RecyclerView下拉刷新实现

来源：互联网发布：高级软件测试面试linux 编辑：程序博客网时间：2024/04/29 14:53

RecyclerView下拉刷新实现

实现分析：
1.通过topMargin实现
2.通过改变头部高度实现
这里介绍的使用第二种方法实现：通过滑动监听动态的改变头部高度实现。
这里写图片描述
1.初始化相关参数

protected void onLayout(boolean changed, int l, int t, int r, int b) {        super.onLayout(changed, l, t, r, b);        if (!load) {            //滑动最大高度            scroll_height = getHeight() / 3;            //头部的高度            viewHolder_height = getHeight() / 5;            //得到头部            viewHolder = (ViewGroup) getChildAt(0);            //头部布局参数            params = (ViewGroup.LayoutParams) viewHolder.getLayoutParams();            params.height = 0;            viewHolder.setLayoutParams(params);            //头部 刷新文字            textView = (TextView) viewHolder.findViewById(R.id.textView);            textView.setText("测试。。。。");            //得到下拉刷新控件            rv = (RecyclerView) getChildAt(1);            rv.setOnTouchListener(this);            load = true;        }    }

2.RecyclerView滑动监听

/*        处理RecyclerView触摸事件；     */    @Override    public boolean onTouch(View v, MotionEvent event) {        if (current_Status == START_REFRESHING) {            //正在刷新时屏蔽状态            return true;        }        startDown();        if (start_Drop_Down) {            switch (event.getAction()) {                case MotionEvent.ACTION_DOWN:                    down_Y = event.getRawY();                    break;                case MotionEvent.ACTION_MOVE:                    float move_Y = event.getRawY();                    //判断是否下拉                    float difference = move_Y - down_Y;                    //difference>0：下滑，difference<=0表示上滑                    if (difference <= 0) {                        params.height = 0;                        viewHolder.setLayoutParams(params);                        return false;                    }                    //不是正在刷新                    if (current_Status != START_REFRESHING) {                        //达到头部一半就表示达到刷新条件                        if (params.height >= viewHolder_height / 2) {                            //达到下拉刷新要求的状态                            current_Status = STATE_REFRESHING;                            //更新文本                            textView.setText("放手刷新。。。");                        } else {                            //刷新结束状态（包括刷新完和未达到刷新要求）                            current_Status = STATE_DROP_DOWN;                            //更新文本                            textView.setText("下拉刷新。。。");                        }                        params.height = (int) (difference / 3);                        if (params.height >= scroll_height) {                            params.height = scroll_height;                        }                        viewHolder.setLayoutParams(params);                    }                    break;                case MotionEvent.ACTION_UP:                    if (params.height >= viewHolder_height / 2) {                        current_Status = STATE_REFRESHING;                    } else {                        current_Status = STATE_DROP_DOWN;                    }                    if (current_Status == STATE_REFRESHING) {                        //执行下拉刷新                        new HeadOperation().execute();                    } else if (current_Status == STATE_DROP_DOWN) {                        current_Status = END_REFRESHING;                        //执行下拉刷新结束后的操作                        new HeadOperation().execute();                    }                    break;            }            if (current_Status == STATE_REFRESHING || current_Status == STATE_DROP_DOWN) {                return true;            }        }        return false;    }

3、头部的隐藏和显示操作

//头部的操作：隐藏，显示    class HeadOperation extends AsyncTask<Void, Integer, Integer> {        @Override        protected Integer doInBackground(Void... param) {            int height = params.height;            //显示头部            if (current_Status == STATE_REFRESHING) {                while (true) {//让头部全部露出来                    height = height + 50;                    if (height >= viewHolder_height) {                        height = viewHolder_height;                        break;                    }                    publishProgress(height);                    SystemClock.sleep(10);                }                //改变状态：正在刷新                current_Status = START_REFRESHING;                //改变UI更新状态                update_ui = true;                publishProgress(height);                //刷新中执行的操作                if (listener != null) {                    listener.onRefreshing();                } else {                    //默认刷新时间                    SystemClock.sleep(5000);                    //改变状态：结束刷新                    while (true) {                        height = height - 70;                        if (height <= 0) {                            height = 0;                            break;                        }                        publishProgress(height);                        SystemClock.sleep(10);                    }                    current_Status = END_REFRESHING;                    publishProgress(height);                    return 1;                }            } else if (current_Status == END_REFRESHING) {//隐藏头部                while (true) {                    height = height - 70;                    if (height <= 0) {                        height = 0;                        break;                    }                    publishProgress(height);                    SystemClock.sleep(10);                }                publishProgress(height);                return 1;            }            return -1;        }        @Override        protected void onProgressUpdate(Integer... values) {            params.height = values[0];            viewHolder.setLayoutParams(params);            if (current_Status == START_REFRESHING) {                if (textView != null)                    textView.setText("正在刷新。。。。");            }        }        @Override        protected void onPostExecute(Integer aVoid) {            if (current_Status == END_REFRESHING) {                if (listener != null && update_ui) {                    //刷新完成后的操作，如提示信息什么的                    listener.onEndRefreshing();                    update_ui = false;                }            }        }    }

4、对外的刷新的接口

 //实现刷新监听的方法    public void setOnRefreshListener(OnRefreshListener listener) {        this.listener = listener;    }    //刷新的监听    public interface OnRefreshListener {        //正在刷新：子线程        void onRefreshing();        //停止刷新:主线程        void onEndRefreshing();    }    //提供一个外部停止刷新的方法    public void setEndRefreshing() {        current_Status = END_REFRESHING;        new HeadOperation().execute();    }

5、Activity中

 recyclerView_Refresh.setOnRefreshListener(new RecyclerView_Refresh.OnRefreshListener() {            @Override            public void onRefreshing() {//正在刷新                SystemClock.sleep(3000);                //停止刷新                recyclerView_Refresh.setEndRefreshing();            }            @Override            public void onEndRefreshing() {//结束刷新                Toast.makeText(MainActivity.this, "刷新完成", Toast.LENGTH_SHORT).show();            }        });

需要不同头部动画的自行修改，已做注释；
下载地址

0 0