項目中我們經常有上拉阔馋、下拉刷新的需求，幾乎所有的listView娇掏、RecyclerView都會伴隨著上拉呕寝、下拉刷新的需求，如果我們使用一些開源控件婴梧，換了控件我們就要更新下梢，現(xiàn)在我們自己擼起袖子寫一個通用的刷新控件
思路：
寫一個繼承RelativeLayout的RefreshLayout
添加頭尾控件作為刷新控件
通過事件分發(fā)來進行刷新操作
通過動畫來控制控件移動
目的：讓他的所有子控件都可以使用，哪怕是一個TextView
public class RefreshLayout extends RelativeLayout {
/**
* 滑動控件時拉去的速度比例
*/
private final int V_REFRESH = 2;
/**
* 是否是刷新過程
* true 是
* false 不是
* 為false的時候才可以進行刷新
*/
private boolean mIsRefreshDuring;
/**
* 可以進下拉刷新
*/
private boolean mCanDownPull;
/**
* 可以進行上拉刷新
*/
private boolean mCanUpPull;
/**
* 判斷觸摸后是否是初次移動
*/
private boolean mIsFirstMove;
/**
* y軸呢平移的距離
*/
private int mDistanceY;
/**
* 刷新接口對象
*/
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();
}
/**
* 必須讓頭尾控件實現(xiàn)的接口
*/
public interface HeadAndFootCallBack {
//設置屬性
void setAttribute();
//開始刷新
void startPull();
//停止刷新
void stopPull();
}
/**
* 必須讓被拖動的控件子類實現(xiàn)
*/
public interface PullCallBack {
boolean canDownPull();
boolean canUpPull();
}
private void initData() {
//不調用該方法不能進行繪制
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();
}
/**
* 上拉完成后必須調用該方法
*/
public void upPullFinish() {
mAnimator.setFloatValues(mChildView.getTranslationY(), 0);
mAnimator.start();
((HeadAndFootCallBack) mFootView).stopPull();
}
/**
* 自動下拉刷新
*/
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)/*如果正在進行刷新將不會獲取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)/*不能進行下拉刷新塞蹭，收回*/ {
releaseForDownFinished();
} else if (mFootParams.height > 0 && mFootParams.height < mFootMaxHeight)/*不能進行下拉刷新孽江，收回*/ {
releaseForUpFinished();
} else {
mIsRefreshDuring = false;
mCanIntercept = false;
}
break;
}
super.dispatchTouchEvent(event);
return true;
}
/**
* 每次進行觸摸都需要進行初始化
*/
private void initPull() {
mCanDownPull = false;
mCanUpPull = false;
}
/**
* 不需要進行上拉刷新
*/
private void releaseForUpFinished() {
mAnimator.setFloatValues(mChildView.getTranslationY(), 0);
mAnimator.start();
}
/**
* 不需要進行下拉刷新
*/
private void releaseForDownFinished() {
mAnimator.setFloatValues(mChildView.getTranslationY(), 0);
mAnimator.start();
}
/**
* 上拉時處理手勢
*/
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();
}
}
/**
* 下拉時處理手勢
*/
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必須實現(xiàn)PullCallBack接口");
}
mCallBack = (PullCallBack) getChildAt(1);
//設置動畫
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;
//設置下拉頭初始屬性
mHeaderMaxHeight = mHeaderParams.height;
mHeaderParams.height = 0;
mHeaderView.requestLayout();
//設置上拉尾初始屬性
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;
}
給他添加三個控件，頭尾就是刷新頭番电、尾岗屏，第二個就是正常顯示的控件。必須讓頭尾實現(xiàn)HeadAndFootCallBack接口漱办，來設置屬性这刷，通知開始刷新、結束刷新
難點： 現(xiàn)在來說下開發(fā)時遇到的難點
由于判斷在dispatchTouchEvent中洼冻，導致如果該控件以及子控件都不消費該事件的話崭歧，就會造成事件不會發(fā)送到它，因為如果不消費DOWN事件的話撞牢，之后所有的事件都不會在進行接收。解決方式叔营，讓該控件onTouchEvent方法消返回true屋彪，當子控件不進行事件消費的話，就會返回由該控件消費绒尊，不會造成因DOWN事件不消費而無法接收到事件畜挥，導致dispatchTouchEvent也不消費事件
動畫，動畫就是我的傷痛婴谱，最近在學習估值器
這個控件自認為寫的不錯蟹但，通過他可以幫我們學習事件分發(fā)、動畫谭羔、接口回調华糖，也是有一定的學習意義
