親自動(dòng)手編寫Android通用刷新控件

更新時(shí)間：2017年06月02日 09:09:13 作者：貓雨流心

這篇文章主要記錄了親自動(dòng)手編寫Android通用刷新控件的詳細(xì)過程，具有一定的參考價(jià)值，感興趣的小伙伴們可以參考一下

項(xiàng)目中我們經(jīng)常有上拉、下拉刷新的需求，幾乎所有的listView、RecyclerView都會(huì)伴隨著上拉、下拉刷新的需求，如果我們使用一些開源控件，換了控件我們就要更新，現(xiàn)在我們自己擼起袖子寫一個(gè)通用的刷新控件

項(xiàng)目地址：https://git.oschina.net/qiangshen/commentview.git

思路：

寫一個(gè)繼承RelativeLayout的RefreshLayout
添加頭尾控件作為刷新控件
通過事件分發(fā)來進(jìn)行刷新操作
通過動(dòng)畫來控制控件移動(dòng)

目的：讓他的所有子控件都可以使用，哪怕是一個(gè)TextView

public class RefreshLayout extends RelativeLayout {

  /**
   * 滑動(dòng)控件時(shí)拉去的速度比例
   */
  private final int V_REFRESH = 2;
  /**
   * 是否是刷新過程
   * true 是
   * false 不是
   * 為false的時(shí)候才可以進(jìn)行刷新
   */
  private boolean mIsRefreshDuring;
  /**
   * 可以進(jìn)下拉刷新
   */
  private boolean mCanDownPull;
  /**
   * 可以進(jìn)行上拉刷新
   */
  private boolean mCanUpPull;
  /**
   * 判斷觸摸后是否是初次移動(dòng)
   */
  private boolean mIsFirstMove;
  /**
   * y軸呢平移的距離
   */
  private int mDistanceY;
  /**
   * 刷新接口對(duì)象
   */
  private OnRefresh mOnRefresh;
  /**
   * 用于控制事件攔截的變量
   */
  private boolean mCanIntercept;
  private int mTouchSlop;
  private int mDistance;
  private LayoutParams mHeaderParams;
  private View mHeaderView;
  private View mFootView;
  private int mHeaderMaxHeight;
  private int mStartY;
  private LayoutParams mFootParams;
  private int mFootMaxHeight;
  private PullCallBack mCallBack;
  private View mChildView;
  private ObjectAnimator mAnimator;

  public RefreshLayout(Context context) {
    super(context);
    initData();
  }

  public RefreshLayout(Context context, AttributeSet attrs) {
    super(context, attrs);
    initData();
  }

  public RefreshLayout(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
    initData();
  }

  /**
   * 必須讓頭尾控件實(shí)現(xiàn)的接口
   */
  public interface HeadAndFootCallBack {
    //設(shè)置屬性
    void setAttribute();

    //開始刷新
    void startPull();

    //停止刷新
    void stopPull();
  }

  /**
   * 必須讓被拖動(dòng)的控件子類實(shí)現(xiàn)
   */
  public interface PullCallBack {
    boolean canDownPull();

    boolean canUpPull();
  }

  private void initData() {
    //不調(diào)用該方法不能進(jìn)行繪制
    setWillNotDraw(false);
  }

  /**
   * 下拉刷新完成后必須使用該方法
   */
  public void downPullFinish() {
    mAnimator.setFloatValues(mChildView.getTranslationY(), 0);
    mAnimator.start();
    ((HeadAndFootCallBack) mHeaderView).stopPull();
  }

  /**
   * 上拉完成后必須調(diào)用該方法
   */
  public void upPullFinish() {
    mAnimator.setFloatValues(mChildView.getTranslationY(), 0);
    mAnimator.start();
    ((HeadAndFootCallBack) mFootView).stopPull();
  }

  /**
   * 自動(dòng)下拉刷新
   */
  public void autoDownPullForHead() {
    postDelayed(new Runnable() {
      @Override
      public void run() {
        mCanDownPull = true;
        mCanUpPull = false;
        mAnimator.setFloatValues(10, mHeaderMaxHeight);
        mAnimator.start();
        ((HeadAndFootCallBack) mHeaderView).startPull();
        mOnRefresh.onDownPullRefresh();
      }
    }, 500);
  }

  /**
   * 自動(dòng)下拉刷新
   */
  public void autoUpPullForHead() {
    postDelayed(new Runnable() {
      @Override
      public void run() {
        mCanDownPull = false;
        mCanUpPull = true;
        mAnimator.setFloatValues(0, mFootMaxHeight);
        mAnimator.start();
        ((HeadAndFootCallBack) mFootView).startPull();
        mOnRefresh.onUpPullRefresh();
      }
    }, 500);
  }

  @Override
  public boolean onInterceptTouchEvent(MotionEvent ev) {
    return mCanIntercept;
  }

  @Override
  public boolean onTouchEvent(MotionEvent event) {
    return true;
  }

  @Override
  public boolean dispatchTouchEvent(MotionEvent event) {
    Log.e("shen", "mIsRefreshDuring=" + mIsRefreshDuring);
    if (mIsRefreshDuring)
 /**如果正在進(jìn)行刷新將不會(huì)獲取MotionEvent*/ 
 {
      return super.dispatchTouchEvent(event);
    }
    switch (event.getAction()) {
      case MotionEvent.ACTION_DOWN:
        mStartY = (int) event.getY();
        initPull();
        break;
      case MotionEvent.ACTION_MOVE:
        if (event.getPointerCount() == 1) {
          int moveY = (int) event.getY();
          mDistanceY = (moveY - mStartY) / V_REFRESH;
          if (!mIsFirstMove && mDistanceY != 0 && mDistanceY < mTouchSlop) {
            mCanDownPull = mDistanceY > 0;
            mCanUpPull = !mCanDownPull;
            mIsFirstMove = true;
          }
          if (mCanDownPull && mCallBack.canDownPull()) {
            upDataForDownPull();//下拉刷新
            mChildView.setEnabled(false);
            mCanIntercept = true;
          }
          if (mCanUpPull && mCallBack.canUpPull()) {
            upDataForUpPull();//上拉加載
            mChildView.setEnabled(false);
            mCanIntercept = true;
          }
          mStartY = moveY;
        }
        break;
      case MotionEvent.ACTION_UP:
        mIsRefreshDuring = true;
        mIsFirstMove = false;
        if (mHeaderParams.height >= mHeaderMaxHeight)
 /**可以下拉刷新**/ 
 {
          ((HeadAndFootCallBack) mHeaderView).startPull();
          mOnRefresh.onDownPullRefresh();
        } else if (mFootParams.height >= mFootMaxHeight)
 /**可以上拉刷新**/ 
 {
          ((HeadAndFootCallBack) mFootView).startPull();
          mOnRefresh.onUpPullRefresh();
        } else if (mHeaderParams.height > 0 && mHeaderParams.height < mHeaderMaxHeight)
 /**不能進(jìn)行下拉刷新，收回**/ 
 {
          releaseForDownFinished();
        } else if (mFootParams.height > 0 && mFootParams.height < mFootMaxHeight)
 /**不能進(jìn)行下拉刷新，收回**/ 
 {
          releaseForUpFinished();
        } else {
          mIsRefreshDuring = false;
          mCanIntercept = false;
        }
        break;
    }
    super.dispatchTouchEvent(event);
    return true;
  }

  /**
   * 每次進(jìn)行觸摸都需要進(jìn)行初始化
   */
  private void initPull() {
    mCanDownPull = false;
    mCanUpPull = false;
  }

  /**
   * 不需要進(jìn)行上拉刷新
   */
  private void releaseForUpFinished() {
    mAnimator.setFloatValues(mChildView.getTranslationY(), 0);
    mAnimator.start();
  }

  /**
   * 不需要進(jìn)行下拉刷新
   */
  private void releaseForDownFinished() {
    mAnimator.setFloatValues(mChildView.getTranslationY(), 0);
    mAnimator.start();
  }

  /**
   * 上拉時(shí)處理手勢(shì)
   */
  private void upDataForUpPull() {
    if (mDistanceY != 0) {
      mFootParams.height -= mDistanceY;
      if (mFootParams.height <= 0) {
        mFootParams.height = 0;
      }
      if (mFootParams.height >= mFootMaxHeight) {
        mFootParams.height = mFootMaxHeight;
      }
      mChildView.setTranslationY(-mFootParams.height);
      mFootView.requestLayout();
    }
  }

  /**
   * 下拉時(shí)處理手勢(shì)
   */
  private void upDataForDownPull() {
    if (mDistanceY != 0) {
      mHeaderParams.height += mDistanceY;
      if (mHeaderParams.height >= mHeaderMaxHeight) { //最大
        mHeaderParams.height = mHeaderMaxHeight;
      }
      if (mHeaderParams.height <= 0) { //最小
        mHeaderParams.height = 0;
      }
      mChildView.setTranslationY(mHeaderParams.height);
      mHeaderView.requestLayout();
    }
  }

  @Override
  protected void onAttachedToWindow() {
    super.onAttachedToWindow();
  }

  @Override
  protected void onFinishInflate() {
    super.onFinishInflate();
    //加載頭
    mHeaderView = getChildAt(0);
    if (!(mHeaderView instanceof HeadAndFootCallBack)) {
      new IllegalStateException("HeaderView必須實(shí)現(xiàn)HeadAndFootCallBack接口");
    }
    ((HeadAndFootCallBack) mHeaderView).setAttribute();
    mHeaderParams = (LayoutParams) mHeaderView.getLayoutParams();
    mHeaderParams.addRule(RelativeLayout.ALIGN_PARENT_TOP);

    //加載尾
    mFootView = getChildAt(2);
    if (!(mFootView instanceof HeadAndFootCallBack)) {
      new IllegalStateException("FootView必須實(shí)現(xiàn)HeadAndFootCallBack接口");
    }
    ((HeadAndFootCallBack) mFootView).setAttribute();
    mFootParams = (LayoutParams) mFootView.getLayoutParams();
    mFootParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM);

    mChildView = getChildAt(1);
    if (!(mChildView instanceof HeadAndFootCallBack)) {
      new IllegalStateException("ChildView必須實(shí)現(xiàn)PullCallBack接口");
    }
    mCallBack = (PullCallBack) getChildAt(1);

    //設(shè)置動(dòng)畫
    mAnimator = ObjectAnimator.ofFloat(mChildView, "translationY", 0);
    mAnimator.setInterpolator(new DecelerateInterpolator());
    mAnimator.addUpdateListener(new ValueAnimator.AnimatorUpdateListener() {
      @Override
      public void onAnimationUpdate(ValueAnimator animation) {
        int translationY = (int) mChildView.getTranslationY();
        if (mCanUpPull) { //從移動(dòng)到的位置往下滑
          mFootParams.height = Math.abs(translationY);
          mFootView.requestLayout();
        } else if (mCanDownPull) {
          mHeaderParams.height = Math.abs(translationY);
          mHeaderView.requestLayout();
        }
        Log.e("shen", "translationY=" + translationY);
        Log.e("shen", "mHeaderParams.height=" + mHeaderParams.height);
        if (translationY == 0) {
          mChildView.setEnabled(true);
          mDistanceY = 0; //重置
          mIsRefreshDuring = false; //重置
          mCanIntercept = false;
        } else {
          mIsRefreshDuring = true;
        }
      }
    });
  }

  @Override
  protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
    mTouchSlop = ViewConfiguration.get(getContext()).getScaledTouchSlop();
    mDistance = mTouchSlop * 5;
    //設(shè)置下拉頭初始屬性
    mHeaderMaxHeight = mHeaderParams.height;
    mHeaderParams.height = 0;
    mHeaderView.requestLayout();
    //設(shè)置上拉尾初始屬性
    mFootMaxHeight = mFootParams.height;
    mFootParams.height = 0;
    mFootView.requestLayout();
  }

  /**
   * 下拉/上拉事件監(jiān)聽
   */
  public interface OnRefresh {
    /**
     * 下拉刷新
     */
    void onDownPullRefresh();

    /**
     * 上拉加載
     */
    void onUpPullRefresh();
  }

  public void setOnRefresh(OnRefresh onRefresh) {
    mOnRefresh = onRefresh;
  }

}

給他添加三個(gè)控件，頭尾就是刷新頭、尾，第二個(gè)就是正常顯示的控件。必須讓頭尾實(shí)現(xiàn)HeadAndFootCallBack接口，來設(shè)置屬性，通知開始刷新、結(jié)束刷新

難點(diǎn)： 現(xiàn)在來說下開發(fā)時(shí)遇到的難點(diǎn)

由于判斷在dispatchTouchEvent中，導(dǎo)致如果該控件以及子控件都不消費(fèi)該事件的話，就會(huì)造成事件不會(huì)發(fā)送到它，因?yàn)槿绻幌M(fèi)DOWN事件的話，之后所有的事件都不會(huì)在進(jìn)行接收。解決方式，讓該控件onTouchEvent方法消返回true，當(dāng)子控件不進(jìn)行事件消費(fèi)的話，就會(huì)返回由該控件消費(fèi)，不會(huì)造成因DOWN事件不消費(fèi)而無法接收到事件，導(dǎo)致dispatchTouchEvent也不消費(fèi)事件
動(dòng)畫，動(dòng)畫就是我的傷痛，最近在學(xué)習(xí)估值器

這個(gè)控件自認(rèn)為寫的不錯(cuò)，通過他可以幫我們學(xué)習(xí)事件分發(fā)、動(dòng)畫、接口回調(diào)，也是有一定的學(xué)習(xí)意義

以上就是本文的全部?jī)?nèi)容，希望對(duì)大家的學(xué)習(xí)有所幫助，也希望大家多多支持腳本之家。

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