史上最简单的Recycleview自定义下拉刷新

来源：互联网发布：java老版手机游戏编辑：程序博客网时间：2024/06/06 00:54

public class MyRecycleview extends RelativeLayout implements View.OnTouchListener {    private int touchSlop;//判断为滚动的最小距离    private MarginLayoutParams headparams;//顶部布局管理器    private MarginLayoutParams bottomparams;//底部部布局管理器    private LayoutParams params, bparams;//设置布局摆放位置的容器    private View headview;  //顶部布局文件    private View bottomview;//底部布局文件    private int startTop;//顶部布局初始偏移量    private int startBot;//底部布局初始偏移量    private Boolean once = true; //设置onLayout执行一次的标志位    private boolean cantopull = true;//判断当前是否可以执行下拉操作    private boolean cantopullUp = false;//判断当前是否可以执行上拉操作    private Boolean isMoving = false;//标志是否正在下拉；    private RecyclerView mrecyclerView;    private LinearLayoutManager mlinearlayoutmanager;    private int Ydwon, Ymove, distance;//记录手指触摸及移动时相对应的Y的坐标值    private int currentMarg;    //头部布局当前的偏移量    private Boolean canRefresh = false;  //标志是否下拉到了刷新的位置    private RefreshListener listener;  //监听回调的内部接口    private int status = 0;//当前状态    private TextView head_text, bottom_text;//顶部和底部的文字    public MyRecycleview(Context context) {        this(context, null);    }    public MyRecycleview(Context context, AttributeSet attrs) {        super(context, attrs);        touchSlop = ViewConfiguration.get(context).getScaledTouchSlop();        //拿到顶部布局        headview = LayoutInflater.from(context).inflate(R.layout.myrecycleview_headview, null, false);        head_text = (TextView) headview.findViewById(R.id.pullText);        //设置为屏幕水平居中        params = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);        params.addRule(RelativeLayout.CENTER_HORIZONTAL, TRUE);        addView(headview, params);        headparams = (MarginLayoutParams) headview.getLayoutParams();        bottomview = LayoutInflater.from(context).inflate(R.layout.mrecycleview_bottom, null, false);        bottom_text = (TextView) bottomview.findViewById(R.id.bottom_text);        bparams = new LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);        //设置为居父类布局的底部        bparams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM, TRUE);        addView(bottomview, bparams);        bottomparams = (MarginLayoutParams) bottomview.getLayoutParams();    }

    @Override    protected void onLayout(boolean changed, int l, int t, int r, int b) {        super.onLayout(changed, l, t, r, b);        if (changed && once) {            once = false;            startTop = headview.getHeight();            headparams.topMargin = -startTop;            headview.setLayoutParams(headparams);            startBot = bottomview.getHeight();            bottomparams.bottomMargin = -startBot;            bottomview.setLayoutParams(bottomparams);            mrecyclerView = (RecyclerView) getChildAt(2);            mrecyclerView.setOnTouchListener(this);        }    }   //对recycleview进行事件监听    @Override    public boolean onTouch(View view, MotionEvent motionEvent) {        //判断是否可进行下滑        isenableToPull();        if (cantopull) {            //如果可以下拉            switch (motionEvent.getAction()) {                case MotionEvent.ACTION_DOWN:                    Ydwon = (int) motionEvent.getRawY();                    break;                case MotionEvent.ACTION_MOVE:                    Ymove = (int) motionEvent.getRawY();                    distance = Ymove - Ydwon;                    if (distance > 20 && status != 1) {                        //满足下拉条件                        currentMarg = -startTop + distance / 3;
                        status = 2;//正在下拉状态
                  //如果是处于下拉，或者下拉到了最底部，则需要刷新下拉头的文字信息
                      head_text.setText("下拉加载更多");
                        if (currentMarg > startTop) {                            canRefresh = true;                            currentMarg = startTop;                            status = 4;//松开即可刷新
                           head_text.setText("松开刷新");

                        }                      
                       //正在滑动，不允许判断是否到达顶部                        isMoving = true;                        headparams.topMargin = currentMarg;                        headview.setLayoutParams(headparams);                    } else {                        return false;                    }                    break;                case MotionEvent.ACTION_UP:                    if (canRefresh) {//                        顶部布局回弹至上方                        new ToprefreshTask().execute(-30);                    } else {                        //隐藏顶部布局                        new HideTop().execute(-30);                    }                    //判断滑动结束，可以再次判断是否到达顶部                    isMoving = false;//下拉结束                    break;            }                          //这里是底部上拉加载的模块，原理几乎和顶部下拉加载一样，就没过多实现        else if (cantopullUp) {
//可以模仿着下拉刷新实现，只是下拉变成了上拉，我相信你肯定能ok的            switch (motionEvent.getAction()) {                case MotionEvent.ACTION_DOWN:                           break;                case MotionEvent.ACTION_MOVE:                                     break;                case MotionEvent.ACTION_UP:                                      break;            }        }        return false;    }    //判断是否滑到顶部，或者底部    private void isenableToPull() {        mrecyclerView.addOnScrollListener(new RecyclerView.OnScrollListener() {            @Override            public void onScrolled(RecyclerView recyclerView, int dx, int dy) {                if (!recyclerView.canScrollVertically(-1)) {                    //滑动到了顶部可以下拉                    cantopull = true;                    cantopullUp = false;                } else if (!recyclerView.canScrollVertically(1)) {                    //滑动到了底部，可以上拉                    cantopull = false;                    cantopullUp = true;                } else {                    /**                     *ismoving是判断当在下拉时，列表滚动到了不是顶部的位置，这时，顶部布局就无法复原了，                     * 这里加个标志位，当手指还在拖拽下拉条时，返回当前是否到达顶部，当手指松开屏幕时，ismoving                     * 变为FALSE，回到初始状态，可以判断是否到达顶部了；                     */                    if (!isMoving) {                        cantopull = false;                        cantopullUp = false;                    }                }            }        });    }
//头部下拉到进行刷新时调用class ToprefreshTask extends AsyncTask<Integer, Integer, Integer> {    @Override    protected Integer doInBackground(Integer... integers) {        int topmarg = headparams.topMargin;        while (true) {            topmarg = topmarg + integers[0];            ;            //当回到顶部时，跳出            if (topmarg <= 0) {                topmarg = 0;                break;            }            publishProgress(topmarg);            try {                Thread.sleep(20);            } catch (InterruptedException e) {                e.printStackTrace();            }        }        publishProgress(0);        status = 1;        if (listener != null) {            listener.Refresh();        }        return null;    }    @Override    protected void onProgressUpdate(Integer... values) {        super.onProgressUpdate(values);        headparams.topMargin = values[0];        headview.setLayoutParams(headparams);    }}//隐藏头部的布局文件class HideTop extends AsyncTask<Integer, Integer, Integer> {    @Override    protected Integer doInBackground(Integer... integers) {        int topmarg = headparams.topMargin;        while (true) {            topmarg = topmarg + integers[0];            //当回到顶部时，跳出            if (topmarg <= -startTop) {                topmarg = -startTop;                break;            }            publishProgress(topmarg);            try {                Thread.sleep(20);            } catch (InterruptedException e) {                e.printStackTrace();            }        }        publishProgress(-startTop);        return topmarg;    }    @Override    protected void onPostExecute(Integer integer) {        super.onPostExecute(integer);        headparams.topMargin = integer;        headview.setLayoutParams(headparams);        canRefresh = false;    }    @Override    protected void onProgressUpdate(Integer... values) {        super.onProgressUpdate(values);        headparams.topMargin = values[0];        headview.setLayoutParams(headparams);    }}

    //设置外部调用的的方法    public void setRefreshListener(RefreshListener listener) {        this.listener = listener;    }    //设置外部的监听回调接口    public interface RefreshListener {        void Refresh();    }    public void FinishRefresh()    {        new HideTop().execute(-30);        status = 3;//下拉刷新结束状态；    }}
//上边，需要自定义一个顶部布局文件
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:layout_width="wrap_content"    android:layout_height="100dp"  >    <ProgressBar        android:layout_width="wrap_content"        android:layout_height="50dp"        android:layout_toRightOf="@+id/pullText"        android:background="@drawable/head_backview"/>    <TextView        android:layout_centerVertical="true"        android:id="@+id/pullText"        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:text="下拉刷新"/></RelativeLayout>
//最后在主布局里面添加该自定义的view
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical" android:layout_width="match_parent"    android:layout_height="match_parent">    <com.example.test.demo.view.MyRecycleview        android:layout_width="match_parent"        android:layout_height="match_parent"        android:id="@+id/myrecycleview">          <android.support.v7.widget.RecyclerView        android:layout_width="match_parent"        android:layout_height="match_parent"        android:id="@+id/recyclew"/>    </com.example.test.demo.view.MyRecycleview></LinearLayout>
//在代码中进行初始化，和下拉监听

  myRecycleview.setRefreshListener(new MyRecycleview.RefreshListener() {        @Override        public void Refresh() {
//这里用个延时，模拟向服务器请求数据            try {                Thread.sleep(1500);            } catch (InterruptedException e) {                e.printStackTrace();            }            myRecycleview.FinishRefresh();        }    });}

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