我正在尝试ListView
在滚动发生时为项目设置动画.更具体地说,我试图从iOS 7上的iMessage应用程序模拟滚动动画.我在网上找到了一个类似的例子:
为了澄清,我试图在用户滚动时对项目实现"流畅"运动效果,而不是在添加新项目时实现动画效果.我试图修改我的视图,我BaseAdapter
已经查看了AbsListView
源代码,看看我是否能以某种方式附加一个AccelerateInterpolator
可以调整发送到子视图的绘制坐标的地方(如果这甚至是如何AbsListView
设计).到目前为止,我一直无法取得任何进展.
有没有人对如何复制这种行为有任何想法?
有关谷歌搜索帮助的记录:这在ios上被称为"UIKit Dynamics".
如何复制消息在iOS 7中弹跳气泡
它内置于最近的iOS版本中.然而,它仍然有点难以使用.(2014)这是每个人都复制的帖子:广泛复制的文章令人惊讶的是,UIKit Dynamics仅适用于苹果的"收藏视图",而不是苹果的"桌面视图",因此所有的iOS debs都必须将内容从表视图转换为"集合视图"
每个人都在使用的库是BPXLFlowLayout作为起点,因为那个人几乎破解了复制iphone短信应用程序的感觉.事实上,如果你将它移植到Android我猜你可以使用那里的参数来获得相同的感觉.我注意到在我的android fone系列中,HTC手机在他们的UI上有这种效果.希望能帮助到你.Android摇滚!
我花了几分钟时间来探索这个问题,看起来它可以很容易地用API 12及以上版本完成(希望我不会错过任何东西......).要获得非常基本的卡片效果,只需在适配器的getView()末尾处输入几行代码,然后再将其返回到列表中.这是整个适配器:
public class MyAdapter extends ArrayAdapter<String>{ private int mLastPosition; public MyAdapter(Context context, ArrayList<String> objects) { super(context, 0, objects); } private class ViewHolder{ public TextView mTextView; } @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR1) @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder; if (convertView == null) { holder = new ViewHolder(); convertView = LayoutInflater.from(getContext()).inflate(R.layout.grid_item, parent, false); holder.mTextView = (TextView) convertView.findViewById(R.id.checkbox); convertView.setTag(holder); } else { holder = (ViewHolder) convertView.getTag(); } holder.mTextView.setText(getItem(position)); // This tells the view where to start based on the direction of the scroll. // If the last position to be loaded is <= the current position, we want // the views to start below their ending point (500f further down). // Otherwise, we start above the ending point. float initialTranslation = (mLastPosition <= position ? 500f : -500f); convertView.setTranslationY(initialTranslation); convertView.animate() .setInterpolator(new DecelerateInterpolator(1.0f)) .translationY(0f) .setDuration(300l) .setListener(null); // Keep track of the last position we loaded mLastPosition = position; return convertView; } }
请注意,我正在跟踪要加载的最后一个位置(mLastPosition),以确定是从底部向上(如果向下滚动)还是从顶部向下(如果我们向上滚动)为视图设置动画.
很棒的是,你可以通过修改初始的convertView属性(例如convertView.setScaleX(float scale))和convertView.animate()链(例如.scaleX(float))来做更多的事情.
在返回你的convertView之前将它放在你的getView()方法中试试这个:
Animation animationY = new TranslateAnimation(0, 0, holder.llParent.getHeight()/4, 0); animationY.setDuration(1000); Yourconvertview.startAnimation(animationY); animationY = null;
llParent = RootLayout,其中包含自定义行项.
这个实现非常好.虽然有一些闪烁,可能是因为当适配器将新视图添加到顶部或底部时改变了索引.这可以通过观察树中的变化并在运行中移动索引来解决.
public class ElasticListView extends GridView implements AbsListView.OnScrollListener, View.OnTouchListener { private static int SCROLLING_UP = 1; private static int SCROLLING_DOWN = 2; private int mScrollState; private int mScrollDirection; private int mTouchedIndex; private View mTouchedView; private int mScrollOffset; private int mStartScrollOffset; private boolean mAnimate; private HashMap<View, ViewPropertyAnimator> animatedItems; public ElasticListView(Context context) { super(context); init(); } public ElasticListView(Context context, AttributeSet attrs) { super(context, attrs); init(); } public ElasticListView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); init(); } private void init() { mScrollState = SCROLL_STATE_IDLE; mScrollDirection = 0; mStartScrollOffset = -1; mTouchedIndex = Integer.MAX_VALUE; mAnimate = true; animatedItems = new HashMap<>(); this.setOnTouchListener(this); this.setOnScrollListener(this); } @Override public void onScrollStateChanged(AbsListView view, int scrollState) { if (mScrollState != scrollState) { mScrollState = scrollState; mAnimate = true; } if (scrollState == SCROLL_STATE_IDLE) { mStartScrollOffset = Integer.MAX_VALUE; mAnimate = true; startAnimations(); } } @Override public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) { if (mScrollState == SCROLL_STATE_TOUCH_SCROLL) { if (mStartScrollOffset == Integer.MAX_VALUE) { mTouchedView = getChildAt(mTouchedIndex - getPositionForView(getChildAt(0))); if (mTouchedView == null) return; mStartScrollOffset = mTouchedView.getTop(); } else if (mTouchedView == null) return; mScrollOffset = mTouchedView.getTop() - mStartScrollOffset; int tmpScrollDirection; if (mScrollOffset > 0) { tmpScrollDirection = SCROLLING_UP; } else { tmpScrollDirection = SCROLLING_DOWN; } if (mScrollDirection != tmpScrollDirection) { startAnimations(); mScrollDirection = tmpScrollDirection; } if (Math.abs(mScrollOffset) > 200) { mAnimate = false; startAnimations(); } Log.d("test", "direction:" + (mScrollDirection == SCROLLING_UP ? "up" : "down") + ", scrollOffset:" + mScrollOffset + ", toucheId:" + mTouchedIndex + ", fvisible:" + firstVisibleItem + ", " + "visibleItemCount:" + visibleItemCount + ", " + "totalCount:" + totalItemCount); int indexOfLastAnimatedItem = mScrollDirection == SCROLLING_DOWN ? getPositionForView(getChildAt(0)) + getChildCount() : getPositionForView(getChildAt(0)); //check for bounds if (indexOfLastAnimatedItem >= getChildCount()) { indexOfLastAnimatedItem = getChildCount() - 1; } else if (indexOfLastAnimatedItem < 0) { indexOfLastAnimatedItem = 0; } if (mScrollDirection == SCROLLING_DOWN) { setAnimationForScrollingDown(mTouchedIndex - getPositionForView(getChildAt(0)), indexOfLastAnimatedItem, firstVisibleItem); } else { setAnimationForScrollingUp(mTouchedIndex - getPositionForView(getChildAt(0)), indexOfLastAnimatedItem, firstVisibleItem); } if (Math.abs(mScrollOffset) > 200) { mAnimate = false; startAnimations(); mTouchedView = null; mScrollDirection = 0; mStartScrollOffset = -1; mTouchedIndex = Integer.MAX_VALUE; mAnimate = true; } } } private void startAnimations() { for (ViewPropertyAnimator animator : animatedItems.values()) { animator.start(); } animatedItems.clear(); } private void setAnimationForScrollingDown(int indexOfTouchedChild, int indexOflastAnimatedChild, int firstVisibleIndex) { for (int i = indexOfTouchedChild + 1; i <= indexOflastAnimatedChild; i++) { View v = getChildAt(i); v.setTranslationY((-1f * mScrollOffset)); if (!animatedItems.containsKey(v)) { animatedItems.put(v, v.animate().translationY(0).setDuration(300).setStartDelay(50 * i)); } } } private void setAnimationForScrollingUp(int indexOfTouchedChild, int indexOflastAnimatedChild, int firstVisibleIndex) { for (int i = indexOfTouchedChild - 1; i > 0; i--) { View v = getChildAt(i); v.setTranslationY((-1 * mScrollOffset)); if (!animatedItems.containsKey(v)) { animatedItems.put(v, v.animate().translationY(0).setDuration(300).setStartDelay(50 * (indexOfTouchedChild - i))); } } } @Override public boolean onTouch(View v, MotionEvent event) { switch (event.getActionMasked()) { case MotionEvent.ACTION_DOWN: Rect rect = new Rect(); int childCount = getChildCount(); int[] listViewCoords = new int[2]; getLocationOnScreen(listViewCoords); int x = (int)event.getRawX() - listViewCoords[0]; int y = (int)event.getRawY() - listViewCoords[1]; View child; for (int i = 0; i < childCount; i++) { child = getChildAt(i); child.getHitRect(rect); if (rect.contains(x, y)) { mTouchedIndex = getPositionForView(child); break; } } return false; } return false; } }