staggeredGridLayoutManager.findLastVisibleItemPositions(mLastPostions);
                    mLastVisibleItemPosition = findMax(mLastPostions);
                    break;
                default:
                    break;
            }
    
        }

首先获取布局管理器，并判断是那种类型的，因为有三种类型，定义枚举来保存布局类型的参数

/** * * RecycleView的布局管理器的类型 * Created by Alex_MaHao on 2016/5/10. */
    public enum  LayoutManagerType {
        LINEAR_LAYOUT,
        GRID_LAYOUT,
        STAGGERED_GRID_LAYOUT
    }

然后根据布局惯例其的类型获取其当前显示的最大条目，对于瀑布流来说，他如果是垂直的两列瀑布的话，我们需要获取两列中分别最大条目数，进行比较，选出最大条目数。

/** * 当是瀑布流时，获取到的是每一个瀑布最下方显示的条目，通过条目进行对比 */
        private int findMax(int[] lastPositions) {
            int max = lastPositions[0];
            for (int value : lastPositions) {
                if (value > max) {
                    max = value;
                }
            }
            return max;
        }

拿到当前最大的条目数之后，在`onScrollStateChange`中进行判断状态等，

@Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
    
            RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
    
            //RecycleView 显示的条目数
            int visibleCount = layoutManager.getChildCount();
    
            //显示数据总数
            int totalCount = layoutManager.getItemCount();
    
    
            // 四个条件，分别是是否有数据，状态是否是滑动停止状态，显示的最大条目是否大于整个数据（注意偏移量），是否正在加载数据
            if(visibleCount>0
                    &&newState==RecyclerView.SCROLL_STATE_IDLE
                    &&mLastVisibleItemPosition>=totalCount-1
                    &&!isLoadData){
                //可以加载数据
               isLoadData = true;
            }
    
        }

注释很清楚，在加载数据的地方，我们将`isLoadData`设为`true`，同时利用接口回调加载数据，等数据加载完成，通过`setLoadDataStatus`方法设置为`false`

public void setLoadDataStatus(boolean isLoadData){
            this.isLoadData = isLoadData;
        }

如果这样就结束了，感觉很麻烦，对于刷新和加载更多，我们需要在调用的地方分别设置监听，那么我们可以让`LoadDataScrollController`实现`SwipeRefreshLayout`的刷新监听方法，在利用我们定义的统一的上拉刷新和加载数据接口进行处理

/** * 实现上拉加载的监听：加载条件：滑动到最后，且是停止状态，则开始加载数据 * Created by Alex_MaHao on 2016/5/10. */
    public  class LoadDataScrollController extends RecyclerView.OnScrollListener implements SwipeRefreshLayout.OnRefreshListener { 
    
        /** * 当前布局管理器的类型 */
        private LayoutManagerType mLayoutManagerType;
    
    
        /** * 当前RecycleView显示的最大条目 */
        private int mLastVisibleItemPosition;
    
    
        /** * 每列的最后一个条目 */
        private int[] mLastPostions;
    
    
        /** * 是否正在加载数据 包括刷新和向上加载更多 */
        private boolean isLoadData = false;
    
    
        /** * 回调接口 */
        private OnRecycleRefreshListener mListener;
    
    
        public LoadDataScrollController(OnRecycleRefreshListener onRecycleRefreshListener) {
            this.mListener = onRecycleRefreshListener;
        }
    
        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
    
            /** * 获取布局参数 */
            RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
    
            //如果为null，第一次运行，确定布局类型
            if (mLayoutManagerType == null) {
                if (layoutManager instanceof LinearLayoutManager) {
                    mLayoutManagerType = LayoutManagerType.LINEAR_LAYOUT;
                } else if (layoutManager instanceof GridLayoutManager) {
                    mLayoutManagerType = LayoutManagerType.GRID_LAYOUT;
                } else if (layoutManager instanceof StaggeredGridLayoutManager) {
                    mLayoutManagerType = LayoutManagerType.STAGGERED_GRID_LAYOUT;
                } else {
                    throw new RuntimeException("LayoutManager should be LinearLayoutManager,GridLayoutManager,StaggeredGridLayoutManager");
                }
            }
    
            //对于不太能够的布局参数，不同的方法获取到当前显示的最后一个条目数
            switch (mLayoutManagerType) {
                case LINEAR_LAYOUT:
                    mLastVisibleItemPosition = ((LinearLayoutManager) layoutManager).findLastVisibleItemPosition();
                    break;
                case GRID_LAYOUT:
                    mLastVisibleItemPosition = ((GridLayoutManager) layoutManager).findLastVisibleItemPosition();
                    break;
                case STAGGERED_GRID_LAYOUT:
                    StaggeredGridLayoutManager staggeredGridLayoutManager = (StaggeredGridLayoutManager) layoutManager;
                    if (mLastPostions == null) {
                        mLastPostions = new int[staggeredGridLayoutManager.getSpanCount()];
                    }
                    staggeredGridLayoutManager.findLastVisibleItemPositions(mLastPostions);
                    mLastVisibleItemPosition = findMax(mLastPostions);
                    break;
                default:
                    break;
            }
    
        }
    
        @Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
    
            RecyclerView.LayoutManager layoutManager = recyclerView.getLayoutManager();
    
            //RecycleView 显示的条目数
            int visibleCount = layoutManager.getChildCount();
    
            //显示数据总数
            int totalCount = layoutManager.getItemCount();
    
    
            // 四个条件，分别是是否有数据，状态是否是滑动停止状态，显示的最大条目是否大于整个数据（注意偏移量），是否正在加载数据
            if(visibleCount>0
                    &&newState==RecyclerView.SCROLL_STATE_IDLE
                    &&mLastVisibleItemPosition>=totalCount-1
                    &&!isLoadData){
                //可以加载数据
              if(mListener!=null){
                  isLoadData = true;
                  mListener.loadMore();
              }
            }
    
        }
    
    
        /** * 当是瀑布流时，获取到的是每一个瀑布最下方显示的条目，通过条目进行对比 */
        private int findMax(int[] lastPositions) {
            int max = lastPositions[0];
            for (int value : lastPositions) {
                if (value > max) {
                    max = value;
                }
            }
            return max;
        }
    
    
        public void setLoadDataStatus(boolean isLoadData){
            this.isLoadData = isLoadData;
        }
    
        @Override
        public void onRefresh() {
            //刷新数据的方法
            if(mListener!=null){
                isLoadData = true;
                mListener.refresh();
            }
    
        }
    
        /** * 数据加载接口回调 */
        interface OnRecycleRefreshListener{
            void refresh();
            void loadMore();
        }
    }

最后看一下main的代码

/** * 使用原生的SwipeRefreshLayout和代码判断 * 实现RecyclewView 的刷新和加载更多 * * Created by Alex_MaHao on 2016/5/10. */
    public class SwipeRefreshActivity extends AppCompatActivity implements LoadDataScrollController.OnRecycleRefreshListener { 
    
    
        private SwipeRefreshLayout mSwipeRefresh;
    
        private RecyclerView mRecycle;
    
        private HomeAdapter mAdapter;
    
        private LoadDataScrollController mController;
    
    
        private ProgressDialog pd;
    
        @Override
        protected void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
    
            setContentView(R.layout.activity_recycle_swiperefresh);
    
            mRecycle = ((RecyclerView) findViewById(R.id.swipe_target));
    
            mSwipeRefresh = ((SwipeRefreshLayout) findViewById(R.id.swipe_refresh));
    
            mSwipeRefresh.setColorSchemeColors(Color.RED,Color.GREEN,Color.BLUE);
    
            /** * 创建控制器，同时使当前activity实现数据监听回调接口 */
            mController = new LoadDataScrollController(this);
    
    
    
            mAdapter = new HomeAdapter();
    
            //设置垂直的线性布局管理器，Orientation --> VERTICAL:垂直 HORIZONTAL:水平
            LinearLayoutManager layoutManager = new LinearLayoutManager(this);
            layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
    
            //StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL);
    
            //添加分割线
            mRecycle.addItemDecoration(new DividerItemDecoration(getApplicationContext(), DividerItemDecoration.VERTICAL_LIST));
    
    
            mRecycle.setLayoutManager(layoutManager);
    
            mRecycle.setItemAnimator(new DefaultItemAnimator());
    
            mRecycle.setAdapter(mAdapter);
    
            mAdapter.refresh();
    
            /** * 设置监听 */
            mRecycle.addOnScrollListener(mController);
    
            mSwipeRefresh.setOnRefreshListener(mController);
    
        }
    
        @Override
        public void refresh() {
            //刷新的接口调
            mSwipeRefresh.postDelayed(new Runnable() {
                @Override
                public void run() {
                    mAdapter.refresh();
                    mSwipeRefresh.setRefreshing(false);
                    mController.setLoadDataStatus(false);
                }
            },2000);
        }
    
        @Override
        public void loadMore() {
            //加载更多的接口回调
            pd = new ProgressDialog(this);
            pd.show();
            mSwipeRefresh.postDelayed(new Runnable() {
                @Override
                public void run() {
                    mAdapter.add();
                    //设置数据加载结束的监听状态
                    mController.setLoadDataStatus(false);
                    pd.dismiss();
                }
            },2000);
        }
    }

贴个效果图

![这里写图片描述][20160512145720618]

### **`SwipeToLoadLayout`实现上拉加载和下拉刷新** ###

该刷新控件的方式类似于`Ultra-pull-to-refresh`的使用方式。

如下方式添加该库：

repositories {
            maven { url "https://jitpack.io" }
               }
    
     compile 'com.github.Aspsine:SwipeToLoadLayout:1.0.3'

首先我们需要自定义一个头视图和底部视图，头部试图和底部试图的用法相同，所以我们先定义一个头部视图类：

/** * 基础的refreshHeadView */
    public class RefreshHeaderView extends TextView implements SwipeRefreshTrigger, SwipeTrigger { 
    
        public RefreshHeaderView(Context context) {
            super(context);
        }
    
        public RefreshHeaderView(Context context, AttributeSet attrs) {
            super(context, attrs);
        }
    
        public RefreshHeaderView(Context context, AttributeSet attrs, int defStyleAttr) {
            super(context, attrs, defStyleAttr);
        }
    
        @TargetApi(Build.VERSION_CODES.LOLLIPOP)
        public RefreshHeaderView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {
            super(context, attrs, defStyleAttr, defStyleRes);
        }
    
        @Override
        public void onRefresh() {
            //下拉到一定位置松开之后，调用此方法
            setText("refresh");
    
            Log.i("info","onRefresh");
        }
    
        @Override
        public void onPrepare() {
    
            //下拉之前调用此方法
            Log.i("info","onPrepare");
        }
    
        @Override
        public void onMove(int yScrolled, boolean isComplete, boolean automatic) {
            if (!isComplete) {
                //当前Y轴偏移量大于控件高度时，标识下拉到界限，显示“松开已刷新”
                if (yScrolled >= getHeight()) {
    
                } else {
                    //未达到偏移量
    
                }
            } 
            Log.i("info","onMove");
        }
    
        @Override
        public void onRelease() {
            //达到一定滑动距离，松开刷新时调用
            setText("onRelease");
            Log.i("info","onRelease");
        }
    
        @Override
        public void onComplete() {
            //加载完成之后调用此方法
            setText("complete");
            Log.i("info","onComplete");
        }
    
        @Override
        public void onReset() {
            //重置
            setText("onReset");
            Log.i("info","onReset");
        }
    }

其需要实现接口`SwipeRefreshTrigger`和`SwipeTrigger`。

而底部需要实现`SwipeTrigger`和`SwipeLoadMoreTrigger`。

布局文件中如下使用

查找控件，设置监听

swipeToLoadLayout.setOnRefreshListener(this);
            swipeToLoadLayout.setOnLoadMoreListener(this);

在我们之前的代码中，加入了log信息，我们可以看一下log信息。…代表多次`onMove()`方法多次调用。

05-10 10:30:34.396 23814-23814/com.mahao.alex.systemwidgetdemo I/info: onPrepare
    05-10 10:30:34.536 23814-23814/com.mahao.alex.systemwidgetdemo I/info: onMove
    ..........................................................................
    05-10 10:30:34.886 23814-23814/com.mahao.alex.systemwidgetdemo I/info: onMove
    05-10 10:30:34.896 23814-23814/com.mahao.alex.systemwidgetdemo I/info: onRelease
    05-10 10:30:34.906 23814-23814/com.mahao.alex.systemwidgetdemo I/info: onMove
    ..........................................................................
    05-10 10:30:35.086 23814-23814/com.mahao.alex.systemwidgetdemo I/info: onMove
    05-10 10:30:35.106 23814-23814/com.mahao.alex.systemwidgetdemo I/info: onRefresh
    05-10 10:30:37.116 23814-23814/com.mahao.alex.systemwidgetdemo I/info: onComplete
    05-10 10:30:37.416 23814-23814/com.mahao.alex.systemwidgetdemo I/info: onMove
    ..........................................................................
    05-10 10:30:37.516 23814-23814/com.mahao.alex.systemwidgetdemo I/info: onMove
    05-10 10:30:37.916 23814-23814/com.mahao.alex.systemwidgetdemo I/info: onReset

首先会调用`onPrepare()方法`，`onMove()`方法会一直调用,只要视图有偏移，就会调用。下拉到一定距离之后，松开调用`onRelaease()`,回归到刷新位置时回调`onRefresh()`，加载完成调用`onComplete()`，视图开始缩小，最后隐藏之后调用`onReset()`

根据需求自定义视图，

![这里写图片描述][20160512145747071]

定义我们的椭圆,使用自定义控件

/** * CircleView 圆盘控件，可以旋转 * Created by Alex_MaHao on 2016/5/10. */
    public class CircleView extends View { 
    
        /** * 控件的半径 */
        private int mRadius;
    
        /** * 绘制弧形的画笔 */
        private Paint mArcPaint;
    
        /** * 绘制弧形的区域 */
        private RectF mRange;
    
    
        private int[] colors = {Color.RED, Color.BLUE, Color.YELLOW, Color.GREEN};
    
        public CircleView(Context context) {
            this(context, null, 0);
        }
    
        public CircleView(Context context, AttributeSet attrs) {
            this(context, attrs, 0);
        }
    
        public CircleView(Context context, AttributeSet attrs, int defStyleAttr) {
            super(context, attrs, defStyleAttr);
    
            init();
        }
    
        private void init() {
            mArcPaint = new Paint();
            mArcPaint.setAntiAlias(true);
            mArcPaint.setDither(true);
            mArcPaint.setStyle(Paint.Style.FILL);
        }
    
        @Override
        protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
            super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    
            int width = 0;
            int height = 0;
    
            int widthSize = MeasureSpec.getSize(widthMeasureSpec);
            int widthMode = MeasureSpec.getMode(widthMeasureSpec);
    
            int heightSize = MeasureSpec.getSize(heightMeasureSpec);
            int heightMode = MeasureSpec.getMode(heightMeasureSpec);
    
    
            if (widthMode == MeasureSpec.EXACTLY) {
                width = widthSize;
            } else {
                width = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 45, getResources().getDisplayMetrics());
            }
    
            if (heightMode == MeasureSpec.EXACTLY) {
                height = heightSize;
            } else {
                height = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 45, getResources().getDisplayMetrics());
            }
    
            //获取半径
            mRadius = Math.min(width, height) / 2;
            /** * 设置宽高为固定值 */
            setMeasuredDimension(mRadius * 2, mRadius * 2);
    
             mRange = new RectF(0, 0, mRadius * 2, mRadius * 2);
        }
    
    
        @Override
        protected void onDraw(Canvas canvas) {
    
            float degree = 360/colors.length/2f;
    
            for (int i = 0; i < 8; i++) {
                mArcPaint.setColor(colors[i%4]);
                canvas.drawArc(mRange,-90f+degree*i,degree,true,mArcPaint);
            }
    
        }
    }

绘制头部刷新试图

**
     * 自定义的下拉刷新控件 头部
     * Created by Alex_MaHao on 2016/5/10.
     */
    public class CircleRefreshHeaderView extends RelativeLayout implements SwipeTrigger, SwipeRefreshTrigger { 
    
        CircleView mCircleView;
    
        TextView mDescText;
    
        private ObjectAnimator anim;
    
        private boolean isRelease;
    
        public CircleRefreshHeaderView(Context context) {
            this(context, null, 0);
        }
    
        public CircleRefreshHeaderView(Context context, AttributeSet attrs) {
            this(context, attrs, 0);
        }
    
        public CircleRefreshHeaderView(Context context, AttributeSet attrs, int defStyleAttr) {
            super(context, attrs, defStyleAttr);
    
            initView();
        }
    
        /** * 初始化布局 */
        private void initView() {
    
            int circlewidth = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 30, getResources().getDisplayMetrics());
    
            mCircleView = new CircleView(getContext());
    
            LinearLayout.LayoutParams circleParams = new LinearLayout.LayoutParams(circlewidth,circlewidth);
    
            mCircleView.setLayoutParams(circleParams);
    
            mDescText = new TextView(getContext());
    
            LinearLayout.LayoutParams descParams = new LinearLayout.LayoutParams(circlewidth*3, ViewGroup.LayoutParams.WRAP_CONTENT);
    
            descParams.gravity = Gravity.CENTER;
            descParams.setMargins(circlewidth/2,0,0,0);
            mDescText.setLayoutParams(descParams);
            mDescText.setTextSize(12);
            mDescText.setTextColor(Color.GRAY);
            mDescText.setText("下拉刷新");
    
            //添加线性的父布局
            LinearLayout ll = new LinearLayout(getContext());
            RelativeLayout.LayoutParams llParams = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
            llParams.addRule(CENTER_IN_PARENT);
            ll.setLayoutParams(llParams);
            ll.setPadding(10,10,10,10);
    
            ll.addView(mCircleView);
            ll.addView(mDescText);
    
            addView(ll);
        }
    
        @Override
        public void onRefresh() {
    
            //开始刷新，启动动画
            anim = ObjectAnimator.ofFloat(mCircleView, "rotation", mCircleView.getRotation(), mCircleView.getRotation()+360f)
                    .setDuration(500);
            anim.setRepeatCount(ValueAnimator.INFINITE);
            anim.setRepeatMode(ValueAnimator.RESTART);
            anim.start();
    
            mDescText.setText("正在加载数据");
        }
    
        @Override
        public void onPrepare() {
            isRelease = false;
        }
    
        @Override
        public void onMove(int yScroll, boolean isComplete, boolean b1) {
            if (!isComplete) {
                if (yScroll < getHeight()) {
                    mDescText.setText("下拉刷新");
                } else {
                    mDescText.setText("松开刷新更多");
                }
    
                //如果是仍在下拉状态，则圆环跟随滑动进行滚动
                if (!isRelease)
                    mCircleView.setRotation(((float) yScroll) / getHeight() * 360f);
            }
    
    
        }
    
        @Override
        public void onRelease() {
            isRelease = true;
        }
    
        @Override
        public void onComplete() {
            anim.cancel();
            mDescText.setText("加载完成");
        }
    
        @Override
        public void onReset() {
            //重置时，将动画置为初始状态
            mCircleView.setRotation(0f);
        }
    }

布局文件

public class SwipeToLayoutActivity extends AppCompatActivity implements OnRefreshListener, OnLoadMoreListener { 
    
    
    
        private RecyclerView mRecycleView;
    
        SwipeToLoadLayout swipeToLoadLayout;
    
        private HomeAdapter adapter;
    
    
        @Override
        protected void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_recycle_swipetolayout);
    
    
            swipeToLoadLayout = ((SwipeToLoadLayout) findViewById(R.id.swipeToLoadLayout));
    
    
            mRecycleView = ((RecyclerView) findViewById(R.id.swipe_target));
    
    
            adapter = new HomeAdapter();
    
            //设置垂直的线性布局管理器，Orientation --> VERTICAL:垂直 HORIZONTAL:水平
            LinearLayoutManager layoutManager = new LinearLayoutManager(this);
            layoutManager.setOrientation(LinearLayoutManager.VERTICAL);
    
    // StaggeredGridLayoutManager layoutManager = new StaggeredGridLayoutManager(2,StaggeredGridLayoutManager.VERTICAL);
    
            //添加分割线
            mRecycleView.addItemDecoration(new DividerItemDecoration(getApplicationContext(), DividerItemDecoration.VERTICAL_LIST));
    
            mRecycleView.setLayoutManager(layoutManager);
    
            mRecycleView.setItemAnimator(new DefaultItemAnimator());
    
            mRecycleView.setAdapter(adapter);
    
            adapter.refresh();
    
            /** * 设置下拉刷新和上拉加载监听 */
            swipeToLoadLayout.setOnRefreshListener(this);
            swipeToLoadLayout.setOnLoadMoreListener(this);
    
        }
    
    
    
    
        @Override
        public void onRefresh() {
            swipeToLoadLayout.postDelayed(new Runnable() {
                @Override
                public void run() {
                    adapter.refresh();
                    swipeToLoadLayout.setRefreshing(false);
                }
            },2000);
        }
    
        @Override
        public void onLoadMore() {
            swipeToLoadLayout.postDelayed(new Runnable() {
                @Override
                public void run() {
    
                    adapter.add();
                    swipeToLoadLayout.setLoadingMore(false);
                }
            },2000);
        }
    }

OK。肯定有小伙伴使用该框架时一直报错，为什么，看框架的源码，有如下一段

this.mHeaderView = this.findViewById(id.swipe_refresh_header);
     this.mTargetView = this.findViewById(id.swipe_target);
     this.mFooterView = this.findViewById(id.swipe_load_more_footer);

可以看出，作者是根据固定的id值获取的，所以在我们的布局文件中，必须使用固定的三个id。

如有需求，可移步[我的github][github]获取源码。源码在systemwidgetdemo中。

[20160512145720618]: /images/20220722/c43ed5bdbd4f47af9e6dc3fa0e1ed557.png
[20160512145747071]: /images/20220722/4c726ab3e0124301a8a6426109821962.png
[github]: https://github.com/AlexSmille/alex_mahao_sample

RecyclerView 下拉刷新和上拉加载

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