一.方案制定

二.设计

• 创建RecyclerView.Adapter

• 需要在ViewHodler里面添加一个计时器组件，使用Handler就足够满足需求。我们需要在进入屏幕时，开启倒计时，在滑出屏幕后，停止计时器来节省CPU资源。

• 需要注意的是：进入屏幕会触发Recycler.Adapter的onBindViewHolder()函数，滑出屏幕会触发onViewRecycled()。

  有以上准备，我们就可以进入撸码环节了。

三.编码

主要工作都在与RecyclerView.Holder中。

public class ChatItemHolder extends BaseViewHolder {
        //用来判断是倒计时还是正计时
        public boolean isCountdown;
        //这个是我的业务逻辑,触发正反计时就看是否反馈信息
        public boolean isFeedback;
		//倒计时/正计时时间
        public long delay;
        //倒计时任务
        private Runnable countdownRunnable = new Runnable() {
            @Override
            public void run() {
                delay -= 1000;
                if (delay == 0) {
                    isCountdown = false;
                } else {
                    isCountdown = true;
                }
                updateTimerState();
            }
        };
        //正计时任务
        private Runnable positiveTimeRunnable = new Runnable() {
            @Override
            public void run() {
                delay += 1000;
                updateTimerState();
            }
        };
        //启动倒计时
        public void startCountdown() {
            timerHandler.postDelayed(countdownRunnable, 1000);
        }
        //结束倒计时
        public void endCountDown() {
            timerHandler.removeCallbacks(countdownRunnable);
        }
        //启动正计时
        public void startPositiveTime() {
            timerHandler.postDelayed(positiveTimeRunnable, 1000);
        }
        //结束正计时
        public void endPositiveTime() {
            timerHandler.removeCallbacks(positiveTimeRunnable);
        }

        //更新UI
        public void updateTimerState() {
            if (isFeedback) {  //如果已反馈关闭计时器
                endCountDown();
                endPositiveTime();
            } else {//进行计时并显示的格式为1天1时1分1秒
                long time = delay / 1000; //变成秒
                long temp = time % (24 * 3600);
                long day = time / (24 * 3600); //天
                long hour = temp / 3600; //小时
                long minute = temp % 3600 / 60; //分钟
                long second = temp % 60; //秒
                if (isCountdown) {
                    if (day == 0) {
                        setText(R.id.command_feedback_state, "反馈剩余时间:" + hour + "时" + minute + "分" + second + "秒");
                    } else {
                        setText(R.id.command_feedback_state, "反馈剩余时间:" + day + "天" + hour + "时" + minute + "分" + second + "秒");
                    }
                    setTextColor(R.id.command_feedback_state, Color.parseColor("#1890ff"));
                    setBackgroundResource(R.id.command_feedback_state,
                            R.drawable.shape_solid_null_stroke_1890ff_corner);
                    startCountdown();
                } else {
                    if (day == 0) {
                        setText(R.id.command_feedback_state, "超时时间:" + hour + "时" + minute + "分" + second + "秒");
                    } else {
                        setText(R.id.command_feedback_state, "超时时间:" + day + "天" + hour + "时" + minute + "分" + second + "秒");
                    }
                    setTextColor(R.id.command_feedback_state, Color.parseColor("#ff001b"));
                    setBackgroundResource(R.id.command_feedback_state,
                            R.drawable.shape_solid_null_stroke_ff001b);
                    startPositiveTime();
                }
            }
        }


        public void display(CommandChatBean.Data.Records record) {
            long time = DateUtil.ifsUtcStringToLocalForLong(record.getCzsx());
            delay = time - System.currentTimeMillis();
            isCountdown = delay > 0;
            isFeedback = !TextUtils.isEmpty(record.getCcFksj());
            delay = Math.abs(delay);
            updateTimerState();
        }

        public void onRecycled() {
            endCountDown();
            endPositiveTime();
        }

        public ChatItemHolder(View view) {
            super(view);
        }
    }
    //recyclerView内写入的方法:该方法是为了关闭页面后可以移除所有计时任务
    public void recycleTime() {
        if (timerHandler != null) {
            timerHandler.removeCallbacksAndMessages(null);
            timerHandler = null;
        }
    }

我这里使用的是封装好的AdapterHelper,可以直接集成RecyclerView.ViewHolder进行获取控件在进行更新。替换我下面的代码逻辑：

  setText(R.id.command_feedback_state, "超时时间:" + hour + "时" + minute + "分" + second + "秒");
                    } else {
                        setText(R.id.command_feedback_state, "超时时间:" + day + "天" + hour + "时" + minute + "分" + second + "秒");
                    }
                    setTextColor(R.id.command_feedback_state, Color.parseColor("#ff001b"));
                    setBackgroundResource(R.id.command_feedback_state,
                            R.drawable.shape_solid_null_stroke_ff001b);

RecyclerAdapter的onBindViewHolder(ChatItemHolder viewHolder,int position)中使用方式：

···
if (!TextUtils.isEmpty(records.getCzsx()) && TextUtils.isEmpty(records.getCcFksj())) {
                baseViewHolder.setVisible(R.id.command_feedback_state, true);
                baseViewHolder.display(records);
            }
            if (TextUtils.isEmpty(records.getCzsx())) {
                baseViewHolder.setVisible(R.id.command_feedback_state, false);
            }
            if (!TextUtils.isEmpty(records.getCcFksj())) {
                baseViewHolder.setVisible(R.id.command_feedback_state, true);
                baseViewHolder.setText(R.id.command_feedback_state,
                        "已反馈：" + DateUtil.ifsUtcStringToLocalForString(records.getCcFksj()));
                baseViewHolder.setTextColor(R.id.command_feedback_state, Color.parseColor("#4BBA55"));
                baseViewHolder.setBackgroundResource(R.id.command_feedback_state,
                        R.drawable.shape_solid_null_stroke_4bba55);
            }
···            

今天就分享到这里了，祝小伙伴新年快乐！