android实现按钮获取焦点延迟加载

看到京东电视app的按钮获取焦点后才加载数据，之前网上没找到好的说法，所以自己实现了记录一下以便后续学习。

主要是按钮获取焦点以后，初始化一个定时器Timer延迟500ms加载数据，如果失去焦点，取消这个定时器就ok了。其实原理很简单，下面是我实现的一个效果。

package com.longmaster.iptv.health.DoctorP2P.mode;

import android.content.Context;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;

import com.longmaster.iptv.health.R;
import com.longmaster.iptv.health.common.Constants;
import com.longmaster.iptv.health.widget.MagicTextView.MagicTextView;

import org.VideoWebInterface.DepartmentParam;

import java.util.ArrayList;
import java.util.List;
import java.util.Timer;
import java.util.TimerTask;

import cn.longmaster.lmkit.event.MessageProxy;
import cn.longmaster.lmkit.utils.AppLogger;

/**
 * Created by yzq on 2017/5/8
 */

public class ButtonAdapter extends RecyclerView.Adapter<ButtonAdapter.MyViewHolder> {
  private List<DepartmentParam> mDepartmentList = new ArrayList<>();
  private LayoutInflater mInflater;
  private Context mContext;
  private boolean mIsLostFocus = false;
  private LinearLayoutManager mLinearLayoutManager;
  private RecyclerView mRecyclerView;
  private TimerTask mTimerTask;
  private Timer mTimer;
  private boolean isLoadData = true;

  public ButtonAdapter(Context context) {
    super();
    this.mContext = context;
    mInflater = LayoutInflater.from(context);
  }

  public void setLayoutManager(LinearLayoutManager linearLayoutManager, RecyclerView re) {
    mLinearLayoutManager = linearLayoutManager;
    mRecyclerView = re;
  }

  public void setDepartmentList(List list) {
    mDepartmentList = list;
  }

  public void setFocus(boolean isFocus) {
    mIsLostFocus = isFocus;
  }

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

  public void clear() {
    mDepartmentList.clear();
  }

  @Override
  public int getItemCount() {
    return mDepartmentList.size();
  }

  @Override
  public void onBindViewHolder(final MyViewHolder holder, final int position) {
    holder.tv.setText(mDepartmentList.get(position).GetDeptName());
    holder.tv.setFocusable(true);
  }

  @Override
  public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
    View view = mInflater.inflate(R.layout.list_class_item, parent, false);
    MyViewHolder holder = new MyViewHolder(view);
    return holder;
  }

  class MyViewHolder extends RecyclerView.ViewHolder {

    MagicTextView tv;
    RelativeLayout mOuterBgRL;

    public MyViewHolder(final View view) {
      super(view);
      RecyclerView.LayoutParams param = (RecyclerView.LayoutParams) itemView.getLayoutParams();
      param.height = LinearLayout.LayoutParams.WRAP_CONTENT;
      param.width = LinearLayout.LayoutParams.MATCH_PARENT;
      itemView.setVisibility(View.VISIBLE);

      tv = (MagicTextView) view.findViewById(R.id.class_name);
      mOuterBgRL = (RelativeLayout) view.findViewById(R.id.rl_class_outer_bg);

      tv.setOnFocusChangeListener(new View.OnFocusChangeListener() {
        @Override
        public void onFocusChange(View v, boolean hasFocus) {
          if (hasFocus) {
            mOuterBgRL.setBackgroundResource(R.drawable.p2p_select);

            if (isLoadData) {
              mTimerTask = new TimerTask() {
                @Override
                public void run() {
                  int iPosition = getAdapterPosition();
                  DepartmentParam departmentParam = mDepartmentList.get(iPosition);
                  MessageProxy.sendMessage(Constants.Message.P2P_SELECTION_DOCTOR_CLASS, iPosition, departmentParam);
                }
              };
              mTimer = new Timer();
              mTimer.schedule(mTimerTask, 500);
            }

          } else {

            clearTimer();

            if (mIsLostFocus) {
              mOuterBgRL.setBackgroundResource(R.drawable.p2p_unselect);
            }

          }
        }
      });
      tv.setOnKeyListener(new View.OnKeyListener() {
        @Override
        public boolean onKey(View v, int keyCode, KeyEvent event) {

          if (event.getAction() == KeyEvent.ACTION_DOWN) {
            int mCurrentSelectPosition = getAdapterPosition();
            int mDepartmentCount = mDepartmentList.size();
            AppLogger.e("mCurrentSelectPosition>>>>>>>>", mCurrentSelectPosition + "----" + mDepartmentCount);
            switch (keyCode) {
              case KeyEvent.KEYCODE_DPAD_LEFT:

                setIsLoadData(true);
                setFocus(true);

                if (mCurrentSelectPosition == (mLinearLayoutManager.findFirstVisibleItemPosition())) {
                  mRecyclerView.smoothScrollBy(-400, 0);
                }

                View view1 = mLinearLayoutManager.findViewByPosition(mCurrentSelectPosition - 1);

                if (view1 != null) {
                  setViewFocus(view1.findViewById(R.id.class_name));
                }

                return true;
              case KeyEvent.KEYCODE_DPAD_RIGHT:

                if (mCurrentSelectPosition == mDepartmentCount - 1) {
                  return true;
                }

                setIsLoadData(true);
                setFocus(true);

                if (mCurrentSelectPosition == (mLinearLayoutManager.findLastVisibleItemPosition())) {
                  mRecyclerView.smoothScrollBy(400, 0);
                }

                View view = mLinearLayoutManager.findViewByPosition(mCurrentSelectPosition + 1);

                if (view != null) {
                  setViewFocus(view.findViewById(R.id.class_name));
                }

                return true;

              case KeyEvent.KEYCODE_BACK:
                break;
              case KeyEvent.KEYCODE_DPAD_UP:
                break;
              case KeyEvent.KEYCODE_DPAD_DOWN:
                setFocus(false);
                mOuterBgRL.setBackgroundResource(R.drawable.p2p_key_down);

                break;
            }
          }
          return false;
        }
      });
    }

  }

  public void setViewFocus(View view) {
    view.setFocusable(true);
    view.setFocusableInTouchMode(true);
    view.requestFocus();
    view.requestFocusFromTouch();
  }

  private void clearTimer() {
    if (mTimer != null) {
      mTimer.cancel();
    }
    if (mTimerTask != null) {
      mTimerTask.cancel();
    }

  }

}

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