這篇文章主要介紹如何寫一個(gè)Android通用刷新控件,文中介紹的非常詳細(xì),具有一定的參考價(jià)值,感興趣的小伙伴們一定要看完!
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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) { //*** 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
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