懸浮佈局的最差實現方式,懸浮頭部實現,viewpager巢狀滑動
阿新 • • 發佈:2018-11-16
給部分程式碼看個大概實現,繼承 linearLayout,自己處理滑動,自己計運算元佈局中第一個佈局為摺疊部分。
其實,用scrollview,將listview以及懸浮部分高度設定為螢幕高度,效果直接,省事,滑動體驗更好。巢狀佈局也沒有滑動衝突
public class ScrollableLayout extends LinearLayout { private final String tag = "cp:scrollableLayout"; private float mDownX; private float mDownY; private float mLastY; private int minY = 0; private int maxY = 0; private int mHeadHeight; private int mExpandHeight; private int mTouchSlop; private int mMinimumVelocity; private int mMaximumVelocity; // 方向 private DIRECTION mDirection; private int mCurY; private int mLastScrollerY; private boolean needCheckUpdown; private boolean updown; private boolean mDisallowIntercept; private boolean isClickHead; private boolean isClickHeadExpand; private View mHeadView; private ViewPager childViewPager; private Scroller mScroller; private VelocityTracker mVelocityTracker; private Context context; private boolean isMain; /** * 滑動方向 * */ enum DIRECTION { UP,// 向上劃 DOWN// 向下劃 } public interface OnScrollListener { void onScroll(int currentY, int maxY); } private OnScrollListener onScrollListener; public void setOnScrollListener(OnScrollListener onScrollListener) { this.onScrollListener = onScrollListener; } private ScrollableHelper mHelper; public ScrollableHelper getHelper() { return mHelper; } public ScrollableLayout(Context context) { super(context); init(context); } public ScrollableLayout(Context context, AttributeSet attrs) { super(context, attrs); init(context); } @TargetApi(Build.VERSION_CODES.HONEYCOMB) public ScrollableLayout(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(context); } @TargetApi(Build.VERSION_CODES.LOLLIPOP) public ScrollableLayout(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); init(context); } private void init(Context context) { this.context = context; mHelper = new ScrollableHelper(); mScroller = new Scroller(context); final ViewConfiguration configuration = ViewConfiguration.get(context); mTouchSlop = configuration.getScaledTouchSlop(); mMinimumVelocity = configuration.getScaledMinimumFlingVelocity(); mMaximumVelocity = configuration.getScaledMaximumFlingVelocity(); } public boolean isSticked() { return mCurY == maxY; } /** * 擴大頭部點選滑動範圍 * * @param expandHeight */ public void setClickHeadExpand(int expandHeight) { mExpandHeight = expandHeight; } public int getMaxY() { return maxY; } public void isMainPage(boolean isMain) { this.isMain = isMain; } public boolean isHeadTop() { return mCurY == minY; } public int getCurY() { return mCurY; } public boolean canPtr() { return updown && mCurY == minY && mHelper.isTop(); } public void requestScrollableLayoutDisallowInterceptTouchEvent(boolean disallowIntercept) { super.requestDisallowInterceptTouchEvent(disallowIntercept); mDisallowIntercept = disallowIntercept; } @Override public boolean dispatchTouchEvent(MotionEvent ev) { float currentX = ev.getX(); float currentY = ev.getY(); float deltaY; int shiftX = (int) Math.abs(currentX - mDownX); int shiftY = (int) Math.abs(currentY - mDownY); switch (ev.getAction()) { case MotionEvent.ACTION_DOWN: needCheckUpdown = true; updown = true; mDownX = currentX; mDownY = currentY; mLastY = currentY; checkIsClickHead((int) currentY, mHeadHeight, getScrollY()); checkIsClickHeadExpand((int) currentY, mHeadHeight, getScrollY()); initOrResetVelocityTracker(); mVelocityTracker.addMovement(ev); mScroller.forceFinished(true); break; case MotionEvent.ACTION_MOVE: if (mDisallowIntercept) { break; } initVelocityTrackerIfNotExists(); mVelocityTracker.addMovement(ev); deltaY = mLastY - currentY; if (needCheckUpdown) { if (shiftX > mTouchSlop && shiftX > shiftY) { needCheckUpdown = false; updown = false; } else if (shiftY > mTouchSlop && shiftY > shiftX) { needCheckUpdown = false; updown = true; } } if (updown && shiftY > mTouchSlop && shiftY > shiftX && (!isSticked() || mHelper.isTop() || isClickHeadExpand)) { if (childViewPager != null) { childViewPager.requestDisallowInterceptTouchEvent(true); } scrollBy(0, (int) (deltaY + 0.5)); } mLastY = currentY; break; case MotionEvent.ACTION_UP: if (updown && shiftY > shiftX && shiftY > mTouchSlop) { mVelocityTracker.computeCurrentVelocity(1000, mMaximumVelocity); float yVelocity = -mVelocityTracker.getYVelocity(); boolean dislowChild = false; if (Math.abs(yVelocity) > mMinimumVelocity) { mDirection = yVelocity > 0 ? DIRECTION.UP : DIRECTION.DOWN; if ((mDirection == DIRECTION.UP && isSticked()) || (!isSticked() && getScrollY() == 0 && mDirection == DIRECTION.DOWN)) { dislowChild = true; } else { mScroller.fling(0, getScrollY(), 0, (int) yVelocity, 0, 0, -Integer.MAX_VALUE, Integer.MAX_VALUE); mScroller.computeScrollOffset(); mLastScrollerY = getScrollY(); invalidate(); } } if (!dislowChild && (isClickHead || !isSticked())) { int action = ev.getAction(); ev.setAction(MotionEvent.ACTION_CANCEL); boolean dispathResult = super.dispatchTouchEvent(ev); ev.setAction(action); return dispathResult; } } break; default: break; } super.dispatchTouchEvent(ev); return true; } public void scrolltoTop() { updown = false; mScroller.startScroll(0, mCurY, 0, -mCurY, 500); invalidate(); } public void scrolltoBottom() { updown = false; mScroller.startScroll(0, 0, 0, maxY, 500); invalidate(); } @TargetApi(Build.VERSION_CODES.ICE_CREAM_SANDWICH) private int getScrollerVelocity(int distance, int duration) { if (mScroller == null) { return 0; } else if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) { return (int) mScroller.getCurrVelocity(); } else { return distance / duration; } } @Override public void computeScroll() { if (mScroller.computeScrollOffset()) { int currY = mScroller.getCurrY(); if (updown) { if (mDirection == DIRECTION.UP) { // 手勢向上劃 if (isSticked()) { int distance = mScroller.getFinalY() - currY; int duration = calcDuration(mScroller.getDuration(), mScroller.timePassed()); mHelper.smoothScrollBy(getScrollerVelocity(distance, duration), distance, duration); mScroller.forceFinished(true); return; } else { scrollTo(0, currY); } } else { // 手勢向下劃 if (mHelper.isTop() || isClickHeadExpand) { int deltaY = (currY - mLastScrollerY); int toY = getScrollY() + deltaY; scrollTo(0, toY); if (mCurY <= minY) { mScroller.forceFinished(true); return; } } invalidate(); } mLastScrollerY = currY; } else { scrollTo(0, currY); if (mCurY <= minY) { mScroller.forceFinished(true); return; } invalidate(); mLastScrollerY = currY; } } } @Override public void scrollBy(int x, int y) { int scrollY = getScrollY(); int toY = scrollY + y; if (toY >= maxY) { toY = maxY; } else if (toY <= minY) { toY = minY; } y = toY - scrollY; super.scrollBy(x, y); } @Override public void scrollTo(int x, int y) { if (updown) { if (y >= maxY) { y = maxY; } else if (y <= minY) { y = minY; } } mCurY = y; if (onScrollListener != null) { onScrollListener.onScroll(y, maxY); } super.scrollTo(x, y); } private void initOrResetVelocityTracker() { if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } else { mVelocityTracker.clear(); } } private void initVelocityTrackerIfNotExists() { if (mVelocityTracker == null) { mVelocityTracker = VelocityTracker.obtain(); } } private void recycleVelocityTracker() { if (mVelocityTracker != null) { mVelocityTracker.recycle(); mVelocityTracker = null; } } private void checkIsClickHead(int downY, int headHeight, int scrollY) { isClickHead = downY + scrollY <= headHeight; } private void checkIsClickHeadExpand(int downY, int headHeight, int scrollY) { if (mExpandHeight <= 0) { isClickHeadExpand = false; } isClickHeadExpand = downY + scrollY <= headHeight + mExpandHeight; } private int calcDuration(int duration, int timepass) { return duration - timepass; } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { super.onMeasure(widthMeasureSpec, MeasureSpec.makeMeasureSpec(MeasureSpec.getSize(heightMeasureSpec) + maxY, MeasureSpec.EXACTLY)); } @Override protected void onLayout(boolean changed, int l, int t, int r, int b) { super.onLayout(changed, l, t, r, b); mHeadView = getChildAt(0); if (isMain) { maxY = mHeadView.getMeasuredHeight() - DensityUtils.dip2px(context, 48);//減去首頁titlebar頂部高度 } else { maxY = mHeadView.getMeasuredHeight(); } mHeadHeight = mHeadView.getMeasuredHeight(); } @Override protected void onFinishInflate() { if (mHeadView != null && !mHeadView.isClickable()) { mHeadView.setClickable(true); } int childCount = getChildCount(); for (int i = 0; i < childCount; i++) { View childAt = getChildAt(i); if (childAt != null && childAt instanceof ViewPager) { childViewPager = (ViewPager) childAt; } } super.onFinishInflate(); } }