如何写一个Android通用刷新控件

这篇文章主要介绍如何写一个Android通用刷新控件，文中介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们一定要看完！

思路：

• 写一个继承RelativeLayout的RefreshLayout

• 添加头尾控件作为刷新控件

• 通过事件分发来进行刷新操作

• 通过动画来控制控件移动

目的：让他的所有子控件都可以使用，哪怕是一个TextView

public class RefreshLayout extends RelativeLayout {      /**      * 滑动控件时拉去的速度比例      */     private final int V_REFRESH = 2;     /**      * 是否是刷新过程      * true 是      * false 不是      * 为false的时候才可以进行刷新      */     private boolean mIsRefreshDuring;     /**      * 可以进下拉刷新      */     private boolean mCanDownPull;     /**      * 可以进行上拉刷新      */     private boolean mCanUpPull;     /**      * 判断触摸后是否是初次移动      */     private boolean mIsFirstMove;     /**      * y轴呢平移的距离      */     private int mDistanceY;     /**      * 刷新接口对象      */     private OnRefresh mOnRefresh;     /**      * 用于控制事件拦截的变量      */     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();     }      /**      * 必须让头尾控件实现的接口      */     public interface HeadAndFootCallBack {         //设置属性         void setAttribute();          //开始刷新         void startPull();          //停止刷新         void stopPull();     }      /**      * 必须让被拖动的控件子类实现      */     public interface PullCallBack {         boolean canDownPull();          boolean canUpPull();     }      private void initData() {         //不调用该方法不能进行绘制         setWillNotDraw(false);     }      /**      * 下拉刷新完成后必须使用该方法      */     public void downPullFinish() {         mAnimator.setFloatValues(mChildView.getTranslationY(), 0);         mAnimator.start();         ((HeadAndFootCallBack) mHeaderView).stopPull();     }      /**      * 上拉完成后必须调用该方法      */     public void upPullFinish() {         mAnimator.setFloatValues(mChildView.getTranslationY(), 0);         mAnimator.start();         ((HeadAndFootCallBack) mFootView).stopPull();     }      /**      * 自动下拉刷新      */     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);     }      /**      * 自动下拉刷新      */     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)/*如果正在进行刷新将不会获取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();//上拉加载                         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)/*不能进行下拉刷新，收回*/ {                     releaseForDownFinished();                 } else if (mFootParams.height > 0 && mFootParams.height < mFootMaxHeight)/*不能进行下拉刷新，收回*/ {                     releaseForUpFinished();                 } else {                     mIsRefreshDuring = false;                     mCanIntercept = false;                 }                 break;         }         super.dispatchTouchEvent(event);         return true;     }      /**      * 每次进行触摸都需要进行初始化      */     private void initPull() {         mCanDownPull = false;         mCanUpPull = false;     }      /**      * 不需要进行上拉刷新      */     private void releaseForUpFinished() {         mAnimator.setFloatValues(mChildView.getTranslationY(), 0);         mAnimator.start();     }      /**      * 不需要进行下拉刷新      */     private void releaseForDownFinished() {         mAnimator.setFloatValues(mChildView.getTranslationY(), 0);         mAnimator.start();     }      /**      * 上拉时处理手势      */     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();         }     }      /**      * 下拉时处理手势      */     private void upDataForDownPull() {         if (mDistanceY != 0) {             mHeaderParams.height += mDistanceY;             if (mHeaderParams.height >= mHeaderMaxHeight) { //***                 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();         //加载头         mHeaderView = getChildAt(0);         if (!(mHeaderView instanceof HeadAndFootCallBack)) {             new IllegalStateException("HeaderView必须实现HeadAndFootCallBack接口");         }         ((HeadAndFootCallBack) mHeaderView).setAttribute();         mHeaderParams = (LayoutParams) mHeaderView.getLayoutParams();         mHeaderParams.addRule(RelativeLayout.ALIGN_PARENT_TOP);          //加载尾         mFootView = getChildAt(2);         if (!(mFootView instanceof HeadAndFootCallBack)) {             new IllegalStateException("FootView必须实现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必须实现PullCallBack接口");         }         mCallBack = (PullCallBack) getChildAt(1);          //设置动画         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) { //从移动到的位置往下滑                     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;         //设置下拉头初始属性         mHeaderMaxHeight = mHeaderParams.height;         mHeaderParams.height = 0;         mHeaderView.requestLayout();         //设置上拉尾初始属性         mFootMaxHeight = mFootParams.height;         mFootParams.height = 0;         mFootView.requestLayout();     }      /**      * 下拉/上拉事件监听      */     public interface OnRefresh {         /**          * 下拉刷新          */         void onDownPullRefresh();          /**          * 上拉加载          */         void onUpPullRefresh();     }      public void setOnRefresh(OnRefresh onRefresh) {         mOnRefresh = onRefresh;     }  }

给他添加三个控件，头尾就是刷新头、尾，第二个就是正常显示的控件。必须让头尾实现HeadAndFootCallBack接口，来设置属性，通知开始刷新、结束刷新

难点： 现在来说下开发时遇到的难点

• 由于判断在dispatchTouchEvent中，导致如果该控件以及子控件都不消费该事件的话，就会造成事件不会发送到它，因为如果不消费DOWN事件的话，之后所有的事件都不会在进行接收。解决方式，让该控件onTouchEvent方法消返回true，当子控件不进行事件消费的话，就会返回由该控件消费，不会造成因DOWN事件不消费而无法接收到事件，导致dispatchTouchEvent也不消费事件

• 动画，动画就是我的伤痛，最近在学习估值器

以上是"如何写一个Android通用刷新控件"这篇文章的所有内容，感谢各位的阅读！希望分享的内容对大家有帮助，更多相关知识，欢迎关注行业资讯频道！